CN106091983B - The complete scaling method of Vision Measuring System With Structured Light Stripe comprising scanning direction information - Google Patents
The complete scaling method of Vision Measuring System With Structured Light Stripe comprising scanning direction information Download PDFInfo
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- CN106091983B CN106091983B CN201610389198.6A CN201610389198A CN106091983B CN 106091983 B CN106091983 B CN 106091983B CN 201610389198 A CN201610389198 A CN 201610389198A CN 106091983 B CN106091983 B CN 106091983B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
- G01B11/2518—Projection by scanning of the object
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
- G01B11/254—Projection of a pattern, viewing through a pattern, e.g. moiré
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Abstract
The complete scaling method of Vision Measuring System With Structured Light Stripe comprising scanning direction information belongs to the scaling method field of line-structured light vision system, this method is that the conversion thinking of relative motion coordinate system is incorporated under the auxiliary of the relative motion caliberating device based on line slide rail system, directly several are disposably obtained using conventional Light-plane calibration process include striation location information and the reversed relative motion uncalibrated image of scanning direction information simultaneously, so as to also very significantly reduce the operand needed for computing system solution structure light plane space equation while demarcating steps are simplified.The method of the present invention accurately can solve and fit scanning direction vector equation, and scanning direction can be any direction, and final whole new definition and establish comprising the more complete Vision Measuring System With Structured Light Stripe scaling method determined including scan vector step.The present invention has the double effects for improving calibration efficiency and reducing calibrated error.
Description
Technical field
The invention belongs to the scaling method fields of line-structured light vision system, and in particular to one kind includes scanning direction information
The complete scaling method of Vision Measuring System With Structured Light Stripe.
Background technology
Vision measurement technology can be well adapted for the new standard that modern industry proposes workpiece configurations size detection and will
It asks, is a kind of contactless profile measurement means for having both precision and efficiency.Line-structured light vision system is vision measurement technology
One of Typical Representative, basic principle is that spatial attitude is projected on space object to be detected using linear laser diode is complete
Known laser plane forms projection striation, and the projection striation is made to be moved along known scanning direction on a surface of an,
Multiple photos are shot by high-precision video camera respectively to different location of the aforementioned projection striation in scanning process again.Then,
Using optical losses detection technique, the pixel coordinate of the striation characteristic point of body surface is extracted；Then the knot obtained using calibration
Structure light vision system parameter, the pixel coordinate of features described above point is projected in camera coordinate system, so as to obtain body surface
3D contour features.
To realize the Constructed Lighting Vision System parameter of above-mentioned coordinate conversion, structured-light system is being applied to actually to measure it
Before, it needs to be respectively completed camera calibration and Light-plane calibration by the method demarcated.Wherein, camera calibration is to obtain
Intrinsic parameters of the camera is taken, and Light-plane calibration is the space equation to ask for laser plane.
At present, in technical field of visual measurement generally use Zhang Zhengyou in its open source literature Zhang Z. (2000) .A
flexible new technique for camera calibration.IEEE Trans.on Pattern Analysis
and Machine Intelligence,22(11):A kind of camera marking method for being itd is proposed in 1330-1334. is completed to take the photograph
This process of camera calibration.
The present inventor is in A Flexible Calibration Method Using the Planar
Targetwith a Square Pattern for Line Structured Light VisionSystem.Sun,
Qiucheng,et al.A Flexible Calibration Method Using the Planar Target with a
Square Pattern for Line Structured Light Vision System.PloS one 9.9:e106911.
(SCI) a kind of line-structured light vision system calibration method using square pattern plane template is disclosed in 2014., in the document
In, camera calibration is realized using the camera marking method of traditional Zhang Zhengyou, and disclose a kind of by extraction such as Fig. 3
To tetra- angular coordinate Corner points of ABCD of square pattern plane template square pattern shown in Fig. 4
Extraction determines the plane space equation The target of plane template as shown in Figure 5 under its camera coordinate system
The method of plane in camera coordinate frame, to determine structure optical plane as shown in Figure 1
Space plane equations of the Structured light plane in this patent camera coordinate system shown in Fig. 2.In addition, at this
Utilization knot as shown in Figure 6 to 8 is also disclosed in a kind of line-structured light scaling method using square pattern plane template
Imaging of the structure laser projection striation in cameras photograph further parses and determines structure optical plane Structured
The throwing that light plane are formed respectively with the square pattern plane template square pattern under different spaces posture inclination angle
The method for solving of the space equation of shadow intersection line segment EF or E ' F ' finally, passes through the space equations of EF line segments and E ' F ' line segments
Space equation, you can acquire space equations of the structure optical plane Structured light plane under camera coordinate system.
However, a kind of line-structured light using square pattern plane template disclosed in including aforementioned the present inventor
Including scaling method, it is concentrated mainly on structure optical plane at present with the relevant academic discussion of line-structured light vision system calibration
Space plane equation determine and arithmetic accuracy relevant with camera calibration link and the problems such as efficiency on, be usually only completed
Two processes of calibration and Light-plane calibration of video camera.But calibrated line-structured light vision system will be completed and be applied to
During workpiece configurations profile scan and identification, video camera and linear laser diode is projected as an entirety and photographic unit,
It also needs separately to determine the projection and structure optical plane Structured light plane that photographic unit is projected is opposite
Generated direction of relative movement when measured three-dimension object makes scanning motion, thus, it is also necessary to further laser be put down
The direction of Surface scan is demarcated, to obtain scanning direction vector equation of the structured-light system under camera coordinate system, thus
It could complete the integral calibrating process of line-structured light vision system.However at present, related determining line-structured light vision system scanning
The method in direction is less, and conventional method is as shown in Figure 8：The old straight line by being approximately parallel to scanning object long axis of body direction is slided
Rail realizes that the method for approximate given scanning direction is to utilize whole projection and photographic unit 1 and square with line slide rail system
Shape projection target target 2, wherein, whole projection and photographic unit 1 based on line slide rail system include line slide rail 1-1, sliding block
1-2, video camera 1-3 and linear laser diode 1-4；Video camera 1-3 and linear laser diode 1-4 are fixed on sliding block 1-2, sliding block 1-
2 are slidably connected with line slide rail 1-1；Rectangular projection target plate 2 is placed in the dynamic coverage of video camera 1-3；Straight line swashs
Light device 1-4 is identical with the direction of video camera 1-3 and keeps opposing stationary and is transported along the x-axis direction for being parallel to camera coordinate system
It is dynamic, ensured in the movement angle in this direction by line slide rail, ensure line slide rail side as possible in scanning process
To parallel with the x-axis of camera coordinate system, the less parallel refers between line slide rail 1-1 and scanning object long axis of body
Angular range is less than 2 °.However, ensure even with the present inventor in the linear rail system auxiliary mentioned in aforementioned documents
The depth of parallelism of the collimation of relative motion, scanning direction and target plane is still difficult to Efficient Support, and larger systematic error is in institute
Inevitably.And on the other hand, if re-using other householder methods after the calibration process for having been completed structured-light system
Separately demarcate and obtain the scanning direction vector for completing calibrated line-structured light vision system under camera coordinate systemThen
The complexity of calibration process certainly will be added significantly to, meanwhile, it may not only be unable to cut, even introduce new bigger instead
Error deviates factor.
At present, relevant discussion in the art can not yet explore a kind of line for including scanning direction information with regard to the above problem
The complete scaling method of structure light vision measuring systems makes it that can synchronize and realizes Constructed Lighting Vision System calibration process and determine to sweep
Direction is retouched, and the stated accuracy of vision measurement system can be greatly improved and simplify calibration process.
Invention content
In order to solve the complete scaling method of existing Vision Measuring System With Structured Light Stripe, there is no can synchronize to determine to tie
Structure light vision system parameter and determining scanning direction vector, and the stated accuracy of vision measurement system can be greatly improved and simplified and marked
The technical issues of determining process, the present invention provide a kind of Vision Measuring System With Structured Light Stripe comprising scanning direction information and completely demarcate
Method.
The technical solution adopted for solving the technical problem of the present invention is as follows：
The complete scaling method of Vision Measuring System With Structured Light Stripe comprising scanning direction information, includes the following steps：
Step 1：The relative motion based on line slide rail system that foundation is approximately parallel to scanning object long axis of body direction is auxiliary
Help caliberating device：
Establish being slided based on straight line for whole projection and photographic unit and rectangular projection target plate based on line slide rail system
The relative motion auxiliary calibration device of rail system, wherein, whole projection and photographic unit based on line slide rail system include straight
Line sliding rail, sliding block, video camera and linear laser diode；Video camera and linear laser diode are fixed on sliding block, and sliding block is slided with straight line
Rail is slidably connected；Rectangular projection target plate is placed in the dynamic coverage of video camera；The court of linear laser diode and video camera
It is opposing stationary to identical and holding；
Step 2：Initial alignment is carried out to the parameter of video camera, specifically includes following sub-step：
Step 2.1：Conversion coordinate system is established, i.e.,：Establish world coordinate system, camera coordinate system, image physical coordinates system
With image pixel plane coordinate system；
Three-dimensional coordinate point coordinates (x in world coordinate systemw,yw,zw) video camera point coordinates (x is converted to successivelyc,yc,
zc), ideal image point coordinates (xu,yu), true picture pixel point coordinates (xd,yd) and actual pixels point coordinates (xp,yp)；Separately
Outside, with reference to the camera marking method of Zhang Zhengyou by the z of world coordinate systemwAxial coordinate is set as 0, i.e. zw=0；At this point, world coordinates
The coordinate representation of arbitrary point is (x in systemw,yw, 0) or it is only meant as the two-dimensional points coordinate (x of world coordinate system XY axial planesw,
yw)；
Step 2.2：Traditional gridiron pattern camera calibration plate is done into repeatedly different postures in the coverage of video camera
Under change of pitch angle and shoot three width more than photos, then the inner parameter and external parameter of video camera are demarcated；
I.e. by obtaining inner parameter matrixWith distortion factor K=(k1,k2,p1,p2)；
Wherein α and β represents the scale factor of U axis and V axis in pixel planes respectively, and γ represents two reference axis of pixel planes
The out of plumb factor, (u0,v0) represent the coordinate that the intersection point of camera optical axis and the plane of delineation is fastened in pixel coordinate；k1,k2It represents
The coefficient of radial direction distortion function in image physical coordinates system；p1,p2Tangential distortion function in image physical coordinates system is represented respectively
Coefficient；
Step 3：Using the relative motion auxiliary calibration device based on line slide rail system described in step 1, obtain and swash
Light projects striation space plane equation, specifically includes following sub-step：
Step 3.1：Make the sliding block edge in the relative motion auxiliary calibration device based on line slide rail system described in step 1
Line slide rail sequentially moves (k-1) a fixed step-length unit (9 >=k >=1, k take natural number), and allows linear laser diode by laser
The projection striation EF of structure optical plane S is projected to always on static rectangular projection target plate, this uses video camera point in the process
It is other that corresponding width calibrating template photo under each position is shot to rectangular projection target plate, until obtaining k width includes target plate
With the calibrating template photo of projection striation；
Step 3.2：The method for solving and demarcating according to linear model includes target plate and throwing to the k width described in step 3.1
The calibrating template photo of shadow striation carries out rectangular block Corner Detection and Light stripes center extraction detection, specifically includes following sub-step
Suddenly：
Step 3.2.1：Four angle point ABCD to translational moving system coordinate on transformed rectangular projection target plate are carried out
Corner Detection：
Step 3.2.1.1：Carry out translational moving system coordinate conversion：K width described in step 3.1 is included into target plate and projection
The calibrating template photo of striation is regarded as stationary by Constructed Lighting Vision System under identical shooting condition and rectangular projection target
Acquisition is shot when plate moves fixed step-length unit in camera coordinate system along the opposite direction with scanning direction respectively
K width scaling board photos, you can equivalence obtain relative motion reverse state under scaling board space occurs in camera coordinate system
Heterodromous i width new images (9 >=i >=1, i take natural number)；
Step 3.2.1.2：For any one described in step 3.2.1.1 heterodromous i width new images, examined using angle point
Method of determining and calculating distinguishes the pixel detection coordinate of four angle points of black box in detection template imageWherein i=
1 ..., 9 represent the width number sequence number of image, and j=1 ..., 4 represent the serial number of four angle points in the figure in current single image：Profit
Following expression can be established with the inner parameter described in step 2.2 and calibrating external parameters model：
The pixel of four angle point ABCD in any one described in step 3.2.1.1 heterodromous i width new images is examined
Survey coordinateCorrespondence is converted into ideal image coordinate system coordinateWherein Represent the angle point image coordinate system coordinate for including distortion,Represent the ideal image coordinate system coordinate of angle point；
Coordinate is detected using corner pixelsThe corresponding two-dimensional points coordinate value in its world coordinate systemAccording to the model of Zhang Zhengyou, following equation can be obtained
In formula (1), S represents scale factor, and often the corresponding external parameter of target plate includes R in photos image iiAnd Ti
Two parameters；Ri=[r1,r2,r3] it is spin matrix, ri(i=1,2,3) spin matrix R is representediI-th row, TiRepresent translation
Vector；If
H=[r1 r2 Ti]
Then equation (1) can be expressed as form：
Divide out s in equation (2), can obtain
WhereinThe i-th row of representing matrix H, (3) formula also may indicate that into following form
(4) formula is rewritten as matrix form to obtain
Step 3.2.1.3：IfIt, can be by step according to formula (5) then when i sequentially takes 1 to 4
3.2.1.1 the ideal image coordinate system coordinate of four angle point ABCD in described every heterodromous i width new images(j=sequentially takes 1 to 4) according to formula (5) two equations of corresponding acquisition and can be expressed as homogeneous side
Journey group Lx=0；Therefore when i sequentially takes 1 to 4, add up to and obtain eight equations altogether；
Wherein L is 8 × 9 coefficient matrix；Singular value decomposition is carried out to matrix L, then the corresponding right side of matrix L minimum singular value
Singular vector is the solution of equation group；So as to solve spin matrix RiWith translation vector Ti, so as to obtain step
3.2.1.1 the space equation of plane where described any one heterodromous i width new images, and it is right further to obtain its institute
That answers sequentially takes in the calibrating template photo k that each width of step 3.2 includes target plate and projects striation in the space equation i of plane
2 ... 9, the spin matrix R of (i takes natural number)iWith translation vector TiThe two external parameters；
Step 3.2.1.4：Rectangle included in every described in step 3.2.1.1 heterodromous i width new images is thrown
Laser projection striation on shadow target plate carries out striation widthwise central detection, detects to be incident upon using optical losses detection algorithm
The pixel coordinate point of optical losses in every width target plate imageWherein i=1 ..., 9, (i takes natural number) represents figure
The width number sequence number of picture, j=1 ..., N (N takes natural number) represent the number of optical losses pixel coordinate point；
Step 3.2.2：Utilize photos every described in the inner parameter of video camera described in step 2.2 and step 3.2.1.3
The corresponding spin matrix R of target plate in imageiWith translation vector TiThe two external parameters throw the pixel point coordinates of optical losses
To get to corresponding three-dimensional camera coordinate system coordinate points in shadow to camera coordinate systemSo as to obtain with light
Center line is the laser projection striation point set of characterization；
Step 3.3：Step 3.2.1 to step 3.2.2 is repeated, until sequentially obtain i=1 ..., 9 corresponding nine groups
Target plate is included with k width and projects the one-to-one laser projection striation spatial point set of calibrating template photo of striation；
Step 4：Whole three-dimensional points on nine groups of laser projection striations that step 3 is obtained project to unified take the photograph
It in camera coordinate system, and is fitted using these point sets to obtain a unique space plane, so as to solve the sky of structure optical plane
Between equation, realize the calibration of optical plane；
Step 5：Utilize intrinsic parameters of the camera described in step 2.2 and the corresponding spin matrix R of scaling board imageiPeace
Move vector TiThe two external parameters, by obtained in the step 3.1 in each image four corner pixels coordinates
It projects in unified camera coordinate system, four groups of three-dimensional point sets can be obtainedWherein i=1 ..., 9 represent figure
The width number sequence number of picture, j=1 ..., 4；Using this four groups of three-dimensional point sets, it is fitted four space parallel lines vector equations：
Step 6：The mean value of four space parallel lines vector equations described in step 5 is calculated, obtains equation：
And then it can determine the vector of the scanning direction of system
Beneficial effects of the present invention are as follows：
The present invention innovatively incorporates opposite under the auxiliary of the relative motion auxiliary calibration device based on line slide rail system
Kinetic coordinate system converts thinking, includes light simultaneously so as to directly disposably obtain several using conventional Light-plane calibration process
The reversed relative motion uncalibrated image of location information and scanning direction information, so as to while demarcating steps are greatly simplified,
Also very significantly reduce the operand needed for computing system solution structure light plane space equation.It is in addition, same using several
When include striation location information and the uncalibrated image of scanning direction information, this method accurately can also solve and fit scanning side
To vector equation, and scanning direction can be any direction, thoroughly release and abandoned camera coordinate system with really sweeping
Retouching direction coordinate system needs the artificial error precision that high-precision is kept to overlap to ensure limitation, and final whole new definition and establishes packet
Containing the more complete Vision Measuring System With Structured Light Stripe scaling method including the step of determining scan vector.
The present invention have both improve calibration efficiency and reduce calibrated error double effects, logic link up it is rigorous, abundant
Using and play the prior art on the basis of, come down in a continuous line to its essence, be easy to understand, it is in the field of business have higher amalgamation and
Acceptance, and looking for another way with deficiency, the present invention the shortcomings that for old technology, solves preferable, and therefore, which determines scheme tool
There is higher promotion and use value.
Description of the drawings
Fig. 1 is the figure Figure 1 in paper recited in background technology；
Fig. 2 is the opposite transformational relation schematic diagram between four kinds of camera calibration coordinate systems in Fig. 1；
Fig. 3 is the figure Figure 3 in paper recited in background technology；
Fig. 4 is the left figure in the figure Figure 4 in paper recited in background technology；
Fig. 5 is the figure Figure 6 in paper recited in background technology；
Fig. 6 is the close-up schematic view of I extracting sections optical losses algorithm in Fig. 4；
Fig. 7 is the figure Figure 10 in paper recited in background technology；
Fig. 8 be it is old by be approximately parallel to scanning object long axis of body direction line slide rail Lai approximate given scanning direction
Principle schematic；
Fig. 9 is the structure chart of the relative motion auxiliary calibration device the present invention is based on line slide rail system and its realizes auxiliary
Determine the schematic diagram of approximate given scanning direction；
Figure 10 is the space that the present invention is collective fitted to only one structure optical plane by multigroup laser projection striation point set
The schematic diagram of equation；
Figure 11 is the original that the present invention fits target block relative displacement direction using the angle point ABCD of multigroup rectangular target block
Reason figure.
Specific embodiment
The present invention is described in further details below in conjunction with the accompanying drawings.
As shown in Figures 9 to 11, the Vision Measuring System With Structured Light Stripe comprising scanning direction information of the invention is completely marked
The method of determining includes the following steps：
Step 1：The relative motion based on line slide rail system that foundation is approximately parallel to scanning object long axis of body direction is auxiliary
Caliberating device is helped, by the system, incorporates to innovation formula the exclusive relative motion coordinate system conversion thinking of the present invention, it is auxiliary to realize
It helps and determines approximate given scanning direction vector P：
Establish whole projection based on line slide rail system and photographic unit 1 and rectangular projection target plate 2 based on straight line
The relative motion auxiliary calibration device of slide type rail system, wherein, whole projection and photographic unit 1 based on line slide rail system include
Line slide rail 1-1, sliding block 1-2, video camera 1-3 and linear laser diode 1-4；Video camera 1-3 and linear laser diode 1-4 are fixed on
On sliding block 1-2, sliding block 1-2 is slidably connected with line slide rail 1-1；The dynamic that rectangular projection target plate 2 is placed on video camera 1-3 is clapped
In the range of taking the photograph；Linear laser diode 1-4 is identical with the direction of video camera 1-3 and keeps opposing stationary；
Step 2：Initial alignment is carried out to the parameter of video camera 1-3, specifically includes following sub-step：
Step 2.1：According to well known Tsai R Y in A versatile camera calibration technique
for high-accuracy 3D machine vision metrology using off-the-shelf TV cameras
and lenses》[J].IEEE Journal of Robotics and Automation,1987,3(4):In 323-344 texts
The coordinate transformation method of proposition establishes conversion coordinate system, i.e.,：Establish world coordinate system, camera coordinate system, image physical coordinates
System and image pixel plane coordinate system；
Three-dimensional coordinate point coordinates (x in world coordinate systemw,yw,zw) video camera point coordinates (x is converted to successivelyc,yc,
zc), ideal image point coordinates (xu,yu), true picture pixel point coordinates (xd,yd) and actual pixels point coordinates (xp,yp)；Separately
Outside, with reference to the camera marking method of Zhang Zhengyou by the z of world coordinate systemwAxial coordinate is set as 0, i.e. zw=0；At this point, world coordinates
The coordinate representation of arbitrary point is (x in systemw,yw, 0) or it is only meant as the two-dimensional points coordinate (x of world coordinate system XY axial planesw,
yw)；
Step 2.2：Traditional gridiron pattern camera calibration plate is done into repeatedly different appearances in the coverage of video camera 1-3
Change of pitch angle and three width more than photos of shooting under state, according still further to well known Zhang Zhengyou in Zhang Z. (2000) .A
flexible new technique for camera calibration.IEEE Trans.on Pattern Analysis
and Machine Intelligence,22(11):1330-1334. camera marking method is to video camera 1-3's proposed in
Inner parameter and external parameter are demarcated；
I.e. by obtaining inner parameter matrixWith distortion factor K=(k1,k2,p1,p2)；
Wherein α and β represents the scale factor of U axis and V axis in pixel planes respectively, and γ represents two reference axis of pixel planes
The out of plumb factor, (u0,v0) represent the coordinate that the intersection point of camera optical axis and the plane of delineation is fastened in pixel coordinate；k1,k2It represents
The coefficient of radial direction distortion function in image physical coordinates system；p1,p2Tangential distortion function in image physical coordinates system is represented respectively
Coefficient；
Step 3：Using the relative motion auxiliary calibration device based on line slide rail system described in step 1, obtain and swash
Light projects striation space plane equation, specifically includes following sub-step：
Step 3.1：Make the sliding block 1-2 in the relative motion auxiliary calibration device based on line slide rail system described in step 1
K-1 fixed step-length unit 9 >=k >=1 are sequentially moved along line slide rail 1-1, k takes natural number, and allows linear laser diode 1-4 will
The projection striation EF of laser structure optical plane (Structured light plane) S projects to static rectangular projection target always
On target 2, this respectively shoots rectangular projection target plate 2 corresponding width mark under each position using video camera 1-3 in the process
Solid plate photo includes target plate and projects the calibrating template photo of striation until obtaining k width；
Step 3.2：According to the present inventor in well known A Flexible Calibration Method Using the
Planar Targetwith a Square Pattern for Line Structured Light
VisionSystem.Sun,Qiucheng,et al.A Flexible Calibration Method Using the
Planar Target with a Square Pattern for Line Structured Light Vision
System.PloS one 9.9:E106911. the linear model solution disclosed in (SCI) 2014. and scaling method, to step
K width described in 3.1 includes target plate and the calibrating template photo progress rectangular block Corner Detection for projecting striation and optical losses carry
Detection is taken, specifically includes following sub-step：
Step 3.2.1：According to movement principle of relativity, the K width scaling board photos of acquisition are shot in step 3.1, with identical bat
Take the photograph under environment, Constructed Lighting Vision System is fixed, and rectangular projection target plate in camera coordinate system along with scanning direction
The scaling board photo of captured acquisition is equivalent in the case of opposite direction moves, and accordingly, translational moving system coordinate is converted
Four angle point ABCD on rectangular projection target plate 2 afterwards carry out Corner Detection：
Step 3.2.1.1：Carry out translational moving system coordinate conversion：K width described in step 3.1 is included into target plate and projection
The calibrating template photo of striation is regarded as stationary by Constructed Lighting Vision System under identical shooting condition and rectangular projection target
Acquisition is shot when plate moves fixed step-length unit in camera coordinate system along the opposite direction with scanning direction respectively
K width scaling board photos, you can equivalence obtain relative motion reverse state under scaling board space occurs in camera coordinate system
Heterodromous i width new images 9 >=i >=1, i take natural number；
Step 3.2.1.2：For any one described in step 3.2.1.1 heterodromous i width new images, using well known
JeanY B. are in Pyramidal implementation of the Lucas Kanade feature tracker
Corner Detection Algorithm disclosed in description of the algorithm. documents is black in detection template image respectively
The pixel detection coordinate of four angle point ABCD of color gridWherein i=1 ..., 9 represent the width number sequence number of image, j=
1 ..., 4 represent the serial number of four angle points in the figure in current single image：Using the inner parameter described in step 2.2 and outside
Portion's parameter calibration model can establish following expression：
The pixel of four angle point ABCD in any one described in step 3.2.1.1 heterodromous i width new images is examined
Survey coordinateCorrespondence is converted into ideal image coordinate system coordinateWherein Represent the angle point image coordinate system coordinate for including distortion,Represent the ideal image coordinate system coordinate of angle point；
Coordinate is detected using corner pixelsThe corresponding two-dimensional points coordinate value in its world coordinate systemAccording to the model of Zhang Zhengyou, following equation can be obtained
In formula (1), S represents scale factor, and often the corresponding external parameter of target plate includes R in photos image iiAnd Ti
Two parameters；Ri=[r1,r2,r3] it is spin matrix, riI=1,2,3 represents spin matrix RiI-th row, TiExpression is translated towards
Amount；If
H=[r1 r2 Ti]
Then equation (1) can be expressed as form：
Divide out s in equation (2), can obtain
WhereinThe i-th row of representing matrix H, (3) formula also may indicate that into following form
(4) formula is rewritten as matrix form to obtain
Step 3.2.1.3：IfIt, can be by step according to formula (5) then when i sequentially takes 1 to 4
3.2.1.1 the ideal image coordinate system coordinate of four angle point ABCD in described every heterodromous i width new imagesJ=sequentially takes and 1 to 4 can obtain two equations according to formula (5) is corresponding and can be expressed as homogeneous equation
Group Lx=0；Therefore when i sequentially takes 1 to 4, eight equations can be obtained altogether by adding up to；
Wherein L is 8 × 9 coefficient matrix；Singular value decomposition is carried out to matrix L, then the corresponding right side of matrix L minimum singular value
Singular vector is the solution of equation group；So as to solve spin matrix RiWith translation vector Ti, so as to obtain step
3.2.1.1 the space equation of plane where described any one heterodromous i width new images, and it is right further to obtain its institute
That answers sequentially takes in the calibrating template photo k that each width of step 3.2 includes target plate and projects striation in the space equation i of plane
2 ... 9, i take the spin matrix R of natural numberiWith translation vector TiThe two external parameters；
Step 3.2.1.4：According to the present inventor in a kind of cable architectures based on spatial moment of Chinese patent CN103400399A
Method disclosed in light center extracting method is to included in every described in step 3.2.1.1 heterodromous i width new images
Rectangular projection target plate on laser projection striation carry out striation widthwise central detection, utilize optical losses detection algorithm detection
Go out the pixel coordinate point for being incident upon optical losses in every width target plate imageWherein i=1 ..., 9, i take natural number
Represent the width number sequence number of image, j=1 ..., NN take the number of natural number expression optical losses pixel coordinate point；
Step 3.2.2：Utilize photos every described in the inner parameter of video camera described in step 2.2 and step 3.2.1.3
The corresponding spin matrix R of target plate in imageiWith translation vector TiThe two external parameters throw the pixel point coordinates of optical losses
To get to corresponding three-dimensional camera coordinate system coordinate points in shadow to camera coordinate systemSo as to obtain with striation
Center line is the laser projection striation point set of characterization；
Step 3.3：Step 3.2.1 to step 3.2.2 is repeated, until sequentially obtain i=1 ..., 9 corresponding nine groups
Target plate is included with k width and projects the one-to-one laser projection striation spatial point set of calibrating template photo of striation；
Step 4：Whole three-dimensional points on nine groups of laser projection striations that step 3 is obtained project to unified take the photograph
It in camera coordinate system, and is fitted using these point sets to obtain a unique space plane, so as to solve the sky of structure optical plane
Between equation, realize the calibration of optical plane；
Step 5：Utilize intrinsic parameters of the camera described in step 2.2 and the corresponding spin matrix R of scaling board imageiPeace
Move vector TiThe two most important external parameters, by the picture of obtained in the step 3.1 in each image four angle point ABCD
Plain coordinateIt projects in unified camera coordinate system, four groups of three-dimensional point sets can be obtainedWherein i
The width number sequence number of=1 ..., 9 expression images, j=1 ..., 4；Using this four groups of three-dimensional point sets, it is fitted four space straight parallels
Line vector equation：
Step 6：The mean value of four space parallel lines vector equations described in step 5 is calculated, obtains equation：
And then it can determine the vector of the scanning direction of system
The present invention has both the double effects for improving calibration efficiency and reducing calibrated error, has higher popularization and uses valency
Value.
Claims (1)
1. include the complete scaling method of Vision Measuring System With Structured Light Stripe of scanning direction information, it is characterised in that：This method packet
Include following steps：
Step 1：Establish the auxiliary mark of the relative motion based on line slide rail system for being approximately parallel to scanning object long axis of body direction
Determine device：
Establish whole projection based on line slide rail system and photographic unit (1) and rectangular projection target plate (2) based on straight line
The relative motion auxiliary calibration device of slide type rail system, wherein, whole projection and photographic unit (1) packet based on line slide rail system
Include line slide rail (1-1), sliding block (1-2), video camera (1-3) and linear laser diode (1-4)；Video camera (1-3) and linear laser
Device (1-4) is fixed on sliding block (1-2), and sliding block (1-2) is slidably connected with line slide rail (1-1)；Rectangular projection target plate (2)
It is placed in the dynamic coverage of video camera (1-3)；Linear laser diode (1-4) is identical with the direction of video camera (1-3) and protects
It holds opposing stationary；
Step 2：Initial alignment is carried out to the parameter of video camera (1-3), specifically includes following sub-step：
Step 2.1：Conversion coordinate system is established, i.e.,：Establish world coordinate system, camera coordinate system, image physical coordinates system and figure
As pixel planes coordinate system；
Three-dimensional coordinate point coordinates (x in world coordinate systemw,yw,zw) video camera point coordinates (x is converted to successivelyc,yc,zc), reason
Think image point coordinates (xu,yu), true picture pixel point coordinates (xd,yd) and actual pixels point coordinates (xp,yp)；In addition, reference
The camera marking method of Zhang Zhengyou is by the z of world coordinate systemwAxial coordinate is set as 0, i.e. zw=0；At this point, appoint in world coordinate system
The coordinate representation of meaning point is (xw,yw, 0) or it is only meant as the two-dimensional points coordinate (x of world coordinate system XY axial planesw,yw)；
Step 2.2：Traditional gridiron pattern camera calibration plate is done into repeatedly different postures in the coverage of video camera (1-3)
Under change of pitch angle and shoot three width more than photos, then the inner parameter and external parameter of video camera (1-3) are demarcated；
I.e. by obtaining inner parameter matrixWith distortion factor K=(k1,k2,p1,p2)；
Wherein α and β represents the scale factor of U axis and V axis in pixel planes respectively, and γ represents not hanging down for two reference axis of pixel planes
The straight factor, (u0,v0) represent the coordinate that the intersection point of camera optical axis and the plane of delineation is fastened in pixel coordinate；k1,k2Represent image
The coefficient of radial direction distortion function in physical coordinates system；p1,p2Represent that tangential distortion function is in image physical coordinates system respectively
Number；
Step 3：Using the relative motion auxiliary calibration device based on line slide rail system described in step 1, obtain laser and throw
Shadow striation space plane equation, specifically includes following sub-step：
Step 3.1：Make sliding block (1-2) edge in the relative motion auxiliary calibration device based on line slide rail system described in step 1
Line slide rail (1-1) sequentially moves (k-1) a fixed step-length unit, and 9 >=k >=1, k take natural number, and allows linear laser diode
(1-4) projects to the projection striation EF of laser structure optical plane S on static rectangular projection target plate (2) always, this process
It is middle that corresponding width calibrating template photo under each position is shot to rectangular projection target plate (2) respectively using video camera (1-3),
It includes target plate until obtaining k width and projects the calibrating template photo of striation；
Step 3.2：The method for solving and demarcating according to linear model includes target plate and projected light to the k width described in step 3.1
The calibrating template photo of item carries out rectangular block Corner Detection and Light stripes center extraction detection, specifically includes following sub-step：
Step 3.2.1：Four angle point ABCD to translational moving system coordinate on transformed rectangular projection target plate (2) carry out angle
Point detection：
Step 3.2.1.1：Carry out translational moving system coordinate conversion：K width described in step 3.1 is included into target plate and projection striation
Calibrating template photo be regarded as stationary by Constructed Lighting Vision System under identical shooting condition and rectangular projection target plate exists
The k width of acquisition is shot when moving fixed step-length unit along the opposite direction with scanning direction in camera coordinate system respectively
Scaling board photo, you can equivalence obtains scaling board under relative motion reverse state and space occurs in camera coordinate system reversely transports
Dynamic i width new images, 9 >=i >=1, i take natural number；
Step 3.2.1.2：For any one described in step 3.2.1.1 heterodromous i width new images, calculated using Corner Detection
Method distinguishes the pixel detection coordinate of four angle points of black box in detection template imageWherein i=1 ..., 9 tables
The width number sequence number of diagram picture, j=1 ..., 4 represent the serial number of four angle points in the figure in current single image：Utilize step
Inner parameter and calibrating external parameters model described in 2.2 can establish following expression：
The pixel detection of four angle point ABCD in any one described in step 3.2.1.1 heterodromous i width new images is sat
MarkCorrespondence is converted into ideal image coordinate system coordinateWherein Represent the angle point image coordinate system coordinate for including distortion,Represent the ideal image coordinate system coordinate of angle point；
Coordinate is detected using corner pixelsThe corresponding two-dimensional points coordinate value in its world coordinate systemRoot
According to the model of Zhang Zhengyou, following equation can be obtained
In formula (1), S represents scale factor, and often the corresponding external parameter of target plate includes R in photos image iiAnd TiTwo
Parameter；Ri=[r1,r2,r3] it is spin matrix, riRepresent spin matrix RiI-th row, i=1,2,3, TiRepresent translation vector；
If
H=[r1 r2 Ti]
Then equation (1) can be expressed as form：
Divide out s in equation (2), can obtain
WhereinThe i-th row of representing matrix H, i=1,2,3, (3) formula also may indicate that into following form
(4) formula is rewritten as matrix form to obtain
Step 3.2.1.3：IfIt, can be by step according to formula (5) then when i sequentially takes 1 to 4
3.2.1.1 the ideal image coordinate system coordinate of four angle point ABCD in described every heterodromous i width new imagesAccording to formula (5) two equations of corresponding acquisition and it can be expressed as homogeneous equation group Lx=0, j sequentially
Take 1 to 4；Therefore when i sequentially takes 1 to 4, add up to and obtain eight equations altogether；
Wherein L is 8 × 9 coefficient matrix；Singular value decomposition is carried out to matrix L, then the corresponding right side of matrix L minimum singular value is unusual
Vector is the solution of equation group；So as to solve spin matrix RiWith translation vector Ti, so as to obtain step 3.2.1.1 institutes
The space equation of plane where stating any one heterodromous i width new images, and further obtain corresponding to it in step
Rapid 3.2 each width includes target plate and projects the calibrating template photo k of striation sequentially takes 2 in the space equation i of plane ... 9
Spin matrix RiWith translation vector TiThe two external parameters, i take natural number；
Step 3.2.1.4：To rectangular projection target included in every described in step 3.2.1.1 heterodromous i width new images
Laser projection striation on target carries out striation widthwise central detection, detects to be incident upon every width using optical losses detection algorithm
The pixel coordinate point of optical losses in target plate imageWherein i=1 ..., 9 represents the width number sequence number of image, i
Natural number is taken, j=1 ..., N represent the number of optical losses pixel coordinate point, and N takes natural number；
Step 3.2.2：Utilize photos image every described in the inner parameter of video camera described in step 2.2 and step 3.2.1.3
The corresponding spin matrix R of middle target plateiWith translation vector TiThe two external parameters arrive the pixel coordinate projection of optical losses
To get to corresponding three-dimensional camera coordinate system coordinate points in camera coordinate systemSo as to obtain in striation
Heart line is the laser projection striation point set of characterization；
Step 3.3：Step 3.2.1 to step 3.2.2 is repeated, until it is nine groups and k corresponding sequentially to obtain i=1 ..., 9
Width includes target plate and projects the one-to-one laser projection striation spatial point set of calibrating template photo of striation；
Step 4：Whole three-dimensional points on nine groups of laser projection striations that step 3 is obtained project to unified video camera
It in coordinate system, and is fitted using these point sets to obtain a unique space plane, so as to solve the space side of structure optical plane
Journey realizes the calibration of optical plane；
Step 5：Utilize intrinsic parameters of the camera described in step 2.2 and the corresponding spin matrix R of scaling board imageiAnd translation vector
TiThe two external parameters, by obtained in the step 3.1 in each image four corner pixels coordinatesIt projects to
In unified camera coordinate system, four groups of three-dimensional point sets can be obtainedWherein i=1 ..., 9 represent image
Width number sequence number, j=1 ..., 4；Using this four groups of three-dimensional point sets, it is fitted four space parallel lines vector equations：
Step 6：The mean value of four space parallel lines vector equations described in step 5 is calculated, obtains equation：
And then it can determine the vector of the scanning direction of system
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| CN108458671B (en) * | 2018-03-08 | 2020-01-03 | 西安知微传感技术有限公司 | Calibration method of line structured light three-dimensional measurement system |
| CN108662987B (en) * | 2018-04-23 | 2021-06-08 | 西南交通大学 | Calibration method of 2D camera type laser measuring head |
| CN110163918B (en) * | 2019-04-24 | 2023-03-28 | 华南理工大学 | Line structure cursor positioning method based on projective geometry |
| CN110091891B (en) * | 2019-05-05 | 2020-03-31 | 中铁检验认证中心有限公司 | High-speed train dynamic limit measuring method and device, storage medium and electronic equipment |
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| CN111126450B (en) * | 2019-11-29 | 2024-03-19 | 上海宇航系统工程研究所 | Modeling method and device for cuboid space vehicle based on nine-line configuration |
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| CN111366912B (en) * | 2020-03-10 | 2021-03-16 | 上海西井信息科技有限公司 | Laser sensor and camera calibration method, system, device and storage medium |
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