BEMD Based Cross Bilateral Filtering Technique for Speckle Reduction in Ultrasound Images

Abstract

In this paper, Bidimensional Empirical Mode Decomposition (BEMD) based Cross Bilateral Filter (CBF) technique for speckle reduction in ultra- sound images has been proposed. The reference image is obtained by denoising the noisy image using pixel- wise Wiener filtering. Then, both the noisy image and the reference image are decomposed into a set of In- trinsic Mode Functions (IMFs) and the residue im- age using BEMD technique. CBF is applied between noisy image IMFs and the corresponding reference im- age IMFs. The image is reconstructed back with these modified IMFs and the residue. The proposed method exploits the edge information in the reference image for improving the quality of the denoised image. The per- formance of the proposed method has been tested for real ultrasound images and simulated images having noise of different variance. The experimental results show that the proposed algorithm performs better than other state-of-art methods in terms of Edge Keeping Index (EKI), Correlation Coefficient (CC), Figure of Merit (FOM), Structural Similarity (SSIM), Peak Sig- nal to Noise Ratio (PSNR) and Signal to Noise Ratio (SNR) for synthetic images. The algorithm gives bet- ter performance for real ultrasound images in terms of Mean to Variance Ratio (MVR) and Equivalent Num- ber of Looks (ENL).