Image contrast enhancement by preserving brightness using global and local features

• Published in: Proceedings of third International Conference on Computational Intelligence and Information Technology pp. 262 - 271
• Main Authors: Kotkar, V.A, Gharde, S.S
• Format: Conference Proceeding
• Language: English
• Published: Stevenage, UK IET 2013; The Institution of Engineering & Technology
• Subjects: Computer vision and image processing techniques; Integral transforms; Optical, image and video signal processing; local features; digital image processing; local then bidirectional smooth histogram stretching; backward gamma transform; image enhancement methods; BR parameters; image contrast enhancement; transforms; brightness preservation; bin interval control mechanism; AWIE; bidirectional smooth histogram stretching method; AGCID; VHA; global features; WLBSHS; brightness; image enhancement; PSNR EME parameters; AMBE parameters; weighted of local and bidirectional smooth histogram stretching; forward gamma transform
• ISBN: 9781849198592; 1849198594
• DOI: 10.1049/cp.2013.2601

Image enhancement is one of the most significant techniques in digital image processing. This paper introduces two image enhancement methods, Weighted of Local and Bidirectional Smooth Histogram Stretching (WLBSHS) and Local then Bidirectional Smooth Histogram Stretching (LBSHS). WLBSHS uses local and global enhancement in weighted approach. Main purpose of local enhancement is sharpening edges of objective and exploring local information. For global enhancement, Bidirectional Smooth Histogram Stretching (BSHS) method is used. We divide the histogram in two parts and use forward and backward gamma transform on these parts, with bin interval control mechanism. We develop the hybrid method which is use to enhance the contrast of image with preserving its brightness by making the mixture of global and local enhancement. In this research we considered AMBE, E, PSNR EME, BR parameters for evaluating the enhanced image. This hybrid method is found to be better than AWIE, AGCID and VHA.