基于电子快门实现CCD曝光量无级调节技术

Technology of stepless adjustment to CCD exposure based on electronic shutter

为了在景物照度变化条件下保持图像特定目标的亮度基本恒定,提升摄像测控系统的性能,提出了CCD电子快门配合分档光圈实现曝光量无级调节的自适应控制方法。该方法针对光圈换档和电子快门动作在延时性能上的显著差异,将光圈换档对光通量的粗调和电子快门时间的精调两者实时配合,来控制曝光量,算法的实际运用需要通过实验建立光圈换档动力学模型。

To keep a constant luminance of the specific image object despite of a variable lighting, and therefore to enhance the performance of the video measurement ＆ control system, an auto-adaptive control method of stepless adjustment to CCD exposure was put forward. The method was carried out by the coordination of electronic shutter and motor-driven iris diaphragm. With the lag of the mechanical diaphragm gear in change presenting such a striking contrast to that of electronic shutter pulse operation, the light exposure could be controlled precisely by cooperating a coarse adjustment with a fine-tuning one in the real-time process of gearchange. The motor-driven diaphragm gear accomplishes the coarse tuning of luminous flux scope, meanwhile the fine-tuning is adjusted by locating the electronic shutter pulse to acquire the precise shutter time. The dynamic model of the diaphragm gearchange should be established through lens experiments before setting up and applying the algorithm practically.