Optical remote sensing image enhancement with weak structure preservation via spatially adaptive gamma correction

Image structure information is a watershed that distinguishes the content of an image, so it is very important for image enhancement techniques to correct uneven intensity of low-contrast optical remote sensing images with both strong and weak structures preservation. In this paper, a novel enhancement scheme, called spatially adaptive gamma correction (SAGC), is proposed to improve the visualization of optical remote sensing images with structures especially weak structure preservation. The SAGC method includes the following four parts: Firstly, the base image with strong structures and the detail image with weak structures are obtained by the employment of the relative total variation (RTV) method. Secondly, the base image is enhanced by a proposed adaptive gamma correction method. Thirdly, an enhancement factor is proposed to correct the detail image with weak structures. Finally, the high-contrast optical remote sensing image is obtained by the enhanced base image with the combination of the corrected detail image. Both quantitative and qualitative results on real low-contrast optical remote sensing images demonstrate that the proposed image enhancement scheme outperforms the state-of-the-arts in terms of brightness improvement, contrast enhancement, and detail preservation.