Background

The human tracking algorithm called OpenPose can detect joint points and calculate joint angles. However, the reliability and validity of OpenPose have not been clarified yet.

Research question: Are there the enough reliability and validity of OpenPose based motion analysis?

Methods

20 healthy young subjects participated in this study. The motion task was a bilateral squat. The joint angles of the trunk, hip, knee, and ankle were calculated using OpenPose and VICON. Kinematic measurements by three-dimensional motion analysis devices were recorded using VICON. Simultaneously, the images were taken with a digital camera from the right side. After the images were processed with OpenPose, joint angles were calculated from estimated joint points. To confirm the test-retest reliability within device, intraclass correlation coefficients [ICC (1, 3)] were calculated. To confirm the validity, linear regression analysis and ICC [2,1] between the data obtained by OpenPose and VICON were calculated. Furthermore, the agreement between the data obtained by OpenPose and VICON was assessed by Bland-Altman analysis.

Results

ICCs [1,3] of the data obtained by OpenPose and VICON were almost perfect. There were significant associations between the data obtained by OpenPose and VICON. ICCs [2,1] between the data obtained by OpenPose and VICON were almost perfect or substantial for trunk, knee and ankle joints, and fair on the hip joint. There were fixed biases on knee and ankle joints, and proportional biases on trunk and hip joint.

Significance

OpenPose based motion analysis is reliable and has the advantage of being low cost and easier to operate than conventional methods. In future, to consider the clinical utility of OpenPose, it is necessary to identify the error between the true values indicating actual joint movement and data obtained by OpenPose with its correction for fixed and proportional biases.

(295 words)

中文翻译：

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使用人体姿态跟踪算法验证双侧深蹲运动分析系统的可靠性和有效性。

背景

称为OpenPose的人类跟踪算法可以检测关节点并计算关节角度。但是，OpenPose的可靠性和有效性尚未阐明。

研究问题：基于OpenPose的运动分析是否具有足够的可靠性和有效性？

方法

20名健康的年轻受试者参加了这项研究。运动任务是双边蹲下。使用OpenPose和VICON计算躯干，臀部，膝盖和脚踝的关节角度。使用VICON记录了三维运动分析设备的运动学测量值。同时，图像是用数码相机从右侧拍摄的。用OpenPose处理图像后，根据估计的关节点计算关节角度。为了确认设备内重测的可靠性，计算了类内相关系数[ICC（1，3）]。为了确认有效性，计算了OpenPose和VICON获得的数据之间的线性回归分析和ICC [2,1]。此外，通过Bland-Altman分析评估了OpenPose和VICON获得的数据之间的一致性。

结果

OpenPose和VICON获得的数据的ICC [1,3]几乎是完美的。OpenPose和VICON获得的数据之间存在显着关联。OpenPose和VICON获得的数据之间的ICC [2,1]对于躯干，膝盖和踝关节几乎是完美的或相当大的，而在髋关节上则相当。膝关节和踝关节存在固定偏差，躯干和髋关节存在比例偏差。

意义

与传统方法相比，基于OpenPose的运动分析是可靠的，并且具有成本低廉和易于操作的优点。将来，要考虑OpenPose的临床实用性，有必要识别出指示实际关节运动的真实值与OpenPose对其固定和比例偏差进行校正后获得的数据之间的误差。

（295字）