机器视觉系统前置矩形LED阵列的优化布置

为获得均匀光照，提高视觉测量系统图像的品质，对前置对称安装的矩形发光二极管(LED)光源布置问题进行了研究。考虑到解析法要求光轴与辐照面法线平行，提出采用优化的方法布置光源。根据光源的结构特征，以方差作为主要指标，建立优化目标函数。考虑到目标函数的非凸性，采用模拟退火算法（SA）对问题进行求解。搭建实验平台对照度分布进行了测量，考察均匀度在95%以上的区域，优化方法的结果与实验结果基本一致，误差在4%以内。结果表明，确定的优化目标合理，提出的光源优化布置方法有效。

Abstract

Positioning of forward symmetrically installed square light-emitting diode (LED) arrays are studied to achieve uniform illumination with which high quality images can be gathered for machine vision measurement. The optimization method is used to solve this problem because the optical axes of the arrays are not perpendicular to the irradiated plane, which can′t be solved by analytic method. The variance is chosen to establish the mathematical model of goal function on the base of the structure characteristics of LEDs. The simulated annealing (SA) algorithm is chosen for solving the non-convex objective function. An experiment system is developed for illumination photometry. The sizes of area with 95% of uniformity of the analytic method are a little larger than those of the optimization based method. The maximum difference is within 4%. The results show that the optimization objective is reasonable and the method is feasible.

参考文献

[1] C K Cowan. Automatic camera and light-source placement using CAD models [C]. Workshop on Directions in Automated CAD-Based Vision, 1991. 22-32.

[2] 张旭苹, 汪家其, 张益昕, 等. 大尺度三维几何尺寸立体视觉测量系统实现[J]. 光学学报, 2012, 32(3): 0315002.

Zhang Xuping, Wang Jiaqi, Zhang Yixin, et al.. Large-scale three-dimensional stereo vision geometric measurement system [J]. Acta Optica Sinica, 2012, 32(3): 0315002.

[3] 卢清华, 许重川, 王华, 等. 基于机器视觉的大幅面陶瓷地砖尺寸测量研究[J]. 光学学报, 2013, 33(3): 0312004.

Lu Qinghua, Xu Chongchuan, Wang Hua, et al.. Research on dimension measurement of large size ceramic floor tiles based on machine vision [J]. Acta Optica Sinica, 2013, 33(3): 0312004.

[4] Y Ding, X Liu, Z R Zheng, et al.. Freeform LED lens for uniform illumination [J]. Opt Express, 2008, 16(17): 12958-12966.

[5] S Mersch. Overview of machine vision lighting techniques [C]. SPIE, 1987. 36-38.

[6] S K Yi, R M Haralick, L G Shapiro. Optimal sensor and light-source positioning for machine vision [J]. Computer Vision and Image Understanding, 1995, 61(1): 122-137.

[7] C K Cowan, B Modayur. Edge-based placement of camera and light source for object recognition and location [C]. Proceedings of IEEE Internaitonal Conference on Robotics and Automation, Atlanta, 1993. 586-591.

[8] E J Sieczka, K G Harding. Light source design for machine vision [C]. SPIE, 1991. 2-10.

[9] Z M Zhu, X H Qu, G X Jia, et al.. Uniform illumination design by configuration of LED array and diffuse reflection surface for color vision application [J]. J Display Technology, 2011, 7(2): 84-89.

[10] Li Lin, Wang Zhong, Pei Fangying, et al.. Improved illumination for vision-based defect inspection of highly reflective metal surface [J]. Chin Opt Lett, 2013, 11(2): 35-38.

[11] A J W Whang, Y Y Chen, Y T Teng. Designing uniform illumination systems by surface-tailored lens and configurations of LED arrays [J]. Journal of Display Technology, 2009, 5(3): 94-103.

[12] I Moreno, A M Avendao, R I Tzonchev. Designing light-emitting diode arrays for uniform near-field irradiance [J]. Appl Opt, 2006, 45(10): 2265-2272.

[13] I Moreno,J Muoz, R Ivanov. Uniform illumination of distant targets using a spherical light-emitting diode array [J]. Optical Engineering, 2007, 46(3): 033001.

[14] S K Kopparapu. Lighting design for machine vision application [J]. Image and Vision Computing, 2006, 24(7): 720-726.

[15] D Ramane, A Shaligram. Optimization of multi-element LED source for uniform illumination of plane surface [J]. Opt Express, 2011, 19(104): A639-A648.

[16] 李林, 王光珍, 王丽莉, 等. 实现均匀照明的LED系统设计方法[J]. 光学学报, 2012, 32(2): 0222002.

Li Lin, Wang Guangzhen, Wang Lili, et al.. Lens design for uniform illumination with LED [J]. Acta Optica Sinica, 2012, 32(2): 0222002.

[17] 赖丽萍, 庄其仁, 梁德娟, 等. 基于近场侧面均匀照明的LED投射器研究[J]. 光学学报, 2014, 34(3): 0211002.

Lai Liping, Zhuang Qiren, Liang Dejuan, et al.. Investigation of uniform illumination of the near-field on the lateral panels using LED projectors [J]. Acta Optica Sinica, 2014, 34(3): 0211002.

[18] 吴雯岑, 赵辉, 刘伟文, 等. 精密视觉测量中照明对图像质量的影响[J]. 上海交通大学学报, 2009, 43(6): 931-934.

Wu Wencen, Zhao Hui, Liu Weiwen, et al.. Effects of illumination on image quality in precision vision measurement [J]. Journal of Shanghai Jiaotong University, 2009, 43(6): 931-934.

[19] C Y Lee, D Lee. Determination of initial temperature in fast simulated annealing [J]. Computational Optimization and Applications, 2014, 58(2): 503-522.

郝飞, 史金飞, 朱松青, 张志胜, 韩亚丽, 陈茹雯. 机器视觉系统前置矩形LED阵列的优化布置[J]. 光学学报, 2014, 34(12): 1215001. Hao Fei, Shi Jinfei, Zhu Songqing, Zhang Zhisheng, Han Yali, Chen Ruwen. Optimal Positioning of Forward Installed Square LED Arrays for Machine Vision System[J]. Acta Optica Sinica, 2014, 34(12): 1215001.

机器视觉系统前置矩形LED阵列的优化布置

关于本站 Cookie 的使用提示

全站搜索

机器视觉系统前置矩形LED阵列的优化布置

相关论文

相关资讯

关于本站 Cookie 的使用提示

全站搜索