Contrast enhancement of back-light images via a regional rank-1 constraint

In this paper, we propose a novel approach for enhancing the contrast of back-light images. Although many contrast enhancement methods have been proposed in the literatures, they are still prone to fail especially in restoring the textural details of the under-exposed regions in back-light images. To cope with this problem, the proposed approach employs a new pixel-wise gain correction scheme that adopts a regional rank-1 constraint. Based on this scheme, the contrast of the back-light image is enhanced notably while allowing smooth intensity changes and suppressing intensity inversions around adjacent pixels. In the experiments, the effectiveness of the proposed method is demonstrated qualitatively and quantitatively comparing with the state-of-the-art methods.