CN104729428A - Coaxial structural light based mirror face part three-dimensional shape measuring system and measuring method - Google Patents

Abstract

The invention discloses a coaxial structural light based mirror face part three-dimensional shape measuring system. The coaxial structural light based mirror face part three-dimensional shape measuring system comprises a projector, an industrial camera, a central processing unit and a light path system. The invention further discloses a measuring method of the measuring system. The measuring method comprises a demarcating stage and a measuring stage. Based on the structure and the measuring algorithm, the problem of the integrality of the accuracy, the efficiency and the data integrity of mirror face part three-dimensional shape measuring with the higher reflectivity is solved.

Description

Based on mirror face part three dimensional shape measurement system and the measuring method of coaxial configuration light

Technical field

The invention belongs to optical three-dimensional measurement technical field, relate to a kind of mirror face part three dimensional shape measurement system based on coaxial configuration light, the invention still further relates to the measuring method of this measuring system.

Background technology

Along with the high speed development of computing machine and the information processing technology, the three-dimensional measurement technology of structure based light reaches its maturity.Multi-line structured light three-dimensional measurement is a kind contactless metering system, has that automaticity is high, speed fast, precision high, is widely used at present in fields such as reverse-engineering, product quality Real-Time Monitoring, dress designing.Time but multi-line structured light three-dimensional measurement is carried out to accurately machined metal primary colors piece surface, multi-line structured light project piece surface can produce local mirror-reflection, reciprocally to penetrate, in these areas of specular reflection, do not observe reflecting object self, can only see its surrounding objects its surface formed picture, this similarly be distortion and can change with the change of viewing angle.In addition, mirror-reflection also can cause forming Gao Guang in the picture, and the region of this Gao Guang comprises stripe information seldom, and its color is different from the color of body surface itself.These factors bring very large interference to the image procossing in subsequent optical non-cpntact measurement, directly have influence on measuring accuracy, even cannot measure.Therefore, in the real-time three-dimensional of strong reflecting metal structural member is measured, the strong reflective problem in metal surface and repeatedly reflective problem are the bottleneck problems that must solve, and Fundamentals of Measurement theory and gordian technique need to break through.

For this problem, propose different solutions both at home and abroad.Traditional method is at the low chemical reagent of measured lens surface parts surface spraying one deck reflecting rate, as developer etc.The reflection characteristic method improving piece surface by coating can improve the precision of optical measurement greatly, but also exists that to measure operation long, the shortcomings such as destruction surface of the work performance.Document 1 (patent: Japan, JP 2010-185820 publication) a kind of lighting system of novelty is proposed, the light that lighting source is sent can not shine directly on testee, thus reduce the specular reflectance of metal parts, but the method that the document relates to just uses two dimensional image treatment technology, cannot measure and highly wait three-dimensional information.Liu Yuankun (Liu Yuankun, Su Xianyu, Wu Qingyang, based on class minute surface three dimension profile measurement method [J] of streak reflex. Acta Optica .2006.2 (11): 1636-1640.) etc. a kind of 3 D measuring method of class mirror article surface is proposed, he using thin film transistor (TFT) as projection source, the picture of the projection source utilizing single industrial camera observed objects surface to reflect is measured, but the measurement range of this method is less, and measuring accuracy is not high yet.Christopher (Christopher Waddington, Jonathan Kofman.Analysis ofmeasurement sensitivity to illuminance and fringe-pattern gray levels forfringe-pattern projection adaptive to ambient lighting [J] .Opt Laser Eng.2010; 48 (2): 251 – 256.) etc. for object illumination and fringe gray level level made striped projection measuring accuracy sensitivity analysis.The method only have adjusted the gray level of maximum candy strip for eliminating the impact of surround lighting, and avoids the saturated of image.When the brightness of surround lighting is higher, the saturated signal to noise ratio (S/N ratio) that can reduce stripe pattern of image.Disclose a kind of line-structured light triangulation method based on polarization structure light in patent US7092094B2, utilize polaroid to suppress mirror-reflection and the reciprocal light penetrated, there is certain effect.But this method needs the angle of constantly adjustment polaroid in measuring process, cause measuring process to be responsible for, inefficiency, the real-time that cannot be used for industry spot measures requirement.

Summary of the invention

The object of this invention is to provide a kind of mirror face part three dimensional shape measurement system based on coaxial configuration light, solve the precision of the stronger mirror face part optical 3-dimensional topography measurement of reflectivity, efficiency and data integrity issues.

Another object of the present invention is to provide the measuring method of above-mentioned measuring system.

The technical solution adopted in the present invention is, a kind of mirror face part three dimensional shape measurement system based on coaxial configuration light, comprises projector, industrial camera, central processing unit and light path system; Projector is other arranges light path system, light path system is made up of Fresnel Lenses, spectroscope, the first anti-reflection mirror and the second anti-reflection mirror, projector is installed in parallel in the focus place of Fresnel Lenses side, spectroscope level is that miter angle is arranged on Fresnel Lenses opposite side, Fresnel Lenses upper horizontal arranges the first anti-reflection mirror, Fresnel Lenses lower horizontal arranges the second anti-reflection mirror, below second anti-reflection mirror, chessboard calibration plate is set, the top of the first anti-reflection mirror arranges industrial camera, and central processing unit is connected with projector and industrial camera respectively.

Another technical scheme of the present invention is, a kind of measuring method of the mirror face part three dimensional shape measurement system based on coaxial configuration light, comprises calibration phase and measuring phases:

Calibration phase:

Step 1, projective structure light also gathers image, concrete steps are: the below first chessboard calibration plate being placed on the second anti-reflection mirror, projector projects goes out divergent shape structural light stripes pattern and becomes parallel shape structural light stripes by Fresnel Lenses, and the structural light stripes of level is by passing through the second anti-reflection mirror vertical directive chessboard calibration plate after dichroic mirror; Often project a width structural light stripes on chessboard calibration plate, industrial camera will catch by the second anti-reflection mirror, spectroscope and the first anti-reflection mirror the chessboard calibration plate illuminated by structural light stripes, by data line transfer to central processing unit, the image sequence number of vertical direction striped is 20 width, add the scaling board image that 1 width projection is complete in vain, 1 width projection is entirely black, the scaling board image of one group is 42 width, converts chessboard calibration plate after shooting, gathers 42 width images of next group;

Step 2, demarcates the internal reference matrix of industrial camera: complete 5 groups of scaling board pictures to be collected, and central processing unit, first by the chessboard calibration board size information inputted, generates the world coordinates information (X of each angle point _w, Y _w, Z _w), due to XOY plane and the chessboard calibration plate target planes overlapping of world coordinate system, therefore Z _w=0; Then Corner Detection is carried out to first complete white scaling board image, generate the camera image coordinate information (x of each angle point _c, y _c), the internal reference matrix of industrial camera is drawn with Zhang Zhengyou scaling method;

Step 3, the internal reference matrix of labeling projection instrument: utilize the code structure striations image sequence of horizontal direction and vertical direction to come direct light component and the indirect light component of computed image, if S={I ₁, I ₂..., I _kbe the coded structured light stripe pattern sequence inputted, p is certain pixel on figure, and direct light component and the indirect light component of some p are respectively L _d(p) and L _gp (), then have:

$L_p^{+}={\max }_{0<i\&le;k}{I}_i\left(p\right),L_p^{-}={\min }_{0<i\&le;k}{I}_i\left(p\right)---\left(1\right)$

$L_d\left(p\right)=\frac{L_p^{+}-L_p^{-}}{1-b},L_g\left(p\right)=2\frac{L_p^{-}-b{L}_p^{+}}{1-b^2}---\left(2\right)$

Wherein K represents the sum of the coded structured light stripe pattern sequence of input; I is current coded structured light stripe pattern sequence; L ⁺ _prepresent the max pixel value of some p in all Selective sequences; L ⁺ _prepresent the minimum pixel value of some p in all Selective sequences; B ∈ [0,1), representing the ratio of environmental light brightness and the brightness of projector direct light, is determined by the dark fringe gray-scale value of projector projects;

Step 4, utilizes the L of each pixel of image _d(p) and L _gp (), carries out Threshold segmentation to the structural light stripes in image, then decode to the image after Threshold segmentation with the inverse process of coding, draw each pixel coordinate on each projector image; The a that sets up an office is the some pixels on camera image, and b point is the corresponding pixel on projector image planes of a, a and b at the respective homogeneous pixel coordinate as plane is:

a＝[x _c，y _c，1] ^T，b＝[x _p，y _p，1] ^T(3)

Wherein [x _c, y _c, 1] ^tfor an a at camera as the homogeneous coordinates in plane; [x _p, y _p, 1] ^tfor a b at projector as the homogeneous coordinates in plane;

Step 5, the homography matrix between defining point a and b is H, makes formula (4) below minimum:

$\hat{H}=\underset{H}{\arg \min }\underset{\&ForAll;a}{\mathrm{\&Sigma;}}{\left|\right|a-\mathrm{Hb}\left|\right|}^2---\left(4\right)$

Wherein for the minimum value of above-mentioned functional;

Step 6, the angle point under each camera image coordinate system that step 2 obtains formula (5) below of applying can show that this angle point is corresponding under projector image coordinate system

$\stackrel{\&OverBar;}{b}=\hat{H}\&CenterDot;\stackrel{\&OverBar;}{a}---\left(5\right)$

Step 7, by obtaining each corner pixels coordinate (x under camera image coordinate system above _c, y _c) corresponding pixel coordinate (x under projector image coordinate system _p, y _p), and the world coordinates information of angle point is (X _w, Y _w, Z _w), use the method for Zhang Zhengyou can demarcate the internal reference matrix drawing projector;

Step 8, the outer ginseng matrix between labeling projection instrument and camera: for the chessboard calibration plate image determining attitude, the transformational relation between camera coordinates system C and projector coordinates system C ' is such as formula shown in (6):

C'＝R·C+T (6)

Wherein [R, T] is the outer ginseng matrix between camera and projector;

Step 9, according to the inside and outside parameter of video camera and projector, draws reprojection's error of demarcation, as the criterion of stated accuracy;

Measuring phases:

Step 10, imports the calibrating parameters that calibration phase obtains;

Step 11, projective structure light also gathers image: below mirror face part being placed on the second anti-reflection mirror, according to the Part I of calibration phase, successively to mirror face part projective structure light;

Step 12, industrial camera can catch the mirror face part illuminated by structural light stripes, by data line transfer to central processing unit by the second anti-reflection mirror, spectroscope and the first anti-reflection mirror;

Step 13, calculate the three-dimensional information of testee: central processing unit to this 42 width the mirror face part image that irradiates by structured light carry out the calculating of direct light component and indirect light component, Threshold segmentation is carried out to the structural light stripes in image, then with the inverse process of coding, the image after Threshold segmentation is decoded, in conjunction with the calibration result of measurement mechanism, thus draw the three-dimensional appearance information of testee.

The invention has the beneficial effects as follows, for the reflective problem of metallic mirror surface part, structurally, the present invention utilizes Fresnel Lenses to form a parallel structured light, parallel construction striations be mapped to level be miter angle spectroscope on, after the mirror that is split reflection by anti-reflection mirror vertical sand shooting to mirror face part, the light of reflection is vertically upward through spectroscope, enter camera, so both eliminated reflective, turn avoid in image the inverted image producing camera; In Measurement Algorithm, direct light component and the indirect light component of part reflection configuration light is first calculated during decoding, can distinguish camera collection to image in specular light and diffuse, thus Threshold segmentation is carried out to the structural light stripes of mirror face part reflection, effectively can solve mirror face part and reflect the excessive problem of the structural light stripes Threshold segmentation error that causes.The present invention solves the precision of the stronger mirror face part optical 3-dimensional topography measurement of reflectivity, efficiency and data integrity issues from structure and Measurement Algorithm.

Accompanying drawing explanation

Fig. 1 is that three-dimensional measuring apparatus of the present invention demarcates schematic diagram.

Fig. 2 is three-dimensional measuring apparatus instrumentation plan of the present invention.

Fig. 3 is the calibration algorithm process flow diagram in the present invention.

Fig. 4 is the measurement procedure figure in the present invention.

In figure, 1. projector, 2. Fresnel Lenses, 3. industrial camera, 4. the first anti-reflection mirror, 5. spectroscope, 6. light path system, 7. the second anti-reflection mirror, 8. structural light stripes, 9. chessboard calibration plate, 10. central processing unit, 11. mirror face parts.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

A kind of mirror face part three dimensional shape measurement system based on coaxial configuration light of the present invention, structural representation as Figure 1-Figure 2,

Comprise: projector 1, industrial camera 3, central processing unit 10 and light path system 6.

Projector 1 is other arranges light path system 6, light path system 6 is by Fresnel Lenses 2, spectroscope 5, first anti-reflection mirror 4 and the second anti-reflection mirror 7 form, projector 1 is installed in parallel in the focus place of Fresnel Lenses 2 side, spectroscope 5 level is that miter angle is arranged on Fresnel Lenses 2 opposite side, Fresnel Lenses 2 upper horizontal arranges the first anti-reflection mirror 4, Fresnel Lenses 2 lower horizontal arranges the second anti-reflection mirror 7, below second anti-reflection mirror 7, chessboard calibration plate 9 is set, the top of the first anti-reflection mirror 4 arranges industrial camera 3, central processing unit 10 is connected with projector 1 and industrial camera 3 respectively.

Projector 1: in chronological order structured light provision pattern is projected on measurand and chessboard scaling board 9 successively by light path system 6.

Industrial camera 3: for the image of catching measurand and chessboard scaling board 9 and the structured light provision pattern changed in chronological order.

Central processing unit 10: with image pick-up card, for connecting projector 1 above and industrial camera 3,1024*768 is set to according to by the resolution of projector 1, the projector 1 that central processing unit 10 controls projects 42 width structured light provision patterns, and the order of projection is complete white, 1 width black, 20 width horizontal directions, the 20 width vertical direction structured light provision patterns entirely of 1 width.In addition, by above-mentioned industrial camera 3 gather the measurement scene image that illuminates by structural light stripes 8, in conjunction with the inside and outside parameter of demarcating the measuring system obtained, above-mentioned carrying out is decoded and calculates the three-dimensional point cloud information of measurand.

Light path system 6: be made up of Fresnel Lenses 2, spectroscope 5 and the anti-reflection mirror 7 of the first anti-reflection mirror 4, second, projector 1 is installed in parallel in the focus place of Fresnel Lenses 2, the divergent structure striations that projector 1 projects becomes parallel construction striations after Fresnel Lenses 2, parallel construction striations be mapped to level be miter angle spectroscope 5 on, the mirror 5 that is split reflection after by the second anti-reflection mirror 7 vertical sand shooting in measurand and chessboard scaling board 9.

Measuring method based on the mirror face part three dimensional shape measurement system of coaxial configuration light comprises calibration phase and measuring phases:

Calibration phase: accompanying drawing 1 is shown in by calibration structure schematic diagram, calibration algorithm process flow diagram is shown in Fig. 3.

Step 1, projective structure light also gathers image, concrete steps are: the below first chessboard calibration plate 9 being placed on the second anti-reflection mirror 7, projector 1 projects divergent shape structural light stripes pattern and becomes parallel shape structural light stripes by Fresnel Lenses 2, by the second anti-reflection mirror 7 vertically directive chessboard calibration plate 9 after the structural light stripes of level is reflected by spectroscope 5; Often project a width structural light stripes on chessboard calibration plate 9, industrial camera 3 will catch by the second anti-reflection mirror 7, spectroscope 5 and the first anti-reflection mirror 4 the chessboard calibration plate 9 illuminated by structural light stripes, by data line transfer to central processing unit 10, the present invention's projector 1 resolution used is 1024*768, according to the coding rule of structural light stripes, the image sequence number of horizontal direction striped is 2*log ₂1024=20 width, the image sequence number 2*log of vertical direction striped ₂768=19.1699, rounds up here, therefore the image sequence number of vertical direction striped is 20 width, add the scaling board image that 1 width projection is complete in vain, 1 width projection is entirely black, the scaling board image of one group is 42 width, converts chessboard calibration plate 9 after shooting, gathers 42 width images of next group.

Step 2, demarcates the internal reference matrix of industrial camera: complete 5 groups of scaling board pictures to be collected, and central processing unit 10, first by chessboard calibration plate 9 dimension information inputted, generates the world coordinates information (X of each angle point _w, Y _w, Z _w), due to XOY plane and the chessboard calibration plate 9 target planes overlapping of world coordinate system, therefore Z _w=0.Then Corner Detection is carried out to first complete white scaling board image, generate the camera image coordinate information (x of each angle point _c, y _c), the internal reference matrix of industrial camera is drawn with the scaling method of Zhang Zhengyou.

Step 3, the internal reference matrix of labeling projection instrument 1: utilize the code structure striations image sequence of horizontal direction and vertical direction to come direct light component and the indirect light component of computed image, if S={I ₁, I ₂..., I _kbe the code structure striations image sequence inputted, p is certain pixel on figure, and direct light component and the indirect light component of some p are respectively L _d(p) and L _gp (), then have:

$L_p^{+}={\max }_{0<i\&le;k}{I}_i\left(p\right),L_p^{-}={\min }_{0<i\&le;k}{I}_i\left(p\right)---\left(1\right)$

$L_d\left(p\right)=\frac{L_p^{+}-L_p^{-}}{1-b},L_g\left(p\right)=2\frac{L_p^{-}-b{L}_p^{+}}{1-b^2}---\left(2\right)$

Wherein K represents the sum of the coded structured light stripe pattern sequence of input; I is current coded structured light stripe pattern sequence; L ⁺ _prepresent the max pixel value of some p in all Selective sequences; L ⁺ _prepresent the minimum pixel value of some p in all Selective sequences; Wherein b ∈ [0,1), representing that ambient light intensity accounts for the ratio of projector direct light intensity, is determined by the dark fringe gray-scale value of projector projects.

Step 4, utilizes the L of each pixel of image _d(p) and L _gp (), carries out Threshold segmentation to the structural light stripes in image, then decode to the image after Threshold segmentation with the inverse process of coding, draw each pixel coordinate on each projector image.The a that sets up an office is the some pixels on camera image, and b point is the corresponding pixel on projector image planes of a, a and b at the respective homogeneous pixel coordinate as plane is:

a＝[x _c，y _c，1] ^T，b＝[x _p，y _p，1] ^T(3)

Wherein [x _c, y _c, 1] ^tfor an a at camera as the homogeneous coordinates in plane; [x _p, y _p, 1] ^tfor a b at projector as the homogeneous coordinates in plane.

Step 5, between defining point a and b homography matrix be H, make formula (4) below minimum:

$\hat{H}=\underset{H}{\arg \min }\underset{\&ForAll;a}{\mathrm{\&Sigma;}}{\left|\right|a-\mathrm{Hb}\left|\right|}^2---\left(4\right)$

Wherein for the minimum value of above-mentioned functional.

Step 6, the angle point under each camera image coordinate system that step 2 obtains formula (5) below of applying can show that this angle point is corresponding under projector image coordinate system

$\stackrel{\&OverBar;}{b}=\hat{H}\&CenterDot;\stackrel{\&OverBar;}{a}---\left(5\right)$

Step 7, by obtaining each corner pixels coordinate (x under camera image coordinate system above _c, y _c) corresponding pixel coordinate (x under projector image coordinate system _p, y _p), and the world coordinates information of angle point is (X _w, Y _w, Z _w), use the method for Zhang Zhengyou can demarcate the internal reference matrix drawing projector.

Step 8, the outer ginseng matrix between labeling projection instrument and camera: for the chessboard calibration plate image determining attitude, the transformational relation between camera coordinates system C and projector coordinates system C ' is such as formula shown in (6):

C’＝R·C+T (6)

Wherein [R, T] is the outer ginseng matrix between camera and projector.

Step 9, according to the inside and outside parameter of video camera and projector, draws reprojection's error of demarcation, as the criterion of stated accuracy.

Measuring phases: schematic diagram as shown in Figure 2; Process flow diagram as shown in Figure 4.

Step 10, imports the calibrating parameters that calibration phase obtains.

Step 11, projective structure light also gathers image: below mirror face part 11 being placed on the second anti-reflection mirror 7, according to the Part I of calibration phase, successively to mirror face part 11 projective structure light.

Step 12, industrial camera 3 can catch the mirror face part 11 illuminated by structural light stripes, by data line transfer to central processing unit 10 by the second anti-reflection mirror 7, spectroscope 5 and the first anti-reflection mirror 4.

Step 13, calculate the three-dimensional information of testee: central processing unit 10 to this 42 width mirror face part 11 image that irradiates by structured light carry out the calculating of direct light component and indirect light component, Threshold segmentation is carried out to the structural light stripes in image, then with the inverse process of coding, the image after Threshold segmentation is decoded.In conjunction with the calibration result of measurement mechanism, thus draw the three-dimensional appearance information of testee.

Measuring process is divided into calibration phase and measuring phases, after once demarcating, if the structural parameters of system do not change, then can carry out lasting repetitive measurement.Patent of the present invention uses the DLP projector of brightness constancy as structured light light source, utilize semi-transparent semi-reflecting spectroscope vertical reflection structured light to chessboard calibration plate and measure body surface, the three-dimensional appearance information of body surface again with different intensity light vertical reflection light to semi-transparent semi-reflecting spectroscope and through eyeglass gather by camera, utilize the one side anti-reflection eyeglass close with projector light wave to increase effective light transmission rate in process, utilize inside surface to be atomized the impact of blackening process minimizing parasitic light.

Claims (3)

1. based on a mirror face part three dimensional shape measurement system for coaxial configuration light, it is characterized in that, comprise projector (1), industrial camera (3), central processing unit (10) and light path system (6);

Projector (1) is other arranges light path system (6), light path system (6) is by Fresnel Lenses (2), spectroscope (5), first anti-reflection mirror (4) and the second anti-reflection mirror (7) form, projector (1) is installed in parallel in the focus place of Fresnel Lenses (2) side, spectroscope (5) level is that miter angle is arranged on Fresnel Lenses (2) opposite side, Fresnel Lenses (2) upper horizontal arranges the first anti-reflection mirror (4), Fresnel Lenses (2) lower horizontal arranges the second anti-reflection mirror (7), second anti-reflection mirror (7) below arranges chessboard calibration plate (9), the top of the first anti-reflection mirror (4) arranges industrial camera (3), central processing unit (10) is connected with projector (1) and industrial camera (3) respectively.

2. a kind of mirror face part three dimensional shape measurement system based on coaxial configuration light according to claim 1, it is characterized in that, described central processing unit (10) is with image pick-up card.

3. based on a measuring method for the mirror face part three dimensional shape measurement system of coaxial configuration light, it is characterized in that, comprise calibration phase and measuring phases:

Calibration phase:

Step 1, projective structure light also gathers image, concrete steps are: the below first chessboard calibration plate (9) being placed on the second anti-reflection mirror (7), projector (1) projects divergent shape structural light stripes pattern and becomes parallel shape structural light stripes by Fresnel Lenses (2), and the structural light stripes of level is by passing through the second anti-reflection mirror (7) vertically directive chessboard calibration plate (9) after spectroscope (5) reflection; Often project a width structural light stripes on chessboard calibration plate (9), industrial camera (3) will pass through the second anti-reflection mirror (7), spectroscope (5) and the first anti-reflection mirror (4) and catch the chessboard calibration plate (9) illuminated by structural light stripes, by data line transfer to central processing unit (10), the image sequence number of vertical direction striped is 20 width, add the scaling board image that 1 width projection is complete in vain, 1 width projection is entirely black, the scaling board image of one group is 42 width, convert chessboard calibration plate (9) after shooting, gather 42 width images of next group;

Step 2, demarcates the internal reference matrix of industrial camera: complete 5 groups of scaling board pictures to be collected, and central processing unit (10), first by chessboard calibration plate (9) dimension information inputted, generates the world coordinates information (X of each angle point _w, Y _w, Z _w), due to XOY plane and chessboard calibration plate (9) the target planes overlapping of world coordinate system, therefore Z _w=0; Then Corner Detection is carried out to first complete white scaling board image, generate the camera image coordinate information (x of each angle point _c, y _c), the internal reference matrix of industrial camera is drawn with Zhang Zhengyou scaling method;

Step 3, the internal reference matrix of labeling projection instrument (1): utilize the code structure striations image sequence of horizontal direction and vertical direction to come direct light component and the indirect light component of computed image, if S={I ₁, I ₂..., I _kbe the coded structured light stripe pattern sequence inputted, p is certain pixel on figure, and direct light component and the indirect light component of some p are respectively L _d(p) and L _gp (), then have:

$L_p^{+}={\max }_{0<i\&le;k}{I}_i\left(p\right),L_p^{-}={\min }_{0<i\&le;k}{I}_i\left(p\right)---\left(1\right)$

$L_d\left(p\right)=\frac{L_p^{+}-L_p^{-}}{1-b},L_g\left(p\right)=2\frac{L_p^{-}-b{L}_p^{+}}{1-b^2}---\left(2\right)$

Wherein K represents the sum of the coded structured light stripe pattern sequence of input; I is current coded structured light stripe pattern sequence; L ⁺ _prepresent the max pixel value of some p in all Selective sequences; L ⁺ _prepresent the minimum pixel value of some p in all Selective sequences; B ∈ [0,1), representing the ratio of environmental light brightness and the brightness of projector direct light, is determined by the dark fringe gray-scale value of projector projects;

Step 4, utilizes the L of each pixel of image _d(p) and L _gp (), carries out Threshold segmentation to the structural light stripes in image, then decode to the image after Threshold segmentation with the inverse process of coding, draw each pixel coordinate on each projector image; The a that sets up an office is the some pixels on camera image, and b point is the corresponding pixel on projector image planes of a, a and b at the respective homogeneous pixel coordinate as plane is:

a＝[x _c，y _c，1] ^T，b＝[x _p，y _p，1] ^T(3)

Wherein [x _c, y _c, 1] ^tfor an a at camera as the homogeneous coordinates in plane; [x _p, y _p, 1] ^tfor a b at projector as the homogeneous coordinates in plane;

Step 5, the homography matrix between defining point a and b is H, makes formula (4) below minimum:

$\hat{H}=\underset{H}{\arg \min }\underset{\&ForAll;a}{\mathrm{\&Sigma;}}{\left|\right|a-\mathrm{Hb}\left|\right|}^2---\left(4\right)$

Wherein for the minimum value of above-mentioned functional;

Step 6, the angle point under each camera image coordinate system that step 2 obtains formula (5) below of applying can show that this angle point is corresponding under projector image coordinate system

$\stackrel{\&OverBar;}{b}=\hat{H}\&CenterDot;\stackrel{\&OverBar;}{a}---\left(5\right)$

Step 7, by obtaining each corner pixels coordinate (x under camera image coordinate system above _c, y _c) corresponding pixel coordinate (x under projector image coordinate system _p, y _p), and the world coordinates information of angle point is (X _w, Y _w, Z _w), use the method for Zhang Zhengyou can demarcate the internal reference matrix drawing projector;

Step 8, the outer ginseng matrix between labeling projection instrument and camera: for the chessboard calibration plate image determining attitude, the transformational relation between camera coordinates system C and projector coordinates system C ' is such as formula shown in (6):

C′＝R·C+T (6)

Wherein [R, T] is the outer ginseng matrix between camera and projector;

Step 9, according to the inside and outside parameter of video camera and projector, draws reprojection's error of demarcation, as the criterion of stated accuracy;

Measuring phases:

Step 10, imports the calibrating parameters that calibration phase obtains;

Step 11, projective structure light also gathers image: below mirror face part (11) being placed on the second anti-reflection mirror (7), according to the Part I of calibration phase, successively to mirror face part (11) projective structure light;

Step 12, industrial camera (3) can catch the mirror face part (11) illuminated by structural light stripes, by data line transfer to central processing unit (10) by the second anti-reflection mirror (7), spectroscope (5) and the first anti-reflection mirror (4);

Step 13, calculate the three-dimensional information of testee: central processing unit (10) to this 42 width mirror face part (11) image that irradiates by structured light carry out the calculating of direct light component and indirect light component, Threshold segmentation is carried out to the structural light stripes in image, then with the inverse process of coding, the image after Threshold segmentation is decoded, in conjunction with the calibration result of measurement mechanism, thus draw the three-dimensional appearance information of testee.