CN111768396A - Distortion measurement method and device of virtual display equipment - Google Patents
Distortion measurement method and device of virtual display equipment Download PDFInfo
- Publication number
- CN111768396A CN111768396A CN202010631071.7A CN202010631071A CN111768396A CN 111768396 A CN111768396 A CN 111768396A CN 202010631071 A CN202010631071 A CN 202010631071A CN 111768396 A CN111768396 A CN 111768396A
- Authority
- CN
- China
- Prior art keywords
- distortion
- coordinate information
- smia
- image
- checkerboard
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000691 measurement method Methods 0.000 title claims description 13
- 238000000034 method Methods 0.000 claims abstract description 23
- 238000004364 calculation method Methods 0.000 claims abstract description 9
- 238000005259 measurement Methods 0.000 claims abstract description 9
- 239000008186 active pharmaceutical agent Substances 0.000 claims description 24
- 238000004422 calculation algorithm Methods 0.000 claims description 15
- 230000002093 peripheral effect Effects 0.000 claims description 9
- 238000004590 computer program Methods 0.000 claims description 6
- 235000005121 Sorbus torminalis Nutrition 0.000 claims description 3
- 244000152100 Sorbus torminalis Species 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims 2
- 238000011156 evaluation Methods 0.000 abstract description 4
- 230000003287 optical effect Effects 0.000 description 29
- 238000010586 diagram Methods 0.000 description 9
- 241000226585 Antennaria plantaginifolia Species 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 240000000136 Scabiosa atropurpurea Species 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000003190 augmentative effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000012938 design process Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/0002—Inspection of images, e.g. flaw detection
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/10—Segmentation; Edge detection
- G06T7/13—Edge detection
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/70—Determining position or orientation of objects or cameras
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/30—Subject of image; Context of image processing
- G06T2207/30168—Image quality inspection
Landscapes
- Engineering & Computer Science (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Quality & Reliability (AREA)
- Testing, Inspecting, Measuring Of Stereoscopic Televisions And Televisions (AREA)
Abstract
The invention discloses a distortion measuring method and a distortion measuring device of virtual display equipment, which divide an image picture acquired from the virtual display equipment into four quadrilateral areas, respectively calculate the TV distortion or/and SMIA TV distortion of each quadrilateral area, and then add absolute values of the distortions of all parts to obtain the total trapezoidal distortion. The distortion measuring method is simple and easy to implement, and can easily realize rapid measurement and evaluation of the trapezoidal distortion by computer-assisted identification and calculation.
Description
Technical Field
The invention relates to the field of virtual reality, in particular to a distortion measuring method and device of virtual display equipment.
Background
Virtual display devices include, but are not limited to, Virtual Reality (VR) technology, Augmented Reality (AR), Mixed Reality (MR), and heads-up display (HUD) and the like. The optical parameters of the device display module directly affect the user experience and comfort, and one important optical parameter is the Distortion (Distortion) of the image. Distortion refers to the squeezing, stretching, shifting, twisting, etc. of the geometric position of image pixels generated during the imaging of the virtual display device relative to a reference system, resulting in changes in the geometric position, size, shape, orientation, etc. of the image.
Distortions include, but are not limited to, Barrel Distortion (Barrel Distortion), pincushion Distortion (pincushion Distortion), Mustache Distortion (Mustache Distortion), Keystone Distortion (Keystone Distortion), or other more complex superposition modalities. Whether the distortion is serious or not can directly influence the use experience of a user. Therefore, in the development and production process, the objective expression of the distortion is one of the core works of the optical module of the virtual display device.
As shown in fig. 1, Barrel Distortion (Barrel Distortion), the relative size of the image becomes progressively smaller from the center point of the image to the edge points of the image, appearing as if a normal size picture were wrapped around a ball. The shape of the water barrel is similar to that of a traditional water barrel, so the name of the water barrel is obtained.
As shown in fig. 2, the Pincushion Distortion (Pincushion Distortion) appears to be effective in that the relative size of the image gradually increases from the center point of the image to the edge point of the image, and a picture of a normal size is attached to the inner wall of the ball. The pillow is shaped like a pillow, so the name is obtained.
As shown in fig. 3, the Mustache Distortion is a mixture of the above two types of Distortion, and may be called a hybrid Distortion. The kind of distortion also changes from barrel distortion to pincushion distortion (or more complex mixture) in the process of spreading from the center to the edges. Just as the straight line in the upper half of the picture becomes like a Mustache shape, we call it "Mustache distortion".
As shown in fig. 4, Keystone Distortion (Keystone Distortion) gradually increases or decreases the relative size of an image from one edge of the image to another edge point, and looks like a trapezoid. So it is called keystone distortion (keystone distortion). Wherein the shape may be an isosceles trapezoid, a right trapezoid, or other irregular trapezoid.
Although some technical solutions for measuring the three distortions have been provided in the prior art, none of the existing distortion measurement methods is suitable for measuring keystone distortion.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a distortion measuring method and device of virtual display equipment, which can objectively evaluate trapezoidal distortion.
The technical scheme of the invention is as follows: there is provided a distortion measuring method of a virtual display device for measuring keystone distortion of the virtual display device, the method comprising the steps of:
t1: acquiring an image picture of virtual display equipment; the image has trapezoidal distortion;
t2: dividing the acquired image frame into four quadrilateral areas, and acquiring coordinate information of four corner points of each quadrilateral area and coordinate information of midpoints of upper and lower sides;
t3: respectively calculating the TV distortion value or/and the SMIA TV distortion value of each quadrilateral area according to the acquired coordinate information of the four corner points of each quadrilateral area and the coordinate information of the middle points of the upper side and the lower side;
t4: adding the absolute values of the TV distortion values or SMIA TV distortion values of the quadrilateral areas calculated in the step T3 to obtain a total trapezoidal distortion value K of the virtual display deviceTVOr/and SMIA TV total distortion value KSMIA。
Further, the dividing the acquired image picture into four quadrilateral areas includes:
the image picture is longitudinally divided into a left quadrilateral area and a right quadrilateral area; when longitudinally dividing, the longitudinally dividing line is a connecting line of the midpoints of the upper bottom edge and the lower bottom edge of the image picture; then transversely dividing the image frame into an upper quadrilateral area and a lower quadrilateral area; when transversely dividing, a transverse dividing line is a connecting line of midpoints of the left side and the right side of the image picture; or the like, or, alternatively,
the image picture is divided into four quadrilateral areas, namely, an upper left quadrilateral area, a lower left quadrilateral area, an upper right quadrilateral area and a lower right quadrilateral area simultaneously by longitudinal division and transverse division; when the transverse division and the longitudinal division are carried out, the transverse division line and the longitudinal division line are respectively connecting lines of midpoints of the left side and the right side and midpoints of the upper side and the lower side.
Further, the acquired image frame is a frame capable of identifying corners, and is a pure color frame or a non-pure color frame.
Further, the image picture is an image picture comprising a checkerboard card.
Furthermore, the image picture of the checkerboard card comprises a plurality of sub-checkerboards which form a plurality of rows and a plurality of columns; the checkerboard card comprises unidentifiable angular points and identifiable angular points, wherein the unidentifiable angular points are angular points of outermost peripheral rows and columns of the whole checkerboard card; the acquiring of coordinate information of four corner points of each quadrilateral region and coordinate information of midpoints of upper and lower sides comprises the following steps:
acquiring corner point coordinates of four corners on the outermost peripheral line and the row of the checkerboard card and corner point coordinates of midpoints of two lines at the head and the tail;
and obtaining coordinate information of the four corner points of the four corners of each quadrilateral region and coordinate information of the midpoints of the upper side and the lower side according to the corner point coordinates of the four corners on the outermost periphery row and the outermost periphery row of the checkerboard card, the corner point coordinates of the midpoints of the head row and the tail row and the coordinates of other identifiable corner points.
Further, the acquiring the corner coordinates of the four corners on the outermost periphery of the checkerboard card and the four corners on the column and the corner coordinates of the middle points of the first row and the last row comprises:
acquiring coordinate information of each identifiable corner point on the checkerboard based on the acquired image picture;
acquiring side length information of the sub-chequers based on coordinate information of each corner point which can be identified by the chequers;
and obtaining the coordinates of the corner points of four corners at the outermost periphery of the checkerboard card and at four corners at the top and the tail of the checkerboard card and the coordinates of the center points of the two lines according to the side length information of the sub-checkerboard and the coordinate information of each recognizable corner point on the checkerboard.
Further, the obtaining of the side length information of the sub-checkerboard based on the coordinate information of each identifiable corner point on the checkerboard includes:
selecting one corner point from the identifiable corner points as a target corner point;
acquiring first coordinate information of the target corner point, and additionally acquiring second coordinate information of at least one corner point on a line where the target corner point is located and third coordinate information of at least one corner point on a column where the target corner point is located;
and determining the side length of the sub-checkerboard according to the relative position relationship among the first coordinate information, the second coordinate information and the third coordinate information of the target corner point.
Further, in step T4, the TV total keystone distortion value K is calculatedTVThe algorithm of (1) is as follows:
KTV＝(|Dleft|+|Dright|+|Dupper|+|Dlower|)×100％；
wherein DleftRefers to the TV distortion value, D, on the left or upper left side of the displayed imagerightRefers to the TV distortion value, D, on the right or upper right side of the displayed imageupperRefers to the TV distortion value, D, of the upper side or lower left side of the displayed image1owerA TV distortion value indicating a lower side or a lower right side of a display image;
calculating the SMIA TV Total distortion value KSMIAThe algorithm of (1) is as follows:
KSMIA＝(|DSleft|+|DSright|+|DSupper|+|DSlower|)×100％；
wherein DSleftIndicates the SMIA TV distortion value, DS, of the left side or upper left side of the display imagerightMeaning SMIA TV distortion value, DS, of the right side or upper right side of the display imageupperSMIA TV distortion value, DS, indicating the upper side or lower left side of a display imagelowerRefers to the SMIA TV distortion value of the lower side or the lower right side of the display image.
The present invention also provides a measuring apparatus for measuring keystone distortion of a virtual display device, comprising:
an acquisition unit configured to acquire an image screen of a virtual display device; the image has trapezoidal distortion; dividing the acquired image frame into four quadrilateral areas, and acquiring coordinate information of four corner points of each quadrilateral area and coordinate information of midpoints of upper and lower sides;
the first calculation unit is used for respectively calculating the TV distortion value or/and the SMIA TV distortion value of each quadrilateral area according to the coordinate information of the four corner points of each quadrilateral area and the coordinate information of the middle points of the upper side and the lower side, which are acquired by the acquisition unit;
a second calculating unit, configured to add the TV distortion values or the absolute values of the SMIA TV distortion values of the quadrilateral areas calculated by the first calculating unit to obtain a total keystone distortion value K of the virtual display deviceTVOr/and SMIATV total distortion value KSMIA。
Further, the present invention also provides a measuring apparatus, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the distortion measuring method of the virtual display device as described above when executing the computer program.
By adopting the scheme, the image picture acquired from the virtual display equipment is divided into four quadrilateral areas, the coordinate information of four corner points of each quadrilateral area and the coordinate information of middle points of the upper side and the lower side are acquired, the TV distortion value or/and the SMIA TV distortion value of each quadrilateral area are calculated, and finally the TV distortion value or/and the absolute value of the SMIA TV distortion value of each quadrilateral area are added to obtain the total trapezoidal distortion value or/and the total SMIA TV distortion value of the virtual display equipment. The distortion measuring method is simple and easy to implement, and can easily realize rapid measurement and evaluation of the trapezoidal distortion by computer-assisted identification and calculation.
Drawings
Fig. 1 is a schematic diagram of barrel distortion.
Fig. 2 is a schematic diagram of pincushion distortion.
Fig. 3 is a schematic diagram of mustache distortion.
Fig. 4 is a schematic diagram of keystone distortion.
Fig. 5 is a schematic diagram of the calculation of the geometric distortion algorithm.
Fig. 6 is a schematic diagram of a checkerboard.
Fig. 7 is a schematic diagram of the calculation of the optical distortion algorithm.
Fig. 8 is a distorted original.
Fig. 9 is a graph of optical distortion fitted to fig. 8.
FIG. 10 is a flow chart of the present invention.
Fig. 11 is a schematic diagram of an image frame divided into four quadrilateral areas, i.e., a left quadrilateral area, a right quadrilateral area, an upper quadrilateral area and a lower quadrilateral area.
Fig. 12 is a schematic diagram of an image frame divided into four quadrilateral areas of upper left, lower left, upper right and lower right.
Fig. 13 is a flowchart of step T2.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments.
In the prior art, there are two existing solutions to measure the three distortions.
The first algorithm, the geometric distortion algorithm, can evaluate barrel distortion and pincushion distortion well. The representative algorithm is a TV distortion/SMIA TV distortion algorithm, which is a distortion measuring scheme widely used on an optical complete machine (such as a camera and the like). Since such optical machines have rectangular image sensors (CMOS, CCD, etc.), it is necessary to evaluate the rectangular output image, as shown in figure 5,
the distortion scheme is calculated on a checkerboard using a suitable graphic card, such as a checkerboard, as shown in fig. 6, and the TV distortion and SMIA TV distortion are calculated by substituting equations by identifying the six corner points. SMIA TV distortion is an emerging standard commonly used in international standards in recent years, and the measuring mode is more reasonable and accurate. Ideally the SMIA TV distortion is equal to 2 times the TV distortion.
The second algorithm, the optical distortion algorithm, can evaluate barrel-shaped and pillow-shaped distortions and can better display the form of the beard-shaped distortion, and is generally a distortion measurement scheme widely used in optical design and optical elements (such as an independent lens without an image sensor). Since such optical elements are rotationally symmetric about the optical axis in design, the distortion is the same for each radial direction (radial direction) extending outward from the optical center. Generally expressed in percentages, wherein a percentage is defined as: the number of pixels deviated is divided by the total number of pixels in the same direction, see figure 7,
optical distortion is difficult to measure, and often a third-order or fifth-order equation is required to fit a distortion curve. For example, fig. 8 and 9 are examples, fig. 8 is an original, and fig. 9 is a fitted optical distortion curve.
Because the optical distortion measurement is difficult, the geometric distortion (TV distortion/SMIA TV distortion) is mostly used for measuring optical finished products (image sensors with rectangles) in the industry; optical distortion is mainly used more in the optical design process, individual optical elements (such as lenses without image sensors) because the optical system is rotationally symmetric.
At the present stage, the first three distortions (barrel distortion, pillow distortion, and beard distortion) have mature schemes and measurement standards to objectively determine whether the distortion of an optical system is good or bad, and only the keystone distortion has no good measurement method so far, and the measurement methods of the first three distortions cannot be used. The reason for this is that conventional optical systems are basically rotationally symmetric systems (e.g., lenses) around the optical axis, and in the rotationally symmetric optical systems, barrel, pillow, and beard distortions occur in most cases, and keystone distortion hardly occurs. There has been no need for a quantitative and objective determination.
However, with the advent of virtual display technology, many optical systems are not designed according to the traditional rotational symmetry (such as free-form optical and aspheric surface folding optical systems), and sometimes the keystone distortion occurs. However, there is no objective evaluation scheme for keystone distortion, and the optical system can be evaluated only by naked eyes, which is a state that needs to be changed urgently.
Because no mature measuring method is available for objectively evaluating the trapezoidal distortion, the invention provides a distortion measuring method of virtual display equipment, and the trapezoidal distortion value can be calculated through the algorithm. Referring to fig. 10, the distortion measuring method includes the following steps:
t1: and acquiring an image picture of the virtual display equipment, wherein the image picture has trapezoidal distortion, and the image picture can be a pure color picture or a non-pure color picture as long as a corner can be identified. The image picture comprises an image picture of a checkerboard card displayed by the virtual display device. The checkerboard card comprises a plurality of sub-checkerboards which form a plurality of rows and a plurality of columns, the sub-checkerboard is the smallest unit checkerboard in the checkerboard card, and the size of each sub-checkerboard is the same.
T2: dividing the image picture obtained in the step T1 into four quadrilateral areas, and obtaining coordinate information of four corner points of each quadrilateral area and coordinate information of midpoints between the upper side and the lower side;
t3: and respectively calculating the TV distortion value or/and the SMIA TV distortion value of each quadrilateral area according to the acquired coordinate information of the four corner points of each quadrilateral area and the coordinate information of the middle points of the upper side and the lower side.
T4: adding the absolute values of the TV distortion values or SMIA TV distortion values of the quadrilateral areas calculated in the step T3 to obtain the total TV trapezoidal distortion number of the virtual display equipmentValue KTVOr/and SMIA TV total distortion value KSMIA。
In step T2, there are the following two dividing methods in dividing the acquired image picture into four quadrangular regions:
the first method comprises the following steps: as shown in fig. 11, the acquired image frame is divided into four quadrilateral areas, namely, a left quadrilateral area, a right quadrilateral area, an upper quadrilateral area and a lower quadrilateral area, and the dividing steps are as follows:
the checkerboard card of the image picture is longitudinally divided into a left quadrilateral area and a right quadrilateral area. When longitudinally dividing, the longitudinally dividing line is a connecting line of the midpoints of the upper side and the lower side of the checkerboard card image picture; and then transversely dividing the checkerboard card of the image picture into an upper quadrilateral area and a lower quadrilateral area. When transversely dividing, the transverse dividing line is a connecting line of the midpoints of the left side and the right side of the chessboard pattern card image picture.
And the second method comprises the following steps: as shown in fig. 12, the checkerboard card of the acquired image picture is divided into four quadrilateral areas, namely, an upper left quadrilateral area, a lower left quadrilateral area, an upper right quadrilateral area and a lower right quadrilateral area, and the dividing steps are as follows:
and simultaneously, longitudinally dividing and transversely dividing the checkerboard card into four quadrilateral areas, namely, an upper left quadrilateral area, a lower left quadrilateral area, an upper right quadrilateral area and a lower right quadrilateral area. When the chessboard pattern card is divided horizontally and longitudinally, the horizontal dividing line and the longitudinal dividing line are respectively the connecting lines of the midpoints of the left side and the right side and the midpoints of the upper side and the lower side of the chessboard pattern card image picture.
After dividing the image picture into four quadrilateral areas by the two methods, respectively calculating the total TV trapezoidal distortion value K of each quadrilateral areaTVOr/and SMIA TV total distortion value KSMIA。
Wherein, the total trapezoidal distortion value K of TV is calculatedTVThe algorithm of (1) is as follows:
KTV＝(|Dleft|+|Dright|+|Dupper|+|Dlower|)×100％；
wherein Dleft refers to the TV distortion value on the left or upper left side of the display image, DrightRefers to the TV distortion value, D, on the right or upper right side of the displayed imageupperRefers to the TV distortion value, D, of the upper side or lower left side of the displayed image1owerRefers to a TV distortion value on the lower side or lower right side of the display image.
Wherein the SMIA TV total distortion value K is calculatedSMIAThe algorithm of (1) is as follows:
KSMIA＝(|DSleft|+|DSright|+|DSupper|+|DSlower|)×100％；
in the above formula, DSleftIndicates the SMIA TV distortion value, DS, of the left side or upper left side of the display imagerightMeaning SMIA TV distortion value, DS, of the right side or upper right side of the display imageupperSMIA TV distortion value, DS, indicating the upper side or lower left side of a display imagelowerRefers to the SMIA TV distortion value of the lower side or the lower right side of the display image.
To calculate the total trapezoidal distortion value K of TVTVOr SMIA TV total distortion value KSMIAFirst, the TV distortion value or SMIA TV distortion value of each quadrilateral area is calculated.
Wherein, the formula for calculating the TV distortion value is as follows:
the formula for calculating the SMIA TV distortion value is as follows:
wherein AB and EF represent the vertical dimension of the connecting line of corner points of each area, and CD represents the vertical dimension of the connecting line of midpoints at the upper side and the lower side of each area.
When the image frame is an image frame of a checkerboard card, it is known that the checkerboard card includes a plurality of black and white sub-checkerboards, thereby forming array corners in a plurality of rows and columns. Due to the edge contrast, the coordinate information of the corner points on the outermost periphery and the upper column of the whole image picture cannot be directly analyzed and obtained according to the obtained image picture of the checkerboard card, and the corner points cannot be identified. Except the corner points on the outermost peripheral rows and columns of the checkerboard card, the coordinate information of the other corner points can be directly obtained, and the corner points are identifiable corner points, namely the corner points positioned in the checkerboard card. That is, when coordinate information of an identifiable corner point on a checkerboard in an image is acquired, any corner point coordinate on a middle row and column can be directly identified except that the coordinate information cannot be determined because the corner point coordinates on the outermost peripheral row and column cannot be accurately distinguished from the background color. That is, the coordinates of the corner points on the remaining rows and columns can be identified except that the coordinates of the corner points on the 1 st row, the 1 st column, the nth row and the mth column can not be identified. That is, for a checkerboard with n rows and m columns, the corner coordinates of the remaining rows and columns can be identified except that the corner coordinates of the 1 st row, the 1 st column, the n th row and the m th column cannot be identified. Wherein n is the number of lines of the checkerboard card; m is the number of columns of the checkerboard card. At this time, if the keystone distortion under 100% of the field of view needs to be acquired, coordinate information of the outermost peripheral line and the upper corner point of the checkerboard card needs to be fitted by other methods.
After the whole checkerboard card is divided into 4 quadrilateral areas, when coordinate information of four corner points of each quadrilateral area and coordinate information of middle points of the upper side and the lower side are obtained, because some corner points in the quadrilateral areas are positioned in the whole checkerboard card, the coordinate information can be directly obtained. Some angular points are positioned at the periphery of the whole checkerboard card and cannot be directly obtained. Therefore, when coordinate information of four corner points of each quadrilateral area and coordinate information of middle points of the upper and lower sides are obtained, it can be considered that the corner point coordinates of the four corners on the outermost periphery and the column of the checkerboard card and the corner point coordinates of the middle points of the two rows of the head and the tail are obtained first, and then the coordinate information of the four corner points of each quadrilateral area and the coordinate information of the middle points of the upper and lower sides are obtained according to the corner point coordinates of the four corners on the outermost periphery and the column of the checkerboard card, the corner point coordinates of the middle points of the two rows of the head and the tail and the coordinates of.
Referring to fig. 13, when obtaining the coordinates of the corner points of the four corners on the outermost row and the four corners on the column of the checkerboard card and the coordinates of the corner points of the middle points of the first two rows and the last two rows, the specific method is as follows:
step T201: and acquiring coordinate information of each identifiable corner point on the checkerboard based on the acquired image picture.
Step T202: and acquiring the side length information of the sub-chequer based on the coordinate information of each corner point which can be identified by the chequer.
When the method is specifically operated, the implementation steps comprise:
selecting one corner point from the identifiable corner points as the target corner point; when selecting the target corner point, any recognizable corner point can be selected as the target corner point. For example, in one embodiment, the corner point of the second row and the second column in the checkerboard card is used as the target corner point, or the corner point of the (n-1) th row and the (m-1) th column in the checkerboard card is used as the target corner point.
Acquiring first coordinate information of the target corner point; and additionally acquiring second coordinate information of at least one corner point on the row where the target corner point is located and third coordinate information of at least one corner point on the column where the target corner point is located, so as to determine side length information of the sub-checkerboard according to the relative position relationship between the second coordinate information, the third coordinate information and the first coordinate information (for example, according to the number information and the coordinate information of each corner point).
And finally, determining the side length of the sub-checkerboard according to the relative position relationship among the first coordinate information of the target corner point, the second coordinate information and the third coordinate information.
And determining the length and the width of the sub-checkerboard according to the relative position relationship among the first coordinate information, the second coordinate information and the third coordinate information of the target corner point. For example, the coordinates of the three corner points are (a, b), (c, b), and (a, d), the first side length information m of the checkerboard is (c-a)/K1, and the second side length information n of the checkerboard is (d-b)/K2. Wherein, K1, K2 are used for identifying the relative position relation or number information between three corner points. The values of m and n may be the same or different, the values of m and n are the same when the checkerboard grid is square, and the values of m and n are different when the checkerboard grid is rectangular.
T203: and obtaining the coordinates of the corner points of four corners at the outermost periphery of the checkerboard card and at four corners at the top and the tail of the checkerboard card and the coordinates of the center points of the two lines according to the side length information of the sub-checkerboard and the coordinate information of each recognizable corner point on the checkerboard.
After the side length information of the sub-checkerboards is obtained, in order to obtain the coordinate information of the unidentifiable angular points in the checkerboard card, the coordinate information of the angular points on the outermost peripheral sub-checkerboard in the checkerboard card, which are associated with the unidentifiable angular points, needs to be additionally obtained. Wherein the coordinate information of the corner point associated with the unrecognizable corner point may be: coordinate information of a corner point belonging to the same row, column or diagonal as the unrecognizable corner point. It will be appreciated that the coordinate information of the corner point associated with the non-identifiable corner point may comprise or may be calculated from the coordinate information of the identifiable corner point as described above.
Finally, respectively substituting the coordinate information of the four corner points of each quadrilateral area and the coordinate information of the middle points of the upper side and the lower side into a TV distortion formula and a SMIA TV distortion formula to obtain the TV distortion value and the SMIA TV distortion value of each quadrilateral area, and finally adding the TV distortion value or the absolute value of the SMIA TV distortion value of each quadrilateral area to obtain a TV trapezoidal total distortion numerical value KTVOr SMIA TV total distortion value KSMIA。
The present invention also provides a measuring apparatus for measuring keystone distortion of a virtual display device, comprising:
an acquisition unit configured to acquire an image screen of a virtual display device; the image has trapezoidal distortion; dividing the acquired image frame into four quadrilateral areas, and acquiring coordinate information of four corner points of each quadrilateral area and coordinate information of midpoints of upper and lower sides;
the first calculation unit is used for respectively calculating the TV distortion value or/and the SMIA TV distortion value of each quadrilateral area according to the coordinate information of the four corner points of each quadrilateral area and the coordinate information of the middle points of the upper side and the lower side, which are acquired by the acquisition unit;
a second calculation unit for calculating the TV distortion value orAdding absolute values of distortion values of SMIA TV to obtain total trapezoidal distortion value K of the virtual display equipmentTVOr/and SMIATV total distortion value KSMIA。
The present invention also provides a measuring apparatus comprising: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, the processor when executing the computer program implementing the steps in any of the various virtual image distance measurement method embodiments described above.
In application, the measuring device may be a desktop computer, an industrial personal computer, a super mobile personal computer, a notebook computer, a palm computer, a tablet computer, a mobile phone, a personal digital assistant, a cloud server, and the like. The measurement device may include, but is not limited to, a processor, a memory. The measurement apparatus may include more or fewer components than those shown, or some of the components may be combined, or different components may include, for example, input-output devices, network access devices, etc.
In summary, the present invention divides the image frame acquired from the virtual display device into four quadrilateral areas, acquires the coordinate information of the four corner points of each quadrilateral area and the coordinate information of the middle points of the upper and lower sides, respectively calculates the TV distortion value or/and the SMIA TV distortion value of each quadrilateral area, and finally adds the TV distortion value or/and the absolute value of the SMIA TV distortion value of each quadrilateral area to obtain the total keystone distortion value or/and the total SMIA TV distortion value of the virtual display device. The distortion measuring method is simple and easy to implement, and can easily realize rapid measurement and evaluation of the trapezoidal distortion by computer-assisted identification and calculation.
The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A distortion measurement method of a virtual display device, for measuring keystone distortion of the virtual display device, the method comprising the steps of:
t1: acquiring an image picture of virtual display equipment; the image has trapezoidal distortion;
t2: dividing the acquired image frame into four quadrilateral areas, and acquiring coordinate information of four corner points of each quadrilateral area and coordinate information of midpoints of upper and lower sides;
t3: respectively calculating the TV distortion value or/and the SMIA TV distortion value of each quadrilateral area according to the acquired coordinate information of the four corner points of each quadrilateral area and the coordinate information of the middle points of the upper side and the lower side;
t4: adding the absolute values of the TV distortion values or SMIA TV distortion values of the quadrilateral areas calculated in the step T3 to obtain a total trapezoidal distortion value K of the virtual display deviceTVOr/and SMIA TV total distortion value KSMIA。
2. The distortion measurement method of a virtual display device according to claim 1, wherein the dividing the acquired image screen into four quadrangular regions comprises:
the image picture is longitudinally divided into a left quadrilateral area and a right quadrilateral area; when longitudinally dividing, the longitudinally dividing line is a connecting line of the midpoints of the upper side and the lower side of the image picture; then transversely dividing the image frame into an upper quadrilateral area and a lower quadrilateral area; when transversely dividing, a transverse dividing line is a connecting line of midpoints of the left side and the right side of the image picture; or the like, or, alternatively,
the image picture is divided into four quadrilateral areas, namely, an upper left quadrilateral area, a lower left quadrilateral area, an upper right quadrilateral area and a lower right quadrilateral area simultaneously by longitudinal division and transverse division; when the transverse division and the longitudinal division are carried out, the transverse division line and the longitudinal division line are respectively connecting lines of midpoints of the left side and the right side and midpoints of the upper side and the lower side.
3. The distortion measurement method of a virtual display device according to claim 1, wherein the acquired image picture is a picture in which a corner can be identified, which is a solid color picture or a non-solid color picture.
4. The distortion measurement method of a virtual display apparatus according to claim 3, wherein the image picture is an image picture including a checkerboard card.
5. The distortion measurement method of the virtual display apparatus according to claim 4, wherein the image screen of the checkerboard card includes a plurality of sub-checkerboards forming a plurality of rows and a plurality of columns; the checkerboard card comprises unidentifiable angular points and identifiable angular points, wherein the unidentifiable angular points are angular points of outermost peripheral rows and columns of the whole checkerboard card; the acquiring of the coordinate information of the four corner points of each quadrilateral region and the coordinate information of the middle points of the upper side and the lower side comprises the following steps:
acquiring corner point coordinates of four corners on the outermost peripheral line and the row of the checkerboard card and corner point coordinates of midpoints of two lines at the head and the tail;
and obtaining coordinate information of the four corner points of the four corners of each quadrilateral region and coordinate information of the midpoints of the upper side and the lower side according to the corner point coordinates of the four corners on the outermost periphery row and the outermost periphery row of the checkerboard card, the corner point coordinates of the midpoints of the head row and the tail row and the coordinates of other identifiable corner points.
6. The distortion measurement method of the virtual display device according to claim 5, wherein the acquiring corner coordinates of four corners on the outermost peripheral row and the column of the checkerboard card and the corner coordinates of the middle points of the first two rows and the last two rows comprises:
acquiring coordinate information of each identifiable corner point on the checkerboard based on the acquired image picture;
acquiring side length information of the sub-chequers based on coordinate information of each corner point which can be identified by the chequers;
and obtaining the coordinates of the corner points of four corners at the outermost periphery of the checkerboard card and at four corners at the top and the tail of the checkerboard card and the coordinates of the center points of the two lines according to the side length information of the sub-checkerboard and the coordinate information of each recognizable corner point on the checkerboard.
7. The distortion measurement method of the virtual display device according to claim 6, wherein the obtaining of the side length information of the sub-checkerboard based on the coordinate information of each identifiable corner point on the checkerboard comprises:
selecting one corner point from the identifiable corner points as a target corner point;
acquiring first coordinate information of the target corner point, and additionally acquiring second coordinate information of at least one corner point on a line where the target corner point is located and third coordinate information of at least one corner point on a column where the target corner point is located;
and determining the side length of the sub-checkerboard according to the relative position relationship among the first coordinate information, the second coordinate information and the third coordinate information of the target corner point.
8. The distortion measuring method of claim 1, wherein in step T4, the TV total keystone distortion value K is calculatedTVThe algorithm of (1) is as follows:
KTV＝(|Dleft|+|Dright|+|Dupper|+|Dlower|)×100％；
wherein DleftRefers to the TV distortion value, D, on the left or upper left side of the displayed imagerightRefers to the TV distortion value, D, on the right or upper right side of the displayed imageupperRefers to the TV distortion value, D, of the upper side or lower left side of the displayed image1owerA TV distortion value indicating a lower side or a lower right side of a display image;
calculating the SMIA TV Total distortion value KSMIAThe algorithm of (1) is as follows:
KSMIA＝(|DSleft|+|DSright|+|DSupper|+|DSlower|)×100％；
wherein DSleftIndicates the SMIA TV distortion value, DS, of the left side or upper left side of the display imagerightFinger display image right side orUpper right SMIA TV distortion value, DSupperSMIA TV distortion value, DS, indicating the upper side or lower left side of a display imagelowerRefers to the SMIA TV distortion value of the lower side or the lower right side of the display image.
9. A measurement apparatus for measuring keystone distortion of a virtual display device, comprising:
an acquisition unit configured to acquire an image screen of a virtual display device; the image has trapezoidal distortion; dividing the acquired image frame into four quadrilateral areas, and acquiring coordinate information of four corner points of each quadrilateral area and coordinate information of midpoints of upper and lower sides;
the first calculation unit is used for respectively calculating the TV distortion value or/and the SMIA TV distortion value of each quadrilateral area according to the coordinate information of the four corner points of each quadrilateral area and the coordinate information of the middle points of the upper side and the lower side, which are acquired by the acquisition unit;
a second calculating unit, configured to add the TV distortion values or the absolute values of the SMIA TV distortion values of the quadrilateral areas calculated by the first calculating unit to obtain a total keystone distortion value K of the virtual display deviceTVOr/and SMIA TV total distortion value KSMIA。
10. A measuring apparatus comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements a distortion measuring method of a virtual display device according to any one of claims 1 to 8 when executing the computer program.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010631071.7A CN111768396B (en) | 2020-07-03 | 2020-07-03 | Distortion measurement method and device for virtual display equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010631071.7A CN111768396B (en) | 2020-07-03 | 2020-07-03 | Distortion measurement method and device for virtual display equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111768396A true CN111768396A (en) | 2020-10-13 |
| CN111768396B CN111768396B (en) | 2024-02-09 |
Family
ID=72723588
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010631071.7A Active CN111768396B (en) | 2020-07-03 | 2020-07-03 | Distortion measurement method and device for virtual display equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111768396B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112465760A (en) * | 2020-11-19 | 2021-03-09 | 深圳惠牛科技有限公司 | Checkerboard corner point identification method, device, equipment and storage medium |
| CN113570517A (en) * | 2021-07-20 | 2021-10-29 | 杨建弘 | Method for correcting two-dimensional graph of part, part measuring method and system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105447871A (en) * | 2015-12-04 | 2016-03-30 | 北京和众视野科技有限公司 | Distortion correction algorithm of fixed focus imaging system |
| CN105869142A (en) * | 2015-12-21 | 2016-08-17 | 乐视致新电子科技（天津）有限公司 | Method and device for testing imaging distortion of virtual reality helmets |
| US20170161951A1 (en) * | 2015-12-08 | 2017-06-08 | Oculus Vr, Llc | Autofocus virtual reality headset |
| CN110049314A (en) * | 2019-04-19 | 2019-07-23 | 信利光电股份有限公司 | Utilize the method and device of gridiron pattern test table detection mould group TV distortion |
| CN110677634A (en) * | 2019-11-27 | 2020-01-10 | 成都极米科技股份有限公司 | Trapezoidal correction method, device and system for projector and readable storage medium |
| CN110996083A (en) * | 2019-12-19 | 2020-04-10 | 成都极米科技股份有限公司 | Trapezoidal correction method and device, electronic equipment and readable storage medium |
-
2020
- 2020-07-03 CN CN202010631071.7A patent/CN111768396B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105447871A (en) * | 2015-12-04 | 2016-03-30 | 北京和众视野科技有限公司 | Distortion correction algorithm of fixed focus imaging system |
| US20170161951A1 (en) * | 2015-12-08 | 2017-06-08 | Oculus Vr, Llc | Autofocus virtual reality headset |
| CN105869142A (en) * | 2015-12-21 | 2016-08-17 | 乐视致新电子科技（天津）有限公司 | Method and device for testing imaging distortion of virtual reality helmets |
| CN110049314A (en) * | 2019-04-19 | 2019-07-23 | 信利光电股份有限公司 | Utilize the method and device of gridiron pattern test table detection mould group TV distortion |
| CN110677634A (en) * | 2019-11-27 | 2020-01-10 | 成都极米科技股份有限公司 | Trapezoidal correction method, device and system for projector and readable storage medium |
| CN110996083A (en) * | 2019-12-19 | 2020-04-10 | 成都极米科技股份有限公司 | Trapezoidal correction method and device, electronic equipment and readable storage medium |
Non-Patent Citations (1)
| Title |
|---|
| 杨帆: "可估量曲面的自主感知与多投影校正技术研究", 《中国博士学位论文全文数据库 信息科技辑》, no. 03, pages 1 - 159 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112465760A (en) * | 2020-11-19 | 2021-03-09 | 深圳惠牛科技有限公司 | Checkerboard corner point identification method, device, equipment and storage medium |
| CN112465760B (en) * | 2020-11-19 | 2024-06-28 | 深圳惠牛科技有限公司 | Checkerboard extrinsic angular point identification method, device, equipment and storage medium |
| CN113570517A (en) * | 2021-07-20 | 2021-10-29 | 杨建弘 | Method for correcting two-dimensional graph of part, part measuring method and system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111768396B (en) | 2024-02-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6166852B1 (en) | Method and system for measuring lens distortion | |
| CN104363986B (en) | A kind of image processing method and equipment | |
| EP2849149B1 (en) | Projection system, image processing device, and projection method | |
| KR101579876B1 (en) | Image processing apparatus, image processing method, and computer readable medium | |
| CN106815869B (en) | Optical center determining method and device of fisheye camera | |
| CN106648510B (en) | The display methods and device of a kind of display resolution | |
| US9183634B2 (en) | Image processing apparatus and image processing method | |
| CN105141838B (en) | Demosaicing methods and the device for using this method | |
| CN111768396B (en) | Distortion measurement method and device for virtual display equipment | |
| CN113344986B (en) | Point cloud registration result evaluation method, device, equipment and storage medium | |
| CN107071376A (en) | One kind projection tiled display bearing calibration and device | |
| KR20100038168A (en) | Composition analysis method, image device having composition analysis function, composition analysis program, and computer-readable recording medium | |
| US9269004B2 (en) | Information processing terminal, information processing method, and program | |
| US10516822B2 (en) | Method and device for merging images of calibration devices | |
| TWI443604B (en) | Image correction method and image correction apparatus | |
| JP7432793B1 (en) | Mapping methods, devices, chips and module devices based on three-dimensional point clouds | |
| CN106340062B (en) | A kind of generation method and device of three-D grain model file | |
| CN113052912A (en) | Camera calibration method and device | |
| TWI462027B (en) | Image processing device and image processing method thereof | |
| CN111768395B (en) | Distortion measurement method and device for virtual display equipment | |
| JP5955003B2 (en) | Image processing apparatus, image processing method, and program | |
| JP6906177B2 (en) | Intersection detection device, camera calibration system, intersection detection method, camera calibration method, program and recording medium | |
| CN111551346B (en) | Method, device and system for measuring field angle and computer storage medium | |
| JP5645448B2 (en) | Image processing apparatus, image processing method, and program | |
| JP3204175U (en) | Image matching device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |