Research On Night Low Illumination Image Enhancement Method Based On Single Image

Pictures obtained at night often have problems such as low overall brightness,low contrast,and invisible details.On the one hand,they cannot meet the needs of people's visual senses,on the other hand,they will cause greater subsequent image processing such as image recognition and target tracking.influences.Aiming at this problem,this paper studies the night low-light image enhancement method.The specific work and main results are as follows:(1)Aiming at the problem that the overall brightness of the low-light image at low light level is low and the details are not visible,a nighttime low-light image enhancement method inspired by photographic film development is proposed.Inspired by the development of photographic film,the idea of this method is proposed:the nighttime low-light image is regarded as a film image,the negative image of the input image is correspondingly developed,and then the developed image is enhanced by the method of dark primary color prior,and finally reversed.Get a clear,enhanced nighttime image.Experiments show that this method greatly improves image quality,enriches image information,improves sharpness,and enhances nighttime images simply and effectively.(2)A nighttime low-illumination image with a bright light source or a large difference in local brightness and darkness is prone to halo problems during image enhancement,so another method is proposed-based on a two-channel nighttime image enhancement method.The method combines the existing dark primary colors and bright primary colors to verify the nighttime image.First use the bright channel a priori to obtain the initial transmission estimate,then use the dark channel as the complementary channel to correct the potential error transmission estimate obtained from the bright channel prior,and propose a fine transmission process,using the bootstrap filter to preserve the input.The edge information of the image,thereby avoiding the halo effect that occurs during the enhancement process,and finally obtaining a sharpened nighttime image enhancement.Experiments with a large number of low illumination images have shown that this method produces very high quality enhanced images compared to other state of the art methods.(3)The above two methods have room for improvement in the enhancement of the dark region details of the low-light image at night,so a nighttime image enhancement method based on CLAHE is proposed.The method combines CLAHE and photographic film development-inspired nighttime low-light image enhancement method,and adds denoising processing to obtain an enhanced image.The method not only has obvious advantages in detail enhancement of dark regions,but also enhances the vivid color of the image,and can avoid the overexposure phenomenon in the process of processing the nighttime low illumination image with bright light source to some extent.