CN2911653Y - Video tensiometer - Google Patents
Video tensiometer Download PDFInfo
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- CN2911653Y CN2911653Y CN 200620055383 CN200620055383U CN2911653Y CN 2911653 Y CN2911653 Y CN 2911653Y CN 200620055383 CN200620055383 CN 200620055383 CN 200620055383 U CN200620055383 U CN 200620055383U CN 2911653 Y CN2911653 Y CN 2911653Y
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Abstract
The utility model relates to an instrument to measure the deformation in the test of the strength of materials, and is designed to provide a measuring method and a non-touch type instrument using the method, by which the measuring range can multiple. The main technical proposal is that the two pick-up heads form an image shooting part of the video frequency tensiometer, and a guarantee is made that the visual angle of the adjacent two pick-up heads has an overlay area. In the case that the two reticles on the sample are in the measuring range of the first pick-up head, the distance between the two reticles can be determined by an image acquired by the first pick-up head; in the case that reticles on the sample are moved to the visual angle overlay area of the pick-up head, the image switch can be executed. Hereafter, the distance between the lower reticle and the switching position is determined by means of an image acquired by the first pick-up head; the distance between the upper reticle and the switching position is determined by means of an image acquired by the second pick-up head; the distance between the two reticles is determined by adding the two distances above; in the case that the lower reticle of the sample is moved over the switching position, the distance between the two reticles is determined by an image acquired by the second pick-up head.
Description
Technical field
The utility model relates to the method and the instrument of distortion measurement in the materials mechanics experimental, a kind of video tens(i)ometer that is used for contactless large-deformation measuring of saying so more specifically.
Technical background
Some material is rubber for example, and plastics etc. have very big deflection, measures this class distortion of materials amount and be a difficult problem of failing fine solution for a long time in tension test.Adopted following several measuring method at present, and the method for the most extensive employing both at home and abroad is so-called contact type measurement.
1. contact type measurement technology
Contact type measurement will be drawn two graticules earlier on tested sample, use two chucks that stretch out from measuring mechanism to clamp this two graticules respectively then.When these two graticules moved, chuck was promptly driven together and is moved in tension test.When each chuck moves, its other end is by a silk thread, adopt metal or non-metal wire, drive the rotation of a potentiometer or photoelectric encoder, thereby mobile the changing into of chuck measured the required electric potential signal or the position signalling of electric impulse signal or scrambler.Contact type measurement mainly contains following shortcoming:
A) measuring accuracy of influence power
The gravity of chuck component, force measurement precision when the friction force that produces when chuck moves and the chuck edge of a knife can influence tension test to sample institute applied pressure.Although the gravity of chuck component can roughly be eliminated by balance, friction force is difficult to balance.The edge of a knife that the more important thing is chuck can produce stress in the contact site to sample institute applied pressure and concentrate, and sample is ruptured and the appreciable impact test findings in advance.
B) regular meeting skids during the edge of a knife
Especially true to film sample, the edge of a knife is neither programmable too sharp keen again can not be too slick and sly, and too sharp keen then stress is concentrated obviously, and too slyness may be skidded again, therefore often makes the deviser turn round and look at this and lose that.
C) the low and difficult maintenance of precision
Because temperature, humidity, wearing and tearing and the tension and relaxation variation of the caused silk thread of reason such as aging and the variation that length variations can cause measuring accuracy, the therefore low and difficult maintenance of this measuring method precision.
B) life-span is short fragile
Directly act on chuck because the energy when sample is broken discharges the great impact power that is produced, make measuring mechanism damage easily by the edge of a knife.
For addressing the above problem, adopting non-contact measurement is the direction that this field is made great efforts for a long time.
2. non-contact measuring technology
The non-contact measuring technology that is adopted in the large-deformation measuring field of material at present mainly contains three kinds.Be photoelectric tracking, laser scanning and the video tens(i)ometer that began one's study in recent years.
2.1 photoelectric tracking technology
Photoelectric tracking large-deformation measuring instrument is the technology of early developing, and it has two parts that are called as photometer head, and each photometer head is followed the tracks of a graticule.Graticule can be drawn on sample with reflectorized material, but mostly be to make graticule with reflectorized material to be attached to then on the graticule position of sample.Each photometer head can send light beam and receive the light that reflects, the light that reflects is converted into electric signal and handles, thereby the tracking direction and the amount of movement of decision photometer head, and the variable in distance between sample two graticules has just been represented in the relative displacement between two photometer heads.
Photoelectric tracking large-deformation measuring instrument has been developed out a lot year, but fails to obtain widespread use all the time, mainly is because it has following shortcoming:
A) reliability is relatively poor
When graticule was drawn on sample, along with sample is stretched, graticule became more and more wideer and color becomes more and more lighter, thereby influences its reflecting power.In order to address this problem, people have adopted the way of decals line.But along with sample is stretched, the accompanying that part of material of graticule is drawn longer and longer, and graticule usually can come off.Both just do not come off, might move yet, therefore influenced measuring reliability.In addition, the variation of the reflective and illumination of surrounding environment also can influence the reliable rows of its work, usually with losing graticule.
B) complex structure costs an arm and a leg
Because photometer head need be followed the tracks of moving of graticule, therefore must there be accurate servo control mechanism to go accurately to control moving of photometer head.This makes that its structure is very complicated, thereby costs an arm and a leg.
2.2 laser scanning
Laser scanner technique scans tested sample repeatedly by a rotary laser source.Post the reflector marking reflector laser on the sample, the laser extensometer receives the light reflect and calculates distance between graticule according to mistiming of sweep velocity and two graticule reflector lasers.
The advantage of laser scanning extensometer is accurately, but because it also needs to use reflector marking, the problem that therefore also has aforementioned reflector marking and brought.Equally, it also is a complex structure, costs an arm and a leg.
2.3 video tens(i)ometer
In recent years, computer image processing technology and image sensor technologies begin to be applied to the large-deformation measuring field, have caused the birth of video tens(i)ometer.The video tens(i)ometer utilizes video camera or digital camera (can reach per second 50 width of cloth) continuously apace and takes the photo of tested sample and import computing machine by image pick-up card.Special measurement software in the computing machine to the image of input handle with determine two graticules in image the position and be the distance of unit with the pixel between them.Follow again according to the physical length of each pixel representative and determine two actual ranges between graticule.Because the captured image of pick-up lens exists parallax and torsional deformation, causes the physical length difference of each pixel at the diverse location representative, this need install the back at the video tens(i)ometer and determine or correction with means for correcting.
Compare with the laser extensometer with photoelectric tracking large-deformation measuring instrument, the video tens(i)ometer has the following advantages:
A) simple in structure
The video tens(i)ometer does not have servo tracking control without any moving-member, and structure is greatly simplified.
B) reliability greatly improves
The video tens(i)ometer is not abutted against the reflective work of receiving graticule, as long as light is suitable, can takes distinct image and get final product work.Its measurement reliability depends primarily on software to treatment of picture.Because without any moving-member, any problem of being brought of wearing and tearing not, its hardware reliability only depends on the reliability of electronic devices and components.
C) precision is high and stable
The measuring accuracy of video tens(i)ometer depend on imageing sensor along the pixel count of direction of measurement and software to the processing of border pixel grey scale, improve this pixel count and can correspondingly improve the precision of measurement.
D) life-span is long
The life-span of video tens(i)ometer depends primarily on the life-span of electronic devices and components, therefore is particularly suitable for the king-sized occasion of experiment work amount.
E) easy to operate
Can seek graticule automatically.
3. the existing limitation of single-lens video tens(i)ometer on large-deformation measuring
The measurement range of video tens(i)ometer depends on the visual angle of camera lens and the camera lens distance to sample.Because must maintaining a certain distance just with sample, the restriction at camera lens visual angle, video tens(i)ometer can reach certain measurement range when operation.This requirement (＜400 millimeters) when measurement range is not too big does not have problem, but along with the expansion of measurement range, this problem becomes and surfaces.After enlarging, the distance between sample and camera lens can bring two problems:
The first, thus the decline of taken image resolution ratio influences measuring accuracy.Though can adopt more high-resolution camera lens and imageing sensor to go to remedy this loss, but this not only can cause the rapid rising of cost, for high-resolution camera lens and imageing sensor, resolution doubles, the lifting of price will be much larger than one times, but also is subjected to the restriction of device availability.
The second, distance add the increasing that conference causes installing inconvenience and testing machine overall dimensions, compare with contact type measurement, this can be a significant disadvantages.
Want not only to enlarge measurement range but also do not increase distance between camera lens and sample, the visual angle that just must increase camera lens, however the increase at visual angle also has certain limit.Along with the increase at camera lens visual angle, the picture quality of off-center area part can significantly descend, and resolution descends, and torsional deformation increases.Thereby measuring accuracy is significantly descended.
The utility model content
The purpose of this utility model is to provide a kind of distance that neither increases camera lens to sample, does not increase measuring method that the measurement range that makes the video tens(i)ometer under the condition at visual angle of camera lens is multiplied and the instrument that adopts this method again.
The utility model is achieved through the following technical solutions its goal of the invention.
The utility model provides a kind of new video tens(i)ometer, mainly comprises measurement mechanism and computing machine.Be characterized in two or more cameras or digital camera are installed on the camera installation base surface of measurement mechanism, the visual angle of each camera can be identical or different.The installation site of camera on installation base surface makes the visual angle of two adjacent cameras have a little overlapping scope, the size of overlapping scope should be taken into account the parameter dispersiveness at camera lens visual angle, Survey Software makes under worst situation, also to have enough overlapping scopes, so that can realize image switching.During measurement sample is installed on the stretching device of testing machine and stretches, each camera is taken pictures simultaneously continuously.Captured image or handle by being inserted in the Survey Software that image pick-up card in the computing machine is input to computing machine, perhaps handle, then measurement result is sent to the testing machine TT﹠C software in the computing machine by Flame Image Process and measuring system that hardware and firmware constituted.Image processing software is by determining two graticule present positions and the pixel count between them, and the physical length apart from representative between per two pixels of determining during then according to calibration both can calculate two distances between the graticule.Ultimate principle of the present utility model be the image that obtains by a plurality of camera in addition amalgamation enlarge the scope of its measurement, only need obtain the image of each camera successively and comply with measuring process provided by the utility model afterwards all images amalgamation, and by two graticules present position and the pixel count between them in obtaining image, both confirmable actual range between them.The maximum magnitude of measuring deducts overlapping areas for the measurement range addition of all cameras.Adopt this instrument both to need not to increase distance between camera and the measured sample, also need not to enlarge the angular field of view of camera, thereby guaranteed the compactedness of whole surveying instrument structure.Owing to need not to adopt high-quality camera to reduce degree of distortion, greatly reduce cost.And can derive the method that adopts a plurality of cameras to enlarge measurement range according to said method.
For existing large-deformation measuring, two cameras are enough generally speaking, so further scheme of the present utility model is the surveying instrument of a kind of present practicality of design, concrete structure is that two cameras are installed on the camera installation base surface of video tens(i)ometer, and the position of installation makes the visual angle of two cameras have the overlapping region.The maximum magnitude of measuring is that the measurement range addition of two cameras deducts overlapping areas.For guaranteeing to have bigger measurement range and considering the parameter dispersiveness at camera lens visual angle, make under worst situation, also to have enough overlapping scopes, overlapping generally speaking scope be controlled at the camera visual angle 10% in.The process of measuring may further comprise the steps:
1. adopt two cameras to constitute the image taking part of video tens(i)ometer, and guarantee that there is the overlapping region in the visual angle of two cameras;
2. sample is installed, and is guaranteed that two graticules on the sample are positioned at the measurement range of first camera simultaneously;
3. tensile sample;
4. when two graticules on the sample are positioned at the measurement range of first camera, the distance that the image one that is obtained by first camera is determined between two graticules;
5. when the last graticule of sample moves to the overlapping region, visual angle of two cameras, carry out image switching, and be defined as switching position two captured image one and positions in the image two of camera going up graticule this moment;
6. then, the image one that is obtained by first camera is determined the distance between the graticule and switching position down, and the image two that is obtained by second camera determines to go up the distances between graticules and the switching position, determines two distances between the graticule with two apart from addition;
7. when the following graticule of sample also moved switching position, carry out the image switching second time, the distance that the image two that is obtained by second camera is determined between two graticules.
Or:
1. adopt two cameras to constitute the image taking part of video tens(i)ometer, and guarantee that there is the overlapping region in the visual angle of two cameras;
2. when when calibration, below the visual angle of each camera, determine a datum line respectively, and make second datum line in the visual angle of second camera be positioned at the overlapping region to have known fixed range between two datum lines;
3. sample is installed, and is guaranteed that two graticules on the sample are positioned at the measurement range of first camera simultaneously;
4. tensile sample;
5. when two graticules on the sample are positioned at the measurement range of first camera, the distance that the image one that is obtained by first camera is determined between two graticules;
6. when the last graticule of sample moved second datum line, carry out image switching, the image one that is obtained by first camera is determined the distance between the graticule and first datum line down, the image two that is obtained by second camera determines to go up the distances between the graticules and second datum line, and the distance between the last graticule and second datum line is added that distance between two datum lines deducts down distance between the graticule and first datum line and is distance between two graticules;
7. when the following graticule of sample moved switching position, carry out the image switching second time, the distance that the image two that is obtained by second camera is determined between two graticules.
For reducing the workload of computing machine or single-chip microcomputer, improve the speed of measuring, the image of each camera output of the present utility model only is made of 1～200 pixel line in the middle of the horizontal visual angle of camera.Because in the process of measuring, camera obtains image p.s. can be up to tens or even frame up to a hundred, and every width of cloth image all must be sent to computing machine or single-chip microcomputer is handled, and certainly will require very high to the computing power of computing machine or single-chip microcomputer.For the large-deformation measuring instrument, mainly be the fore-and-aft distance of measuring graticule, only need the middle image information of image promptly can determine.Existing single camera video tens(i)ometer also is to obtain to choose Useful Information after the image in the middle of image and handle.But, therefore very high to the processing power requirement of computing machine because it is that entire image is transmitted, and single-chip microcomputer is inefficient substantially.The utility model is directly controlled the intermediate information of a camera output image, therefore need not entire image and transmits, and greatly reduces the treatment capacity of data, even single-chip microcomputer also can obtain between the image for twice at camera and finish treatment of picture.Therefore, the frequency that camera image is obtained can further improve, and helps further improving the precision of measuring.
In the process of measuring, the two ends of the clamp clamps sample by Material Testing Machine, and stretch; Two cameras on the measurement mechanism obtain the image of whole drawing process, and the picture signal of obtaining can be carried out following two kinds of transmission:
First kind is directly image to be sent to computing machine after obtaining image at every turn, is carried out Flame Image Process and is calculated as stated above by computing machine.The hardware configuration that adopts this mode is that described two cameras directly are connected with installation image pick-up card on computers, and the image that obtains by the image pick-up card acquisition camera also is sent to and handles in the computing machine and calculate.
Second kind is directly to carry out Flame Image Process at every turn after obtaining image and calculate as stated above on measurement mechanism, and result of calculation is sent to computing machine does subsequent treatment and output.To be described measurement mechanism be connected with the computing machine that is used to handle measurement data by special Flame Image Process and measuring system the hardware configuration that adopts this mode.Described Flame Image Process and measuring system are integrated by image acquisition hardware and single-chip microcomputer, and camera is connected with Flame Image Process and measuring system, is connected with computing machine by communication interface.Further camera can become one with Flame Image Process and measuring system.The picture that camera obtains is directly handled in single-chip microcomputer and is calculated after being obtained by image acquisition hardware, and last result of calculation is sent in the computing machine, this mode is installed more simple, and helps and different user's Survey Software compatibilities, has wider application surface.
The utility model has following substantive distinguishing features and progress with respect to prior art.
1. the utility model instrument provides bigger measurement range, can measure the bigger material of deflection, and neither increases the distance of camera lens to sample, does not increase the visual angle of camera lens again;
2. the apparatus structure compactness need not to adopt high resolving power, high-precision camera lens also can reach high precision;
3. the production cost of instrument is low, is easy to promote;
4. the center image of output lens only in measuring process greatly reduces data processing amount, has improved the processing speed of computing machine or single-chip microcomputer, helps more high-precision measurement;
5. camera and the direct-connected mode of image pick-up card that is installed in the computing machine, hardware configuration is simple, is easy to realize low production cost;
6. adopt camera and image acquisition hardware and the integrated mode of single-chip microcomputer, use simply, but the instrument independent operation, thereby can be applicable to the measuring system and the Survey Software of different user, application surface is extensive.
Description of drawings
Fig. 1 is for enlarging the synoptic diagram of measurement range to the distance of sample by the expansion camera;
Fig. 2 is for enlarging the synoptic diagram of measurement range by the visual angle that enlarges camera;
Fig. 3 is the structural representation of the utility model video tens(i)ometer;
Fig. 4 is the synoptic diagram of the utility model measuring process;
Fig. 5 is the synoptic diagram of the utility model calibrated ruler;
Fig. 6 is the utility model hardware configuration synoptic diagram;
Fig. 7 A is that the utility model is measured process flow diagram first;
Fig. 7 B is that the utility model is measured the process flow diagram second portion;
Fig. 7 C is that the utility model is measured the process flow diagram third part;
Fig. 8 is the utility model calibration process flow diagram.
Embodiment
Below in conjunction with accompanying drawing the utility model is described further.
The measurement range of video tens(i)ometer depends on the visual angle of camera lens and the camera lens distance to sample.Because must maintaining a certain distance just with sample, the restriction at camera lens visual angle, video tens(i)ometer can reach certain measurement range when operation.This requirement (＜400 millimeters) when measurement range is not too big does not have problem, but along with the expansion of measurement range, what this problem became surfaces, for this problem is described, please referring to Fig. 1.
Suppose that when the visual angle of camera lens was a, its maximum measurement range was A, if adopt the camera lens at same visual angle, want maximum measurement range is expanded to A1 from A that the distance between sample and camera lens just must expand L1 to from L, this can bring two problems:
The first, thus the decline of taken image resolution ratio influences measuring accuracy.Though can adopt more high-resolution camera lens and imageing sensor to go to remedy this loss, but this not only can cause the rapid rising of cost, for high-resolution camera lens and imageing sensor, resolution doubles, the lifting of price will be much larger than one times, but also is subjected to the restriction of device availability.
The second, distance add the increasing that conference causes installing inconvenience and testing machine overall dimensions.Compare with contact type measurement, this can be a significant disadvantages, has caused the not compact of structure.
Want not only to enlarge measurement range but also do not increase distance between camera lens and sample, the visual angle that just must increase camera lens is referring to Fig. 2.When the visual angle when a is increased to β, measurement range is increased to A1 from A.Yet the increase at visual angle also has certain limit.Along with the increase at camera lens visual angle, the picture quality of off-center area part can significantly descend, and resolution descends, and torsional deformation increases, thereby measuring accuracy is significantly descended.
So how could neither increase the distance of camera lens to sample, do not increase again under the condition at visual angle of camera lens the measurement range of video extension meter be multiplied? this problem to be solved in the utility model just.
Fig. 3 is the dual camera large deformation video tens(i)ometer structural representation that the utility model proposed.This instrument is improved on existing single camera video tens(i)ometer, mainly comprises measurement mechanism 1 and computing machine 3.The visual angle that two cameras or digital camera 11 and 12, two cameras have been installed on measurement mechanism 1 can be identical or different.The measurement range A1 and the measurement range A2 that should guarantee two cameras when mounted have a bit of overlapping scope d, as shown in Figure 3.The size of overlapping scope should be taken into account the parameter dispersiveness at camera lens visual angle, makes also to have enough overlapping scopes under worst situation, so that Survey Software can realize image switching.When measuring, sample is positioned on the plane 21.Adopt the clamp clamps sample two ends of testing machine to stretch.Two cameras 11 and 12 are taken pictures simultaneously continuously, captured image or handle by being inserted in the Survey Software that image pick-up card in the computing machine is input to computing machine 3, perhaps handled by Flame Image Process and measuring system 13 that hardware and firmware constituted, the user's TT﹠C software that is sent to computing machine 3 is then handled.
The maximum measurement range Amax of this video tens(i)ometer can be obtained by Fig. 3, supposes that the measurement range of two cameras 11,12 is respectively A1 and A2, and overlapping scope is d, then Amax=A1+A2-d.If A1=A2=A, then Amax=2A-d.Because d is very little with respect to A, therefore, the measurement range of this video tens(i)ometer approximately is the twice of single camera.
The measuring method of video tens(i)ometer of the present utility model can be explained by Fig. 4.In explanation after this, be called as image one by camera 11 captured images, and be called as image two by camera 12 captured images.Inferior 1 and 2 is represented the graticule position in image one and image two respectively among the figure.A among the figure is divided into (a) to view, and (b), (c), (d) four kinds of situations are represented sample 4 four kinds of situations that graticule moves in tension test respectively.
Measuring available following two kinds of methods carries out:
Method 1
When measuring beginning, two graticule a1 on the sample 4 and a1 ' must be positioned at the measurement range A1 of camera 11, i.e. situation (a).In the initial period of tension test, graticule only appears in the image one, and Survey Software is only determined the distance of two graticules by image one, i.e. line segment a1a1 ' is in last graticule moves to overlapping scope d.
When last graticule moves to overlapping scope, i.e. situation (b), Survey Software will be carried out image switching, and promptly the position of determining to go up graticule by image one changes into by image two and determining.Switching can be carried out when any position in graticule moves to overlapping scope d.Software determine to be gone up the position of graticule in image one and image two simultaneously during switching, i.e. b1 ' and b2 ', and this position is defined as the image switching position.After this, b1 ' and b2 ' promptly become the image switching position in image 1 and image 2 respectively, till graticule moves to the image switching position down.
After the switching, i.e. situation (c), Survey Software is determined the position of graticule up and down respectively by image of taking simultaneously two and image one, and calculates the length of line segment c1b1 ' and b2 ' c2 ' respectively.Distance between two graticules then equals this two line segments sum, that is: graticule distance=line segment c1b1 '+line segment b2 ' c2 '.
Along with further stretching, following graticule also enters or has surmounted switching position, i.e. situation (d).Software carries out the image switching second time, and after this, the position of two graticules is all obtained by image two, and the distance between two graticules is recorded by image two fully, i.e. d2d2 '.
Method 2
Method 2 at first will be established two datum line O1 and O2 respectively in image one and image two, as shown in Figure 4.The second datum line O2 must be positioned at overlapping scope d.The first datum line O1 and the second datum line O2 indicate by calibrating installation and established when the calibration video tens(i)ometer by Survey Software, and till after this remaining unchanged when the video tens(i)ometer is calibrated once more.Have known fixed range between O1 line and the O2 line, therefore can be used to set up the contact between image one and the image two.The measuring principle of method 2 is as follows:
When situation (a), two graticules obtain by image one, the distance between graticule equal graticule to the O1 line apart from a1 ' O1 deduct down graticule to the O1 line apart from a1O1.
When in last graticule moves to overlapping scope d, surpassing the O2 line, i.e. situation (b), Survey Software will be carried out image switching, and promptly the position of determining to go up graticule by image one changes into by image two and determining.Switching can surpass any position of O2 line and carry out in overlapping scope d.
After the switching, i.e. situation (c), Survey Software is determined the position of graticule up and down respectively by image of taking simultaneously two and image one.Distance between two graticules then can followingly be calculated: graticule distance=c2 ' O2+O2O1-c1O1, and wherein graticule is to the distance of O2 line in c2 ' the O2 representative, and graticule is to the distance of O1 line down in the c1O1 representative, and O2O1 represents the O2 line to the fixed range between the O1 line.
Instantly graticule also moves to when surpassing the O2 line in the overlapping scope d, i.e. situation (d), and software carries out the image switching second time.After this, two graticules are all determined by image two, the distance between two graticules equal graticule to the O2 line apart from d2 ' O2 deduct down graticule to the O2 line apart from d2O2.
The calibration of video tens(i)ometer of the present utility model
Because phtographic lens exists parallax and torsional deformation, and the used wide-angle lens of large-deformation measuring is particularly remarkable, and therefore, the video tens(i)ometer is calibration earlier after installation.The purpose of calibration is the physical length apart from representative that will determine along between per two pixels of direction of measurement (Pixel).
Calibrated ruler (calibration rod) is adopted in calibration usually.The calibrated ruler that existing video tens(i)ometer is adopted when calibration has two kinds, and a kind of upward drawing has parallel lines, and when taking the image of calibrated ruler with camera, these lines promptly are divided into many sections to the image that photographed along direction of measurement.Because the distance between parallel lines is known, Survey Software only need be determined each section along the pixel count on the direction of measurement, can calculate in the physical length apart from representative between per two pixels on that section.Circular pattern is adopted in another kind of calibrated ruler design, and this calibrated ruler can be calibrated simultaneously along a plurality of directions, but here institute at large-deformation measuring only need the calibration of a direction, adopt this calibrated ruler and inconvenience.
More than the design of two kinds of calibrated rulers all do not possess measuring basis line O1 that indicates image one and image two that said method 2 mentioned and the function of O2.The utility model has designed a kind of new calibration steps, not only can realize above-mentioned functions simply, also the parallel lines calibrated ruler has been done improvement, makes the calibration software design more simple.
As shown in Figure 5, new calibrated ruler adopts chequered with black and white pane to replace parallel lines to remove separate image.A special black block that has white gap is arranged in the middle part.Special color lump has two effects, and the one, when being installed, the video tens(i)ometer helps to adjust overlapping scope; The 2nd, the black and white separatrix below this color lump promptly is the measuring basis line O2 of image two, sees the B enlarged drawing of Fig. 5.The measuring basis line O1 of image one sees the C enlarged drawing of Fig. 5 by article one black and white separatrix representative of the measurement range that enters camera 11.
Take the photo of calibrated ruler during calibration earlier simultaneously with two cameras 11 and 12, then image is sent to Survey Software.Software is begun to calibrate by the bottommost of image one, when running into article one black and white separatrix, just it is asserted the O1 line.When calibration software runs into special black block, to the calibration end of image one.Software transfers to be calibrated image two, and that black and white separatrix below the special black block, just enters article one black and white separatrix of the measurement range of camera 12, is asserted the O2 line.
Black block is not run through in white gap in the middle of special black block, but stays one section black, forms " U " type that lies low.It is poor that the bottom vertical line of " U " type of being somebody's turn to do can be used to the horizontal level of correcting image one and image two.But the correction of horizontal level difference helper applications when specimen width is narrower is being determined the position of graticule in image two fast after the image switching.
New calibrated ruler has the following advantages:
1. adopt chequered with black and white pane to replace parallel lines to remove separate image, make software more simple.When with the parallel lines separate image, software needs to determine earlier the center of each parallel lines, determines the pixel count between two parallel lines then.After adopting the design of black and white piece, software only need determine that the black and white separatrix can determine the pixel count in each section.Determine the black and white separatrix than the center of determining a line come simple.
2. segmentation is more accurate.The lines of parallel lines segmentation must have certain width, and software is identification accurately.The segmentation of black and white piece does not have this requirement.
3. image switching when having realized calibration to the simplicity of design of special black block, the functions such as correction of the horizontal level difference of definite and image one and the image two of measuring basis line O2.
Must be pointed out that calibrated ruler of the present utility model also can be made following modification:
The black and white piece of following the characteristic distributions of the torsional deformation that produces according to camera lens to adopt width not wait.
Adopt panes different colours or different gray scales to replace the black and white piece.
Adopt the special black block of other pattern or use and replace special black block etc. with other rectangular different pane of color of determining.
The utility model has following two kinds of schemes on hardware configuration:
Scheme 1
The simplest embodiment be adopt general binary channels image pick-up card with two with its camera of compatibility mutually.Image pick-up card is inserted the expansion slot of computing machine and the driver that provides with card is installed.Two cameras are installed makes it have the described overlapping scope of the utility model.Remaining task is write software exactly and is carried out Flame Image Process, to realize the described measuring method of the utility model.
Scheme 2
The hardware design of scheme 1 need be opened user's computer and insert image pick-up card and the corresponding driving program is installed.This is not too convenient in the use, and is difficult to incorporate the existing testing machine measurement and control program of user.
Scheme 2 adopts computing machine outside by hardware and is stored in software in the single-chip microcomputer (or digital signal processor) and cooperates and finish basic Flame Image Process, imports measurement result (graticule apart from) in the computing machine user trial machine measurement and control program by RS232 or USB communication interface then.Measurement and control program is then controlled the video tens(i)ometer by RS232 or USB communication interface.
Figure 6 shows that the hardware structure diagram of scheme 2.Camera must be selected the camera with digital signal output for use.The output image of two cameras is deposited in video memory one and two respectively.The address generates and latchs part in order to generate required address signal of memory image and the address signal that latchs from single-chip microcomputer.In the beginning of each width of cloth image output, width of cloth signal pulse is made as the address " 0 ".After this, under the effective condition of the signal of being expert at, each pixel pulse adds 1 with the address in order, thereby deposits value one every trade of each pixel in the image in storer.The capable signal of two cameras is transfused to single-chip microcomputer to determine whether image output finishes.After image storage was finished, single-chip microcomputer then can be chosen image 1 or image 2 is handled by address latch signal and data bus strobe signal.
The shooting of two cameras is passed through I by single-chip microcomputer
2The C bus is controlled fully.Because the Single-chip Controlling camera is only exported centre tens row of each width of cloth image, therefore between the output of two width of cloth images, single-chip microcomputer has time enough to handle the image of being stored.
The measurement process flow diagram of single-chip microcomputer or computer realization the utility model method is shown in Fig. 7 A, 7B and 7C.Measuring process begins, and shown in Fig. 7 A, the RS232 interface between first initialization survey instrument and the computing machine is carried out the preparation that data transmit.Two cameras 11 of initialization and 12 are carried out the preparation of image acquisition and measurement then.Next judge that the order of receiving is measuring command or calibration command or other orders, enters respectively in the subroutine separately.If be process of measurement, survey mark M is set to 1, and image switching sign S1 is initialized as 0, begins to take and memory image.When the piece image storage finishes, judge whether earlier to carry out image switching, promptly whether image switching sign S1 is 1.If image switching sign S1 is not 1, enter modules A, in image one, determine the position of graticule up and down, judge then whether surpass second datum line O2, the words that surpass then are set at 1 with image switching sign S1 if going up graticule.Next calculate the distance of graticule up and down, the output result finishes C.
If image switching sign S1 is 1 in the said process, then enter module B, judge earlier whether the sign of image switching for the second time S2 is 0.If be 0, in image one, determine the subscript line position, judge again whether graticule surpasses O2 down.Following graticule surpasses O2 and then switching mark S2 is made as 1.But no matter descend graticule surpass the O2 line whether all in image two definite on the position of graticule.Next calculate the distance of graticule up and down, the output result finishes C.If judge that the sign of image switching for the second time S2 is not 0, then in image two, determine next to calculate the distance of graticule up and down in graticule position up and down, the output result finishes C.
If receive calibration command, then enter module D.At first two cameras are taken the image of calibrated rulers, and the initial position from image one begins to seek the black and white separatrix then.Record article one black and white separatrix is the first datum line O1.Next order is sought the black and white separatrix in image, if be the separatrix, and the exact position that then defines boundaries, and the calibration value of definite pixel.When running into special black and white piece, the black and white separatrix below it is recorded as the second datum line O2.Stride across white gap then and begin to seek the black and white separatrix in image two, if be the separatrix, calibration until last pixel, is finished in the exact position that then defines boundaries, and the calibration value of definite pixel, gets back to master routine by E and waits for Next Command.
Claims (9)
1. a video tens(i)ometer is characterized in that going up two or more cameras of installation at the camera installation base surface (14) of measurement mechanism (1), and the installation site of camera on installation base surface (14) makes the visual angle of two adjacent cameras have the overlapping region.
2. video tens(i)ometer according to claim 1 is characterized in that two cameras (11,12) are installed on the camera installation base surface of video tens(i)ometer, and the position of installation makes the visual angle of two cameras (11,12) have a little overlapping region.
3. video tens(i)ometer according to claim 2 is characterized in that the image of camera output is made of 1～200 pixel line in the middle of the horizontal visual angle of camera.
4. according to claim 1 or 2 or 3 described video tens(i)ometers, it is characterized in that described overlapping region be controlled at the camera visual angle 10% in.
5. video tens(i)ometer according to claim 4 is characterized in that described measurement mechanism (1) and is used for images acquired and is connected with the computing machine (3) of handling measurement data.
6. video tens(i)ometer according to claim 5, it is characterized in that described camera directly be installed in computing machine (3) on image pick-up card be connected.
7. video tens(i)ometer according to claim 4 is characterized in that described measurement mechanism (1) is connected with the computing machine that is used to handle measurement data (3) by Flame Image Process and measuring system (13).
8. video tens(i)ometer according to claim 7, it is characterized in that described Flame Image Process and measuring system (13) are integrated by image acquisition hardware and single-chip microcomputer or DSP, camera is connected with Flame Image Process and measuring system (13), is connected with computing machine (3) by communication interface.
9. video tens(i)ometer according to claim 8 is characterized in that camera and Flame Image Process and measuring system (13) become one, and is connected with computing machine (3) by communication interface.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100398983C (en) * | 2006-02-27 | 2008-07-02 | 王化谦 | Double-camera video frequency large-deformation measurement method and video frequency extension device based thereon |
| CN103376065A (en) * | 2012-04-26 | 2013-10-30 | 北京隆盛泰科石油管科技有限公司 | Classified bar code extensometer system and method for measuring whole stress-strain curve |
| CN106705874A (en) * | 2015-07-23 | 2017-05-24 | 苏州工业园区职业技术学院 | Machine-vision-technology-based non-contact measurement system for material deformation |
| JPWO2020065815A1 (en) * | 2018-09-27 | 2021-08-30 | 株式会社島津製作所 | Material tester |
-
2006
- 2006-02-27 CN CN 200620055383 patent/CN2911653Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100398983C (en) * | 2006-02-27 | 2008-07-02 | 王化谦 | Double-camera video frequency large-deformation measurement method and video frequency extension device based thereon |
| CN103376065A (en) * | 2012-04-26 | 2013-10-30 | 北京隆盛泰科石油管科技有限公司 | Classified bar code extensometer system and method for measuring whole stress-strain curve |
| CN103376065B (en) * | 2012-04-26 | 2016-06-22 | 北京隆盛泰科石油管科技有限公司 | Class bar code extensometer system and the method measuring Complete stress-strain curve thereof |
| CN106705874A (en) * | 2015-07-23 | 2017-05-24 | 苏州工业园区职业技术学院 | Machine-vision-technology-based non-contact measurement system for material deformation |
| JPWO2020065815A1 (en) * | 2018-09-27 | 2021-08-30 | 株式会社島津製作所 | Material tester |
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