A Quantitive Analysis of Frequency Domain Filters for Sector Scan SONAR Image Processing

The SONAR (Sound Navigation and Ranging) images are perturbed by a multiplicative noise called speckle noise, due to the coherent nature of the scattering phenomenon. Removing noise from the SONAR image is still a challenging problem for researcher. There is no unique technique for image enhancement for noise reduction. Several approaches have been introduced and each has its own assumption, advantages and disadvantages. This paper proposes performance comparison of frequency domain filtering techniques such as low pass, high pass and band pass filters based on fast fourier transform method for the removal of underwater speckle noise from the real Sector Scan SONAR images. These three filters are compared by computing the error metrics such as Peak Signal to Noise Ratio (PSNR) and Mean Square Error (MSE). Low pass filter is found to be the suitable filter in frequency domain which tends to reduce the speckle, preserving the structural features and textural information of the scene.