EVALUATION OF OPTICAL FLOW TECHNIQUE ON DETECTION OF INTERNAL DISPLACEMENT OF TISSUE IN ULTRASOUND IMAGES

The elastic properties of soft tissues depend on their molecular building blocks,and on the microscopic and macroscopic structural organisation of these blocks. The credibility of elasticity measure depends upon the correct measure of tissue displacement after it is forced with a specific external stress. When two ultrasound images of a tissue before and after stress are acquired, displacement of tissue after enforcing stress cannot relied on techniques that visually measure the displacement. In this study, we have selected technique based on the computation optical flow and assume that the image brightness pattern is constant over time. In this paper, the results of displacement estimation of normal and abnormal masses in breast tissues under external stresses are calculated using optical flow technique. In the first, two ultrasound B-mode images are taken with different enforcing stresses. When mass move in breast tissue, displacement based on intensity of masses are calculated. The displacement is calculated by findings of the local translation of mass edge. The translation information is then used to estimate the elasticity of tissue for diagnostic purpose. In this algorithm, we estimate the translation parameters, length and relative displacement of mass (strain).

Keywords:

Ultrasound , Ultrasonic Tissue Characterisation , Displacement , Optical flow , Breast