基于近场均匀照明的纸病检测系统光源优化方案

Light Source Optimization Scheme for Paper Defect Detection System Based on the Uniform Illumination of the Near-field

关键词:  纸病检测  机器视觉  均匀照明  光源优化  灰度均匀

Key Words:paper defect detection  machine vision  uniform illumination  light source optimization  uniform gray scale

摘要:针对纸病检测系统中采集到的图像存在横向灰度不均匀现象，基于几何光学辐射照度理论，围绕纸病检测系统光源模块照射到被检测纸张上的照度均匀分布问题开展了应用技术研究。依据斯派罗法则，确定了光源模块中LED灯珠间的最优距离函数；从机器视觉的角度出发，利用实验法确定了光源阵列中不同位置灯珠的功率优化函数；采用图像灰度均匀度指标，对光源的改进效果进行了验证。结果表明，本优化方案可以将获取到的图像灰度均匀度由优化前的57.8%提高到98.6%，有效地提高了纸张的成像质量，可降低后期的图像处理难度，有望提高应用程序的执行效率。

Abstract:The image collected in the paper defect detection system has lateral gray unevenness. Based on the theory of geometrical optical irradiance, this paper studied the application technology concerning the uniform distribution of illuminance on the paper detected by the light source module of the paper defect detection system. According to the Sparrow's criterion, the optimal distance function between the LED beads in the light source module was determined. From the perspective of machine vision, the power optimization function of the LED beads at different positions in the light source array was determined by experimental method. The improvement effect of the light source was verified by using the image gray uniformity index. The experimental results showed that the optimization scheme could increase the gray uniformity of the acquired image to 98.6%, which was greatly improved compared with 57.8% before optimization, effectively improved the image quality of the paper and reduced the difficulty of image processing in the later stage, which was expected to improve the execution efficiency of the application program.