A Study on Multi- Spectral Satellite Image Enhancement based on Histogram Equalization

The image enhancement techniques are applied either to single-band images or separately to the individual bands of a multi-band image set. Histogram modification is a one of classical method for image enhancement technique is histogram equalization. It is method of self-acting process since it does not request any information, just only the probability of each intensity level of satellite image. However, the enhanced satellite image is obtained by the global area histogram equalization will cause an effect of intensity saturation in some areas/features. This defeat is appeared because of the process attempted to merge the adjacent gray levels together in order to flatten the histogram. To reduce this defeat, a method of local area histogram equalization is suggested. Initially, the original image will be dived into small grid areas by using spatial re- sizing technique, since this technique gives high accurately boundaries of region. The histogram of all pixels in each grid will be equalized independently. The method of segmented grid histogram equalization will be applied to each scene of multi-spectral satellite imageries. The enhanced satellite image can be gives the good spatial and good spectral accuracy. The resultant image obtained from the proposed method is obviously more details compared to the normal method.