A New Approach to Estimation of Muscle Pennation Angle in Ultrasound Image

Ultrasound imaging has been an effective tool for measuring the muscle architectures, including the pennation angle. In this work, we proposed a new approach combining wavelet transform (WT) and Hough transform (HT) to detect the straight line-shaped patterns of aponeurosis, fascicle or bone, and then to quantify the pennation angles in ultrasound images. The results indicated that the proposed algorithm could well detect the pennatoin angles with correlation coefficient of 0.946, standard root mean square error of 0.758°, and relative root mean square error of 2.253%, where the manually measured values were taken as standard. The results suggest that the proposed algorithm provides an alternative approach for the computer-aided orientation estimation of muscle architecture.