Adaptive Anisotropic Diffusion for Ultrasonic Image Denoising and Edge Enhancement

Utilizing echoic intension and distribution from different organs and local details of human body, ultrasonic image can catch important medical pathological changes, which unfortunately may be affected by ultrasonic speckle noise. A feature preserving ultrasonic image denoising and edge enhancement scheme is put forth, which includes two terms: anisotropic diffusion and edge enhancement, controlled by the optimum smoothing time. In this scheme, the anisotropic diffusion is governed by the local coordinate transformation and the first and the second order normal derivatives of the image, while the edge enhancement is done by the hyperbolic tangent function. Experiments on real ultrasonic images indicate effective preservation of edges, local details and ultrasonic echoic bright strips on denoising by our scheme.

• Shujun Fu
• Qiuqi Ruan
• Wenqia Wang
• Yu Li

• anisotropic diffusion
• coordinate transformation
• directional derivatives
• edge enhancement
• hyperbolic tangent function
• image denoising.

[1] K. Z.Abd-Elmoniem, et al, "Real-time speckle reduction and coherence
enhancement in ultrasound imaging via nonlinear anisotropic diffusion,"
IEEE Transactions on Biomedical Engineering, 49(9): 997-1014, 2002.
[2] Feng Ruo, Liu Zhong Qi, Yao JinZhong, et al. The Principle and Design
of Ultrasonic Diagnosis Equipment, The medicine science and technology
press, Beijing, China, 1993.
[3] C.B. Burkhardt, "Speckle in ultrasound B-mode scans," IEEE Trans.
Sonics Ultrason., vol.SU-25, no.1:1-6, 1978.
[4] T.Loupas, W.N. Mcdicken, P. L. Allan, "An adaptive weighted median
filter for speckle suppression in medical ultrasonic images," IEEE Trans.
Circuits Syst., 36 (1):129-135, 1989.
[5] J.C. Bamber, C. Daft, "Adaptive filtering for reduction of speckle in
ultrasound pulse-echo images," Ultrasonics, 1:41-44, 1986.
[6] J.C. Bamber, J.V. Philps, "Real-time implementation of coherent speckle
suppression in B-scan images," Ultrasonics, 29(5): 218-224, 1991.
[7] D.L. Donoho, "De-noising by soft-thresholding," IEEE Trans. Inform
Theory, 41(5): 613-627, 1995.
[8] G. Aubert, P. Kornprobst. Mathematical Problems in Image Processing:
Partial Differential Equations and the Calculus of Variations. Applied
Mathematical Sciences, volume 147, Springer-Verlag, 2001.
[9] P. Perona, J. Malik, "Scale-space and edge detection using anisotropic
diffusion," IEEE Trans. Pattern Anal. Machine Intell, 12(7): 629-639,
1990.
[10] C. A. Z. Barcelos, et al, "A well-balanced flow equation for noise removal
and edge detection," IEEE Trans. Image Processing, 12(7): 751-
763, 2003.