Estimation of Local Attenuation and Its Application to Rationalized Gain Control
The aim of this paper is to provide a local attenuation estimation algorithm from ultrasound images. Using the computed attenuation coefficients locally, we define a 2-D table for tissue attenuation compensation in the sense of a rationalized gain control. To handle the frequency shift in the broadband system, we use nonlinear least squares (NLS) data fitting directly to the local amplitude changes due to the tissue attenuation. By looking at the convergence of the NLS method, e.g., the Levenberg-Marquardt algorithm, we proposed a technique to test the possible tissue heterogeneity locally. Algorithms have been verified both in phantom and in vivo images. Results showed that the proposed method can have at most 4% relative error in estimating attenuation coefficients of phantom images in a broadband system. It also showed a uniform in vivo image after the proposed rationalized gain control.