低照度环境下视频增强技术

在低照度环境下，摄像机捕捉到的夜间视频质量较差，常出现光照不足、对比度低、模糊不清和颜色偏移等问题，影响了视频的判读和理解。针对夜间视频存在的问题，提出不同时段空间背景融合技术和根据Retinex理论利用三边滤波器提取亮度图像的照度分量并结合Sigmiod 非线性拉伸函数对反射分量进行增强处理以突出细节达到图像增强的目的。经实验证明，提出的算法能够提高低照度夜间视频的整体视觉效果，图像的亮度、对比度、清晰度得到改善，突出了视频图像细节，保留了视频重要内容，增强结果自然清晰，避免了图像失真等问题，解决了夜间视频增强中常出现的光晕、鬼影、颜色偏移等问题，便于视频的判读与分析。

Enhancement technology of video under low illumination

The picture quality of the video is very poor under the low illumination night environment, it often appears low contrast, blurred, color offset, etc, and it has influence on interpretation and understanding of the video. For solving the problem of nighttime video, the different time space background fusion technology was proposed based on moving object and a new Retinex image enhancement algorithm. This method improved the whole brightness and the contrast of the video through the strategy of adaptive brightness adjustment. Then the illumination components of brightness images were extracted by the trilateral filter based on the theory of Retinex. The reflecting components of images were obtained through compressing illumination. It was because that the reflecting components of images included large number of particulars and marginal information of images, reflecting components were enhanced through integrating Sigmiod non-linear stretching function. At last, it enhanced the saturation component to get more bright colors. The experiments show that the algorithm can improve the visual effect of the low illumination video at nighttime. The image brightness, contrast, sharpness is improved, and the method not only enhanced the video image detail, but also retained the important content of the video. The method avoid the distortion of images, such as, halo, ghost, color deviation.