面向皮革缺陷检测的离轴LED曲面阵列照明设计

Off-Axis LED Curved Array Lighting Design for Leather Defect Detection

提出了一种曲面LED阵列设计方法。根据光线叠加原理,将LED排列在自由曲面上,通过曲率控制LED的出光角度。基于LED曲面阵列离轴照度分布的解析式,引入了基于模拟退火的粒子群优化算法,设定约束条件,构建均匀度评价函数,优化了LED曲面阵列的数值模型。制作出实物光源进行照度测量与缺陷检测。理论模拟和实物检测结果均显示,倾斜角度为45°,目标面与发光面面积比值为1∶0.85和1∶4时,照度均匀度分别达到91.79%和98.4%。在皮革缺陷检测中的结果表明,采用LED曲面阵列光源可凸显特定缺陷,易于图像处理,能快速准确地识别缺陷。

A design method of curved light-emitting diode(LED)array is proposed.Based on the principle of light superposition,the LEDs are arranged on the free-form surface,and the LED light-emitting angle is controlled through curvature.Based on the analytical formula of off-axis illumination distribution of the LED curved array,a particle swarm optimization algorithm is introduced based on simulated annealing,the constraint conditions are set,a uniformity evaluation function is constructed,and the numerical model of LED curved array is optimized.A physical light source is produced for the illuminance measurement and the defect detection.Both the theoretical simulation and the real detection show that when the inclination angle is 45°and the ratios of the target surface area to the light-emitting surface area are 1∶0.85 and 1∶4,the illumination uniformity is 91.79% and 98.4%,respectively.The results for leather defect detection show that the proposed curved LED array light source can highlight specific defects,quickly and accurately identify defects,and is easy for image processing.