Underwater images are comes under the special category images, because they have some special characteristics, which are different from the normal images. They often suffers from verity of problems such as limited range, non-uniform lightening, low contrast, color diminished etc. If the underwater image is a Multi-channel (color) image then the problem becomes much more complicated. This paper basically addresses the contrast enhancement problem of multi-channel underwater images and hence, proposed a novel algorithm for efficient multi-channel underwater image enhancement. The proposed algorithm mainly concentrates on efficient contrast enhancement of multichannel underwater images based on Adaptive Histogram Equalization (AHE) technique and some additional preprocessing frame work. The Histogram Equalization (HE) method is widely used for image contrast enhancement. This is less effective when the contrast characteristics vary across the image. Since the conditions for the underwater images often supports the image characteristics variations, that is why the Histogram Equalization technique can not able to efficiently enhance very low contrast regions of an underwater image, hence to overcome this problem the algorithm of this paper signifies the use of Adaptive Histogram Equalization (AHE) technique, which is the advance version of HE. Since the AHE it self not able to remove the noises present in the underwater images, the algorithm uses combination of median and Gaussian filter for efficient noise filtering. Hence the algorithm not only provides, efficient image enhancement, as well as provides noise filtration also. The proposed algorithm is a spatial domain approach. The spatial domain is nothing but the image plane it self. The methods in the spatial domain are based on direct manipulation of the pixels and therefore provides faster and efficient image enhancement.
Underwater Image, Enhancement, Histogram Modeling, Adaptive, Histogram Equalization, Median filtering, Gaussian smoothing
