Ultrasound Signal Processing Using Compounding Plane Waves and Wavelet Analysis

Ultrasound (US) images are one of the safest ex-amination resources for medical diagnoses. Many noticeable innovations have arisen recently, particularly the Coherent Plane Waves Compounding (CPWC) and the Wavelet Transform (WT) based analysis. CPWC solves the problem of fast frame rate, achieving thousands of frames per second. However, improving image quality and suppressing or eliminating noises remain a challenge. This work aims to investigate the CPWC and WT-generated images for future applications in Doppler images. Two experiments were carried out: 1) In silico uses stepwise customized procedures with db4 wavelet, 2) In vitro uses representatives of db, symmetry, biorthogonal, and morse wavelets families, with automatic procedures according to built-in functions of MATLAB Wavelet Toolbox. In Experiment 1, the wavelet processing (db4) eliminates some artifacts. It showed qualitatively a gain of contrast and attenuation in other regions. In Experiment 2, SNR and CNR metrics pointed out bior2.4 with the higher values: 1.5101 and 0.7427, respectively. On the other hand, morse wavelet and customized filtering code mark the lowest CR = 0.1464. The experiments made possible some conclusions: The higher the vanishing moments, the better the results. The better results come from stepwise controlling the signal processing; this last approach is convenient for testing novel Doppler techniques, like speckle tracking and Vector Flow image applications.