一种低功耗外部触发补光方案的设计与实现

Design and Implementation of a Low-Power External Trigger Light Supplement

补光系统是视觉技术中关键的组成部分之一。针对嵌入式图像采集系统的常亮、同频补光的方案所产生的功耗高、温度高、图像采集信号与补光信号时序不匹配等问题。提出一种低功耗、图像采集信号与补光信号时序匹配度高、可靠性强的外部触发补光方案。本方案基于ARM对输入PWM信号的占空比与FPGA对MOS管开关的控制来调整补光灯亮度与频率,稳定匹配嵌入式图像采集信号与补光信号的时序,并通过调整补光灯的亮度等级以得到清晰的图像细节,便于提高后期图像处理的鲁棒性。为嵌入式图像采集系统补光方案的应用提供一种新的解决方案。实验结果表明:使用本补光灯系统的嵌入式设备相较常亮方案功耗降低3 W、灯珠温度降低30℃左右,且图像采集信号与补光信号时序匹配稳定在99%以上。

The supplemental light system is one of the key components in vision technology.In view of the problems of high power consumption,high temperature,and timing mismatch between the image acquisition signal and the supplementary light signal caused by the constant brightness of the embedded image acquisition system and the same frequency supplementary light solution.An external trigger supplementary light scheme of low power consumption,high timing matching between image acquisition signal and supplementary light signal,and strong reliability is proposed.This solution adjusts the brightness and frequency of the fill light based on the duty cycle of the input PWM signal by the ARM and the FPGA’s control of the MOS tube switch,and stably matches the timing of the embedded image acquisition signal and the fill light signal,and adjusts the fill light brightness level to obtain clear image details,which is convenient to improve the robustness of post-image processing.It provides a new solution for the application of the supplementary light scheme of the embedded image acquisition system.The experimental results show that the embedded device using this supplementary light system reduces the power consumption by 3W and the lamp bead temperature by about 30 degrees compared with the always-on solution,and the timing matching of the image acquisition signal and the supplementary light signal is stabilized at more than 99%.