基于约束关系的下颈椎运动测量新方法

下颈椎各个关节准确稳定的运动参数是医生对颈椎病进行诊断的重要依据。本文提出了一种满足颈椎耦合约束关系,基于双目视觉原理的下颈椎运动参数测量方法。首先,根据下颈椎围绕瞬时旋转中心运动的特点和下颈椎耦合运动的规律,建立了满足耦合约束关系的下颈椎运动学模型;其次,在下颈椎解剖学特征位置(棘突和横突)上布置标志点,借助多台摄像机,基于双目视觉原理和三维数字图像相关(3D-DIC)技术,直接测量不考虑耦合约束关系的下颈椎前屈、后伸、左旋、右旋及侧屈等运动时的角度;最后,利用考虑耦合约束关系的运动学模型对下颈椎运动角度变化曲线进行了校正。波动范围的分析结果表明测量的稳定性得到了提高。利用本方法实现了对下颈椎关节运动角度的实时测量,提供了一种对下颈椎关节运动进行稳定测量的有效手段。

On a New Measurement Technique of Lower Cervical Spine Movement Based on Constraint Relation

Accurate and stable movement parameters of each lower cervical spine joint is an important basis of diagnosis of cervical spondylosis. Based on binocular vision principle, a movement parameter measurement method of lower cervical spine join is proposed in this paper to meet the requirement of cervical spine coupled constraint relation. Firstly, a kinematic model of lower cervical spine satisfying the coupled constraint relation was established, according to the characteristics of lower cervical spine moving around instantaneous rotation center and of the pattern of coupled motion. Secondly, markers were arranged on anatomical landmarks of lower cervical spine (such as spinous process and transverse process). Based on binocular vision principle (recorded by several cameras) and 3D-DIC technique, the movement angles of each lower cervical spine joint, including flexion, extension, left-handed turn, right-handed turn and lateral flexion etc, were directly measured without taking into account the coupled constraint relation. Finally, according to the kinematic model of lower cervical spine satisfying the coupled constraint relation, the motion angle curves of lower cervical spine were revised. Analytic results of fluctuation range show that the measurement stability increases. Using above-mentioned method, real-time measurement of lower cervical spine joint motion angle is realized, which provids an effective means to stably measure lower cervical spine joint movement.