An Adaptive Approach for image Enhancement and Naturalness Preservation

Abstract

Image enhancement simply means getting a clearer image, that is to process an image so that the result is more suitable than the original image for specific applications. The enhancement process does not increase the inherent information content in the data. But it does increase the dynamic range of the chosen features so that they can be detect easily. Image enhancement and Naturalness preservation plays an important role in image processing and analysis. Naturalness preservation while enhancing the details of an image is very essential to maintain a good perceptual quality. Many algorithms are available for image enhancement. This paper proposes an adaptive method for naturalness preservation and image enhancement. Image Enhancement using bi-log transformation and differential intensity histogram equalization are adaptively adopted to get the best results. First, a brightpass filter is defined to decompose the image into reflectance and illumination. The illumination image is processed and synthesis with reflectance image to obtain the enhanced image. Illumination image can be processed either by using bi-log transformation or differential intensity histogram equalization. Depending upon the cumulative density function of the illumination image, this method adaptively chooses bi-log transformation or histogram equalization for image enhancement. Lightness order error(LOE) is used to measure the naturalness preservation objectively. Lower the LOE value, better the naturalness preserved.