Satellite Image Enhancement using Discrete Wavelet Transform and Morphological Filtering for Remote Monitoring

Background: Satellite images are being used in many fields of research mainly for monitoring the remote areas for analyzing the environmental conditions, land and water resource monitoring etc., these images are affected by clouds and electromagnetic radiation which results in poor perception of image. Objective: To analyze the satellite image, improvement in the resolution of the image and also the clarity is required. In this paper the input satellite image is decomposed to separate r, g, b images and a discrete wavelet transform is performed for dividing the planes into subbands. Among this low frequency sub band is used for further processing because it contains almost all the information about the image. The threshold decomposition technology is used to detect the edges of the selected sub bands of r, g, b. The morphological filtering is applied to the image to sharpen the edges of sub bands. IDWT is taken for the processed image to reconstruct the image. Results: The MSE and PSNR values are calculated for evaluation of the method and the results show that the proposed method gives better improvement in Signal to Noise ratio and it reduces Mean Square Error considerably comparing the values before and after enhancement. Conclusion: In the proposed method, DWT and edge detection using morphological filters succeeded in enhancing low contrast satellite images. The detected edges were sharpened by using Morphological filter dilation and erosion process. By utilizing these detected edges, IDWT is obtained and got the enhanced image by reconstruction. From the results it is identified that the proposed method can be well used to monitor the remote areas obtained by the satellite images with high quality and resolution.