CN101762243A - Structured light vision method for measuring three-dimensional profile of restricted space - Google Patents

Abstract

The invention belongs to the technical field of measurement, and provides a structured light vision method for measuring the three-dimensional profile of a restricted space. A miniature structured light vision measurement system is used to enter the restricted space and perform three-dimensional profile measurement. The miniature structured light vision measurement system consists of a structured light projector 1, a structured light sensor 2, an imaging control unit, an image acquisition card and a computer, wherein the structured light projector 1 consists of a projector, a telecentric imaging lens 3, an optical fiber image bundle 4 and a projection lens 5; and the structured light sensor 2 consists of the projection lens 5 of the structured light projector 1, an endoscopic camera 6, a plane reflector 7 and a plane reflector 8. The measurement method comprises the following steps that: the computer generates a sinusoidal structured light pattern; the projector, the telecentric imaging lens 3, the optical fiber image bundle 4 and the projection lens 5 project the pattern onto the surface of an object to be measured; the endoscopic camera 6 shoots a modulated structured light stripe image; and the three-dimensional information of the surface of the object to be measured is calculated according to a measurement model. The method realizes the miniaturization of the structured light sensor, and provides an effective technical means for realizing the off-line and on-line measurement of the three-dimensional profile of the restricted space.

Description

A kind of structured light vision method for measuring three-dimensional profile of restricted space

Technical field

The invention belongs to the three-dimensional measurement field, relate to a kind of structured light vision method for measuring three-dimensional profile of restricted space.

Background technology

The measurement of three-dimensional object surface pattern is called reverse engineering again in mechanical manufacturing field, the important effect of play more and more in modern processing and manufacturing and actual job production.Along with more and more widely the application in scientific research, medical diagnosis, engineering design, the on-the-spot mark analysis of criminal investigation, automatic on-line detection, quality control, robot and many production runes of the non-contact detecting technology of three-dimensional object surface shape, people are also more and more higher to the requirement of measuring three-dimensional morphology, and its application is also in continuous expansion.

In body surface three-dimensional is measured, small size and large-sized measurement are the emphasis and the focuses of current research, development need along with modern processing and manufacturing and production operation, the small size on-line measurement is subjected to domestic and international researcher's great attention gradually, as the synthetic geometry parameter of the small component surface of tooth impression-taking, engine, integrated IC chip, the small-sized machine parts wear measurement of run up miniature tourbillon planar survey and duty etc.These member stock sizes are less, and some parts has non-dismountable property.Modern processing manufacturing industry need be with production quality control in the production and processing stage, and target is to realize zero waste product manufacturing, and requirement can realize the three-dimensional surface shape on-line measurement of parts in process of manufacture for this reason.For the parts in the production operation process, in order at utmost to prolong its serviceable life, need in time to understand the surface abrasion and the dynamic deformation of parts, also requirement can realize the on-line measurement of parts three-dimensional appearance.People's (model illumination such as model illumination, Li Ruijun, a kind of novel three-dimensional topography measurement device based on optical fiber image transmission beam, the patent No. 200520070076.8) develops a kind of novel three-dimensional topography measurement device, realized telemeasurement, but the detecting head of above-mentioned measurement mechanism can only launch vertically, can not measure the inside surface of vertical axial, can not satisfy the three-dimensional profile of restricted space measurement requirement fully.Therefore, research baby surface three-dimensional on-line measuring, even in the restricted clearance that can deep enough measure field, embed and be integrated into an urgent demand that the 3-D measuring apparatus that has small-sized projection mechanism in the processing and manufacturing system has become modern processing manufacturing industry and production operation.

Summary of the invention

Technical matters to be solved by this invention is: propose a kind of structured light vision method for measuring three-dimensional profile of restricted space, develop a kind of structured light sensor that can enter restricted clearance, for the on-line measurement of three-dimensional profile of restricted space provides a kind of effective technology means.

Technical solution of the present invention is:

1, a kind of two-sided target is characterized in that, two-sided target is designated as a flat board, and two dull and stereotyped plane A are parallel with B, and the A face is provided with the black and white chessboard square of arranged, and the quantity of square is 4～25, the length of side 1～5mm of square, and precision is 0.01～0.05mm; The B face is the onesize blank of same material; Two-sided target target thickness is 2～10mm.

2, a kind of structured light vision method for measuring three-dimensional profile of restricted space, use small-scale structure light vision measurement system to enter restricted clearance and carry out measuring three-dimensional morphology, said small-scale structure light vision measurement system is made up of structured light projector 1, structured light sensor 2, imaging control module, image pick-up card and computing machine; Structured light projector 1 is made up of projector, telecentric imaging camera lens 3, optical fiber image transmission beam 4 and projection lens 5; Structured light sensor 2 is made up of projection lens 5 and endoscopic camera 6, plane mirror 7 and the plane mirror 8 of structured light projector 1; Image card is installed in the calculating; The imaging control module is the driving circuit of endoscopic camera 6; The structured light patterns that is generated by computer programming is connected to projector by data line and throws; Projector is by telecentric imaging camera lens 3 and optical fiber image transmission beam 4 couplings, and telecentric imaging camera lens 3 will be imaged on from the structured light patterns of projector outgoing on the incident end face of optical fiber image transmission beam 4; The projection lens 5 of optical fiber image transmission beam 4 exit ends is incident upon the testee surface with structured light patterns through flat mirror reflects mirror 8; The structural light stripes image that endoscopic camera 6 is taken through the testee modulation by plane mirror 7, is handled images acquired in computing machine by the image pick-up card images acquired, according to measurement model, calculates the three-dimensional information of body surface; It is characterized in that measuring process is divided into calibration phase and measuring phases, but continuous coverage after once demarcating, and concrete steps are:

2.1, calibration phase:

2.1.1, structured light sensor is fixed on the multiple degrees of freedom The Cloud Terrace projective patterns of shielding construction light projector; The described two-sided target of step 1 is positioned on the measuring table of distance structure optical sensor 20～100mm, and two-sided target target A faces up, and takes two-sided target target image by endoscopic camera, is called the camera calibration image;

2.1.2, on measuring table overturning step 1 described two-sided target, guarantee that two-sided target target B faces up; To two-sided target target B face, black quantity from the chessboard square is 4～160 by structured light projector projection black and white chessboard calcspar case, the length of side 50～300pixels of square, and precision is 0.5pixel; Projection pattern is known as the location of pixels on the plane at projector; Take two-sided target target image by endoscopic camera, be called the structured light projector uncalibrated image;

2.1.3, by rotation and translation The Cloud Terrace, change the attitude and the position of structured light sensor, repeating step 2.1.1 and 2.1.2 take 6～8 groups of camera calibration images and structured light projector uncalibrated image respectively;

2.1.4, the camera calibration image calibrating camera parameters that utilizes step 2.1.1～2.1.3 to take; The structured light projector uncalibrated image calibration structure light projector parameter of utilizing step 2.1.1～2.1.3 to take;

2.2, measuring phases:

2.2.1, utilize the vertical sinusoidal light candy strip of 4 width of cloth that structured light projector throws one-period successively to the testee surface, adjacent image projector as the plane on the phase difference value of respective pixel be π/4; Take the image of testee successively by endoscopic camera, be called one group of vertical sinusoidal light stripe pattern; Calculate initial vertically wrapped phase figure by four step phase-shift methods;

2.2.2, the periodicity of vertical sinusoidal light candy strip is increased by 1, repeating step 2.2.1 N-1 time altogether, obtain the N that periodicity 1～N increases progressively continuously and organize vertical sinusoidal light stripe pattern, and find the solution respectively and obtain the vertical wrapped phase figure of the N width of cloth, the N value is the integer between 2～10;

2.2.3, utilize the time phase method of development that the vertical wrapped phase figure that is blocked in the scope at [π, π] is launched, obtain a width of cloth and launch phase diagram longitudinally, scope is [(N-1) π, (N-1) π]; Linear corresponding relation by phase place and projector pixel coordinate, obtain video camera as same place on the plane at projector as the horizontal ordinate on the plane, said same place be meant the same space point video camera as the plane on and projector as the plane on corresponding pixel;

2.2.4, change the projecting pattern of structured light projector into laterally positive line-structured light, repeating step 2.2.1～2.2.3, obtain video camera as same place on the plane at projector as the ordinate on the plane;

2.2.5, demarcate the small-scale structure light vision measurement system model parameter obtain by step 2.1, utilize video camera to calculate the three-dimensional coordinate of spatial point under world coordinate system as the pixel on the plane as pixel on the plane and corresponding projector.

3, as the described small-scale structure optical sensor that is applied to restricted clearance of step 2, it is characterized in that structured light sensor 2 the has been integrated projection lens 5 and the endoscopic camera 6 of structured light projector; Structured light projection and tested image taking all adopt the mirror image mode, form the angular position relation by the virtual video camera of plane mirror 7 acquisitions, virtual projection camera lens and the testee that plane mirror 8 obtains.

Advantage of the present invention is:

The first, introduce the plane mirror steering structure in the structured light sensor, shortened the lateral separation between structured light projector and the video camera, realized the miniaturization of detecting head;

The second, structured light sensor adopts level crossing to change original triangle and measures light path, makes sensor can measure the object that is parallel to camera optical axis, promptly can go deep into restricted clearance and measure operation;

Three, adopt method of development expansion time phase wrapped phase, improved robustness and the noise resisting ability measured than classic method;

Four, set up structured light projector model and camera model, made to rise to recovery three-dimensional data points cloud by traditional calculating one dimension elevation information, for the multi-view angle three-dimensional data splicing is laid a good foundation based on the structural light measurement of separating the phase mode;

Five, used two-sided target in the calibration process, only the needs upset once can realize the demarcation to projector, cost is low, and is simple and practical, is fit to on-site proving;

Six, simple in measurement system structure, the structured light sensor flexibility is good, and has degree of precision, is fit to the in-site measurement of restricted clearance.

Description of drawings

Fig. 1 is a small-scale structure light vision measurement system synoptic diagram.Among Fig. 1, the 1st, structured light projector, the 2nd, structured light sensor, the 3rd, telecentric imaging camera lens, the 4th, optical fiber image transmission beam, the 5th, projection lens, the 6th, endoscopic camera, the 7th, plane mirror, the 8th, plane mirror.

Fig. 2 is that two-sided target indicates intention.

Fig. 3 is a structured light vision sensor measurement model synoptic diagram.

Embodiment

Below the present invention is described in further details.The present invention proposes a kind of structured light vision method for measuring three-dimensional profile of restricted space, use small-scale structure light vision measurement system to enter restricted clearance and carry out measuring three-dimensional morphology, the principle schematic of said small-scale structure light vision measurement system as shown in Figure 1, measuring system is made up of structured light projector 1, structured light sensor 2, imaging control module, image pick-up card and computing machine; Structured light projector 1 is made up of projector, telecentric imaging camera lens 3, optical fiber image transmission beam 4 and projection lens 5; Structured light sensor 2 is made up of projection lens 5 and endoscopic camera 6, plane mirror 7 and the plane mirror 8 of structured light projector 1; Image card is installed in the calculating; The imaging control module is the driving circuit of endoscopic camera 6; The structured light patterns that is generated by computer programming is connected to projector by data line and throws; Projector is by telecentric imaging camera lens 3 and optical fiber image transmission beam 4 couplings, and telecentric imaging camera lens 3 will be imaged on from the structured light patterns of projector outgoing on the incident end face of optical fiber image transmission beam 4; The projection lens 5 of optical fiber image transmission beam 4 exit ends is incident upon the testee surface with structured light patterns through flat mirror reflects mirror 8; The structural light stripes image that endoscopic camera 6 is taken through the testee modulation by plane mirror 7, is handled images acquired in computing machine by the image pick-up card images acquired, according to measurement model, calculates the three-dimensional information of body surface.

As shown in Figure 1, structured light sensor 2 of the present invention the has been integrated projection lens 5 and the endoscopic camera 6 of structured light projector 1 utilizes level crossing to shorten the lateral separation of projection lens and video camera to structure; Structured light projection and tested image taking all adopt the mirror image mode, form the angular position relation by the virtual video camera of plane mirror 7 acquisitions, virtual projection camera lens and the testee that plane mirror 8 obtains, projective structure light projects body surface by primary event, and is received by video camera by another flat mirror reflects.

Said target is a kind of two-sided target, as shown in Figure 2, it is characterized in that, two-sided target is designated as a flat board, and two dull and stereotyped plane A are parallel with B, and the A face is provided with the black and white chessboard square of arranged, the quantity of square is 4～25, the length of side 1～5mm of square, and precision is 0.01～0.05mm; The B face is the onesize blank of same material; Two-sided target target thickness is 2～10mm.

Measuring method of the present invention is to adopt the sinusoidal light projecting pattern, in conjunction with phase-shift measurement algorithm, structured light scaling method, recovers the testee three-dimensional surface shape.

At first introduce the phase-shift measurement method.The phase-shift measurement method is divided into four step phase shift and two steps of phase unwrapping:

(1) produces the sinusoidal structured light pattern by computing machine and throw,, obtain I by the endoscopic camera images acquired by structured light projector ₁..., I ₄Four width of cloth phase shifted images, the phase difference value of same pixel position is α=π/4 in four width of cloth images, and the brightness of four width of cloth image each points can be expressed as so:

I _n(t)＝I _r+I ₀+2A _rA ₀?cos?[φ(t)+φ _n]

$[{\mathrm{\φ}}_n=\frac{(n-1)\mathrm{\π}}{2},n=\mathrm{1,2,3,4}]---\left[1\right]$

I wherein _rAnd I ₀Be the gray-scale value of reference and measured object, A _rAnd A ₀It is the light intensity of reference and measured object.The phase diagram of t time can obtain by through type [2]:

$\mathrm{\φ}\left(t\right)={\tan }^{-1}\left(\frac{\mathrm{\Δ}{I}_{42}\left(t\right)}{\mathrm{\Δ}{I}_{13}\left(t\right)}\right)---\left[2\right]$

Wherein

ΔI _ij(t)＝I _i(t)-I _j(t) [3]

(2) utilize the time phase method of development that the wrapped phase that is blocked in the scope at [π, π] is launched, obtain launching phase diagram, realize the unique corresponding relation of image phase value and three-dimensional coordinate.By throwing time dependent sinusoidal light candy strip of a series of cycles, the structural light stripes image that photographs can be thought a sequence on the time shaft, writing time, the sequence stripe pattern of axle constituted three-dimensional PHASE DISTRIBUTION, respectively each pixel is independently launched along time shaft, so the very low image border of signal to noise ratio (S/N ratio) and the subregion data that can not have influence on other positions.With φ (m, n, t) represent t open phase diagram (t=0,1 ..., s) in (m, the n) phase place of coordinate points can utilize formula [4] directly to try to achieve Δ φ (t):

$\mathrm{\Δ\φ}\left(t\right)={\tan }^{-1}\left[\frac{\mathrm{\Δ}{I}_{42}\left(t\right)\mathrm{\Δ}{I}_{13}(t-1)-\mathrm{\Δ}{I}_{13}\left(t\right)\mathrm{\Δ}{I}_{42}(t-1)}{\mathrm{\Δ}{I}_{13}\left(t\right)\mathrm{\Δ}{I}_{13}(t-1)+\mathrm{\Δ}{I}_{42}\left(t\right)\mathrm{\Δ}{I}_{42}(t-1)}\right]---\left[4\right]$

Calculate s width of cloth phase unwrapping figure by [5] formula at last:

$\mathrm{\φ}(m,n,s)=\underset{t=1}{\overset{s}{\mathrm{\Σ}}}\mathrm{\Δ\φ}(m,n,t)---\left[5\right]$

Small-scale structure light vision measurement system is set up the binocular vision model, and this model is regarded structured light projector as inverted video camera, thereby has the mathematical model identical with video camera.As shown in Figure 3, establish P and be in the space more arbitrarily, it is at world coordinate system O _w-x _wy _wz _wUnder homogeneous coordinates be M=(x _w, y _w, z _w, 1) ^TP be P at video camera as the imaging point on the plane, it is at image coordinate system O _u ^c-x _u ^cy _u ^cUnder homogeneous coordinates be $m_u^c={(x_u^c,y_u^c,1)}^T,$ Q be P at projector as the same place on the plane, it is at image coordinate system O _u ^p-x _u ^py _u ^pUnder homogeneous coordinates be $m_u^p={(x_u^p,y_u^p,1)}^T.$

Camera model is expressed as:

${\mathrm{sm}}_u^c=A^c\left(R^c\right|t^c)M---\left[6\right]$

Wherein s is any non-vanishing scale factor.R ^cAnd t ^cBe the video camera external parameter, represent that respectively world coordinates is tied to the rotation matrix and the translation vector of camera coordinate system.A ^cBe intrinsic parameters of the camera, be expressed as:

$A^c=\left(\begin{array}{ccc}{f}_x^c& 0& u_0^c\\ 0& f_y^c& v_0^{\mathrm{<figure-callout\; id="0"\; label="c"\; filenames="H2010100336014E00013.png"\; state="\{\{state\}\}">c</figure-callout>}}\\ 0& 0& 1\end{array}\right)---\left[7\right]$

F wherein _x ^cAnd f _y ^cBe respectively along x axle and the axial effective focal length of y, (u ₀ ^c, v ₀ ^c) be figure principal point O _pPixel coordinate.

Similar with camera model, the structured light projector model representation is:

$\mathrm{\&rho;}{m}_u^p=A^p\left(R^p\right|t^p)M---\left[8\right]$

Wherein ρ is any non-vanishing scale factor.R ^pAnd t ^pBe the external parameter of structured light projector, represent that respectively world coordinates is tied to the rotation matrix and the translation vector of structured light projector coordinate system.A ^pBe intrinsic parameters of the camera, be expressed as:

$A^p=\left(\begin{array}{ccc}{f}_x^p& 0& u_0^p\\ 0& f_y^p& v_0^{\mathrm{<figure-callout\; id="0"\; label="p"\; filenames="H2010100336014E00013.png"\; state="\{\{state\}\}">p</figure-callout>}}\\ 0& 0& 1\end{array}\right)---\left[9\right]$

Structured light vision method for measuring three-dimensional profile of restricted space of the present invention is characterized in that, measuring process is divided into calibration phase and measuring phases, but continuous coverage after once demarcating, and concrete steps are:

1, calibration phase:

1.1, structured light sensor is fixed on the multiple degrees of freedom The Cloud Terrace projective patterns of shielding construction light projector; Two-sided target is positioned on the measuring table of distance structure optical sensor 20～100mm, two-sided target target A faces up, and takes two-sided target target image by endoscopic camera, is called the camera calibration image.

1.2, on measuring table overturning step 1 described two-sided target, guarantee that two-sided target target B faces up; To two-sided target target B face, the quantity of black and white chessboard square is 4～160 by structured light projector projection black and white chessboard calcspar case, the length of side 50～300pixels of square, and precision is 0.5pixel; Projection pattern is known as the location of pixels on the plane at projector; Take two-sided target target image by endoscopic camera, be called the structured light projector uncalibrated image.

1.3, by rotation and translation The Cloud Terrace, change the attitude and the position of structured light sensor, repeating step 1.1 and 1.2 is taken 6～8 groups of camera calibration images and structured light projector uncalibrated image respectively.

1.4, the camera calibration image calibrating camera parameters that utilizes step 1.1～1.3 to take; The structured light projector uncalibrated image calibration structure light projector parameter of utilizing step 1.1～1.3 to take.

Camera calibration adopts Zhang Zhengyou to demarcate based on the scaling method of planar target, referring to article " a kind of new flexible camera calibration technology " [A flexible new technique for camera calibration], IEEE periodical " pattern analysis and machine intelligence ", 22 (11), the 1330th～1334 page, 2000 years.[IEEETransactions?on?Pattern?Analysis?and?Machine?Intelligence，22(11)，2000)。Structured light projector scaling method and camera calibration are similar.

2, measuring phases:

2.1, utilize the vertical sinusoidal light candy strip of 4 width of cloth that structured light projector throws one-period successively to the testee surface, adjacent image projector as the plane on the phase difference value of respective pixel be π/4; Take the image of testee successively by endoscopic camera, be called one group of vertical sinusoidal light stripe pattern; Calculate initial vertically wrapped phase figure by four step phase-shift methods.

2.2, the periodicity of vertical sinusoidal light candy strip is increased by 1, repeating step 2.1 N-1 time altogether, obtain the N that periodicity 1～N increases progressively continuously and organize vertical sinusoidal light stripe pattern, and find the solution respectively and obtain the vertical wrapped phase figure of the N width of cloth, the N value is the integer between 2～10.

2.3, utilize the time phase method of development that the vertical wrapped phase figure that is blocked in the scope at [π, π] is launched, obtain a width of cloth and launch phase diagram longitudinally, scope is [(N-1) π, (N-1) π]; Linear corresponding relation by phase place and projector pixel coordinate, obtain video camera as same place on the plane at projector as the horizontal ordinate on the plane, said same place be meant the same space point video camera as the plane on and projector as the plane on corresponding pixel.

2.4, change the projecting pattern of structured light projector into laterally positive line-structured light, repeating step 2.1～2.3, obtain video camera as same place on the plane at projector as the ordinate on the plane.

2.5, the external parameter R of the video camera of the two-sided target that utilizes step 2.1 to demarcate to obtain and last position ^cWith t ^cInner parameter A with video camera ^c, as shown in Figure 3, try to achieve video camera as the straight line l in the corresponding space of pixel on the plane by formula [6] ^cEquation; Utilize the external parameter R of the structured light projector of two-sided target and last position ^pWith t ^pInner parameter A with structured light projector ^p, try to achieve projector as the straight line l in the corresponding space of same place on the plane by formula [8] ^pEquation; By two straight-line equations, obtain the three-dimensional coordinate of spatial point under world coordinate system by least square method.

Embodiment

Projector is selected the EP708 of Optoma company for use, and the telecentric imaging camera lens is selected the GCO-23 telecentric imaging camera lens series of Daheng's photoelectricity.According to the restricted clearance measurement requirement, endoscopic camera has less physical dimension, resolution height, response characteristics such as quick, therefore 1/6 inch endoscopic camera of HX-016HP10 type of selecting Hangzhou China core digital technology company limited to produce, the CCD front end sectional dimension of this video camera is controlled in the scope of diameter 15mm, satisfies the requirement of this measuring system miniaturization.

Utilize the scaling method described in the present invention, the parameter of calibration structure light projector is as follows:

$f_x^p=(88\&PlusMinus;2)\&times;{10}^1\mathrm{pixel},$ $f_y^p=(120\&PlusMinus;7)\&times;{10}^1\mathrm{pixel}$

$u_0^p=(30\&PlusMinus;4)\&times;{10}^1\mathrm{pixel},$ $v_0^p=(70\&PlusMinus;4)\&times;{10}^1\mathrm{pixel}$

The parameter of camera calibration:

$f_x^c=(117\&PlusMinus;4)\&times;{10}^1\mathrm{pixel},$ $f_y^c=(116\&PlusMinus;4)\&times;{10}^1\mathrm{pixel}$

$u_0^c=(37\&PlusMinus;2)\&times;{10}^1\mathrm{pixel},$ $v_0^c=(27\&PlusMinus;1)\&times;{10}^1\mathrm{pixel}$

External parameter in the calibration process under last position of structured light projector:

$R^p=\left(\begin{array}{c}-\mathrm{0.004,0.997,0.072}\\ 0.988,-\mathrm{0.007,0.156}\\ \mathrm{0.156,0.072},-0.985\end{array}\right),$ $t^p=\left(\begin{array}{c}-9.67\\ -22.09\\ 83.56\end{array}\right)$

External parameter in the calibration process under last position of video camera

$R^c=\left(\begin{array}{c}-\mathrm{0.106,0.979,0.172}\\ 0.983,-\mathrm{0.130,0.131}\\ \mathrm{0.151,0.155},-0.976\end{array}\right),$ $t^c=\left(\begin{array}{c}-11.32\\ -2.68\\ 80.16\end{array}\right)$

Target unique point in the world coordinate system is heavily thrown back the plane of delineation, calculate the RMS error between heavy cultellation and its real image coordinate.Camera calibration is heavily thrown the RMS pixel error and is [0.281 pixel, 0.292 pixel], and structured light projector is heavily thrown the RMS pixel error and is [0.357 pixel, 0.363 pixel].

Claims (3)

1. a two-sided target is characterized in that, two-sided target is designated as a flat board, and two dull and stereotyped plane A are parallel with B, and the A face is provided with the black and white chessboard square of arranged, and the quantity of square is 4～25, the length of side 1～5mm of square, and precision is 0.01～0.05mm; The B face is the onesize blank of same material; Two-sided target target thickness is 2～10mm.

2. structured light vision method for measuring three-dimensional profile of restricted space, use small-scale structure light vision measurement system to enter restricted clearance and carry out measuring three-dimensional morphology, said small-scale structure light vision measurement system is made up of structured light projector (1), structured light sensor (2), imaging control module, image pick-up card and computing machine; Structured light projector (1) is made up of projector, telecentric imaging camera lens (3), optical fiber image transmission beam (4) and projection lens (5); Structured light sensor (2) is made up of projection lens (5) and endoscopic camera (6), plane mirror (7) and the plane mirror (8) of structured light projector (1); Image card is installed in the calculating; The imaging control module is the driving circuit of endoscopic camera (6); The structured light patterns that is generated by computer programming is connected to projector by data line and throws; Projector is by telecentric imaging camera lens (3) and optical fiber image transmission beam (4) coupling, and telecentric imaging camera lens (3) will be imaged on from the structured light patterns of projector outgoing on the incident end face of optical fiber image transmission beam (4); The projection lens (5) of optical fiber image transmission beam (4) exit end is incident upon the testee surface with structured light patterns through flat mirror reflects mirror (8); Endoscopic camera (6) is taken the structural light stripes image of modulating through testee by plane mirror (7),, in computing machine images acquired is handled by the image pick-up card images acquired, according to measurement model, calculates the three-dimensional information of body surface; It is characterized in that measuring process is divided into calibration phase and measuring phases, but continuous coverage after once demarcating, and concrete steps are:

2.1, calibration phase:

2.1.1, structured light sensor is fixed on the multiple degrees of freedom The Cloud Terrace projective patterns of shielding construction light projector; Two-sided target as claimed in claim 1 is positioned on the measuring table of distance structure optical sensor 20～100mm, and two-sided target target A faces up, and takes two-sided target target image by endoscopic camera, is called the camera calibration image;

2.1.2, on measuring table upset two-sided target as claimed in claim 1, guarantee that two-sided target target B faces up; To two-sided target target B face, the quantity of black and white chessboard square is 4～160 by structured light projector projection black and white chessboard calcspar case, the length of side 50～300pixels of square, and precision is 0.5pixel; Projection pattern is known as the location of pixels on the plane at projector; Take two-sided target target image by endoscopic camera, be called the structured light projector uncalibrated image;

2.1.3, by rotation and translation The Cloud Terrace, change the attitude and the position of structured light sensor, repeating step 2.1.1 and 2.1.2 take 6～8 groups of camera calibration images and structured light projector uncalibrated image respectively;

2.1.4, the camera calibration image calibrating camera parameters that utilizes step 2.1.1～2.1.3 to take; The structured light projector uncalibrated image calibration structure light projector parameter of utilizing step 2.1.1～2.1.3 to take;

2.2, measuring phases:

2.2.1, utilize the vertical sinusoidal light candy strip of 4 width of cloth that structured light projector throws one-period successively to the testee surface, adjacent image projector as the plane on the phase difference value of respective pixel be π/4; Take the image of testee successively by endoscopic camera, be called one group of vertical sinusoidal light stripe pattern; Calculate initial vertically wrapped phase figure by four step phase-shift methods;

2.2.2, the periodicity of vertical sinusoidal light candy strip is increased by 1, repeating step 2.2.1 N-1 time altogether, obtaining periodicity is that the N that 1～N increases progressively continuously organizes vertical sinusoidal light stripe pattern, and finds the solution respectively and obtain the vertical wrapped phase figure of the N width of cloth, and the N value is the integer between 2～10;

2.2.3, utilize the time phase method of development that the vertical wrapped phase figure that is blocked in the scope at [π, π] is launched, obtain a width of cloth and launch phase diagram longitudinally, scope is [(N-1) π, (N-1) π]; Linear corresponding relation by phase place and projector pixel coordinate, obtain video camera as same place on the plane at projector as the horizontal ordinate on the plane, said same place be meant the same space point video camera as the plane on and projector as the plane on corresponding pixel;

2.2.4, change the projecting pattern of structured light projector into laterally positive line-structured light, repeating step 2.2.1～2.2.3, obtain video camera as same place on the plane at projector as the ordinate on the plane;

2.2.5, demarcate the small-scale structure light vision measurement system model parameter obtain by step 2.1, utilize video camera to calculate the three-dimensional coordinate of spatial point under world coordinate system as the pixel on the plane as pixel on the plane and corresponding projector.

3. the small-scale structure optical sensor that is applied to restricted clearance as claimed in claim 2 is characterized in that, structured light sensor (2) has been integrated projection lens of structured light projector (5) and endoscopic camera (6); Structured light projection and tested image taking all adopt the mirror image mode, form the angular position relation by the virtual video camera of plane mirror (7) acquisition, virtual projection camera lens and the testee that plane mirror (8) obtains.

Images