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林业科学 ›› 2018, Vol. 54 ›› Issue (11): 172-179.doi: 10.11707/j.1001-7488.20181124

• 研究简报 • 上一篇    下一篇

移动人造板高清图像采集方法与装置运动学分析

王霄1, 郭慧1, 刘传泽2, 陈龙现2, 周玉成1,2   

  1. 1. 中国林业科学研究院木材工业研究所 北京 100091;
    2. 山东建筑大学信息与电气工程学院 济南 250101
  • 收稿日期:2018-04-02 修回日期:2018-06-03 出版日期:2018-11-25 发布日期:2018-12-04
  • 基金资助:
    中国林业科学研究院中央级公益性科研院所基本科研业务费专项资金(CAFYBB2018MB002);泰山学者优势特色学科人才团队(2015162)。

Method of High Quality Image Acquisition of Moving Wood-Based Panel and Kinematics Analysis of Transmission Mechanism

Wang Xiao1, Guo Hui1, Liu Chuanze2, Chen Longxian2, Zhou Yucheng1,2   

  1. 1. Research Institute of Wood Industry, CAF Beijing 100091;
    2. School of Information and Electrical Engineering, Shandong Jianzhu University Jinan 250101
  • Received:2018-04-02 Revised:2018-06-03 Online:2018-11-25 Published:2018-12-04

摘要: [目的]提出一种适用于移动人造板的高清图像采集方法,解决生产线上相机与板材相对运动引起的图像模糊问题,为人造板表面缺陷自动化检测的可靠性提供保证。[方法]通过机械传动方式实现相机对人造板的同步跟踪,从根本上消除运动模糊。采用凸轮作为驱动机构,使相机与人造板同向运动并借助弹簧实现自动复位;通过合理设计凸轮轮廓线达到相机与人造板同向、等速运动的效果,消除相对运动。利用Adams软件进行运动学仿真,考察结构参数对从动件运动行为的影响,得出最优凸轮轮廓线,并开展试验检验凸轮机构运行效果,通过计算所采集在线图像的PSF函数对运动模糊改善程度作出评价。[结果]运动学仿真结果显示,增大基圆半径可降低凸轮转速,减小凸轮和从动件受力,并提高运行稳定性;匀速段压力角与运动周期呈正比,与主动和从动件间的相互作用力呈反比;滚轮半径变化不会影响相机运动规律,但实际轮廓线与滚轮半径不匹配会导致速度波动增大;摆线式加速方式可使相机加速度曲线连续、光滑,避免刚性和柔性冲击,可作为加速方式的首选。最终确定基圆半径80 mm、匀速段压力角20°、滚轮半径13.5 mm以及摆线式加速规律的凸轮机构并完成加工。基于该凸轮机构完成人造板在线图像采集并提取PSF函数以考察模糊改善效果,结果显示,与相机静止拍摄所得图像相比,同步拍摄得到的图像模糊长度显著降低,在速度0.05~1.2 m·s-1范围内维持在±2像素以内,使图像中人造板及其缺陷近乎清晰。[结论]通过运动学仿真与试验相结合的方式验证了利用凸轮机构实现相机对移动人造板同步跟踪的可行性,有效解决了图像运动模糊问题,使得所拍摄图像人造板清晰度大幅提高,并可缓解传统图像处理耗时久的问题,为人造板表面缺陷在线检测创造了可能性,为人造板检测装置设计提供了新思路。

关键词: 人造板, 运动模糊, 凸轮机构, 表面缺陷, 运动学分析

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

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