Abstract: [Objective] A method to collect the high quality image of the moving wood-based panel is proposed to eliminate the motion blur caused by the relative movement between camera and boards, which guarantees the reliable surface defects identification on the production line.[Method] A high quality image acquisition method was proposed, in which the camera was driven mechanically to track the board in real time in order to eradicate the motion blur. To do this, a cam was used as the driving mechanism and the spring was used for camera restoration. As a result, the camera would move synchronously with the boards based on the appropriate cam contour design, leading to the elimination of the relative movements. The kinematics simulation was carried out using Adams to study the influences of structure parameters on cam movement behavior, and optimize the cam design. The experiment was also conducted to testify the operation efficiency of the proposed method, where the PSF function of each image was computed to evaluate the improvement of the image quality.[Result] According to the simulation result, it was shown that the increases in base radius and pressure angle of constant velocity section would reduce the rotate speed, increase the displacement of the follower, decrease the stress inside the mechanism and improve the movement stability. The roller radius had no impact on the follower movement, but the mismatching between the actual contour and roller radius would lead to the additional speed fluctuation. The cycloidal law made the acceleration of the follower varying consecutively, leading to no flexible impact. At last, the base radius of 80 mm, pressure angle of constant velocity section of 20°, the roller radius of 13.5 mm and cycloidal law for acceleration were selected as the optimized structure parameters of the cam. The optimized cam was machined and was used to collect the board images. It was indicated that the blurring lengths of the images collected by camera moving synchronously with boards were significantly reduced compared with those collected when camera was keeping motionless, and they would maintain within ±2 pixels in the speed range of 0.05-1.2 m·s^-1, leading to the images clear enough to be used for surface testing.[Conclusion] The feasibility of synchronous tracking of camera for moving boards using cam mechanism was verified by both simulation and experiment. The high quality image acquisition method suggested in this study successfully eliminated the motion blur, which significantly improved the image quality and might reduce the time used in conventional image processing. This new method might create possibility of online measurement of the wood-based panel. It also provided the new idea for the wood-based panel testing equipment design.

Key words: wood-based panel, motion blur, cam mechanism, surface defect, kinematics analysis