An integrated bilateral and unsharp masking filter for image contrast enhancement

Noise reduction and contrast enhancement are the two fundamental procedures in most image processing applications. Their effectiveness often play crucial roles in the success of subsequent image operations such as feature segmentation or object recognition. In order to obtain high quality images, the bilateral filer (BF) and the unsharp masking filter (UMF) have often been used as attractive candidates for their proven performances in noise removal and contrast enhancement. The BF is able to remove noises while preserving edge sharpness. On the other hand, the UMF is capable of increasing image contrast. Since the BF is not designed for contrast enhancement and the UMF is not developed for noise reduction, their strengths may not be fully utilized for image quality improvement. In this work, the two filters are integrated in a pipelined process such that the resultant image noise is reduced while the contrast is increased. Experimental results on public-domain and real-life test images demonstrate the effectiveness of the proposed approach.