A novel hybrid technique for visual enhancement of medical ultrasound images

Ultrasound imaging has features like non-invasive nature, real time image formation capacity and relatively low cost, which makes this diagnostic tool attractive and hence has become an important imaging modality in medical diagnoses. However the usefulness of this imaging is degraded by the presence of speckle noise. Hence, speckle suppression in ultrasound images is essential for improving the image quality. In this paper, a novel hybrid method is proposed for enhancing the visual quality of medical ultrasound images. To preserve edges, a nonlinear filter is used in the pre-processing stage. Further the pre-processed image is denoised in wavelet domain using bivariate shrinkage. The quality of the despeckled images is assessed using objective quality assessment metrics such as Peak Signal to Noise Ratio (PSNR), Root Mean Squared Error (RMSE) and Edge Preservation Index (EPI). The quantitative results indicate that the proposed method yields better performance than the existing methods.