Comparison of the performance metrics of median filter and wavelet filter when applied on SONAR images for denoising

Under water image processing is significant due to the poor quality of images acquired. Basically, under water images suffer from degradation due to light scattering, low contrast and blurring. When we utilize those images much of the fine details in the image is lost, so the images must be post-processed to retain information and improve the quality. Filters are used as a preprocessing tool to suppress noise, preserves edges and corners, and to enhance the image. Therefore an attempt has been made to compare and evaluate the performance of two filters namely, median filter and symlet wavelet filter. Compared to median filter, symlet wavelet filter gives desirable results for denoising in terms of PSNR-Peak Signal to Noise Ratio.