Patent ID: 6913574

Claim:
A method for measuring elastic characteristics of a medium, comprising: applying vibrations to the medium; acquiring an N number of ultrasound image frames of the medium; estimating a variation in brightness of a speckle pattern over the N number of ultrasound image frames by calculating an average brightness and variance in brightness for every pixel over the N number of ultrasound image frames, wherein the average brightness and variance in brightness are calculated by the following equations: m N ⁡ ( i , j ) = m N - 1 ⁡ ( i , j ) + 1 N ⁡ [ x N ⁡ ( i , j ) - m N - 1 ⁡ ( i , j ) ] σ N 2 ⁡ ( i , j ) = σ N - 1 2 ⁡ ( i , j ) + m N - 1 2 ⁡ ( i , j ) + 1 N ⁡ [ x N 2 ⁡ ( i , j ) - Nm N 2 ⁡ ( i , j ) - σ N - 1 2 ⁡ ( i , j ) - m N - 1 2 ⁡ ( i , j ) ] wherein N is a current frame number, N−1 is a previous frame number, X N (i,j) represents a brightness value of the (i,j) th pixel in the n th frame, m N (i,j) and m N−1 (i,j) represent an average brightness for the (i,j) th pixel over the N number of frames as counted from the first frame and an average brightness for the (i,j) th pixel over the N−1 number of frames as counted from the first frame, respectively, and σhd N 2 (i,j) and σhd N−1 2 (i,j) represent a variance in brightness for the (i,j) th pixel over the N number of frames as counted from the first frame and a variance in brightness for the (i,j) th pixel over the N−1 number of frames as counted from the first frame, respectively; and measuring the elastic characteristics of the medium based on the estimated brightness variation.