DWT and PCA Based Image Enhancement with Gaussian Filter

A new satellite image contrast enhancement technique based on the Discrete Wavelet Transform (DWT) and Principal Component Analysis has been proposed. By the use of discrete wavelet transform, the input image decomposed into four frequency sub-bands and estimates the eigen values and eigen vectors (PCA) of the low–low subband image and reconstructs the enhanced image by applying inverse DWT. The technique is compared with conventional image equalization techniques such as standard general histogram equalization and local histogram equalization, as well as state-of-the-art techniques such as brightness preserving dynamic histogram equalization and Principal Component Analysis. The experimental results show the superiority of the proposed method over conventional and state-of-the-art techniques.