CN1740739A - Fast colourful three-dimensional chart pasting method based on linear structural laser passive scanning - Google Patents

Abstract

The technical scheme adopted by present invention includes the following steps: creating measurement model, obtaining three-dimensional contour point data of object, utilizing moving table to drive measured object and make it implement translational scanning movement and rotary scanning movement relatively to sensor, shooting color image, utilizing three-dimensional contour point data (x,y,z) measurement model to obtain pixel coordinate (U;,V;), finding (R;,G; and B;) values correspondent to the data points in the color image and making them be fitted together with space coordinate so as to obtain the correspondent coordinate color information (X;,Y;,Z;)-(R;,G;,B;). Said invention also provides its application field and range.

Description

Fast colourful three-dimensional chart pasting method based on linear structural laser passive scanning

Technical field

The present invention relates to computer vision technique, laser measuring technique, the color three dimension digitizing technique specifically, the present invention relates to the fast colourful three-dimensional chart pasting method based on linear structural laser passive scanning.

Background technology

The color three dimension measuring technique has become the hot topic in the three-dimensional measurement area research, existing three-dimensional measurement technology can only be obtained the coordinate information (x of measured surface mostly, y, z), innovation along with production technology development and technology, in animation making, mould Design and Machining, and in the industry such as archaeology, require to obtain occasion through the color three dimension data of color rendering.On the research basis of traditional optical three-dimensional measuring method, further develop out some and can obtain the measuring system of color three dimension information, most of thinkings are to utilize colored CCD as the optical information pick-up transducers, take the coloured image of measured surface, extract chromatic information (R, G B) and with three-dimensional data fits, and obtains the color three dimension data.

The linear structural laser scanning techniques is a kind of optical three-dimensional measurement technology with degree of precision and very fast measuring speed, and in the mould Design and Machining, archaeology industry etc. requires more more than using in the higher three-dimensional measurement to measuring accuracy.This measuring technique specifically comprises the active scan measuring technique again according to the difference of scan mode: promptly the relative measured surface of ccd video camera is kept motionlessly in scanning survey, and the relative measured surface of line-structured light scans.After three-dimensional measurement finished, CCD took the coloured image of same visual field, extracted corresponding chromatic information according to the pixel coordinate of striation, and was integrated into color three dimension information with the anti-three-dimensional information of obtaining.But defective such as there is the parameter calibration difficulty in the active scan measuring technique, and data ordering is irregular usually is restricted in the application.

Another kind scan mode is that drive sweep is measured, can overcome above-mentioned two kinds of defectives preferably, under this mode, sensor is relative with the position of line structure light source motionless, sensor is whole when measuring carries out relative scanning motion with measured surface, the chromatic information of extracting is difficult to map directly to the measurement data points of striation correspondence, if according to the same scanning stepping of scanning three-dimensional measurement and one by one striation gather chromatic information, need long acquisition time.So at the drive sweep measurement, and video camera produces the three-dimension measuring system that moves this class with respect to measured surface in other the scanning process, necessary proposition is a kind of quick, accurately the chromatic information chart pasting method.

Summary of the invention

For overcoming the deficiencies in the prior art, the object of the present invention is to provide a kind of at the line-structured light laser scanning measurement that can realize rotating with the translation drive sweep, set up quick three-dimensional chromatic information chart pasting method, can fast, accurately, intactly chromatic information be fitted on the three dimensional point cloud that laser scanning measurement obtains.

The technical solution used in the present invention is: the fast colourful three-dimensional chart pasting method based on linear structural laser passive scanning comprises the following steps: successively

(1) sets up space measurement coordinate system o _w-x _wy _wz _w, make o _w-x _wy _wz _wFace is right-handed coordinate system in optical plane; Set up image coordinates system on the CCD image planes, wherein the OX axle is along the pixel horizontal direction, and the OY axle is along the pixel longitudinal direction, and 0 is the imaging point of camera lens principal point in the CCD image planes, is the image planes center; The OXc axle of camera coordinate system is parallel with OX axle OY axle respectively with the OZc axis, and the OZc axle is oriented to camera optical axis, i.e. line from the image planes center to the camera lens photocentre; Make line structure optical sensor project body surface and produce a striation, (u v) calculates the world coordinates (x of striation under the space measurement coordinate system that is defined in the optical plane to the computing machine pixel coordinate by extracting on the striation a bit _w, y _w, z _w); Set up the measurement model of system:

$\left\{\begin{array}{c}{X}_d=s_x{d}_x\left({u-u}_0\right)\\ Y_d=d_y\left({v-v}_0\right)\\ X_u=X_d(1+k(X_d^2+Y_d^2))\\ Y_u=Y_d(1+k(X_d^2+Y_d^2))\\ f\·(r_1{x}_w+r_2{y}_w+r_3{z}_w+t_x)/(r_7{x}_w+r_8{y}_w+r_9{z}_w+t_z)=X_u\\ f\·(r_4{x}_w+r_5{y}_w{+r}_6{z}_w+t_y)/(r_7{x}_w+r_8{y}_w+r_9{z}_w-t_z)=Y_u\end{array}\right.$

In the formula, (X _d, Y _d) for any is ideal coordinates at the CCD image coordinates on the aforementioned striation, (X _u, Y _u) be the actual coordinate that calculates after the radial distortion of consideration camera lens, (u v) is the computing machine pixel coordinate of this point, d _x, d _y, be respectively the horizontal and vertical pixel spacing of CCD, f is a lens focus, s _xBe the pixel spacing scale factor that the horizontal direction capture card is gathered, k is the lens distortion coefficient, (u ₀, v ₀) be image planes center pixel coordinate, light-plane parameters r ₁, r ₂, r ₃, r ₄, r ₅, r ₆, r ₇, r ₈, r ₉, t _x, t _y, t _zFor being tied to the transition matrix element of space measurement coordinate system from camera coordinates by what optical plane demarcate to be determined, utilize system that object is rotated scanning survey, obtain the three-D profile point data of object;

(2) testee is maintained on the turntable maintain static, close laser instrument, transfer table is moved to optimum camera site zk, transfer table drives testee and does translation scan motion and rotation sweep motion with respect to sensor, make camera optical axis approach rotating shaft as far as possible, object can be imaged on the image planes central area of video camera, thereby makes the area of camera field of view coverture surface reach maximum:

α＝arctan|r ₁/r ₇|

xt ₁＝|t _x/sinα-|x _A|

z _o＝x _t1·tanα

R wherein ₁, r ₇Be respectively the ox in the light-plane parameters _wThe direction vector of axle, z _k=z _o+ z _A, and x _A, z _ABe respectively turntable when resting on the translation stage starting point, x under world coordinate system a bit in the rotating shaft _wAxle and z _wAxial coordinate absolute value, α are that camera optical axis is at measurement coordinate system o _w-x _wz _wThe deflection on plane, x _T1Be the intersection point of camera optical axis and optical plane distance to turntable center translated line.Utilize the turntable universal stage to drive testee and rotate to the angle position:

θ _i=(α-30)+60i i is respectively 0,1,2,3,4,5,

Corresponding each θ i position, color image shot; (3) (measurement model that z) substitution step (1) is set up calculates (X for x, y with the three-D profile point data _u, Y _u), make Y _u=rX _u, the r scale-up factor.Draw Y equally _A=rX _A, bring measurement model once more into, obtain cubic equation:

$k\left({1+r}^2\right)X_d^3+X_d-X_u=0$

Utilize the Ka Erdan formula to separate this equation and obtain unique real root X _d, obtain X _d, Y _dValue, the substitution measurement model calculates and can obtain again:

$\left\{\begin{array}{c}{u}_i=X_d/s_x{d}_x-u_0\\ v_i=Y_d/d_y-{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="A20051001515100082.png"\; state="\{\{state\}\}">v</figure-callout>}}_0\end{array}\right.,$ According to pixel coordinate (u _i, v _i) (the R of searching data point correspondence in coloured image _i, G _i, B _i) be worth, fitting together with volume coordinate to obtain corresponding coordinate chromatic information (x _i, y _i, z _i)-(R _i, G _i, B _i), 6 groups of data are reintegrated, obtain complete testee color three dimension information.

The present invention can obtain following effect: because the foundation of measurement model of the present invention, thereby provided quick three-dimensional chromatic information chart pasting method, can fast, accurately, intactly chromatic information have been fitted on the three dimensional point cloud that laser scanning measurement obtains.

Description of drawings

Fig. 1 line mechanism laser scanning measurement synoptic diagram

The optimum shooting angle of Fig. 2 is chosen

Fig. 3 rotation sweep data

Fig. 4 color three dimension scanning survey synoptic diagram

Embodiment

Further specify the present invention below in conjunction with drawings and Examples.

Figure 1 shows that the scanning measurement system model, set up space measurement coordinate system o _w-x _wy _wz _wMake o _w-x _wy _wFace is right-handed coordinate system in optical plane.Set up image coordinates system on the CCD image planes, wherein the OX axle is along the pixel horizontal direction, and the OY axle is along the pixel longitudinal direction, and 0 is the imaging point of camera lens principal point in the CCD image planes, is the image planes center.The OXc axle of camera coordinate system is parallel with OX axle OY axle respectively with the OZc axis, and the OZc axle is oriented to camera optical axis, i.e. line from the image planes center to the camera lens photocentre.Line structure optical sensor projects body surface and produces a striation.Formula (1) is the measurement model of system, and (u v) calculates the world coordinates (x of striation under the space measurement coordinate system that is defined in the optical plane to the computing machine pixel coordinate by extracting on the striation a bit _w, y _w, z _w).(X _d, Y _d) this point is ideal coordinates at the CCD image coordinates, and (X _u, Y _u) be the actual coordinate that calculates after the radial distortion of consideration camera lens, (u v) is the computing machine pixel coordinate of this point.In other parameters, d _x, d _y, be respectively laterally vertical pixel spacing of CCD, f is a lens focus, s _xBe the pixel spacing scale factor that the horizontal direction capture card is gathered, k is the lens distortion coefficient, (u ₀, v ₀) be image planes center pixel coordinate.And light-plane parameters r ₁, r ₂, r ₃, r ₄, r ₅, r ₆, r ₇, r ₈, r ₉, t _x, t _y, t _zFor be tied to the transition matrix element of systematic survey coordinate system from camera coordinates, demarcate definite by optical plane.Transfer table drives testee and does translation scan motion and rotation sweep motion with respect to sensor:

$\left\{\begin{array}{c}{X}_d=s_x{d}_x\left({u-u}_0\right)\\ Y_d=d_y\left({v-v}_0\right)\\ X_u=X_d(1+k(X_d^2+Y_d^2))\\ Y_u=Y_d(1+k(X_d^2+Y_d^2))\\ f\&CenterDot;(r_1{x}_w+r_2{y}_w+r_3{z}_w+t_x)/(r_7{x}_w+r_8{y}_w+r_9{z}_w+t_z)=X_u\\ f\&CenterDot;(r_4{x}_w+r_5{y}_w{+r}_6{z}_w+t_y)/r_7{x}_w+r_8{y}_w+r_9{z}_w-t_z=Y_u\end{array}\right.---\left(1\right)$

Utilize system that object is rotated scanning survey, obtain the three-D profile point data of object.Testee maintained on the turntable maintain static, close laser instrument, transfer table is moved to optimum camera site z _k, represented as Fig. 2, guarantee that camera optical axis approaches rotating shaft as far as possible, object can be imaged on the image planes central area of video camera, thereby makes the area of camera field of view coverture surface reach maximum:

α＝arctan|r ₁/r ₇|

x _t1＝|t _x/sinα-|x _A||

z _o＝x _t1·tanα

R wherein ₁, r ₇Be respectively the ox in the light-plane parameters _wThe direction vector of axle, z _k=z _o+ z _A, and x _A, z _ABe respectively turntable when resting on the translation stage starting point, x under world coordinate system a bit in the rotating shaft _wAxle and z _wAxial coordinate absolute value, α are that camera optical axis is at measurement coordinate system o _w-x _wz _wThe deflection on plane.

As shown in Figure 3, be to be even axle striation data because rotation sweep measures to becoming to distribute, every corresponding angle position of striation data serves as at interval these DATA DISTRIBUTION evenly to be divided into 6 groups with 60 degree.Utilize the turntable universal stage to drive testee then and rotate to the angle position:

θ _i＝(α-30)+60·i i＝0，1…5

Guarantee i group data in video camera shooting visual field, color image shot.With three-dimensional data (x, y, z) substitution model (1).Calculate (X _u, Y _u).Make Y _u=rX _u, draw Y equally _d=rX _d, bring (1) formula once more into, obtain cubic equation;

$k\left({1+r}^2\right)X_d^3+X_d-X_u=0$

Utilize the Ka Erdan formula to separate this equation and obtain unique real root X _d, obtain X _d, Y _dValue, substitution Model Calculation again can obtain:

$\left\{\begin{array}{c}{u}_i=X_d/s_x{\mathrm{\&delta;}}_x-u_0\\ v_i=Y_d/{\mathrm{\&delta;}}_y-{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="A20051001515100082.png"\; state="\{\{state\}\}">v</figure-callout>}}_0\end{array}\right.$

According to pixel coordinate (u _i, v _i) (the R of searching data point correspondence in coloured image _i, G _i, B _i) be worth, fitting together with volume coordinate to obtain corresponding coordinate chromatic information (x _i, y _i, z _i)-(R _i, G _i, B _i).At last 6 groups of data are reintegrated, just can be obtained complete testee color three dimension information.Because video camera is taken the subtended angle of revolution object greater than 120 °,, avoided the losing of colouring information of data point so be that shooting interval can intactly obtain chromatic information with 60 °.

This method is primarily aimed at the counter operation of asking chromatic information in the passive type laser scanning measurement system, and for the three-dimension measuring system model of being set up based on the Tsai camera model, this method all has versatility.This method is equally applicable to based on the stereoscopic vision method, and during optical three-dimensional scannings such as phase method were measured, the three-dimension measuring system of the scan mode that video camera moves with respect to measured surface was for the extraction of measured point chromatic information.

Claims (1)

1. the fast colourful three-dimensional chart pasting method based on linear structural laser passive scanning is characterized in that, comprises the following steps: successively

(1) sets up space measurement coordinate system o _w-x _wy _wz _w, make o _w-x _wy _wz _wFace is right-handed coordinate system in optical plane; Set up image coordinates system on the CCD image planes, wherein the OX axle is along the pixel horizontal direction, and the OY axle is along the pixel longitudinal direction, and 0 is the imaging point of camera lens principal point in the CCD image planes, is the image planes center; The OXc axle of camera coordinate system is parallel with OX axle OY axle respectively with the OZc axis, and the OZc axle is oriented to camera optical axis, i.e. line from the image planes center to the camera lens photocentre; Make line structure optical sensor project body surface and produce a striation, (u v) calculates the world coordinates (x of striation under the space measurement coordinate system that is defined in the optical plane to the computing machine pixel coordinate by extracting on the striation a bit _w, y _w, z _w); Set up the measurement model of system:

$\left\{\begin{array}{c}{X}_d=s_x{d}_x(u-u_0)\\ Y_d=d_y(v-v_0)\\ X_u=X_d(1+k(X_d^2+Y_d^2))\\ Y_u=Y_d(1+k(X_d^2+Y_d^2))\\ f\&CenterDot;(r_1{x}_w+r_2{y}_w+r_3{z}_w+t_x)/(r_7{x}_w+r_8{y}_w+r_9{z}_w+t_z)=X_u\\ f\&CenterDot;(r_4{x}_w+r_5{y}_w+r_6{z}_w+t_y)/(r_7{x}_w+r_8{y}_w+r_9{z}_w+t_z)=Y_u\end{array}\right.$

In the formula, (X _d, Y _d) for any is ideal coordinates at the CCD image coordinates on the aforementioned striation, (X _u, Y _u) be the actual coordinate that calculates after the radial distortion of consideration camera lens, (u v) is the computing machine pixel coordinate of this point, d _x, d _y, be respectively the horizontal and vertical pixel spacing of CCD, f is a lens focus, s _xBe the pixel spacing scale factor that the horizontal direction capture card is gathered, k is the lens distortion coefficient, (u ₀, v ₀) be image planes center pixel coordinate, light-plane parameters r ₁, r ₂, r ₃, r ₄, r ₅, r ₆, r ₇, r ₈, r ₉, t _x, t _y, t _zFor being tied to the transition matrix element of space measurement coordinate system from camera coordinates by what optical plane demarcate to be determined, utilize system that object is rotated scanning survey, obtain the three-D profile point data of object;

(2) testee is maintained on the turntable maintain static, close laser instrument, transfer table is moved to optimum camera site zk, transfer table drives testee and does translation scan motion and rotation sweep motion with respect to sensor, make camera optical axis approach rotating shaft as far as possible, object can be imaged on the image planes central area of video camera, thereby makes the area of camera field of view coverture surface reach maximum:

α＝arctan|r ₁/r ₇|

x _t1＝|t _x/sinα-|x _A||

z ₀＝x _t1·tanα

R wherein ₁, r ₇Be respectively the ox in the light-plane parameters _wThe direction vector of axle, z _k=z _o+ z _A, and x _A, z _ABe respectively turntable when resting on the translation stage starting point, x under world coordinate system a bit in the rotating shaft _wAxle and z _wAxial coordinate absolute value, α are that camera optical axis is at measurement coordinate system o _w-x _wz _wThe deflection on plane, x _T1Be the intersection point of camera optical axis and optical plane distance to turntable center translated line.Utilize the turntable universal stage to drive testee and rotate to the angle position:

θ _i=(α-30)+60i i is respectively 0,1,2,3,4,5, corresponding each θ i position, color image shot;

(3) (measurement model that z) substitution step (1) is set up calculates (X for x, y with the three-D profile point data _u, Y _u), make Y _u=rX _u, r is a scale-up factor.Draw Y equally _d=rX _d, bring measurement model once more into, obtain cubic equation:

$k(1+r^2)X_d^3+X_d-X_u=0$

Utilize the Ka Erdan formula to separate this equation and obtain unique real root X _d, obtain X _d, Y _dValue, the substitution measurement model calculates and can obtain again:

$\left\{\begin{array}{c}{u}_i=X_d/s_x{d}_x-u_o\\ v_i=Y_d/d_y-v_o\end{array}\right.,$ According to pixel coordinate (u _i, v _i) (the R of searching data point correspondence in coloured image _i, G _i, B _i) be worth, fitting together with volume coordinate to obtain corresponding coordinate chromatic information (x _i, y _i, z _i)-(R _i, G _i, B _i), 6 groups of data are reintegrated, obtain complete testee color three dimension information.

Images