Ultrasound imaging has been widely used to investigate the architecture properties of skeletal muscle, including the measurement of the pennation angle. In this study, we propose a beamlet-based algorithm to detect th...Ultrasound imaging has been widely used to investigate the architecture properties of skeletal muscle, including the measurement of the pennation angle. In this study, we propose a beamlet-based algorithm to detect the straight line- shaped patterns of aponeurosis, fascicle or bone, and then to quantify the pennation angle ix1 ultrasound images. The results demonstrate that the proposed algorithm can well detect the pennatoin angles in thirty ultrasound images with the correlation coefficient of 0.945, the standard root mean square error of 0.682°, and the relative root mean square error of 3.498%. The results suggest that this beamlet-based algorithm provides an alternative approach for the orientation estimation in muscu- loskeletal ultrasound images.展开更多
Pennate muscle is characterized by muscle fibers that are oriented at a certain angle(pennation angle)relative to the muscle’s line of action and rotation during contraction.This fiber rotation amplifies the shorteni...Pennate muscle is characterized by muscle fibers that are oriented at a certain angle(pennation angle)relative to the muscle’s line of action and rotation during contraction.This fiber rotation amplifies the shortening velocity of muscle,to match loading conditions without any control system.This unique variable gearing mechanism,which characterized by Architecture Gear Ratio(AGR),is involves complex interaction among three key elements:muscle fibers,connective tissue,and the pennation angle.However,how three elements determine the AGR of muscle-like actuator is still unknown.This study introduces a Himisk actuator that arranges five contractile units at a certain pennation angle in a flexible matrix,the experiment and simulation results demonstrated that the proposed actuator could vary AGR automatically in response to variable loading conditions.Based on this actuator,we present a series of actuators by simulations with the varying pennation angle(P),elastic modulus of the flexible matrix(E),and number of contractile units(N)to analyze their effects on AGR,and their interaction by three-factor analysis of variance.The results demonstrated that P and N effect on the AGR significantly,while E effects on AGR slightly,which supported the idea that the P is the essential factor for the AGR,and N is also an important factor due to the capability of force generation.This provides a better understanding of mechanical behavior and an effective optimizing strategy to muscle-like soft actuator.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.60701021)the Innovation Program of Shanghai Municipal Education Commission (Grant No.09YZ15)the Shanghai Leading Academic Discipline Project(Grant No.J50104)
文摘Ultrasound imaging has been widely used to investigate the architecture properties of skeletal muscle, including the measurement of the pennation angle. In this study, we propose a beamlet-based algorithm to detect the straight line- shaped patterns of aponeurosis, fascicle or bone, and then to quantify the pennation angle ix1 ultrasound images. The results demonstrate that the proposed algorithm can well detect the pennatoin angles in thirty ultrasound images with the correlation coefficient of 0.945, the standard root mean square error of 0.682°, and the relative root mean square error of 3.498%. The results suggest that this beamlet-based algorithm provides an alternative approach for the orientation estimation in muscu- loskeletal ultrasound images.
基金supported by the projects of National Natural Science Foundation of China(No.52075216,No.91948302 and No.91848204).
文摘Pennate muscle is characterized by muscle fibers that are oriented at a certain angle(pennation angle)relative to the muscle’s line of action and rotation during contraction.This fiber rotation amplifies the shortening velocity of muscle,to match loading conditions without any control system.This unique variable gearing mechanism,which characterized by Architecture Gear Ratio(AGR),is involves complex interaction among three key elements:muscle fibers,connective tissue,and the pennation angle.However,how three elements determine the AGR of muscle-like actuator is still unknown.This study introduces a Himisk actuator that arranges five contractile units at a certain pennation angle in a flexible matrix,the experiment and simulation results demonstrated that the proposed actuator could vary AGR automatically in response to variable loading conditions.Based on this actuator,we present a series of actuators by simulations with the varying pennation angle(P),elastic modulus of the flexible matrix(E),and number of contractile units(N)to analyze their effects on AGR,and their interaction by three-factor analysis of variance.The results demonstrated that P and N effect on the AGR significantly,while E effects on AGR slightly,which supported the idea that the P is the essential factor for the AGR,and N is also an important factor due to the capability of force generation.This provides a better understanding of mechanical behavior and an effective optimizing strategy to muscle-like soft actuator.
