Wavelet based non local means filter for despeckling of intravascular ultrasound image

In this paper, a novel methodology has been proposed for speckle noise reduction of intravascular ultrasound (IVUS). IVUS, a standard coronary artery diagnosis imaging protocol, is degraded with speckle noise due to the coherent interferences of the ultrasound reflected from the scatters. Presence of such noise creates problem in segmentation and classification of these images. Non local means filter has been applied in wavelet domain to smooth out noise interferences to improve the visual characteristics of IVUS insight. Eventually, a comparison study has also been performed with various filters viz. anisotropic diffusion filter, nonlinear median filter and geometric nonlinear diffusion filter. Mean squared error (MSE) and peak signal to noise ratio (PSNR) has been used to evaluate the efficiency of the proposed filtering methodology.