由于光照度不足, 现有白天彩色成像技术在夜间无法成彩色图像。提出一种适用于低照度条件下的三基色动态采集方法, 采用滤色轮对物体反射光过滤, 利用像增强器对过滤后的单色光放大, 使用图像传感器耦合像增强器上的单色光图像, 实现低照度条件下目标三基色图像的采集。采用直接映射方法将三基色图像融合成彩色图像, 利用无参考图像的评价方法对彩色图像质量进行了评价。实验和评价结果表明, 在低照度条件下, 采用“分离—放大—融合”的方案获取彩色图像在理论和实践上都是可行的, 且在单色采集时可以通过增长曝光时间的手段来提升最终彩色图像的亮度和对比度。对低照度条件下彩色成像系统的设计和研发具有一定的借鉴意义。

The typical daytime color imaging technology can not acquire color images at night due to low illumination.Thus a three-primary-color image dynamic acquisition method adaptive for Low-Light-Level (LLL) condition is proposed.A filter wheel is used for filtering the reflected light,an image intensifier amplifies the monochrome light,the image sensor captures the monochrome images on image intensifier,thus to implement dynamic acquisition of three-primary-color images under LLL condition.Direct mapping method is adopted so as to fuse the three-primary-color image into a color image,and the objective non-reference assessment method is used to assess the quality of the fusion color images.Experimental results show that: 1) Under LLL condition,the “separation-amplification-fusion” scheme is feasible for acquiring a color image both in theory and practice; and 2) The brightness and contrast of color images can be enhanced by lengthening the exposure time.This research can be used as a reference for the design and development of color imaging system under LLL condition.