Abstract: Aiming at the problem of low illumination degraded image enhancement obtained by remote imaging system, an image enhancement algorithm based on fusion Retinex and discrete wavelet singular value decomposition was proposed. In this method, the adaptive full-scale Retinex (AFSR) was used to coarsely extract the illumination and reflection components, and then the reflection components of the extracted image were decomposed into four frequency subbands by discrete wavelet transform, and the singular value matrix of the low-frequency subbands image was estimated. Finally, the inverse wavelet transform was adopted to precisely reconstruct the image. The experimental results show that the visual enhancement effect of the low illumination degraded image processed by the proposed method is better, which is superior to other classical algorithms in terms of objective evaluation indexes such as image contrast, information entropy, average gradient and edge density.