自动调光技术是光学成像系统中的关键技术。为了提高成像质量，提出了基于带电位计的可变光阑和通过外部触发脉冲设置快门时间的全自动调光方法。与单独采用光阑或内同步设置快门时间的调光方法相比，该方法可实现光阑的闭环控制和电子快门的连续调整。在硬件上，由于采用TMS320C28X系列DSP作为主处理芯片，时钟周期可达6.67 ns。其自带Flash和丰富的片内外围设备，能产生光阑电机的驱动脉冲和电位计AD转换，可汇编和用C语言编写。在软件上，采用的调光周期为20 ms，给出了自动调光流程图。经验证，全自动调光方法的动态调光范围大、可靠性高，具有快速响应的特性和广泛的适用性，能够满足工程上对自动调光的需要。

Automatic light adjusting techniques are critical in optical imaging systems. To improve the imaging quality of an optical imaging system, an automatic light adjusting method is put forward. The method is based on the iris with a potentiometer and uses external trigger pulses to set shutter speed. Compared with the light adjusting method which sets shutter speed by using stop alone or by internal synchronization, the closed-loop control of iris and the continuous adjustment of shutter can be realized by using this method. For the hardware, because the DSP in TMS320C28X series is used as the main processing chip, its clock cycle is up to 6.67 ns. With the built-in flash and rich peripherals, the driving pulse for iris motor, the AD conversion of potentiometer, the compilation and the C language programming can be realized. For the software, the light adjusting cycle of 20 ms is used and the flow chart of automatic light adjusting is given. It is verified that this automatic light adjusting method has the features of large dynamic light adjusting range, high reliability, fast response and wide applicability. It can meet the needs of automatic light adjusting in the project.