Research On High-speed,Real-time3-D Measurement Of Moving Object Based On Structured Light Projection

Structured light three-dimensional(3D) shape measurement technique has been widely used in industrial inspection, pattern recognition and reverse en-gineering and showed its perspective application. With the development of indus-trial production and automation, current3D shape measurement techniques based on standard frame rate can not meet the requirement for3D shape measurement of fast moving object. High speed, real-time and moving object measurement technology is becoming the development trend of3D shape measurement tech-nology. Currently,3D shape measurement methods based on structured light can not take into account3D shape measurement of moving object and measure-ment efficiency. Based on gray-coded structured light method, this thesis focused research on high-speed3D shape measurement, motion-compensated synchroniza-tion errors reduction algorithm, heterogeneous parallel computing algorithm and mobile3D shape measurement system. We aim to realize the real-time3D shape measurement of moving object and expand its application in industrial inspection.The major content and research results are summarized as follows:1. Gray-coded structured light method was used for3D shape measurement of moving object by introducing a high-speed projection and real-time images ac-quisition method. In the proposed method, synchronization errors are reduced by shortening the projection time. The proposed method can overcome the re-striction of standard frame rate and achieve continuous3D shape measurement of moving object.2. Based on motion information estimation methods of moving object, we proposed a "motion-compensated algorithm". In this algorithm, the moving velocity information of the object is used to compensate the synchronization er-rors. Experimental results showed that the proposed method can further reduce synchronization errors by estimating the pixel coordinates among captured frames and obtain more accurate3D shape measurement results.3. To solve the processing problem of massive image data, a heterogeneous parallel computing model "CPU+GPU" was introduced. Computing abilities of multiple cores on GPU are utilized to accelerate the3D shape measurement algo- rithm. Current experimental results showed that the proposed method can realize real-time3D shape measurement of moving object at500fps with a resolution of512x512pixels.4. On the basis of study on mobile3D shape measurement techniques, we developed a robot-mounted highly integrated real-time3D shape measurement system, which is capable of compensating the synchronization errors by using the feedback information of the robot. Experimental results showed that the devel-oped real-time3D shape measurement system can overcome the blind estimation problem in centroid-based tracking method, and further expand the3D shape measurement scope.This thesis has conducted work on3D shape measurement of moving object based on high-speed vision, synchronization error reduction algorithm, hetero-geneous parallel computing and mobile3D shape measurement system, which extends the application field of gray-coded structured light method.