WO2022118799A1 - シート特定装置、画像処理装置及びシート特定方法 - Google Patents
シート特定装置、画像処理装置及びシート特定方法 Download PDFInfo
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- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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- G03G15/5029—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control by measuring the copy material characteristics, e.g. weight, thickness
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Definitions
- the present invention relates to a sheet specifying device, an image processing device, and a sheet specifying method.
- the image reading device includes a light emitting element that irradiates the surface of the sheet with light from an oblique direction, and an area sensor that reads the inside of the irradiation area as an image, and reads information about the sheet from the reading result.
- This image reader estimates the surface roughness of the sheet by detecting the shadow image caused by the unevenness of the surface of the sheet from the image in the irradiation area.
- the contrast is higher than when the unevenness is small, so that the size of the unevenness on the surface can be estimated from the contrast.
- this image reading device keeps the fiber direction of the sheet and the light incident direction at approximately 45 degrees by making the incident direction of the light from the light emitting element at an angle of 45 degrees with respect to the transport direction of the sheet, and the fiber direction.
- the configuration is such that there is little variation in detection accuracy.
- the size of the unevenness is estimated by ignoring the influence of the fiber direction of the sheet, so it is difficult to specify the fiber direction of the sheet with this configuration.
- An object of the present invention is to provide a sheet specifying device and an image processing device that can easily specify the fiber direction of a sheet.
- the sheet specifying device includes a light irradiation unit.
- the light irradiation unit projects a first pattern light and a second pattern light having different dependences on the fiber direction on a specific region.
- the specific image is an image of the specific region on the surface of a sheet that is an image formation target or an image reading target, and is used to specify the fiber direction of the surface of the sheet.
- the image processing device includes the sheet specifying device and an image processing unit.
- the image processing unit performs at least one of image formation and image reading on the sheet.
- FIG. 1 is a schematic block diagram of the image processing apparatus according to the first embodiment.
- FIG. 2 is a schematic view showing the appearance and internal configuration of the image processing apparatus according to the first embodiment.
- FIG. 3 is a schematic view showing a light irradiation unit and an image pickup unit of the sheet specifying device according to the first embodiment.
- FIG. 4 is a schematic view showing a light irradiation unit and a sheet of the sheet specifying device according to the first embodiment.
- FIG. 5 is a schematic view showing the principle of detecting the unevenness of the surface of the sheet in the sheet specifying device according to the first embodiment.
- FIG. 6 is a diagram showing an example of a specific image obtained by the sheet specifying device according to the first embodiment.
- FIG. 7 is a flowchart of an operation example of the sheet specifying device according to the first embodiment.
- FIG. 8 is a diagram showing an example of a specific image when a predetermined angle obtained by the sheet specifying device according to the first embodiment is changed.
- FIG. 9 is a graph showing the relationship between the standard deviation obtained by the sheet specifying device according to the first embodiment and the arithmetic mean height.
- FIG. 10 is a table showing the results of calculating the coefficient of determination while changing the line width of the pattern light and the relationship between the irradiation direction of the pattern light and the fiber direction in the sheet specifying device according to the first embodiment.
- FIG. 11 is a schematic diagram showing pattern light that produces a grid pattern in the sheet specifying device according to the first embodiment.
- FIG. 12 is a schematic view showing one aspect of the pattern light used in the sheet specifying device according to the first embodiment.
- FIG. 13 is a flowchart of an operation example of the sheet specifying device according to the first embodiment.
- FIG. 14 is a schematic view showing one aspect of the pattern light used in the sheet specifying device according to the first embodiment.
- FIG. 15 is a schematic view showing one aspect of the pattern light used in the sheet specifying device according to the first embodiment.
- FIG. 16 is a schematic view showing one aspect of the pattern light used in the sheet specifying device according to the first embodiment.
- FIG. 17 is a schematic view showing one aspect of the pattern light used in the sheet specifying device according to the first embodiment.
- FIG. 18 is a schematic view showing one aspect of the pattern light used in the sheet specifying device according to the first embodiment.
- FIG. 19 is a schematic block diagram of the image processing apparatus according to the second embodiment.
- the image processing apparatus 10 has a plurality of functions such as a scanning function for reading an image (image data) from a document, a printing function for forming an image based on the image data, a facsimile function, and a copying function. It is a multifunction device that has.
- the image processing device 10 may have an image processing function including at least one of a function of forming an image and a function of reading an image, and may be a printer, a scanner, a facsimile machine, a copier, or the like.
- the image processing device 10 includes an automatic document transfer device 11, an image reading unit 12, an image forming unit 13, a paper feeding unit 14, an operation display unit 15, and a control unit 16. Be prepared. Since the automatic document transfer device 11 is an ADF (Auto Document Feeder), it is referred to as "ADF” in FIG. 1 and also referred to as "ADF 11" in the following description.
- the image processing device 10 includes a housing 100. The ADF 11, the image reading unit 12, the image forming unit 13, the paper feeding unit 14, the operation display unit 15, and the control unit 16 are provided in the housing 100.
- the ADF 11 conveys a sheet (original) from which an image is read by the image reading unit 12.
- the ADF 11 has a document setting unit, a plurality of transport rollers, a document retainer, a paper ejection unit, and the like.
- the image reading unit 12 reads an image from the sheet and outputs image data corresponding to the read image.
- the image reading unit 12 includes a platen, a light source, a plurality of mirrors, an optical lens, a CCD (Charge Coupled Device), and the like.
- the image forming unit 13 forms an image on the sheet Sh1 (see FIG. 2) based on the image data output from the image reading unit 12. Further, the image forming unit 13 forms an image on the sheet Sh1 based on the image data input from an information processing device external to the image processing device 10 such as a personal computer. As an example in the present embodiment, as shown in FIG. 2, the image forming unit 13 includes a transfer device 131, a fixing device 132, a paper ejection tray 133, and the like, and forms an image on the sheet Sh1 by an electrophotographic method.
- the image forming unit 13 is not limited to the configuration for forming a monochrome image, but is configured to form a full-color image using four colors of C (cyan), M (magenta), Y (yellow), and K (black). There may be. Further, the image forming unit 13 may be configured to form an image on the sheet by an image forming method other than the electrophotographic method, such as an inkjet method.
- the image forming unit 13 forms an image on the sheet Sh1 by using toner as a developer. Specifically, the image forming unit 13 forms an electrostatic latent image by irradiating the surface of the charged photoconductor drum with a laser beam, and develops the electrostatic latent image with toner to develop the photoconductor. A toner image is formed on the surface of the drum.
- the transfer device 131 transfers the toner image to the sheet Sh1 transported through the transport path T1 (see FIG. 2).
- the fixing device 132 melts and fixes the toner image transferred to the sheet Sh1 to the sheet Sh1.
- the fixing device 132 includes a fixing roller and a pressure roller, and heats the toner image transferred to the sheet Sh1 and pressurizes the sheet Sh1 to fix the toner image to the sheet Sh1.
- the sheet Sh1 after image formation is ejected to the output tray 133.
- ink another example of a developing agent
- the paper feeding unit 14 supplies the sheet Sh1 to the image forming unit 13.
- the paper feed unit 14 has a plurality of paper feed cassettes 141, a manual feed tray, a plurality of transport rollers, and the like.
- the paper feed unit 14 conveys the sheet Sh1 from the plurality of paper cassettes 141, the manual feed tray, or the like through the transfer path T1 by a plurality of transfer rollers or the like, and supplies the sheet Sh1 to the image forming unit 13.
- the image forming unit 13 forms an image on the sheet Sh1 supplied from the paper feeding unit 14 through the transport path T1.
- the operation display unit 15 is a user interface in the image processing device 10.
- the operation display unit 15 includes a display unit such as a liquid crystal display that displays various information in response to a control instruction from the control unit 16, and a switch or touch panel that inputs various information to the control unit 16 in response to a user operation. It has an operation unit of.
- the image processing device 10 may include, for example, a voice output unit, a voice input unit, or the like as a user interface in addition to or in place of the operation display unit 15.
- the control unit 16 comprehensively controls the image processing device 10.
- the control unit 16 mainly comprises a computer system having one or more processors and one or more memories.
- the function of the control unit 16 is realized by executing a program by one or more processors.
- the program may be pre-recorded in one or more memories, may be provided through a telecommunication line such as the Internet, and may be recorded on a non-temporary recording medium such as a memory card or optical disk that can be read by a computer system. May be provided.
- One or more processors are composed of one or more electronic circuits including semiconductor integrated circuits.
- the computer system referred to in the present disclosure includes a microcontroller having one or more processors and one or more memories.
- the control unit 16 may be a control unit provided separately from the main control unit that collectively controls the image processing device 10.
- the image processing device 10 further includes a storage unit, a communication unit, a power supply unit, and the like.
- the storage unit includes one or more non-volatile memories, and information such as a control program for causing the control unit 16 to execute various processes is stored in advance.
- the communication unit is an interface for executing data communication between the image processing device 10 and an external device connected via a communication network such as the Internet or a LAN (Local Area Network).
- the power supply unit is a power supply circuit that generates (outputs) electric power for the operation of the image processing device 10.
- the image reading device includes a light emitting element that irradiates the surface of the sheet with light from an oblique direction, and an area sensor that reads the inside of the irradiation area as an image, and reads information about the sheet from the reading result.
- This image reader estimates the surface roughness of the sheet by detecting the shadow image caused by the unevenness of the surface of the sheet from the image in the irradiation area.
- the contrast is higher than when the unevenness is small, so that the size of the unevenness on the surface can be estimated from the contrast.
- this image reading device keeps the fiber direction of the sheet and the light incident direction at approximately 45 degrees by making the incident direction of the light from the light emitting element at an angle of 45 degrees with respect to the transport direction of the sheet, and the fiber direction.
- the configuration is such that there is little variation in detection accuracy.
- the image processing device 10 that can easily improve the accuracy of specifying the unevenness of the surface of the sheet is realized by the configuration described below.
- the image processing device 10 includes the sheet specifying device 2 as shown in FIG.
- the sheet specifying device 2 according to the present embodiment is integrated with the image processing device 10.
- the sheet specifying device 2 includes an acquisition unit 21 and an unevenness specifying unit 22.
- the acquisition unit 21 acquires the specific image Im1 (see FIG. 4).
- the specific image Im1 is an image of a specific region R1 (see FIG. 4) of the surface A1 (see FIG. 3) of the sheet Sh1 which is an image formation target or an image reading target.
- the specific region R1 is a region of the surface A1 of the sheet Sh1 on which the pattern light P1 (see FIG. 3) is projected.
- the unevenness specifying portion 22 specifies unevenness information regarding the unevenness of the surface A1 of the sheet Sh1 based on the specific image Im1.
- the acquisition unit 21 and the unevenness specifying unit 22, which are the components of the sheet specifying device 2 are provided in the control unit 16 as one function of the control unit 16.
- the sheet specifying device 2 and the image processing device 10 provided with the sheet specifying device 2 according to the present embodiment have an advantage that the accuracy of specifying the unevenness of the surface A1 of the sheet Sh1 can be easily improved. That is, the pattern light P1 is projected onto the specific region R1 of the surface A1 of the sheet Sh1 instead of uniformly irradiating the light from the light emitting element. Therefore, the unevenness specifying portion 22 can specify the unevenness information regarding the unevenness of the surface A1 of the sheet Sh1 from the degree of deformation or distortion of the pattern light P1 in the specific image Im1.
- the size of the unevenness is estimated by ignoring the influence of the fiber direction of the sheet, so it is difficult to specify the fiber direction of the sheet with this configuration.
- the image processing device 10 that makes it easy to specify the fiber direction of the sheet is realized by the configuration described below.
- the sheet specifying device 2 includes a light irradiation unit 3 (see FIG. 1).
- the light irradiation unit 3 has a first pattern light P11 (see FIG. 12) and a second pattern light P12 (see FIG. 12) having different dependences on the fiber direction of the surface A1 of the sheet Sh1 on the specific region R1. 12) is projected.
- the specific image Im1 is an image of a specific region R1 of the surface A1 of the sheet Sh1 which is an image formation target or an image reading target, and is an image used for specifying the fiber direction of the surface A1 of the sheet Sh1.
- the pattern light P1 (first pattern light P11 and second pattern light P12) is projected onto the specific region R1 of the surface A1 of the sheet Sh1 instead of uniformly irradiating the light from the light emitting element.
- the pattern light P1 is projected onto the specific region R1 of the surface A1 of the sheet Sh1 instead of uniformly irradiating the light from the light emitting element.
- the sheet specifying device 2 includes a direction specifying unit 24 (see FIG. 1) in addition to the acquisition unit 21.
- the direction specifying unit 24 specifies the fiber direction of the surface A1 of the sheet Sh1 based on the specific image Im1.
- the specific image Im1 is an image of the specific region R1 on which the pattern light P1 is projected on the surface A1 of the sheet Sh1.
- the acquisition unit 21 and the direction specifying unit 24, which are the components of the seat specifying device 2 are provided in the control unit 16 as one function of the control unit 16. In this way, the pattern light P1 is projected onto the specific region R1 of the surface A1 of the sheet Sh1 instead of uniformly irradiating the light from the light emitting element. Therefore, by utilizing the dependence of the pattern light P1 on the fiber direction, it is possible to specify the fiber direction from the specific image Im1. Therefore, according to the configuration of the present embodiment, there is an advantage that the fiber direction of the sheet Sh1 can be easily specified.
- the sheet specifying device 2 constitutes an image processing device 10 together with an image processing unit (image reading unit 12 and image forming unit 13).
- the image processing device 10 includes a sheet specifying device 2 and an image processing unit that performs at least one of image formation and image reading for the sheet Sh1.
- the "sheet” referred to in the present disclosure is a sheet that is an image formation target or an image reading target.
- the sheet Sh1 to be irradiated with the pattern light P1 is the sheet Sh1 to be an image forming target by the image forming unit 13. That is, in the present embodiment, the sheet Sh1 conveyed through the transfer path T1 by the paper feed unit 14 is the irradiation target of the pattern light P1.
- the sheet to be irradiated with the pattern light P1 may be a sheet (original) as an image to be read by the image reading unit 12, that is, a sheet conveyed by the ADF 11.
- the sheet Sh1 is not limited to paper as an example in the present embodiment, but may be, for example, a resin film or the like.
- the "patterned light” referred to in the present disclosure is, for example, light that is projected onto a projection surface (here, the surface A1 of the sheet Sh1) whose shape and direction are controlled from the light irradiation unit 3 (see FIG. 1). It is a so-called structured light. That is, in the region irradiated by the pattern light P1 (specific region R1), the figure, the pattern, the pattern, the pattern, the symbol, the character, the number, etc. corresponding to the pattern light P1 are not uniformly illuminated by the pattern light P1. Is projected.
- the pattern light P1 when the pattern light P1 irradiates the specific region R1, the luminance distribution of the pattern corresponding to the pattern light P1 such as a fringe pattern, a grid pattern, or an arc pattern is generated in the specific region R1.
- the pattern light P1 is not limited to a fixed pattern such as a still image, but causes a luminance distribution of a pattern that changes with the passage of time such as a moving image (including animation) in a specific region R1. May be good.
- the "specific image” referred to in the present disclosure is, for example, an image of a specific region R1 in a state where the pattern light P1 is projected, which is captured by the image pickup unit 4. That is, on the specific image Im1, the pattern light P1 projected on the specific region R1, strictly speaking, the luminance distribution of the pattern corresponding to the pattern light P1 generated in the specific region R1 by the projection of the pattern light P1 is obtained. included.
- the specific image Im1 may be either a monochrome image or a color image, and may be either a still image or a moving image.
- the "unevenness information" referred to in the present disclosure is information on the unevenness of the surface A1 of the sheet Sh1, and includes, for example, information such as the height (or depth) of the unevenness and / or the size of the unevenness in a plan view.
- the surface A1 of the sheet Sh1 has irregularities including at least one of a concave portion and a convex portion. That is, the surface A1 may include only a plurality of concave portions, or may include only a plurality of convex portions. Further, the surface A1 may include a plurality of concave portions and one convex portion.
- the surface A1 includes one mesh-like convex portion and a plurality of concave portions composed of mesh portions surrounded by the convex portions.
- the surface A1 may include one mesh-like recess and a plurality of protrusions composed of mesh portions surrounded by the recesses.
- the unevenness (concave and convex portions) on the surface A1 has an extremely small size that cannot be individually identified by the naked eye, and the surface A1 of one sheet Sh1 contains a large number of irregularities. That is, the unevenness is finer than the entire surface A1, and when a person looks at the surface A1, the unevenness makes the surface A1 look like a rough "pear-skin texture".
- Such a large number of fine irregularities are formed, for example, by a large number of fibers constituting the paper in the case of the paper sheet Sh1, or by embossing or the like in the case of the resin film.
- the information regarding such fine irregularities includes an index indicating the surface roughness such as the arithmetic mean height (Sa) or the arithmetic mean height (Ra) of the line.
- the "fiber direction” referred to in the present disclosure is the direction of the fibers on the surface A1 of the sheet Sh1, for example, in the case of the paper sheet Sh1, the extension direction of a large number of fibers constituting the paper, that is, the flow of the paper (paper).
- the sheet Sh1 has "vertical stitches” in which the fiber direction is along the long side of the sheet Sh1 and “horizontal stitches” in which the fiber direction is along the short sides of the sheet Sh1.
- the transport direction D1 (see FIG. 2) of the sheet Sh1 in the image processing apparatus 10 is a direction along the long side or the short side of the sheet Sh1. Therefore, basically, the fiber direction is along the transport direction D1 of the sheet Sh1 or along the direction orthogonal to the transport direction D1.
- the sheet specifying device 2 includes an acquisition unit 21, an unevenness specifying unit 22, a condition determining unit 23, a direction specifying unit 24, a thickness specifying unit 25, a light irradiation unit 3, and an imaging unit 4. , The thickness sensor 5.
- the acquisition unit 21, the unevenness specifying unit 22, the condition determining unit 23, the direction specifying unit 24, and the thickness specifying unit 25 are provided in the control unit 16 as one function of the control unit 16. That is, in the present embodiment, the image processing device 10 includes the condition determination unit 23, the direction specifying unit 24, and the thickness specifying unit 25 as one function of the control unit 16 in addition to the acquisition unit 21 and the unevenness specifying unit 22.
- the light irradiation unit 3 irradiates the pattern light P1 toward the surface A1 of the sheet Sh1. That is, the light irradiation unit 3 generates the pattern light P1 whose shape and direction are controlled, and by irradiating the surface A1 of the sheet Sh1 with the pattern light P1, the pattern light P1 is applied to the specific region R1 of the surface A1 of the sheet Sh1. To project.
- the pattern light P1 from the light irradiation unit 3 projects a figure, a pattern, a pattern, a pattern, a symbol, a character, a number, or the like corresponding to the pattern light P1 on the specific area R1 of the surface A1 of the sheet Sh1. ..
- the pattern light P1 forms a striped pattern in which bright portions L1 and dark portions L2 are alternately arranged on a specific region R1 as shown in FIG. That is, when the pattern light P1 is projected, the luminance distribution of the fringe pattern including the bright portion L1 and the dark portion L2 is generated in the specific region R1.
- the bright portion L1 is a brighter region than the dark portion L2, in other words, the striped pattern is a pattern in which a plurality of bright portions L1 are arranged at intervals, or a plurality of dark portions L2 are spaced apart from each other. It is a pattern lined up with a space.
- the pattern light P1 is projected to form a striped pattern in which the linear bright portion L1 and the linear dark portion L2 are alternately arranged in the directions orthogonal to the respective longitudinal directions. ..
- linear bright portions L1 and dark portions L2 orthogonal to the transport direction D1 of the sheet Sh1 are arranged so as to be alternately arranged in the transport direction D1.
- the bright part L1 is shown by shading (dot hatching), and the dark part L2 is shown by black.
- the striped pattern on the specific region R1 is likely to be deformed or distorted according to the unevenness of the surface A1.
- the pattern light P1 that produces the fringe pattern as shown in FIG. 4 is merely an example of the pattern light P1, and the pattern light P1 can be appropriately changed.
- the light irradiation unit 3 has a light source 31 and a shield 32.
- the shield 32 transmits the pattern light P1 by blocking a part of the light output from the light source 31.
- the light source 31 includes a light emitting element that emits light when electric power is supplied, and outputs the light generated by the light emitting element toward the shield 32.
- the light source 31 is controlled by a control signal from the control unit 16, and at least the control unit 16 can switch on / off.
- the shield 32 is a component that is arranged between the light source 31 and the specific region R1 of the surface A1 of the sheet Sh1 to shield a part of the light from the light source 31 and transmit the rest.
- the pattern light P1 can be realized with a relatively simple configuration.
- the light source 31 has one or more light emitting elements such as a light emitting diode (LED: Light Emitting Diode) or an organic EL (Electroluminescence), and has a light emitting surface 311 having a rectangular shape in a plan view (see FIG. 3). By making the entire area emit light almost uniformly, surface emission is performed. Further, in the present embodiment, the light source 31 outputs parallel light or light close to parallel light. Therefore, the optical axis Ax1 (see FIG. 3) of the pattern light P1 output from the light irradiation unit 3 is a perpendicular line of the light emitting surface 311 passing through the center (center of gravity) of the light emitting surface 311 of the light source 31.
- LED Light Emitting Diode
- organic EL Electrode
- the light source 31 may have an optical component such as a collimator lens that converts light from a light emitting element into parallel light. As an example in this embodiment, the light source 31 outputs visible light, specifically white light. However, the light source 31 may output light having a wavelength that the imaging unit 4 has sensitivity, and may output light other than white light. For example, light in a wavelength range other than visible light such as infrared rays or ultraviolet rays. May be output.
- the shield 32 is a rectangular plate-shaped component that absorbs or reflects light from the light source 31, and one or more slits 321 (see FIG. 4) are formed. As a result, a part of the light output from the light source 31 is shielded by the shield 32, and the rest is transmitted through the shield 32 through the slit 321 of the shield 32.
- the shield 32 has a plurality of linear slits 321 in order to realize the pattern light P1 that forms a striped pattern in the specific region R1.
- the configuration is not limited to the configuration in which the light transmitted through the slit 321 becomes the bright portion L1, and for example, the pattern light P1 may be realized by "interference fringes" utilizing the interference of light.
- the first virtual straight line connecting the light irradiation unit 3 that irradiates the pattern light P1 and the center of the specific region R1 is inclined at a predetermined angle ⁇ 1 with respect to the second virtual straight line along the transport direction D1 of the sheet Sh1. is doing.
- the angle between the first virtual straight line and the surface A1 of the sheet Sh1 is a predetermined angle ⁇ 1. ..
- the optical axis Ax1 of the pattern light P1 is inclined at a predetermined angle ⁇ 1 with respect to the surface A1 of the sheet Sh1.
- the light irradiation unit 3 obliquely irradiates the specific region R1 with the pattern light P1 at a predetermined angle ⁇ 1 from the downstream side in the transport direction D1, that is, the front side in the traveling direction of the sheet Sh1. It is configured as follows. As a result, the pattern on the specific region R1 is likely to be deformed or distorted according to the unevenness of the surface A1.
- the image pickup unit 4 captures an image of the specific region R1 of the surface A1 of the sheet Sh1 as a specific image Im1.
- the light irradiation section 3 is at least at the imaging timing of the image pickup section 4. Irradiates the specific region R1 with the pattern light P1.
- the image pickup unit 4 and the light irradiation unit 3 are synchronized, and the light irradiation unit 3 irradiates the pattern light P1 in accordance with the image pickup timing of the image pickup unit 4. That is, during the period when the image pickup unit 4 does not perform imaging, the light irradiation unit 3 does not output the pattern light P1, which suppresses unnecessary power consumption in the light irradiation unit 3.
- the image pickup unit 4 includes an image pickup element 41 and an optical component 42.
- the image pickup element 41 includes an area sensor or a line sensor, and outputs the image data of the captured specific image Im1 to the control unit 16 as an electric signal.
- the image pickup unit 4 is a CIS (Contact Image Sensor) type area sensor using a CMOS (Complementary Metal Oxide Semiconductor) sensor as the image pickup element 41.
- CMOS Complementary Metal Oxide Semiconductor
- the present invention is not limited to this example, and the image pickup unit 4 may be, for example, a CCD system using a CCD (Charge Coupled Device) as the image pickup element 41.
- the optical component 42 includes, for example, an image pickup lens, and is arranged between the image pickup element 41 and the specific region R1 of the surface A1 of the sheet Sh1. As a result, the light in the specific region R1 is incident on the image sensor 41 through the optical component 42.
- the image sensor 41 and the optical component 42 are aligned on the perpendicular line of the specific region R1 passing through the center (center of gravity) of the specific region R1. Further, the light receiving surface 411 (see FIG. 3) of the image pickup device 41 is arranged in parallel with the specific region R1. Therefore, the optical axis Ax2 (see FIG.
- the image pickup unit 4 is a perpendicular line of the light receiving surface 411 passing through the center (center of gravity) of the light receiving surface 411 of the image pickup element 41.
- the optical axis Ax2 of the image pickup unit 4 is orthogonal to the specific region R1 and intersects the optical axis Ax1 of the light irradiation unit 3 (pattern light P1) at the center of the specific region R1.
- the area of the specific region R1 imaged by the image sensor 41 is equal to the value obtained by dividing the area of the light receiving surface 411 of the image sensor 41 by the image magnification M of the optical component 42.
- the image magnification M is "1" for the sake of simplicity.
- the image magnification M may be a value other than 1.
- the image pickup unit 4 is integrated with the light irradiation unit 3 to form a sensor unit 20 (see FIG. 2).
- the sensor unit 20 includes a light irradiation unit 3 and an image pickup unit 4.
- the sensor unit 20 is housed in the housing 100 of the image processing device 10, and is electrically connected to at least the control unit 16.
- the sensor unit 20 including the light irradiation unit 3 and the image pickup unit 4 is arranged so as to face the transport path T1 between the paper feed unit 14 and the image forming unit 13. There is. Therefore, the imaging position of the specific region R1 is set on the transport path T1 between the paper feeding unit 14 and the image forming unit 13. That is, the light irradiation unit 3 and the image pickup unit 4 irradiate the pattern light P1 on the sheet Sh1 conveyed from the paper feed unit 14 to the image formation unit 13 at the position between the paper feed unit 14 and the image forming unit 13. Then, the specific image Im1 can be imaged.
- the sensor unit 20 is arranged. Therefore, it is possible to capture a specific image Im1 with one sensor unit 20 for the sheet Sh1 supplied from the plurality of paper cassettes 141 to the image forming unit 13, and it is necessary to provide the sensor unit 20 for each paper cassette 141. do not have.
- the surface A1 of the sheet Sh1 including the specific region R1 is, as an example in the present embodiment, one surface on the side where the image is formed by the image forming unit 13 in the thickness direction of the sheet Sh1, but is not limited to this example.
- the specific region R1 may be set, for example, on one surface (back surface) on the side where the image is not formed by the image forming unit 13 in the thickness direction of the sheet Sh1.
- the light irradiation unit 3 and the image pickup unit 4 are arranged on the back surface side of the sheet Sh1.
- the specific region R1 may be set on both sides of the sheet Sh1 in the thickness direction, for example.
- two sets of the light irradiation unit 3 and the image pickup unit 4 may be provided and arranged on both sides of the sheet Sh1 in the thickness direction, or by turning over the sheet Sh1, one set of the light irradiation unit 3 and the image pickup unit 3 and the image pickup unit 4 are provided.
- the specific image Im1 on both sides of the sheet Sh1 may be imaged.
- the thickness sensor 5 detects a physical quantity related to the thickness of the sheet Sh1.
- the thickness sensor 5 outputs the detected physical quantity as an electric signal to the control unit 16.
- the control unit 16 can specify the thickness of the sheet Sh1.
- the thickness sensor 5 includes an optical sensor that detects the thickness (or basis weight) of the sheet Sh1 by using transmitted light.
- the thickness sensor 5 may be included in the sensor unit 20 or may be provided separately from the sensor unit 20.
- the acquisition unit 21 acquires the specific image Im1 imaged by the image pickup unit 4. Specifically, the acquisition unit 21 acquires the image data of the specific image Im1 imaged by the image pickup unit 4 from the image pickup element 41 of the image pickup unit 4 as an electric signal.
- the acquisition unit 21 controls the light irradiation unit 3 and the image pickup unit 4, and for example, the pattern light P1 is applied to the light irradiation unit 3 at the timing when the sheet Sh1 passes through the position corresponding to the sensor unit 20 in the transport path T1. And let the image pickup unit 4 take an image of the specific image Im1.
- the specific image Im1 acquired by the acquisition unit 21 is temporarily stored in one or more memories.
- the acquisition unit 21 may acquire the specific image Im1 from other than the image pickup unit 4.
- the unevenness specifying unit 22 specifies unevenness information regarding the unevenness of the surface A1 of the sheet Sh1 based on the specific image Im1 acquired by the acquisition unit 21. Thereby, the state of the unevenness of the surface A1 of the sheet Sh1 can be specified.
- the unevenness information includes information regarding at least one of the dimension in the direction orthogonal to the plane along the surface A1 of the unevenness of the surface A1 and the dimension in the direction along the plane. That is, the unevenness information is the height (or depth) of the unevenness which is the dimension in the direction orthogonal to the plane along the surface A1 and / or the size of the unevenness in the plan view which is the dimension in the direction along the plane. Contains information about.
- the unevenness specifying portion 22 calculates a numerical value corresponding to the arithmetic mean height (Sa) of the surface A1 regarding the height (or depth) of the unevenness as unevenness information.
- the unevenness specifying portion 22 specifies the unevenness information based on the degree of deformation or distortion of the pattern light P1 in the specific image Im1. That is, since the specific image Im1 includes the luminance distribution of the pattern (striped pattern in the present embodiment) corresponding to the pattern light P1 generated in the specific region R1 by the projection of the pattern light P1, due to the unevenness of the surface A1. Deformation or distortion occurs in the pattern. For example, even if the pattern light P1 forms a linear pattern, the pattern light P1 projected on the surface A1 undergoes deformation (meandering) or the like according to the unevenness of the surface A1.
- the unevenness specifying portion 22 calculates the unevenness information regarding the unevenness of the surface A1 from the degree of deformation or distortion of the pattern light P1.
- the unevenness specifying portion 22 specifies unevenness information at least based on the variation in the line width of the pattern light P1 on the specific region R1. Thereby, the state of the unevenness of the surface A1 of the sheet Sh1 can be specified by a relatively simple calculation process.
- the condition determination unit 23 determines the image processing conditions based on the unevenness information specified by the unevenness specifying unit 22.
- the image processing conditions referred to here are conditions relating to image formation or image reading. That is, various image processing conditions including an image forming condition relating to image formation executed by the image processing apparatus 10 and / or an image reading condition relating to image reading are determined by the condition determination unit 23.
- the image processing conditions include, for example, the fixing pressure in the image forming unit 13, the fixing temperature, the transport speed of the sheet Sh1, the transfer voltage, and the like, and further, the transport speed, the amount of light, or the resolution of the sheet in the image reading unit 12. Etc. are included.
- the condition determination unit 23 raises the fixing temperature, lowers the transfer speed, and raises the transfer voltage when the arithmetic mean height (Sa) becomes large (that is, coarse) based on the unevenness information.
- Image processing conditions are set automatically. This enables image formation and / or image reading under appropriate image processing conditions according to the unevenness of the surface A1 of the sheet Sh1, leading to improvement in image formation and / or image reading quality (including image quality). ..
- the condition determination unit 23 determines the image processing conditions related to image formation or image reading based on the fiber direction. That is, in the present embodiment, the direction specifying portion 24 specifies the fiber direction of the surface A1 of the sheet Sh1. Therefore, the condition determination unit 23 determines the image processing condition not only based on the unevenness information but also based on the fiber direction. For example, in the inkjet type image forming unit 13, since the curl behavior is different with respect to the fiber direction, the curl direction may be predicted according to the fiber direction and the curl may be corrected.
- the image processing conditions determined by the condition determination unit 23 based on the fiber direction include the conditions for curl correction.
- the condition determination unit 23 determines based on the fiber direction.
- the image processing conditions to be performed may include the conditions for skew correction. This enables image formation and / or image reading under appropriate image processing conditions according to the fiber direction of the surface A1 of the sheet Sh1, and improves the quality (including image quality) of image formation and / or image reading. Connect.
- the condition determination unit 23 may have a function of determining image processing conditions based on at least one of the unevenness information and the fiber direction. That is, the condition determination unit 23 determines the image processing condition based on only one of the unevenness information and the fiber direction, not limited to the configuration of determining the image processing condition based on both the unevenness information and the fiber direction. You may. Further, in the present embodiment, the thickness of the sheet Sh1 is specified by the thickness specifying portion 25. Therefore, the condition determination unit 23 may determine the image processing condition based on the thickness of the sheet Sh1 in addition to or in place of at least one of the unevenness information and the fiber direction.
- the direction specifying unit 24 specifies the fiber direction of the surface A1 of the sheet Sh1 based on the specific image Im1.
- the direction specifying unit 24 specifies the fiber direction based on the deformation or distortion of the pattern light P1 in the specific image Im1. That is, depending on the line width of the pattern light P1 on the specific region R1, the degree of deformation or distortion of the unevenness of the surface A1 due to the pattern light P1 differs depending on the relationship between the extension direction of the pattern light P1 and the fiber direction. .. Therefore, in the present embodiment, the direction specifying unit 24 specifies the fiber direction at least based on the variation in the line width of the pattern light P1 on the specific region R1. Thereby, the fiber direction of the surface A1 of the sheet Sh1 can be specified by a relatively simple arithmetic process.
- the thickness specifying unit 25 specifies the thickness of the sheet Sh1 based on the output of the thickness sensor 5. That is, the thickness specifying portion 25 receives an electric signal representing a physical quantity relating to the thickness of the sheet Sh1 from the thickness sensor 5 and calculates the thickness of the sheet Sh1.
- the sheet specifying device 2 according to the present embodiment is provided with the thickness specifying portion 25, so that it is possible to estimate the type (paper type) of the sheet Sh1 including the thickness in addition to the state of the surface A1 of the sheet Sh1. Is.
- the unevenness specifying unit 22 specifies the unevenness information based on the specific image Im1 will be described with reference to FIGS. 5 and 6.
- the bright portion L1 of the pattern light P1 is schematically shown by a dotted line
- the dark portion L2 is schematically shown by a two-dot chain line.
- convex portion 1 As shown as “convex portion 1" in the upper part of FIG. 5, it is assumed that a rectangular parallelepiped convex portion A11 having a height ⁇ Z from the surface A1 exists on the surface A1 of the sheet Sh1.
- the pattern light P1 is obliquely incident on the surface A1 of the sheet Sh1 at a predetermined angle ⁇ 1. Therefore, the pattern light P1 is projected on the same plane as the surface A1 except for the convex portion A11, and is projected on the convex portion A11 by the height ⁇ Z from the surface A1.
- the projection position of the light P1 is deviated only by the portion of the convex portion A11.
- the height ⁇ Z of the convex portion A11 can be calculated from the shift amount ⁇ X and the above equation 1. Then, from the shift amount ⁇ X for the entire area of the specific area R1, the unevenness information of the entire area of the specific area R1 can be obtained.
- the unevenness information calculated in this way has a correlation with the arithmetic mean height (Sa) of the surface A1.
- the height ⁇ Z of each part of the part A12 can be calculated. That is, similarly to the above example, the height ⁇ Z of the convex portion A12 can be calculated from the above equation 1 by obtaining the shift amount ⁇ X from the specific image Im1. Therefore, for example, as in the case of the paper sheet Sh1, it is possible to calculate the unevenness information even for the unevenness caused by the waviness component generated by the continuous entanglement of a large number of fibers.
- the local unevenness of the fiber is strongly reflected in the calculation result.
- the calculation result does not necessarily have a linear relationship with the arithmetic mean height (Sa). Therefore, in the method of the above-mentioned related technique, for example, if only the glossy paper (gloss paper) having a high flatness is distinguished from the plain paper, the surface roughness of the sheet Sh1 of the same type (for example, the plain paper) may be different. It is difficult to distinguish from the calculation result.
- a table in which the calculation results for various sheets Sh1 and the arithmetic mean height (Sa) are associated with each other is prepared in advance. It is necessary to do.
- the line width of the pattern light P1 and the predetermined angle ⁇ 1 are optimized to reduce the influence of local fibers and the arithmetic mean height.
- Concavo-convex information having high linearity with (Sa) can be calculated. Therefore, in the method of the present embodiment, even if a table (database) in which the calculation result (unevenness information) and the arithmetic mean height (Sa) are associated with each other is not prepared in advance, the calculation result of the unevenness specifying unit 22 can be used. , The arithmetic mean height (Sa) can be uniquely obtained.
- FIG. 6 shows an example of the specific image Im1 obtained by the sheet specifying device 2 according to the present embodiment.
- the predetermined angle ⁇ 1 is 40 degrees
- the resolution (number of pixels) of the imaging element 41 is 100 ⁇ 100
- the line width W1 of the bright portion L1 of the striped pattern by the pattern light P1 is 120 ⁇ m
- the line width W2 of the dark part L2 is 120 ⁇ m.
- the image magnification M is "1"
- the irradiation direction of the pattern light P1 that is, the arrangement direction of the bright portion L1 and the dark portion L2 is the same as the fiber direction.
- the specific image Im1 is composed of a plurality of pixels, and each of the plurality of pixels has a pixel value corresponding to the luminance.
- the relationship between the luminance and the pixel value is defined so that the pixel value increases as the luminance increases. Therefore, in the specific image Im1 in which the specific region R1 on which the pattern light P1 is projected is captured, the pixel value of the pixel corresponding to the bright portion L1 is relatively large, and the pixel value of the pixel corresponding to the dark portion L2 is relatively large. It will be a small value.
- the upper part (“Sa: small”) of FIG. 6 shows a specific image when the pattern light P1 is projected onto a specific area R1 of glossy paper (gloss paper) having a small arithmetic mean height (Sa), that is, high flatness. Shows Im1.
- the specific image Im1 of the above is shown. As shown in FIG.
- steps S1, S2 ... represent the number of the processing procedure (step) executed by the control unit 16.
- the process described below is started, for example, at the position (monitor position) corresponding to the sensor unit 20 in the transport path T1 at the timing when the sheet Sh1 passes through.
- the analysis of the specific image Im1 including the pattern light P1 is aimed at restoring the three-dimensional shape, for example, a plurality of pattern lights P1 are continuously projected and the specific image is calculated to calculate the phase change of the pattern light P1.
- the calculation load is relatively high, it takes a relatively long time to calculate the roughness (unevenness information) of the surface A1, and the cost of hardware (CPU, GPU, memory, etc.) is also compared. It will be high. Therefore, in the present embodiment, instead of the above method, the following method is adopted so that the roughness (concavo-convex information) of the surface A1 can be calculated by a relatively simple arithmetic process.
- the unevenness specifying portion 22 has one row (1 line) of the specific image Im1 with the alignment direction (horizontal direction in FIG. 6) of the bright portion L1 and the dark portion L2 in the specific image Im1 as the “row direction”.
- the width (line width) of at least one of the bright portion L1 and the dark portion L2 is calculated.
- the specific image Im1 is an image of "N pixels ⁇ M rows" in which N pixels are arranged in the arrangement direction of the bright portion L1 and the dark portion L2, and the unevenness specific portion 22 is each row of the M rows included in the specific image Im1.
- the line width is calculated for.
- the unevenness specifying portion 22 obtains the line width of at least one of the bright portion L1 and the dark portion L2 calculated for each row for the entire specific image Im1, and the variation in the line width within the specific image Im1 is large. Is calculated as unevenness information. As a result, the unevenness specifying portion 22 can obtain unevenness information having a correlation with the arithmetic mean height (Sa) of the surface A1 based on the variation in the line width of the pattern light P1.
- step S1 the control unit 16 determines whether the seat Sh1 reaches the monitor position, that is, the position corresponding to the sensor unit 20 in the transport path T1.
- the sheet Sh1 is detected by the sensor at the monitor position, and the control unit 16 determines that the sheet Sh1 reaches the monitor position (S1: Yes). ), The process is shifted to step S2.
- the control unit 16 determines that the seat Sh1 has not reached the monitor position (S1: No), and shifts the process to step S1.
- step S2 the control unit 16 controls the light irradiation unit 3 by the acquisition unit 21 to irradiate the light irradiation unit 3 with the pattern light P1.
- step S3 the control unit 16 controls the image pickup unit 4 by the acquisition unit 21, and causes the image pickup unit 4 to image the specific region R1 in the state where the pattern light P1 is projected.
- the specific image Im1 which is an image of the specific region R1 of the surface A1 of the sheet Sh1 is generated by the image pickup unit 4.
- step S4 the control unit 16 acquires one line (one line) of the specific image Im1 from the image pickup unit 4 by the acquisition unit 21. That is, the acquisition unit 21 acquires the specific image Im1 for one row, which is one pixel in the column direction. Since the image pickup unit 4 (image sensor 41) generally has a specification in which images are sequentially read out line by line, a specific image Im1 is acquired and analyzed line by line in this way (step S5, By performing S6), the amount of memory used can be reduced.
- step S5 the control unit 16 executes preprocessing for the specific image Im1 in the acquisition unit 21.
- the target of the preprocessing is the specific image Im1 for one line (one line) acquired in step S4. That is, the control unit 16 executes preprocessing for the specific image Im1 line by line.
- the pre-processing includes, for example, a filtering process and a binarization process. Specifically, the control unit 16 performs noise removal or the like by a filtering process on the specific image Im1 for one line, and further binarizes it with a certain reference value.
- the reference value used for the binarization process is, for example, an average value of a plurality of pixels, a predetermined value (predetermined value), or the like.
- the pixel corresponding to the bright portion L1 is a “white pixel” as a pixel having a pixel value equal to or higher than the reference value
- the pixel corresponding to the dark portion L2 is a “black pixel” as a pixel having a pixel value less than the reference value.
- the pre-processing may include a trimming process for cutting out only a part of the specific image Im1, and may narrow down the range to be processed in step S6. Further, the filtering process and the like are not essential and can be omitted as appropriate.
- step S6 the control unit 16 extracts the width data indicating the width (line width) of at least one of the bright portion L1 and the dark portion L2 from the specific image Im1 in the unevenness specifying unit 22.
- the target for extracting the width data is the specific image Im1 for one line (one line) acquired in step S4. That is, the control unit 16 extracts the width data for the specific image Im1 line by line. Specifically, the control unit 16 calculates, as width data, how many white pixels correspond to the bright part L1 and black pixels corresponding to the dark part L2 in the specific image Im1 for one line. ..
- control unit 16 extracts the number of white pixels and the number of black pixels for the entire specific image Im1 for one line, thereby summing up the line widths of the plurality of bright portions L1 and a plurality of them. The total line width of the dark part L2 of the book is extracted.
- both the number of pixels of white pixels corresponding to the line width of the bright part L1 and the number of pixels of black pixels corresponding to the line width of the dark part L2 are used as width data.
- only one of the number of pixels may be used as the width data. That is, the control unit 16 may specify the unevenness information by paying attention to the line width of either the bright portion L1 or the dark portion L2. Further, the control unit 16 extracts the number of pixels of white pixels continuous in the row direction and the number of pixels of black pixels continuous in the row direction, so that each bright portion L1 and one dark portion L2 can be used. The line width may be extracted.
- control unit 16 may use the line width of each of the plurality of bright portions L1 (or the dark portion L2) as the width data, or may use the representative value of the line width of the plurality of bright portions L1 (or the dark portion L2) ( For example, the mean value, the mode value, the median value, etc.) may be used as the width data.
- step S7 the control unit 16 determines whether or not the processing is completed up to the final line of the specific image Im1. That is, for the specific image Im1 of "N pixel x M row", the control unit 16 determines that the processing is completed up to the final row if the processing target is the Mth row which is the final row (S7: Yes). ), The process is shifted to step S8. On the other hand, the control unit 16 determines that the processing is not completed up to the final row unless the processing target is the Mth row which is the final row (S7: No), shifts the processing to step S4, and next Acquires a specific image Im1 for one line.
- step S8 the control unit 16 calculates the standard deviation ⁇ of the width data for M rows of the specific image Im1 in the unevenness specifying unit 22.
- the arithmetic mean height (Sa) increases, the undulation component of the height of the surface A1 increases, so that the line widths of the bright part L1 and the dark part L2 vary widely (see FIG. 6), and the standard deviation ⁇ . Becomes larger. That is, the unevenness specifying portion 22 calculates the standard deviation ⁇ as unevenness information.
- step S9 the control unit 16 determines the image processing conditions in the condition determination unit 23. That is, the condition determination unit 23 determines the image processing conditions including the image formation conditions according to the standard deviation ⁇ calculated in step S8. As an example, when the standard deviation ⁇ becomes large, the condition determination unit 23 sets the image formation conditions so as to raise the fixing temperature, lower the transport speed, or raise the transfer voltage. As a result, when an image is formed on the sheet Sh1 by the image forming unit 13, the image forming conditions corresponding to the unevenness of the surface A1 of the sheet Sh1 are automatically applied.
- the irradiation angle of the pattern light P1 will be described with reference to FIG. 8 showing an example of the specific image Im1 when the predetermined angle ⁇ 1 is changed.
- the imaging conditions of the specific image Im1 the arithmetic mean height (Sa) of the specific region R1 is 6 ⁇ m
- the resolution (number of pixels) of the image sensor 41 is 100 ⁇ 100
- the line width W1 of the dark portion L2 is 100 ⁇ m
- the line width W2 of the dark portion L2 is 100 ⁇ m.
- the irradiation direction of the pattern light P1, that is, the arrangement direction of the bright portion L1 and the dark portion L2 is set to be the same as the fiber direction.
- the optical axis Ax1 of the pattern light P1 is tilted at a predetermined angle ⁇ 1 with respect to the surface A1 of the sheet Sh1 (see FIG. 3).
- the predetermined angle ⁇ 1 greatly affects the brightness of the specific image Im1.
- the irradiation angle (predetermined angle) of light on the surface A1 of the sheet Sh1 is taken in order to image the unevenness on the order of several ⁇ m as a shadow image. (Corresponding to ⁇ 1) is set relatively shallow (small).
- the irradiation angle is set to a very shallow angle of about 10 degrees.
- the specific image Im1 becomes a relatively dark image, and it is relatively expensive to obtain the roughness of the surface A1 from the dark image.
- An image sensor 41 with sensitivity is required.
- the roughness of the surface A1 is obtained from the degree of deformation or distortion of the pattern light P1 in the specific image Im1, so that the pattern light P1 is deformed or distorted due to unevenness. And so on. Therefore, in the present embodiment, the predetermined angle ⁇ 1 can be set larger than that of the method of the related technique, and a bright image can be realized as the specific image Im1. Therefore, even with the relatively inexpensive image pickup device 41, the roughness of the surface A1 can be obtained from the specific image Im1.
- the shape of the pattern light P1 projected on the specific region R1 is deformed, and the boundary between the bright part L1 and the dark part L2 of the fringe pattern is broken.
- the shape of the pattern light P1 collapses when the predetermined angle ⁇ 1 is 30 degrees rather than 40 degrees, and when the predetermined angle ⁇ 1 becomes 20 degrees, the shape of the pattern light P1 further collapses and the predetermined angle.
- ⁇ 1 becomes 10 degrees the shape of the pattern light P1 further collapses.
- the inventors have verified various predetermined angles ⁇ 1 and when the sheet Sh1 having an arithmetic mean height (Sa) of the surface A1 of about several ⁇ m is targeted, the predetermined angle ⁇ 1 is 20 degrees or more. Was found to be preferable.
- the predetermined angle ⁇ 1 is preferably 10 degrees or more, and more preferably 15 degrees or more. Further, in the present embodiment, the predetermined angle ⁇ 1 is set to 20 degrees or more so that the shape of the pattern light P1 does not collapse too much. That is, the predetermined angle ⁇ 1 is 20 degrees or more and 90 degrees or less.
- the lower limit of the predetermined angle ⁇ 1 is not limited to 20 degrees, and is, for example, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, and 75 degrees. It may be degrees or 80 degrees.
- the upper limit of the predetermined angle ⁇ 1 is not limited to 90 degrees, and may be, for example, 85 degrees, 80 degrees, 75 degrees, 70 degrees, 65 degrees, 60 degrees, 55 degrees, 50 degrees, or 45 degrees.
- the incident angle of the pattern light P1 is 0 degrees.
- FIG. 9 is a graph showing the relationship between the standard deviation ⁇ as the unevenness information calculated according to the flowchart of FIG. 7 and the actual arithmetic mean height Sa for 48 types of sheets Sh1.
- the horizontal axis is the arithmetic mean height Sa
- the vertical axis is the standard deviation ⁇ (the standard deviation ⁇ is the average value of the five points of the bright part L1 or the dark part L2).
- the standard deviation ⁇ is the average value of the five points of the bright part L1 or the dark part L2.
- the resolution (number of pixels) of the image pickup element 41 is 100 ⁇ 100
- the line width W1 of the bright portion L1 of the striped pattern by the pattern light P1 is 80 ⁇ m
- the line width W2 of the dark portion L2 is set. It is set to 80 ⁇ m.
- the irradiation direction of the pattern light P1, that is, the arrangement direction of the bright portion L1 and the dark portion L2 is set to be the same as the fiber direction.
- the coefficient of determination R2 of the linear regression model of the arithmetic mean height Sa and the standard deviation ⁇ is “0.9684”, and is between the standard deviation ⁇ as unevenness information and the arithmetic mean height Sa. It can be confirmed that it has high linearity.
- FIG. 10 shows the result of calculating the coefficient of determination R2 while changing the line width of the pattern light P1 and the relationship between the irradiation direction of the pattern light P1 and the fiber direction.
- the predetermined angle ⁇ 1 is 40 degrees
- the resolution (number of pixels) of the image pickup element 41 is 100 ⁇ 100.
- the line width W1 of the bright part L1 and the line width W2 of the dark part L2 of the striped pattern by the pattern light P1 are changed in the range of 40 ⁇ m to 200 ⁇ m, and the relationship between the irradiation direction of the pattern light P1 and the fiber direction is changed to “. Change by "identical” (that is, parallel) and "90 °" (that is, orthogonal).
- FIG. 10 it is presumed that the influence of the relationship between the irradiation direction of the pattern light P1 and the fiber direction on the standard deviation ⁇ as unevenness information changes depending on the line width of the pattern light P1. That is, in FIG. 10, it is confirmed that the smaller (thinner) the line width of the pattern light P1, the greater the influence of the relationship between the irradiation direction of the pattern light P1 and the fiber direction on the standard deviation ⁇ as unevenness information. can.
- the width of the fiber of the sheet Sh1 is several tens of ⁇ m or less, and the line width of the pattern light P1 approaches the fiber width, so that the undulation component of the local surface A1 height becomes the bright part L1 and the dark part. It is considered that this is because it tends to occur as a variation in the line width of each of L2.
- the coefficient of determination R2 is “0.85” or more regardless of the relationship between the irradiation direction of the pattern light P1 and the fiber direction. Therefore, when the line width of the pattern light P1 is 100 ⁇ m or more, the influence of the relationship between the irradiation direction of the pattern light P1 and the fiber direction on the standard deviation ⁇ as unevenness information is relatively small, and the effect is relatively small with the irradiation direction of the pattern light P1. The relationship with the fiber direction can be ignored.
- the relationship between the irradiation direction of the pattern light P1 and the fiber direction affects the unevenness information depending on whether the line width W1 of the bright portion L1 and the line width W2 of the dark portion L2 of the striped pattern by the pattern light P1 are 100 ⁇ m or more or less than 100 ⁇ m. Whether or not to do it is decided. That is, when the line width is 100 ⁇ m or more, the relationship between the irradiation direction and the fiber direction does not easily affect the unevenness information, so that the calculated unevenness information can be regarded as “independent of the fiber direction”. On the other hand, if the line width is less than 100 ⁇ m, the relationship between the irradiation direction and the fiber direction tends to affect the unevenness information, so that the calculated unevenness information can be regarded as “depending on the fiber direction”.
- the relationship between the irradiation direction of the pattern light P1 and the fiber direction has a standard deviation ⁇ as unevenness information depending on the line width of the pattern light P1. It can have an impact. Then, by making the line width of the pattern light P1 relatively larger than the width of the fiber of the sheet Sh1, the influence can be reduced, and the standard deviation ⁇ as unevenness information and the arithmetic mean height Sa can be reduced. It will have high linearity.
- the width of at least one of the bright part L1 and the dark part L2 is preferably 60 ⁇ m or more and 500 ⁇ m or less. Further, in order to make the unevenness information less susceptible to the influence of the relationship between the irradiation direction of the pattern light P1 and the fiber direction, the line width W1 of the bright portion L1 and the line width W2 of the dark portion L2 of the striped pattern by the pattern light P1 are used. At least one is preferably 100 ⁇ m or more.
- the line width W1 of the bright portion L1 and the line width W2 of the dark portion L2 of the striped pattern by the pattern light P1 are used. At least one of them is preferably less than 100 ⁇ m.
- the lower limit of the width of at least one of the bright portion L1 and the dark portion L2 is not limited to 60 ⁇ m, and may be, for example, 65 ⁇ m, 70 ⁇ m, 75 ⁇ m, 80 ⁇ m, 85 ⁇ m, 90 ⁇ m, or 95 ⁇ m.
- the upper limit of the width of at least one of the bright portion L1 and the dark portion L2 is not limited to 500 ⁇ m, and may be, for example, 450 ⁇ m, 400 ⁇ m, 350 ⁇ m, 300 ⁇ m, 250 ⁇ m, 200 ⁇ m, 180 ⁇ m, 160 ⁇ m, 140 ⁇ m or 120 ⁇ m. ..
- the grid pattern is a superposition of vertical stripe patterns and horizontal stripe patterns that are orthogonal to each other. Therefore, as shown in FIG. 11, the pattern light P1 that produces the grid pattern is the first pattern light P11 that produces the first stripe pattern (vertical stripe pattern) and the second pattern light P12 that produces the second stripe pattern (horizontal stripe pattern). It can be regarded as a synthetic light of.
- the dark portion L2 is prioritized for the portion where the bright portion L1 and the dark portion L2 of the first pattern light P11 and the second pattern light P12 overlap, but the dark portion L2 is prioritized. May be done. That is, the light portion L1 (shaded) and the dark portion L2 (blackened) of the grid pattern shown in FIG. 11 may be reversed.
- the line width of the first pattern light P11 and the line width of the second pattern light P12 are different from each other. That is, the line width is different between the vertical stripes and the horizontal stripes of the grid pattern.
- the line width W11 of the bright portion L1 of the first pattern light P11 and the line width W12 of the dark portion L2 are compared with the line width W21 of the bright portion L1 and the line width W22 of the dark portion L2 of the second pattern light P12. Is big.
- the line width W11 of the bright portion L1 of the first pattern light P11 and the line width W12 of the dark portion L2 are both 100 ⁇ m
- the line width W22 of is 80 ⁇ m. Therefore, in the example of FIG. 11, the vertical stripe pattern among the grid patterns is wider than the horizontal stripe pattern.
- the fringe pattern includes a first fringe pattern (vertical fringe pattern) and a second fringe pattern (horizontal fringe pattern) that are orthogonal to each other.
- the width of at least one of the bright portion L1 and the dark portion L2 is different between the first striped pattern and the second striped pattern.
- the first fringe pattern is wider than the second fringe pattern for both the bright portion L1 and the dark portion L2, but the present invention is not limited to this example, and only the bright portion L1 or the dark portion L2 is the first.
- the one-striped pattern may be wider than the second-striped pattern.
- the second fringe pattern may be wider than the first fringe pattern for at least one of the bright portion L1 and the dark portion L2.
- the pattern light P1 that produces the grid pattern as described above may be realized by using the grid-shaped shield 32, or may be realized by using two shields 32 in which the slits 321 are formed. .. In the latter case, the lattice pattern as shown in FIG. 11 can be realized by arranging the two shields 32 having different widths of the slits 321 so as to be overlapped with each other so that the directions of the slits 321 are orthogonal to each other.
- the control unit 16 analyzes the line width of the first stripe pattern (vertical stripe pattern) and also analyzes the second stripe pattern (horizontal stripe pattern) when analyzing the specific image Im1. It is possible to analyze the line width of. That is, the control unit 16 can calculate the variation in the line width in the horizontal direction from the first fringe pattern, and can calculate the variation in the line width in the vertical direction from the second fringe pattern. In this way, it is possible to acquire the specific image Im1 necessary for analysis in two directions orthogonal to each other in the vertical direction and the horizontal direction at one time.
- control unit 16 can specify the fiber direction of the surface A1 of the sheet Sh1 by the direction specifying unit 24 from the difference between the calculation result in the vertical direction and the calculation result in the horizontal direction.
- the lateral unevenness information calculated from the first pattern light P11. Is considered "fiber direction independent”.
- the vertical unevenness information calculated from the second pattern light P12 is “fiber direction”. Depends on. "
- the direction specifying unit 24 has the fiber direction orthogonal to the second fringe pattern (horizontal fringe pattern) by the second pattern light P12. Judge that there is. In other words, it is determined that the fiber direction is the same as the arrangement direction of the bright portion L1 and the dark portion L2 of the second pattern light P12. On the other hand, when different results (concavo-convex information) are obtained in the vertical direction and the horizontal direction, the direction specifying portion 24 states that the fiber direction is along the second stripe pattern (horizontal stripe pattern) by the second pattern light P12. to decide.
- the fiber direction is orthogonal to the alignment direction of the bright portion L1 and the dark portion L2 of the second pattern light P12.
- whether or not the unevenness information is the same in the vertical direction and the horizontal direction is determined by whether or not the difference between the unevenness information in the vertical direction and the unevenness information in the horizontal direction is equal to or less than a predetermined value. If the difference is equal to or less than a predetermined value, it is determined that the unevenness information is the same in the vertical direction and the horizontal direction.
- the unevenness information and the fiber direction can be obtained from the specific image Im1. Both can be identified. If the fiber direction is specified, for example, in the inkjet type image forming unit 13, the curl direction can be predicted according to the fiber direction, and the curl correction can be performed by the condition determination unit 23.
- the sheet specifying device 2 of the image processing device 10 specifies the fiber direction from the specific image Im1 by utilizing the dependence of the pattern light P1 on the fiber direction. That is, the method for specifying the fiber direction described below is basically the same as the method described in the column of "[7] Lattice pattern". Therefore, the configuration described below is also applicable to the case of using the pattern light P1 that produces a grid pattern, unless otherwise specified.
- the sheet specifying device 2 includes a first pattern light P11 and a second pattern light P12 having different dependences on the fiber direction.
- P1 is used to specify the fiber direction. That is, when the specific image Im1 is formed, the light irradiation unit 3 projects the first pattern light P11 and the second pattern light P12 having different dependences on the fiber direction of the surface A1 of the sheet Sh1 on the specific region R1.
- the first pattern light P11 and the second pattern light P12 both form a striped pattern in which the bright part L1 and the dark part L2 are alternately arranged on the specific region R1.
- the linear bright portions L1 and dark portions L2 orthogonal to the transport direction D1 of the sheet Sh1 are alternately arranged in the transport direction D1.
- the line width of the first pattern light P11 and the line width of the second pattern light P12 are different from each other.
- the line width W11 of the bright portion L1 of the first pattern light P11 and the line width W12 of the dark portion L2 are compared with the line width W21 of the bright portion L1 and the line width W22 of the dark portion L2 of the second pattern light P12. Is big. Specifically, the line width W11 of the bright portion L1 of the first pattern light P11 and the line width W12 of the dark portion L2 are both 100 ⁇ m, and the line width W21 and the dark portion L2 of the bright portion L1 of the second pattern light P12.
- the line width W22 of is 50 ⁇ m.
- the specific region R1 is divided into a first small region R11 and a second small region R12 in a direction orthogonal to the extension direction of the bright portion L1 and the dark portion L2, that is, in the arrangement direction of the bright portion L1 and the dark portion L2. ..
- the specific region R1 includes the first subregion R11 and the second subregion R12 divided in the transport direction D1.
- the first pattern light P11 is projected onto the first small region R11 of the specific region R1
- the second pattern light P12 is projected onto the second small region R12 of the specific region R1.
- the specific region R1 is bisected in the transport direction D1, the region downstream of the transport direction D1 (lower side of FIG.
- first small region R11 is the first small region R11, and the region upstream of the transport direction D1.
- the region (upper side of FIG. 12) is the second small region R12. That is, in the example of FIG. 12, the first pattern light P11 and the second pattern light P12 are projected onto different regions (first small region R11 or second small region R12) in the specific region R1.
- unevenness information "independent of the fiber direction” can be calculated from the specific image Im1 of the first small region R11 on which the first pattern light P11 having a line width of 100 ⁇ m or more is projected.
- the control unit 16 specifies the fiber direction by comparing the calculation result of the unevenness information by the first pattern light P11 and the calculation result of the unevenness information by the second pattern light P12. Is possible.
- the first fringe pattern is wider than the second fringe pattern for both the bright portion L1 and the dark portion L2, but the present invention is not limited to this example, and only the bright portion L1 or the dark portion L2 is used.
- the one-striped pattern may be wider than the second-striped pattern.
- the second fringe pattern may be wider than the first fringe pattern for at least one of the bright portion L1 and the dark portion L2.
- the above-mentioned line width is only an example, and at least one of the line width W11 of the bright portion L1 and the line width W12 of the dark portion L2 of the first pattern light P11 is not limited to 100 ⁇ m, but is a value larger than 100 ⁇ m, for example, 120 ⁇ m.
- At least one of the line width W11 of the bright portion L1 and the line width W12 of the dark portion L2 of the second pattern light P12 is not limited to 50 ⁇ m, and is not limited to 50 ⁇ m, for example, a value smaller than 50 ⁇ m such as 40 ⁇ m, or a value larger than 50 ⁇ m such as 60 ⁇ m. It may be a value.
- steps S11, S12 ... represent the number of the processing procedure (step) executed by the control unit 16.
- step S11 the control unit 16 calculates the standard deviation ⁇ 1 of the line width of the first pattern light P11 in the unevenness specifying unit 22.
- step S12 the control unit 16 calculates the standard deviation ⁇ 2 of the line width of the second pattern light P12 in the unevenness specifying unit 22.
- the same processing as described in the flowchart of FIG. 7 is performed. In this way, the standard deviation ⁇ 1 as the “fiber direction-independent” unevenness information and the standard deviation ⁇ 2 as the “fiber direction-dependent” unevenness information are derived.
- step S13 the control unit 16 compares the standard deviation ⁇ 1 of the line width of the first pattern light P11 with the standard deviation ⁇ 2 of the line width of the second pattern light P12, and the standard deviation ⁇ 1 and the standard deviation ⁇ 2 are obtained. Determine if they match. At this time, the control unit 16 performs a magnitude comparison between the standard deviation ⁇ 1 and the value obtained by adding the predetermined value ⁇ to the standard deviation ⁇ 2 in the direction specifying unit 24. If the standard deviation ⁇ 1 is smaller than the value obtained by adding the predetermined value ⁇ to the standard deviation ⁇ 2, the direction specifying unit 24 determines that the standard deviation ⁇ 1 matches the standard deviation ⁇ 2 (S13: Yes), and shifts the process to step S14.
- the direction specifying unit 24 determines that the standard deviation ⁇ 1 does not match the standard deviation ⁇ 2 (S13: No), and processes the process in step S15. Migrate.
- the predetermined value ⁇ is, for example, a value determined based on the magnitudes of the standard deviations ⁇ 1 and ⁇ 2, or a predetermined value.
- step S14 the control unit 16 determines in the direction specifying unit 24 that the fiber direction is orthogonal to the second fringe pattern. That is, when the same result (concavo-convex information) is obtained between the first pattern light P11 and the second pattern light P12, the fiber direction of the direction specifying portion 24 is orthogonal to the second fringe pattern by the second pattern light P12. Judge that you are doing. In other words, it is determined that the fiber direction is the same as the arrangement direction of the bright portion L1 and the dark portion L2 of the second pattern light P12 (the transport direction D1 in the example of FIG. 12).
- the unevenness of the surface A1 is reflected in the second fringe pattern by the second pattern light P12. That is, it is specified that the second fringe pattern is orthogonal to the fiber direction.
- step S15 the control unit 16 determines in the direction specifying unit 24 that the fiber direction follows the second fringe pattern. That is, when different results (concavo-convex information) are obtained between the first pattern light P11 and the second pattern light P12, the direction specifying portion 24 has the fiber direction along the second fringe pattern by the second pattern light P12. Judge that there is. In other words, it is determined that the fiber direction is orthogonal to the arrangement direction of the bright portion L1 and the dark portion L2 of the second pattern light P12 (the transport direction D1 in the example of FIG. 12).
- the unevenness of the surface A1 is not reflected in the second fringe pattern by the second pattern light P12. That is, it is specified that the second stripe pattern is along the fiber direction.
- step S16 the control unit 16 determines the image processing conditions in the condition determination unit 23. That is, the condition determination unit 23 determines the image processing conditions including the image formation conditions according to the fiber directions specified in steps S14 and S15. As an example, the condition determination unit 23 predicts the curl direction according to the specified fiber direction, and sets the image processing condition for curl correction. As a result, when an image is formed on the sheet Sh1 by the image forming unit 13, the image forming conditions corresponding to the fiber direction of the surface A1 of the sheet Sh1 are automatically applied.
- the pattern light P1 includes the first pattern light P11 and the second pattern light P12 having different dependences on the fiber direction.
- the direction specifying unit 24 specifies the fiber direction based on the comparison result between the first pattern light P11 and the second pattern light P12 in the specific image Im1.
- the fiber direction can be specified by a relatively simple process by utilizing the dependence of the first pattern light P11 and the second pattern light P12 on the fiber direction.
- the first pattern light P11 and the second pattern light P12 have different dependence on the fiber direction because the line width on the specific region R1 is different. Thereby, the first pattern light P11 and the second pattern light P12 having different dependences on the fiber direction can be realized relatively easily.
- the line width of the first pattern light P11 on the specific region R1 is 100 ⁇ m or more, and the line width of the second pattern light P12 on the specific region R1 is less than 100 ⁇ m.
- the direction specifying unit 24 has at least a variation in the line width of the first pattern light P11 and a variation in the line width of the second pattern light P12 on the specific region R1.
- the fiber direction is specified based on the comparison result of. This makes it possible to specify the fiber direction by a relatively simple calculation of calculating the variation in line width.
- the first pattern light P11 and the second pattern light P12 both form a striped pattern in which the bright portion L1 and the dark portion L2 are alternately arranged on the specific region R1. As a result, the striped pattern on the specific region R1 is likely to be deformed or distorted according to the unevenness of the surface A1.
- the two points described below are the differences from the grid pattern in the pattern light P1 illustrated in FIG. 12. That is, as the first difference, in the example of FIG. 12, the bright portion L1 and the dark portion L2 are arranged in the same direction in the first pattern light P11 and the second pattern light P12. This makes it easy to secure the lengths of both the bright portion L1 and the dark portion L2 in the first pattern light P11 and the second pattern light P12.
- the specific region R1 is a first small region R11 on which the first pattern light P11 is projected and a second small region R12 on which the second pattern light P12 is projected. , Is classified into. As a result, it is easy to distinguish between the first pattern light P11 and the second pattern light P12, so that the fiber direction can be easily specified based on the comparison result between the first pattern light P11 and the second pattern light P12 in the specific image Im1. ..
- the linear bright portions L1 and dark portions L2 along the transport direction D1 of the sheet Sh1 are orthogonal to the transport direction D1. They are arranged so as to be arranged alternately in the direction of the light.
- the specific region R1 includes a first subregion R11 and a second subregion R12 divided in a direction orthogonal to the transport direction D1, and the first pattern light P11 is projected onto the first subregion R11 and the second pattern light P12. Is projected onto the second small area R12.
- the specific region R1 is formed in the first small region R11 and the second small region R12 in the extension direction of the bright portion L1 and the dark portion L2, that is, in the direction orthogonal to the arrangement direction of the bright portion L1 and the dark portion L2. It is divided.
- the specific region R1 includes the first subregion R11 and the second subregion R12 divided in the direction orthogonal to the transport direction D1, and the first pattern light P11 is projected onto the first subregion R11 and the second.
- the pattern light P12 is projected onto the second small region R12.
- the first pattern light P11 and the second pattern light P12 both form a graphic pattern instead of a striped pattern on the specific region R1.
- the first pattern light P11 forms a plurality of circular graphic patterns in the bright portion L1 by the dark portion L2
- the second pattern light P12 is in the bright portion L1.
- a plurality of square-shaped graphic patterns are formed by the dark portion L2.
- the first pattern light P11 forms a plurality of circular graphic patterns in the bright portion L1 by the dark portion L2
- the second pattern light P12 forms the dark portion L2 in the bright portion L1.
- the specific region R1 is divided into the first small region R11 and the second small region R12 in the transport direction D1, and in the pattern light P1y, the specific region R1 is the third in the direction orthogonal to the transport direction D1. It is divided into one small area R11 and a second small area R12.
- the first pattern light P11 and the second pattern light P12 have different dependences on the fiber direction.
- the relationship between the bright portion L1 and the dark portion L2 may be reversed, and for example, the graphic pattern may be formed by the bright portion L1 in the dark portion L2.
- the first pattern light P11 and the second pattern light P12 having different thicknesses are mixed.
- the linear bright portions L1 and dark portions L2 orthogonal to the transport direction D1 of the sheet Sh1 are arranged so as to be alternately arranged in the transport direction D1.
- the line width W11 of the bright portion L1 of the first pattern light P11 and the line width W12 of the dark portion L2 are both 100 ⁇ m
- the line width W21 and the line width W22 of the dark portion L2 are both 50 ⁇ m.
- the total number of thick (line width is 100 ⁇ m) striped pattern and thin (line width is 50 ⁇ m) striped pattern is the same. That is, for example, in the pattern light P1a, the total number of the bright part L1 and the dark part L2 of the first pattern light P11 is four, and the total number of the bright part L1 and the dark part L2 of the second pattern light P12 is also four. be.
- the head of the transport direction D1 is the dark portion L2, but the head is not limited to this, and the head may be the bright portion L1.
- the total number of the bright part L1 and the dark part L2 of the first pattern light P11 having a thick striped pattern is three, and the second pattern light P12 having a thin striped pattern.
- the total number of the bright part L1 and the dark part L2 is two.
- the total number of the bright portion L1 and the dark portion L2 of the first pattern light P11 having a thick striped pattern is two, and the bright portion of the second pattern light P12 having a thin striped pattern.
- the total number of L1 and the dark part L2 is three.
- the total number of the bright portion L1 and the dark portion L2 of the first pattern light P11 having a thick striped pattern is three, and the second pattern light P12 having a thin striped pattern.
- the total number of the bright part L1 and the dark part L2 is one.
- the total number of the bright portion L1 and the dark portion L2 of the first pattern light P11 having a thick striped pattern is one, and the bright portion of the second pattern light P12 having a thin striped pattern.
- the total number of L1 and the dark part L2 is three.
- the pattern lights P1a to P1c having the same total number of measurements have the highest measurement accuracy, followed by the pattern lights P1d and P1e having the highest measurement accuracy, and the pattern lights P1f and P1g having the largest difference in the total number of lines. It will be the lowest.
- the pattern light P1 shown in FIGS. 12 and 14 to 18 is only an example, and the specific embodiment of the pattern light P1 for specifying the fiber direction on the surface A1 of the sheet Sh1 can be appropriately changed.
- the line width is set within a range in which image identification is possible.
- the plurality of components included in the image processing apparatus 10 may be dispersedly provided in a plurality of housings.
- at least one of the acquisition unit 21, the unevenness specifying unit 22, the condition determining unit 23, the direction specifying unit 24, the thickness specifying unit 25, and the like, which are the components of the sheet specifying device 2 is realized as one function of the control unit 16.
- the control unit 16 may be provided in a different housing from the control unit 16. That is, the sheet specifying device 2 does not have to be integrated with the image processing device 10, and at least a part of the sheet specifying device 2 may be provided in a housing different from the image processing device 10.
- the sheet specifying device 2 may have at least a function of specifying the fiber direction of the surface A1 of the sheet Sh1, and the function of specifying the unevenness information regarding the unevenness of the surface A1 of the sheet Sh1 and the thickness of the sheet Sh1 is appropriate. It can be omitted. For example, when the function of specifying the thickness of the sheet Sh1 is omitted, the thickness sensor 5 and the thickness specifying portion 25 may be omitted.
- the optical axis Ax1 of the light irradiation unit 3 is tilted at a predetermined angle ⁇ 1 with respect to the specific region R1 of the sheet Sh1, and the optical axis Ax2 of the image pickup unit 4 is orthogonal to the specific region R1 of the sheet Sh1.
- the optical axis Ax1 of the light irradiation unit 3 may be orthogonal to the specific region R1 of the sheet Sh1, and the optical axis Ax2 of the image pickup unit 4 may be inclined with respect to the specific region R1 of the sheet Sh1.
- Both axes Ax2 may be tilted with respect to the specific region R1 of the sheet Sh1.
- the light irradiation unit 3 may include, for example, a projector, and may project arbitrary pattern light P1 input as projection data onto the specific region R1. That is, the image projected from the projector may be projected onto the specific region R1 as the pattern light P1. In this case, it is easy to adopt a moving image as the pattern light P1.
- the sheet Sh1 to be irradiated with the pattern light P1 is not limited to the sheet being conveyed, and may be, for example, the sheet Sh1 set in the paper feed cassette 141.
- the image magnification is reduced.
- a wide range of the sheet Sh1 can be imaged.
- the image processing device 10A according to the present embodiment is different from the image processing device 10 according to the first embodiment in that the sheet specifying device 2A includes the output unit 26.
- the same configurations as those in the first embodiment will be designated by a common reference numeral and description thereof will be omitted as appropriate.
- the output unit 26 outputs at least one specific result of the unevenness specifying part 22, the direction specifying part 24, and the thickness specifying part 25.
- the output unit 26 outputs the specific result by displaying it on the operation display unit 15 and notifies the user.
- the mode of outputting the specific result by the output unit 26 is not limited to the display on the operation display unit 15, but may be transmission to an external device, writing to a non-temporary recording medium readable by a computer system, or the like.
- the output unit 26 is provided in the control unit 16 as a function of the control unit 16.
- the content output by the output unit 26 is, for example, the standard deviation ⁇ as the unevenness information, the arithmetic mean height (Sa), or the information indicating the type of the sheet Sh1 in the case of the specific result of the unevenness specifying unit 22.
- the content output by the output unit 26 is, for example, the fiber direction, or information indicating whether the grain is “vertical” or “horizontal”.
- the output unit 26 may output information such as a life estimation result, a recommendation of the maintenance time, or a recommendation of the type of the sheet Sh1, which is estimated from the specific result of the unevenness specifying unit 22 or the like.
- the parts of the image processing apparatus 10A may be worn when the sheet Sh1 is conveyed, but the rougher the surface A1 of the sheet Sh1 to be conveyed, the easier the wear progresses. That is, the progress of deterioration of the image processing device 10A differs depending on the surface roughness of the sheet Sh1 to be used. Therefore, for example, if the unevenness information of the sheet Sh1 is known in addition to the number of sheets to be conveyed, the image processing device 10A The accuracy of life estimation is improved.
- the output unit 26 outputs information such as the life estimation result of the image processing device 10A or the recommendation of the maintenance time of the image processing device 10A by displaying it on the operation display unit 15, for example, and notifies the user. Is possible. Further, in order to extend the life of the image processing device 10A, the output unit 26 can notify the user, for example, information such as a recommendation of the sheet Sh1 having a higher flatness than the sheet Sh1 in use. ..
- the sheet specifying device 2A as described in the first embodiment, it is possible to calculate unevenness information having high linearity with the arithmetic mean height (Sa). Therefore, even if the sheet Sh1 is not registered in the database or the like in advance, it can be reflected in, for example, the life estimation of the image processing apparatus 10A.
- the output unit 26 may output information such as the estimation results of the front and back surfaces of the sheet Sh1 estimated from the specific results of the unevenness specifying unit 22 and the like. That is, depending on the type of the sheet Sh1, the back surface may be coarser than the front surface, and the roughness may differ between the front and back surfaces of the sheet Sh1. Therefore, if the unevenness information of each of the front and back surfaces of the sheet Sh1 is known, the front and back surfaces of the sheet Sh1 can be estimated. Therefore, the output unit 26 can output information such as the estimation results of the front and back sides of the sheet Sh1 by displaying it on the operation display unit 15, for example, and notify the user. In this case, it is necessary to take a specific image Im1 on both sides of the sheet Sh1 in the thickness direction. Therefore, the two sensor units 20 may be arranged so as to sandwich the transport path T1, the specific image Im1 on both sides may be imaged by one sensor unit 20 using a mirror or the like, and the sheet Sh1 may be turned inside out. You may.
- condition determination unit 23 may be omitted as appropriate.
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Abstract
Description
[1]画像処理装置の全体構成
まず、図1及び図2を参照しつつ、本実施形態に係る画像処理装置10の全体構成について説明する。
本開示でいう「シート」は、画像の形成対象又は画像の読み取り対象であるシートである。本実施形態では一例として、パターン光P1の照射対象となるシートSh1は、画像形成部13による画像の形成対象としてのシートSh1であることとする。つまり、本実施形態では、給紙部14により搬送路T1を搬送されるシートSh1を、パターン光P1の照射対象とする。ただし、この例に限らず、パターン光P1の照射対象となるシートは、画像読取部12による画像の読み取り対象としてのシート(原稿)、つまりADF11により搬送されるシートであってもよい。また、シートSh1は、本実施形態では一例として紙であるが、紙に限らず、例えば、樹脂フィルム等であってもよい。
次に、図1~図4を参照しつつ、本実施形態に係るシート特定装置2の構成について、より詳細に説明する。
次に、図5~図7を参照しつつ、本実施形態に係るシート特定方法、つまりシート特定装置2の動作について説明する。
まず、凹凸特定部22が、特定画像Im1に基づいて凹凸情報を特定する原理について、図5及び図6を参照して説明する。図5では、パターン光P1の明部L1を点線で模式的に示し、暗部L2を二点鎖線で模式的に示している。
ΔX=ΔZ/tanθ1 ・・・(式1)
次に、凹凸特定部22にて、特定画像Im1に基づいて凹凸情報を特定する具体的処理について、図7を参照して説明する。図7に示すフローチャートにおけるステップS1、S2・・・は、制御部16により実行される処理手順(ステップ)の番号を表している。以下に説明する処理は、例えば、搬送路T1のうちセンサーユニット20に対応する位置(モニター位置)をシートSh1が通過するタイミングに合わせて開始する。
具体的には、ステップS1において、制御部16は、シートSh1がモニター位置、つまり搬送路T1のうちセンサーユニット20に対応する位置に到達するかを判断する。給紙部14が画像形成部13にシートSh1を供給するに際して、シートSh1がモニター位置のセンサーで検知されることをもって、制御部16は、シートSh1がモニター位置に到達すると判断し(S1:Yes)、処理をステップS2に移行させる。一方、シートSh1がモニター位置のセンサーで検知されなければ、制御部16は、シートSh1がモニター位置に到達していないと判断し(S1:No)、処理をステップS1に移行させる。
ステップS2において、制御部16は、取得部21にて光照射部3を制御して、光照射部3にパターン光P1を照射させる。これにより、シートSh1の表面A1の特定領域R1にパターン光P1が投影される。ステップS3において、制御部16は、取得部21にて撮像部4を制御し、パターン光P1が投影されている状態の特定領域R1を撮像部4にて撮像させる。これにより、シートSh1の表面A1の特定領域R1の画像である特定画像Im1が、撮像部4にて生成される。
ステップS4において、制御部16は、取得部21にて特定画像Im1のうち、1行(1ライン)分の画像を撮像部4から取得する。つまり、取得部21は、列方向において1画素分となる1行分の特定画像Im1を取得する。撮像部4(撮像素子41)としては、画像の読み出しが1行毎に順次行われる仕様が一般的であるため、このように、1行毎に特定画像Im1を取得して解析(ステップS5、S6)を行うことで、メモリーの使用量を少なく抑えることができる。
ステップS5において、制御部16は、取得部21にて、特定画像Im1について前処理を実行する。このとき、前処理の対象となるのは、ステップS4で取得された1行(1ライン)分の特定画像Im1である。つまり、制御部16は、特定画像Im1について1行単位で前処理を実行する。前処理は、例えば、フィルタリング処理と、二値化処理と、を含む。具体的には、制御部16は、1行分の特定画像Im1について、フィルタリング処理にてノイズ除去等を行い、さらに、ある基準値にて二値化する。
ステップS6において、制御部16は、凹凸特定部22にて、特定画像Im1から明部L1及び暗部L2の少なくとも一方の幅(線幅)を示す幅データを抽出する。このとき、幅データの抽出対象となるのは、ステップS4で取得された1行(1ライン)分の特定画像Im1である。つまり、制御部16は、特定画像Im1について1行単位で幅データの抽出を実行する。具体的には、制御部16は、1行分の特定画像Im1のうち、明部L1に相当する白画素、及び暗部L2に相当する黒画素が何画素ずつあるかを、幅データとして算出する。このとき、制御部16は、1行分の特定画像Im1の全体について、白画素の画素数及び黒画素の画素数を抽出することにより、複数本の明部L1の線幅の合計、及び複数本の暗部L2の線幅の合計を抽出する。
ステップS7において、制御部16は、特定画像Im1の最終行まで処理が完了した否かを判断する。つまり、「N画素×M行」の特定画像Im1については、制御部16は、処理の対象が最終行となるM行目であれば、最終行まで処理が完了したと判断し(S7:Yes)、処理をステップS8に移行させる。一方、制御部16は、処理の対象が最終行となるM行目でなければ、最終行まで処理が完了していないと判断し(S7:No)、処理をステップS4に移行させ、次の1行分の特定画像Im1を取得する。
ステップS8において、制御部16は、凹凸特定部22にて、特定画像Im1のM行分の幅データの標準偏差σを算出する。算術平均高さ(Sa)が大きくなると、表面A1の高さのうねり成分が大きくなるため、明部L1及び暗部L2の各々の線幅のばらつきが大きくなって(図6参照)、標準偏差σが大きくなる。つまり、凹凸特定部22は、標準偏差σを凹凸情報として算出する。
ステップS9において、制御部16は、条件決定部23にて、画像処理条件を決定する。つまり、条件決定部23は、ステップS8で算出された標準偏差σに応じて、画像形成条件を含む画像処理条件を決定する。一例として、標準偏差σが大きくなると、条件決定部23は、定着温度を上げたり、搬送速度を低下させたり、転写電圧を上げたりするように、画像形成条件を設定する。これにより、画像形成部13にてシートSh1に画像が形成される際には、当該シートSh1の表面A1の凹凸に応じた画像形成条件が自動的に適用される。
次に、パターン光P1の照射角度について、所定角度θ1を変えた場合の特定画像Im1の一例を示す図8を参照して説明する。図8では、特定画像Im1の撮像条件として、特定領域R1の算術平均高さ(Sa)が6μm、撮像素子41の解像度(画素数)が100×100、パターン光P1による縞パターンの明部L1の線幅W1を100μm、暗部L2の線幅W2を100μmとする。さらに、パターン光P1の照射方向、つまり明部L1及び暗部L2の並び方向を繊維方向と同一とする。
次に、パターン光P1の線幅について、図9及び図10を参照して説明する。図9は、48種類のシートSh1について、図7のフローチャートに従って算出される凹凸情報としての標準偏差σと、実際の算術平均高さSaとの関係性を示すグラフである。図9では、横軸を算術平均高さSaとし、縦軸を標準偏差σ(標準偏差σは、明部L1又は暗部L2の5箇所の平均値)とする。図9では、特定画像Im1の撮像条件として、撮像素子41の解像度(画素数)が100×100、パターン光P1による縞パターンの明部L1の線幅W1を80μm、暗部L2の線幅W2を80μmとする。さらに、パターン光P1の照射方向、つまり明部L1及び暗部L2の並び方向を繊維方向と同一とする。
次に、格子パターンを生じるパターン光P1について、図11を参照して説明する。つまり、特定領域R1には、パターン光P1が投影されることにより、明部L1及び暗部L2を含む格子パターンの輝度分布が生じる。
次に、特定画像Im1から、シートSh1の表面A1における繊維方向の特定を行うための方法について、図12~図18を参照して説明する。
ここにおいて、シート特定装置2は、一例として、図12に示すように、繊維方向に対する依存性が異なる第1パターン光P11及び第2パターン光P12を含むパターン光P1を利用して、繊維方向を特定する。つまり、光照射部3は、特定画像Im1を形成するに際して、特定領域R1に、シートSh1の表面A1の繊維方向に対する依存性が異なる第1パターン光P11及び第2パターン光P12を投影する。
次に、方向特定部24にて、特定画像Im1に基づいて繊維情報を特定する具体的処理について、図13を参照して説明する。図13に示すフローチャートにおけるステップS11、S12・・・は、制御部16により実行される処理手順(ステップ)の番号を表している。
ステップS11において、制御部16は、凹凸特定部22にて第1パターン光P11の線幅の標準偏差σ1を算出する。ステップS12において、制御部16は、凹凸特定部22にて第2パターン光P12の線幅の標準偏差σ2を算出する。ここで、標準偏差σ1,σ2を求めるために、具体的には、図7のフローチャートで(特にステップS1~S8)で説明した処理と同様の処理が行われる。このようにして、「繊維方向に依存しない」凹凸情報としての標準偏差σ1、及び「繊維方向に依存する」凹凸情報としての標準偏差σ2が導出される。
ステップS13において、制御部16は、第1パターン光P11の線幅の標準偏差σ1と第2パターン光P12の線幅の標準偏差σ2との比較を行って、標準偏差σ1と標準偏差σ2とが一致するか否かを判断する。このとき、制御部16は、方向特定部24にて、標準偏差σ1と、標準偏差σ2に所定値αを加算した値との、大小比較を行う。標準偏差σ1が、標準偏差σ2に所定値αを加えた値より小さければ、方向特定部24は、標準偏差σ1が標準偏差σ2に一致すると判断し(S13:Yes)、処理をステップS14に移行させる。標準偏差σ1が、標準偏差σ2に所定値αを加えた値より大きければ、方向特定部24は、標準偏差σ1が標準偏差σ2に一致しないと判断し(S13:No)、処理をステップS15に移行させる。
ステップS14において、制御部16は、方向特定部24にて、繊維方向が第2縞パターンに直交していると判断する。つまり、第1パターン光P11と第2パターン光P12とで同一の結果(凹凸情報)が得られる場合には、方向特定部24は、繊維方向が第2パターン光P12による第2縞パターンに直交していると判断する。言い換えれば、繊維方向が、第2パターン光P12の明部L1及び暗部L2の並び方向(図12の例では搬送方向D1)と、同一であると判断される。要するに、「繊維方向に依存しない」凹凸情報と「繊維方向に依存する」凹凸情報とが一致することから、第2パターン光P12による第2縞パターンに、表面A1の凹凸が反映されていること、つまり第2縞パターンが繊維方向に直交していることが特定される。
ステップS16において、制御部16は、条件決定部23にて、画像処理条件を決定する。つまり、条件決定部23は、ステップS14,S15で特定された繊維方向に応じて、画像形成条件を含む画像処理条件を決定する。一例として、条件決定部23は、特定された繊維方向に応じてカール方向を予測し、カール矯正のための画像処理条件を設定する。これにより、画像形成部13にてシートSh1に画像が形成される際には、当該シートSh1の表面A1の繊維方向に応じた画像形成条件が自動的に適用される。
以上説明したように、本実施形態では、パターン光P1は、繊維方向に対する依存性が異なる第1パターン光P11及び第2パターン光P12を含む。この場合、方向特定部24は、特定画像Im1における第1パターン光P11と第2パターン光P12との比較結果に基づいて、繊維方向を特定する。これにより、第1パターン光P11及び第2パターン光P12の繊維方向に対する依存性を利用して、比較的簡単な処理で繊維方向を特定可能である。
以下、繊維方向を特定するために用いられるパターン光P1の他の態様を例示する。以下では、図12に示すパターン光P1と同様の点については適宜説明を省略する。
画像処理装置10に含まれる複数の構成要素は、複数の筐体に分散して設けられていてもよい。例えば、シート特定装置2の構成要素である取得部21、凹凸特定部22、条件決定部23、方向特定部24及び厚み特定部25等の少なくとも1つは、制御部16の一機能として実現される構成に限らず、制御部16とは、別の筐体に設けられていてもよい。つまり、シート特定装置2は、画像処理装置10と一体でなくてもよく、シート特定装置2の少なくとも一部が画像処理装置10とは別の筐体に設けられていてもよい。
本実施形態に係る画像処理装置10Aは、図19に示すように、シート特定装置2Aが出力部26を備える点で、実施形態1に係る画像処理装置10と相違する。以下、実施形態1と同様の構成については、共通の符号を付して説明を適宜省略する。
Claims (19)
- 画像の形成対象又は画像の読み取り対象であるシートの表面の特定領域の画像であって前記シートの前記表面の繊維方向の特定に用いられる特定画像を形成するに際して、前記特定領域に、前記繊維方向に対する依存性が異なる第1パターン光及び第2パターン光を投影する光照射部を備える、
シート特定装置。 - 前記第1パターン光と前記第2パターン光とは、前記特定領域上における線幅が異なることで、前記繊維方向に対する依存性が異なる、
請求項1に記載のシート特定装置。 - 前記特定領域上における前記第1パターン光の線幅は100μm以上であって、前記特定領域上における前記第2パターン光の線幅は100μm未満である、
請求項2に記載のシート特定装置。 - 前記繊維方向に基づいて、画像の形成又は画像の読み取りに関する画像処理条件を決定する条件決定部を更に備える、
請求項1に記載のシート特定装置。 - 前記光照射部と前記特定領域の中心とを結ぶ第1仮想直線は、前記シートの搬送方向に沿った第2仮想直線に対して、所定角度で傾斜している、
請求項1に記載のシート特定装置。 - 前記所定角度は、20度以上90度以下である、
請求項5に記載のシート特定装置。 - 前記第1パターン光及び前記第2パターン光は、いずれも前記特定領域上に明部と暗部とが交互に並ぶ縞パターンを形成する、
請求項1に記載のシート特定装置。 - 前記第1パターン光と前記第2パターン光とでは、前記明部及び前記暗部の並び方向が同一である、
請求項7に記載のシート特定装置。 - 前記特定領域は、前記第1パターン光が投影される第1小領域と、前記第2パターン光が投影される第2小領域と、に区分される、
請求項1に記載のシート特定装置。 - 前記光照射部は、
光源と、
前記光源から出力される光の一部を遮ることにより、前記第1パターン光及び前記第2パターン光を透過させる遮蔽体と、を有する、
請求項1に記載のシート特定装置。 - 請求項1に記載のシート特定装置と、
前記シートを対象として、画像の形成と画像の読み取りとの少なくとも一方を実行する画像処理部と、を備える、
画像処理装置。 - 画像の形成対象又は画像の読み取り対象であるシートの表面のうちパターン光が投影されている特定領域の画像である特定画像を取得する取得部と、
前記特定画像に基づいて、前記シートの前記表面の繊維方向を特定する方向特定部と、を備える、
シート特定装置。 - 前記パターン光は、前記繊維方向に対する依存性が異なる第1パターン光及び第2パターン光を含み、
前記方向特定部は、前記特定画像における前記第1パターン光と前記第2パターン光との比較結果に基づいて、前記繊維方向を特定する、
請求項12に記載のシート特定装置。 - 前記第1パターン光と前記第2パターン光とは、前記特定領域上における線幅が異なることで、前記繊維方向に対する依存性が異なる、
請求項13に記載のシート特定装置。 - 前記特定領域上における前記第1パターン光の線幅は100μm以上であって、前記特定領域上における前記第2パターン光の線幅は100μm未満である、
請求項14に記載のシート特定装置。 - 前記方向特定部は、少なくとも前記特定領域上における前記第1パターン光の線幅のばらつきと前記第2パターン光の線幅のばらつきとの比較結果に基づいて、前記繊維方向を特定する、
請求項13に記載のシート特定装置。 - 前記繊維方向に基づいて、画像の形成又は画像の読み取りに関する画像処理条件を決定する条件決定部を更に備える、
請求項12に記載のシート特定装置。 - 前記特定画像に基づいて、前記シートの前記表面の凹凸に関する凹凸情報を特定する凹凸特定部を更に備える、
請求項12に記載のシート特定装置。 - 画像の形成対象又は画像の読み取り対象であるシートの表面のうちパターン光が投影されている特定領域の画像である特定画像を取得することと、
前記特定画像に基づいて、前記シートの前記表面の繊維方向を特定することと、を有する、
シート特定方法。
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JP2004038879A (ja) * | 2002-07-08 | 2004-02-05 | Canon Inc | 映像読取装置及び画像形成装置 |
JP2007078517A (ja) * | 2005-09-14 | 2007-03-29 | Oki Data Corp | 表面平滑性測定装置 |
JP2009300085A (ja) * | 2008-06-10 | 2009-12-24 | Arc Harima Kk | 表面性状測定装置 |
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JP2019191020A (ja) * | 2018-04-26 | 2019-10-31 | 富士ゼロックス株式会社 | 表面特性取得装置、表面特性取得システム及びプログラム |
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JPH1023203A (ja) * | 1996-07-01 | 1998-01-23 | Ricoh Co Ltd | 紙分類装置 |
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JP2007078517A (ja) * | 2005-09-14 | 2007-03-29 | Oki Data Corp | 表面平滑性測定装置 |
JP2009300085A (ja) * | 2008-06-10 | 2009-12-24 | Arc Harima Kk | 表面性状測定装置 |
JP2010250017A (ja) * | 2009-04-14 | 2010-11-04 | Canon Inc | 記録材表面検出装置及びそれを備える画像形成装置 |
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