Research On System Calibration Technology Based On Binocular Stereo Vision

In the binocular laser scanner system,the same object is observed by two cameras which are placed in parallel to obtain the real-time image information.At the same time,the light strip is projected on the visual surface of the object,and the three-dimensional information of the object is accurately obtained by combining the deflection of the perceptual image and the laser rotation of the light strip.In this paper,the camera calibration and system calibration of the laboratory binocular laser scanning system are realized.The calibration of the camera is completed by the Zhang Zhengyou checkerboard calibration method.The equation of the axis of the laser rotation is further solved based on the calibrated camera parameters.The following work has been completed in this paper:(1)Camera calibration completed through the checkerboard calibration method.In the experiment,we made a checkerboard target of 710?,and the length of the lattice is 20 mm.According to the physical coordinates and the corresponding point coordinates in the image,camera parameters are obtained based on the camera internal linear constraints.(2)The calibration of laser rotation axis in the scanner system has been completed.In the process of the laser beam scanning through the front mirror,the linear laser stripe forms two beams on the two plane of the stereoscopic target.The left camera coordinate system is selected as the benchmark,and the right camera coordinate system is transformed to the left camera coordinate system through 3D reference transformation.The beam image captured by the camera is extracted from the stripe center.Then it is converted to the camera coordinate system,and the laser plane equation is obtained according to the proposed feature point method and the fitting plane method.Finally,the position of the target if kept still,and another laser projection image is taken to obtain the plane equations after the laser is rotated.From the intersection of the two laser planes obtained above,the linear equation of the laser rotation axis in the camera coordinate system can be determined.The calibration of two cameras and laser rotation axes in the binocular laser scanning system are realized in this paper.The average error between the image point coordinates calculated by the re-projection method and the detected image point coordinates using the actual image sub-pixel is 0.416152 pixels.The rotation matrix between the two cameras is solved during the system calibration phase and basically conforms to the unit matrix.The axisoffset of the rotation vector is close to the baseline distance.Based on the above results,the laser plane equation is obtained.Finally,six sets experiments are carried out to ensure the stability of the solution process of the rotation axis of the laser.The calibration results meet the demand of adding laser plane constraints,and can be used to eliminate the noise data during the scanning process,and can remove the large error data points as well.