Low-light Image Enhancement Based on Detail Preservation and Brightness Fusion

Images captured by complementary metal-oxide semiconductor (CMOS) cameras under low-light environments have problems, including low contrast, high noise, blurred details, and insufficient enhancement algorithms. Although CMOS cameras can improve image brightness, they do not consider how to retain the detailed information of the original image. Therefore, this paper proposes a detail-preserving low-light image enhancement method. First, each channel in the original low-light image was processed using an adaptive filter to improve the effect of noise on the image. Subsequently, a detail layer and a basic layer are obtained from the filtered image. The detail layer is used to preserve the texture of the image, and the basic layer is used to enhance its brightness. Moreover, the detail layer is obtained via coarse illumination and light components, whereas the basic layer brightness enhancement is obtained using the alpha algorithm to fuse the original image, gamma correction result, and gamma priori correction result. Finally, the luminance channels of the detailed and basic layers are fused to obtain an enhanced image. The experimental results showed that the average gradient and information entropy of the fused detailed image were significantly improved. In addition, among the five selected methods, the SSIM index was higher than those of other algorithms, indicating less distortion in the enhanced images. Good results were achieved for both the BRISQUE and PSNR indicators.