CN103837085B - The displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise and method - Google Patents
The displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise and method Download PDFInfo
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Abstract
The displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise and method, belong to micro-displacement detection technique field.The present invention is to solve that existing vision-based detection measures the system detection method to target micrometric displacement, the problem that the measurement result precision that exists is low.Device includes high speed CCD camera, laser tracker and diffuse-reflectance projection screen, and object moves on diffuse-reflectance projection screen；Method is primarily based on imaging point and the principle of the object fixed point conjugation of laser tracker acquisition of object fixed point, sets up corresponding relation look-up table；Then adopting high speed CCD camera screen hot spot imaging to object successively, it is thus achieved that the conjugate point of object subpoint, the calculation method obtaining or tabling look-up in conjunction with bilinear interpolation of tabling look-up obtains the coordinate figure that object subpoint is fastened at projection screen coordinate.The present invention is used for measuring displacement of targets vector.
Description
Technical field
The present invention relates to the displacement of targets device for measuring vector quantity based on laser tracker pointwise demarcation and method, belong to micro-displacement detection technique field.
Background technology
Micro-displacement detection technique is significant in modern precision fields of measurement, by the high-acruracy survey to micro-displacement, and in conjunction with the structural parameters of space layout, it is possible to complete the accurate measurement to a series of important parameters such as angle, speed, linearity, flatnesses.It can be also used for assessing the control accuracy of all kinds of existing instruments simultaneously, it is possible to detection objective body mobile accuracy in space.
The displacement measuring technology that precision is higher in the world at present is double-frequency laser interferometry method, and its displacement accuracy recorded is nanoscale.But this method can only measure the one-dimensional scalar shift value of prism of corner cube, it is impossible to measuring two-dimensional vector shift value, and can not follow the tracks of concrete target in kind, visual field is only small, has bigger limitation on using.
At present in fields of measurement, generally adopt vision detection technology that the positional information of space object is measured, this measuring method cost is low, precision is high, visual field is big, and it is easily installed transport, strong adaptability, then coordinate high-precision image processing algorithm namely can realize the high speed to objective body, on a large scale and high-precision location and displacement measuring and calculating.
In typical vision-based detection measurement scheme, if the displacement of the lines vector of thing side is measured by the optical imagery equation adopting perspective model, this measurement system is generally made up of light source, camera lens, ccd video camera, image collecting device and image processing software, and it calculates the space position parameter of object by visual imaging theory.Measuring principle is as shown in Figure 2.
The principle of typical vision measurement displacement is: ccd video camera utilizes camera lens that the object point A on object plane screen is carried out imaging, forms picture point B in CCD image planes.When target object point on screen from A1Point moves to A2Point, then imaging point in CCD image planes from B1Point moves to B2Point.Picture point can be calculated from B by follow-up image processing algorithm1Point moves to B2Point displacement be x, then target object point on screen from A1Point moves to A2The displacement of point is d, and the relation that each parameter meets is:
Wherein, l is the photocentre vertical dimension to screen 4 of imaging system, and f is the lens focus of ccd video camera 2.Method can calculate objective body displacement vector values on the screen 4 easily accordingly.There is following defect in the preparation method of this displacement vector values:
1, manufacturability defect: CCD camera and camera lens in the fabrication process, exist manufacturability defect, and its lens focus exists certain error with the setting value f dispatched from the factory, this error introduces measures equation, can cause measurement error.And the accurate location of imaging system photocentre is difficult to determine, and then being difficult to provide the photocentre accurate distance l to screen in reality is measured, measurement result is all caused error to affect by this.
If 2 perspective model errors: if perspective model is fairly simple, it does not have considering that screen and primary optical axis exist the problems such as angle, when screen plane out-of-flatness, or when screen and primary optical axis exist angle, the imaging formula of system is all untenable.And in practical situation, there is distortion in camera lens, can cause very big nonlinearity erron, the kind of distortion is different, the error distribution caused is also different, and the way by demarcating that is difficult to corrects problems, thus limit vision detection system to the power of test of target micrometric displacement and accuracy of detection.
Summary of the invention
The invention aims to solve existing vision-based detection and measure the system detection method to target micrometric displacement, the problem that the measurement result precision that exists is low, it is provided that a kind of displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise and method.
The displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise of the present invention, it includes high speed CCD camera, laser tracker and diffuse-reflectance projection screen, and object moves on diffuse-reflectance projection screen；
High speed CCD camera is for carrying out imaging to the object fixed point on diffuse-reflectance projection screen, and laser tracker is for measuring the object fixed point coordinate on diffuse-reflectance projection screen.
Described diffuse-reflectance projection screen is the square being spliced by the ground glass of two pieces of 1000mm × 500mm × 3mm, the back spraying coating black paint vehicle of this diffuse-reflectance projection screen.
Based on the measuring method of the above-mentioned displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise, it comprises the following steps:
Step one: on setting diffuse-reflectance projection screen, 1 A1 is as object fixed point, laser tracker obtaining this object fixed point A1 at the coordinate figure that projection screen coordinate is fastened is A1 (U1, V1)；
Step 2: keep object fixed point A1 to fix, utilize high speed CCD camera that this object fixed point A1 is carried out imaging, the image planes of high speed CCD camera obtain the corresponding conjugate point B1 of object fixed point A1, after conjugate point B1 is carried out image procossing, obtain the conjugate point B1 coordinate figure B1 (m1, n1) fastened at image coordinates；
Step 3: on diffuse-reflectance projection screen, with object fixed point A1 for benchmark, more selected 24 objects fixed point Ai, i=2,3,4 ..., 25, make 25 object fixed points spacing with 25cm on diffuse-reflectance projection screen uniformly arrange, then successively according to the method for step one and step 2, until completing the measuring and calculating to the 25th object fixed point, it is thus achieved that Ai (Ui, Vi) and Bi (mi, ni) corresponding relation look-up table, i=1,2,3 ..., 25；
Step 4: adopt high speed CCD camera that object projects the screen hot spot imaging of acquisition successively on diffuse-reflectance projection screen, it is thus achieved that the conjugate point Bj (mj, nj), j=1,2,3 of object subpoint ...；
Step 5: search conjugate point Bj (mj, nj) in described corresponding relation look-up table, if Bj (mj, nj) overlaps with certain some Bi (mi, ni) in corresponding relation look-up table, then performs step 6；Otherwise perform step 7；
Step 6: obtain, according to corresponding relation look-up table, the coordinate figure that object subpoint is fastened at projection screen coordinate, then perform step 8；
Step 7: according to Bj (mj in described corresponding relation look-up table, nj) immediate four known calibration point Bi (mi around, ni), the calculation method adopting bilinear interpolation obtains Aj (Uj, Vj), the coordinate figure that the object subpoint that Aj (Uj, Vj) is corresponding with conjugate point Bj (mj, nj) is fastened at projection screen coordinate；Then step 8 is performed；
Step 8: by the initial value of the Aj (Uj, Vj) obtained in step 4 to step 7 process and final value, calculates and obtains object displacement vector on diffuse-reflectance projection screen.
Described object fixed point is hot spot or target ball.
Described conjugate point B1 is carried out image procossing after, obtain the conjugate point B1 coordinate figure B1 (m1 fastened at image coordinates, n1) method particularly includes: first the 8 bit image gradation datas of the conjugate point B1 that high speed CCD camera obtains are carried out dual threshold pixel extraction, the method utilizing linear interpolation in the effective pixel area of conjugate point B1 increases valid pixel number, recycle the barycenter extraction algorithm based on intensity-weighted and calculate the acquisition conjugate point B1 coordinate figure B1 (m1, n1) fastened at image coordinates.
The method utilizing linear interpolation in the effective pixel area of conjugate point B1 increases valid pixel number, recycle the barycenter extraction algorithm based on intensity-weighted to calculate the detailed process obtaining the conjugate point B1 coordinate figure B1 (m1, n1) fastened at image coordinates and be:
A bit to assume below, illustrates this detailed process:
Pre-set the image gradation data storehouse of conjugate point, this data base includes multiple pixel f (p arranged in arrays, q), p is the line number of matrix, q is matrix column number, the 8 bit image gradation datas of the conjugate point B1 that setting high-speed ccd video camera obtains are f (u, v), and (u, v) is positioned at pixel f (2,2), the f (2 in image gradation data storehouse to this image gradation data f, 3), f (3,2) and between f (3,3)
The method then utilizing linear interpolation obtains f (u, 2):
F (u, 2)=f (2,2)+(u-2) [f (3,2)-f (2,2)],
Obtaining f (u, 3) again through f (2,3) and f (3,3) interpolation is:
F (u, 3)=f (2,3)+(u-2) [f (3,3)-f (2,3)],
Finally, f (u, 2) and f (u, 3) is utilized to be interpolated, it is thus achieved that f (u, v):
f(u,v)=f(u,2)+(v-2)·[f(u,3)-f(u,2)]；
The then pixel f (2 of former composition hot spot, 2), f (2,3), f (3,2) and f (3,3) is by after interpolation, become f (2,2), f (2,3), f (3,2), f (3,3) and f (u, v)；
Based on this, utilize the barycenter extraction algorithm based on intensity-weighted to calculate and obtain the coordinate figure B1 (m1, n1) that fastens at image coordinates of conjugate point B1 and be:
Advantages of the present invention: the invention belongs to a kind of vision detection technology of micro-displacement measurement technical field, it is calculated based on the demarcation of laser tracker, it had both maintained the advantage of the big visual field high speed dynamic tracking of vision detection technology, was also effectively improved the accuracy of detection to micro-displacement.
The present invention, based on vision detection technology, solves the multinomial problem in vision detection technology cleverly, and relation and the linear difference algorithm searched with correspondence instead of original optical measurement equation, directly eliminate polynomial system error.And the bilinearity difference arithmetic adopted, effectively eliminate all linearity errors in system, be a kind of novel Micro-Displacement.
Apparatus of the present invention and method make use of laser tracker to the pinpoint characteristic measurement application of objective body, can improve the service efficiency of laser tracker cleverly.
The present invention effectively solves the test problems of the displacement of targets vector under large visual field environment, meets the testing requirement of high accuracy and big visual field simultaneously.The actual positioning precision to hot spot can reach 0.2mm, and field of detection is 1m, and relative accuracy of detection is 0.02%.In addition this detection method also has dynamic tracking effect at a high speed, it is possible to application in practice.
Accompanying drawing explanation
Fig. 1 is the principle schematic of the displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise of the present invention；
Fig. 2 is the schematic diagram that typical vision measures systematic survey displacement；
Fig. 3 is the schematic diagram being increased valid pixel by the method for linear interpolation；
Fig. 4 adopts the method for bilinear interpolation to table look-up to obtain the schematic diagram of Aj (Uj, Vj) in step 7.
Detailed description of the invention
Detailed description of the invention one: present embodiment is described below in conjunction with Fig. 1, the displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise described in present embodiment, it includes high speed CCD camera 1, laser tracker 2 and diffuse-reflectance projection screen 3, and object moves on diffuse-reflectance projection screen 3；
High speed CCD camera 1 for carrying out imaging to the object fixed point on diffuse-reflectance projection screen 3, and laser tracker 2 is for measuring the object fixed point coordinate on diffuse-reflectance projection screen 3.
In present embodiment, the space ranging scope of laser tracker 2 is not less than 50m, and measurable angle range is better than 100 ° in the vertical direction, and horizontal direction is better than 180 °, and positioning precision is better than 20 μm+5 μm/m.
The lens focus of high speed CCD camera 1 is 16mm, and single pixel dimension is 7 μ m 7 μm, and resolution is 2560 pixel × 1920 pixels, and image planes are of a size of 16.0mm × 12.1mm, and frame frequency 1130 frame is per second.
The operation principle of measurement apparatus is: within the scope of available field of view, and high speed CCD camera 1 and diffuse-reflectance projection screen 3 form a set of optical imaging system.Therefore, any object point A on diffuse-reflectance projection screen 3, after optical imagery, corresponding picture point B can be formed in the image planes of high speed CCD camera 1.And each picture point in A point and B point conjugation, each object point on diffuse-reflectance projection screen 3 and CCD image planes, there is conjugate relation one to one.The i.e. image coordinates system existence anduniquess corresponding relation of projection screen coordinate system and high speed CCD camera 1.
Detailed description of the invention two: embodiment one is described further by present embodiment, described in present embodiment, diffuse-reflectance projection screen 3 is the square being spliced by the ground glass of two pieces of 1000mm × 500mm × 3mm, the back spraying coating black paint vehicle of this diffuse-reflectance projection screen 3.
In present embodiment, the surface area of diffuse-reflectance projection screen 3 is 1m × 1m, and the black paint vehicle at its back side is used for eliminating secondary reflecting.The planarity requirements of ground glass is better than 0.2mm, and two pieces of ground glass seam are less than 0.5mm, and the flatness of diffuse-reflectance projection screen 3 entirety is better than 0.5mm, and ground perpendicularity is better than 0.1 °.
Detailed description of the invention three: present embodiment is described below in conjunction with Fig. 1, based on the measuring method of the above-mentioned displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise described in present embodiment, it comprises the following steps:
Step one: on setting diffuse-reflectance projection screen 3,1 A1 is as object fixed point, laser tracker 2 obtaining this object fixed point A1 coordinate figure in projection screen coordinate system 4 is A1 (U1, V1)；
Step 2: keep object fixed point A1 to fix, utilize high speed CCD camera 1 that this object fixed point A1 is carried out imaging, the image planes of high speed CCD camera 1 obtain the corresponding conjugate point B1 of object fixed point A1, after conjugate point B1 is carried out image procossing, obtain conjugate point B1 coordinate figure B1 (m1, n1) in image coordinates system 5；
Step 3: on diffuse-reflectance projection screen 3, with object fixed point A1 for benchmark, more selected 24 objects fixed point Ai, i=2,3,4 ..., 25, make 25 object fixed points spacing with 25cm on diffuse-reflectance projection screen 3 uniformly arrange, then successively according to the method for step one and step 2, until completing the measuring and calculating to the 25th object fixed point, it is thus achieved that Ai (Ui, Vi) and Bi (mi, ni) corresponding relation look-up table, i=1,2,3 ..., 25；
Step 4: adopt high speed CCD camera 1 that object projects the screen hot spot imaging of acquisition successively on diffuse-reflectance projection screen 3, it is thus achieved that the conjugate point Bj (mj, nj), j=1,2,3 of object subpoint ...；
Step 5: search conjugate point Bj (mj, nj) in described corresponding relation look-up table, if Bj (mj, nj) overlaps with certain some Bi (mi, ni) in corresponding relation look-up table, then performs step 6；Otherwise perform step 7；
Step 6: obtain object subpoint coordinate figure in projection screen coordinate system 4 according to corresponding relation look-up table, then perform step 8；
Step 7: according to Bj (mj in described corresponding relation look-up table, nj) immediate four known calibration point Bi (mi around, ni), the calculation method adopting bilinear interpolation obtains Aj (Uj, Vj), Aj (Uj, Vj) is the coordinate figure in projection screen coordinate system 4 of the object subpoint with conjugate point Bj (mj, nj) correspondence；Then step 8 is performed；
Step 8: by the initial value of the Aj (Uj, Vj) obtained in step 4 to step 7 process and final value, calculates and obtains object displacement vector on diffuse-reflectance projection screen 3.
In present embodiment, complete after conjugate pair answers look-up table, can measure.In measurement, high speed CCD camera 1 is to screen hot spot imaging, it is thus achieved that the conjugate point of object subpoint, then makes a look up in corresponding relation look-up table.If conjugate point is not calibrated in a lookup table, then adopt the calculation method based on bilinear interpolation, obtain its coordinate figure in projection screen coordinate system 4 according to four known calibration points about.
Finally, draw object displacement vector on diffuse-reflectance projection screen 3 according to the change of Aj (Uj, Vj) by simply resolving relation, thus achieve the high-precision two dimension miniature linear displacement detection of big visual field.
The measuring principle basis of present embodiment is the corresponding conjugate relation of object point and picture point in imaging system, and it establishes the corresponding search relationship of object plane coordinate system and image coordinates system, be a kind of theoretical with bilinear interpolation be the inquiring arithmetic of auxiliary.
Detailed description of the invention four: embodiment three is described further by present embodiment, object fixed point described in present embodiment is hot spot or target ball.
Detailed description of the invention five: embodiment four is described further by present embodiment, after conjugate point B1 being carried out image procossing described in present embodiment, obtain conjugate point B1 coordinate figure B1 (m1 in image coordinates system 5, n1) method particularly includes: first the 8 bit image gradation datas of the conjugate point B1 that high speed CCD camera 1 obtains are carried out dual threshold pixel extraction, the method utilizing linear interpolation in the effective pixel area of conjugate point B1 increases valid pixel number, recycle the barycenter extraction algorithm based on intensity-weighted and calculate acquisition conjugate point B1 coordinate figure B1 (m1 in image coordinates system 5, n1).
In present embodiment, owing to the image intensity value of hot spot region is higher, if the 8 bit image gradation datas of the conjugate point B1 obtained are arranged as from high to low by gray value: 255, 255, 236, 221, 219, 219, 217, 216, 209, 208, 201, 197, 164, 133, 112 ..., in above-mentioned Grey imaging data: gray value is the barycenter region that pixel is hot spot of 255, gray value is the pixel of 236-197 is hot spot endocyclic area, gray value is the point of 164-112 is hot spot outer region, the gray value point less than 100 is background area, the gray scale interval value in above-mentioned each region is for drafting value, actual segmentation threshold produces according to on-the-spot illumination debugging.For improving the algorithm positioning precision to facula mass center, reality adopt the position that the pixel data of hot spot endocyclic area carries out facula mass center extract.Namely setting gray scale higher limit by algorithm, namely upper threshold is 236, gray scale lower limit, and namely bottom threshold is 197, selects gray value pixel between two threshold values to carry out follow-up facula mass center and extracts, i.e. Double Thresholding Segmentation method.
The pixel coordinate extracted through Double Thresholding Segmentation method is the approximate region at hot spot place, and in actual imaging, screen distance camera is farther out, and camera is less to the valid pixel after hot spot imaging, and computational accuracy is inadequate.And then adopt the coordinate figure calculating facula mass center according to gray scale square weighting centroid algorithm, utilizing linear interpolation to increase valid pixel number and then to improve the positioning precision of facula mass center in hot spot imaging approximate region, after barycenter resolves, the hot spot that provides is better than the physical pixel size of 10 times at the coordinate precision of image coordinates system 5.
Described image procossing is for realizing the precise positioning to screen hot spot and dynamic tracking, pass through image processing algorithm, the real-time location coordinates information that glossing up is fastened can be given at projection screen coordinate, it is possible to follow the tracks of at a high speed the movement locus of hot spot, provide track fitting image.Realize dynamically following the tracks of on a large scale and static high-acruracy survey hot spot simultaneously.It both can complete the high-acruracy survey to hot spot static position coordinate, can complete again in big visual field, the high speed of target body movements track to be followed the tracks of, provide the displacement value that objective body moves simultaneously.
Detailed description of the invention six: present embodiment is described below in conjunction with Fig. 1, Fig. 3 and Fig. 4, embodiment five is described further by present embodiment, the method utilizing linear interpolation described in present embodiment in the effective pixel area of conjugate point B1 increases valid pixel number, the detailed process recycling the barycenter extraction algorithm calculating acquisition conjugate point B1 coordinate figure B1 (m1, n1) in image coordinates system 5 based on intensity-weighted is:
A bit to assume below, illustrates this detailed process:
Pre-set the image gradation data storehouse of conjugate point, this data base includes multiple pixel f (p arranged in arrays, q), p is the line number of matrix, q is matrix column number, the 8 bit image gradation datas of the conjugate point B1 that setting high-speed ccd video camera 1 obtains are f (u, v), and (u, v) is positioned at pixel f (2,2), the f (2 in image gradation data storehouse to this image gradation data f, 3), f (3,2) and between f (3,3)
The method then utilizing linear interpolation obtains f (u, 2):
F (u, 2)=f (2,2)+(u-2) [f (3,2)-f (2,2)],
Obtaining f (u, 3) again through f (2,3) and f (3,3) interpolation is:
F (u, 3)=f (2,3)+(u-2) [f (3,3)-f (2,3)],
Finally, f (u, 2) and f (u, 3) is utilized to be interpolated, it is thus achieved that f (u, v):
f(u,v)=f(u,2)+(v-2)·[f(u,3)-f(u,2)]；
The then pixel f (2 of former composition hot spot, 2), f (2,3), f (3,2) and f (3,3) is by after interpolation, become f (2,2), f (2,3), f (3,2), f (3,3) and f (u, v)；This pixel increases mode, it is possible to increase the precision of subsequent arithmetic.
Based on this, utilization based on the barycenter extraction algorithm calculating acquisition conjugate point B1 coordinate figure B1 (m1, n1) in image coordinates system 5 of intensity-weighted is:
In the inventive method, if CCD camera imaging system obtains the pixel coordinate Bi (mi, ni) of a certain hot spot, then the space coordinates Ai (Ui, Vi) of hot spot on its unique corresponding screen.It tables look-up principle sketch as shown in Figure 4:
According to the principle that look-up table is set up, there is one-to-one relationship in hot spot space coordinates Ai (Ui, Vi) on screen and hot spot pixel coordinate Bi (mi, ni) in imaging system image planes.
After system building completes, first demarcating, in sketch, 1-4 point is fixed point, namely there is A1 (U1, V1), A2 (U2, V2), A3 (U3, V3), A4 (U4, V4) and B1 (m1, n1), B2 (m2, n2), B3 (m3, n3), B4 (m4, n4) one-to-one relationship, is stored in this relation appointment region, namely sets up demarcation look-up table.
After demarcation completes, the hot spot on screen can be carried out detection and location and follow the tracks of at a high speed by system, in actually detected, imaging system is to the hot spot imaging on screen, obtained the pixel coordinate Bi (mi, ni) of hot spot imaging by algorithm, bring this pixel coordinate into look-up table and make a look up:
If 1 Bi (mi, ni) is by chance B1 (m1, n1), B2 (m2, n2), B3 (m3, n3), B4 (m4, n4) or known calibration point, then directly can obtain space coordinates A1 corresponding to hot spot (U1, V1), A2 (U2 in a lookup table, V2), A3 (U3, V3)
A4(U4,V4)。
If 2 Bi (mi, ni) are not known calibration points, the space coordinates Ai (Ui, Vi) of its correspondence namely cannot be found in look-up table.Assume that Bi (mi, ni) is for B5 (m5, n5), it is impossible to directly given the space coordinates A5 (U5, V5) of its correspondence by look-up table.Then construct interpolation algorithm, utilize known A1 (U1, V1), A2 (U2, V2), A3 (U3, V3), A4 (U4, V4) with B1 (m1, n1), B2 (m2, n2), B3 (m3, n3), the corresponding relation of B4 (m4, n4), structure interpolating function A5 (U5, V5)=f [B (m5, n5)], calculate space coordinates A5 (U5, V5) corresponding to B5 (m5, n5).
The inventive method, if coordinating the interval of twice detection, it is possible to calculate the movement velocity of target hot spot；The coordinate figure of algorithm storage hot spot and then the running orbit of record hot spot can also be passed through.It does not use Optical Formula in detection process, and then avoids the impact of the multiple image errors such as focal length value error and lens distortion.Its measuring principle is in that visual imaging, as long as namely hot spot is without departing from screen, namely within the visual field of imaging system, system just can detect the position of hot spot, not by the impact of hot spot movement velocity.According to optical imaging concept, if there are two hot spots on screen simultaneously, namely comprise the positional information of two hot spots in Polaroid gradation data, then can pass through the position coordinates simultaneously recording two hot spots that improves of algorithm, and then simultaneously complete the detection of the position to multiple target hot spots and follow the tracks of.The detection target of measurement system is the hot spot on screen, and this hot spot is sent by the generating laser specified, and is incident upon on diffuse-reflectance screen and forms hot spot to be detected.Generating laser can according to demand, be fixed in different target to be measured by practical application, such as turntable, theodolite, guide rail etc., and then complete the corner accuracy of target to be measured, the isoparametric measurement of linearity.Can also two generating lasers be placed in two targets to be measured, control two targets to be measured and carry out identical action, the track of the detection system detection hot spot that two targets to be measured of detection send simultaneously, by the comparison of track, the kinematic accuracy of two targets to be measured of assessment.
Claims (5)
1. the measuring method of the displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise, described measurement apparatus includes high speed CCD camera (1), laser tracker (2) and diffuse-reflectance projection screen (3), and object is upper mobile at diffuse-reflectance projection screen (3)；
High speed CCD camera (1) is for carrying out imaging to the object fixed point on diffuse-reflectance projection screen (3), and laser tracker (2) is used for the object fixed point coordinate measuring on diffuse-reflectance projection screen (3)；
It is characterized in that, it comprises the following steps:
Step one: set diffuse-reflectance projection screen (3) upper 1 A1 as object fixed point, being obtained this object fixed point A1 coordinate figure in projection screen coordinate system (4) by laser tracker (2) is A1 (U1, V1)；
Step 2: keep object fixed point A1 to fix, utilize high speed CCD camera (1) that this object fixed point A1 is carried out imaging, the image planes of high speed CCD camera (1) obtain the corresponding conjugate point B1 of object fixed point A1, after conjugate point B1 is carried out image procossing, obtain conjugate point B1 coordinate figure B1 (m1, n1) in image coordinates system (5)；
Step 3: on diffuse-reflectance projection screen (3), with object fixed point A1 for benchmark, selected 24 objects fixed point Ai, i=2,3 again, 4, ..., 25, make 25 object fixed points uniformly arrange with the spacing of 25cm on diffuse-reflectance projection screen (3), then successively according to the method for step one and step 2, until completing the measuring and calculating to the 25th object fixed point, it is thus achieved that Ai (Ui, Vi) and Bi (mi, ni) corresponding relation look-up table, i=1,2,3, ..., 25；
Step 4: adopt the screen hot spot imaging that object is obtained by high speed CCD camera (1) successively in the upper projection of diffuse-reflectance projection screen (3), it is thus achieved that the conjugate point Bj (mj, nj), j=1,2,3 of object subpoint ...；
Step 5: search conjugate point Bj (mj, nj) in described corresponding relation look-up table, if Bj (mj, nj) overlaps with certain some Bi (mi, ni) in corresponding relation look-up table, then performs step 6；Otherwise perform step 7；
Step 6: obtain object subpoint coordinate figure in projection screen coordinate system (4) according to corresponding relation look-up table, then perform step 8；
Step 7: according to Bj (mj in described corresponding relation look-up table, nj) immediate four known calibration point Bi (mi around, ni), the calculation method adopting bilinear interpolation obtains Aj (Uj, Vj), Aj (Uj, Vj) is the coordinate figure in projection screen coordinate system (4) of the object subpoint with conjugate point Bj (mj, nj) correspondence；Then step 8 is performed；
Step 8: by the initial value of the Aj (Uj, Vj) obtained in step 4 to step 7 process and final value, calculates and obtains object displacement vector on diffuse-reflectance projection screen (3).
2. the measuring method of the displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise according to claim 1, it is characterised in that
Described object fixed point is hot spot or target ball.
3. the measuring method of the displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise according to claim 2, it is characterized in that, described conjugate point B1 is carried out image procossing after, obtain conjugate point B1 coordinate figure B1 (m1 in image coordinates system (5), n1) method particularly includes: first the 8 bit image gradation datas of the conjugate point B1 that high speed CCD camera (1) obtains are carried out dual threshold pixel extraction, the method utilizing linear interpolation in the effective pixel area of conjugate point B1 increases valid pixel number, recycle the barycenter extraction algorithm based on intensity-weighted and calculate acquisition conjugate point B1 coordinate figure B1 (m1 in image coordinates system (5), n1).
4. the measuring method of the displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise according to claim 3, it is characterized in that, the method utilizing linear interpolation in the effective pixel area of conjugate point B1 increases valid pixel number, the detailed process recycling the barycenter extraction algorithm calculating acquisition conjugate point B1 coordinate figure B1 (m1, n1) in image coordinates system (5) based on intensity-weighted is:
A bit to assume below, illustrates this detailed process:
Pre-set the image gradation data storehouse of conjugate point, this data base includes multiple pixel f (p arranged in arrays, q), p is the line number of matrix, q is matrix column number, the 8 bit image gradation datas of the conjugate point B1 that setting high-speed ccd video camera (1) obtains are f (u, v), and (u, v) is positioned at pixel f (2,2), the f (2 in image gradation data storehouse to this image gradation data f, 3), f (3,2) and between f (3,3)
The method then utilizing linear interpolation obtains f (u, 2):
F (u, 2)=f (2,2)+(u-2) [f (3,2)-f (2,2)],
Obtaining f (u, 3) again through f (2,3) and f (3,3) interpolation is:
F (u, 3)=f (2,3)+(u-2) [f (3,3)-f (2,3)],
Finally, f (u, 2) and f (u, 3) is utilized to be interpolated, it is thus achieved that f (u, v):
F (u, v)=f (u, 2)+(v-2) [f (u, 3)-f (u, 2)]；
The then pixel f (2 of former composition hot spot, 2), f (2,3), f (3,2) and f (3,3) is by after interpolation, become f (2,2), f (2,3), f (3,2), f (3,3) and f (u, v)；
Based on this, utilization based on the barycenter extraction algorithm calculating acquisition conjugate point B1 coordinate figure B1 (m1, n1) in image coordinates system (5) of intensity-weighted is:
5. the measuring method of the displacement of targets device for measuring vector quantity demarcated based on laser tracker pointwise according to claim 1, it is characterized in that, described diffuse-reflectance projection screen (3) is the square being spliced by the ground glass of two pieces of 1000mm × 500mm × 3mm, the back spraying coating black paint vehicle of this diffuse-reflectance projection screen (3).
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| CN107631693B (en) * | 2017-09-14 | 2020-02-07 | 重庆大学 | Two-dimensional multipoint laser displacement measurement system |
| CN109993935B (en) * | 2019-03-14 | 2022-03-29 | 华南理工大学 | Device and method for positioning construction machinery and monitoring safety area of construction machinery |
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| CN111203861B (en) * | 2020-01-06 | 2021-10-19 | 珠海格力电器股份有限公司 | Calibration method and calibration system for robot tool coordinate system |
| CN111872544B (en) * | 2020-07-31 | 2022-01-18 | 深圳市学而用科技有限公司 | Calibration method and device for laser light-emitting indication point and galvanometer coaxial vision system |
| CN112432594A (en) * | 2020-10-22 | 2021-03-02 | 中国计量科学研究院 | Machine vision six-degree-of-freedom measurement method based on physical decoupling |
| CN112629831B (en) * | 2020-12-09 | 2022-09-02 | 北京航天飞腾装备技术有限责任公司 | Laser weapon facula monitoring and tracking system |
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