Abstract:

In order to improve the brightness and contrast of low illumination images, we propose a new color image enhancement method based on Retinex theory. Firstly, we evaluate the illumination image of the V component by domain transform filtering in the HSV space based on the Retinex theory. We divide the V component by illumination to get the reflection image. Then, we enhance the illumination image by the adaptive Gamma correction and increase the contrast of the illumination image by the CLAHE. Finally, we multiply the enhanced illumination image by the reflection image and then transform the enhanced image into RGB space. The proposed method can achieve more natural enhancement effect, suppress strong light enhancement and highlight image details. Furthermore, the proposed method overcomes the drawbacks of low contrast, color distortion, over enhancement and halo artifact, which exist in the former methods. It can also deal with many kinds of images, such as high dynamic range images (HDR), non-uniform illumination images and low exposure images. Experimental results demonstrate that the proposed method can achieve better visual quality than traditional methods.

Key words: Retinex theory, color image enhancement, domain transform filtering, adaptive Gamma correction, CLAHE