Contrast resolution enhancement based on wavelet shrinkage and gray level mapping technique

The speckle pattern produced by the use of a coherent transducer in forming the B-mode ultrasound images is also a source of contrast resolution-degradation. We have presented the soft thresholding rule to relieve artifacts from the discrete wavelet transform of an image. Our study begins with the estimation of the required determinants to obtain the desired noise/resolution trade off, extended to the gray level mapping technique (GLM) application. The GLM application is used to further enhance the ultrasound images in different contrast levels. Experiments have shown that the proposed methods have significantly improved PSNR in the specular and reflectance area. Both techniques are translated into a PC-based tool that could be transferred into ultrasound system that can be implemented for real time image processing