Computer finger tracking system for skin movement evaluation by using multiple image modalities

• Main Authors: Jhao-WeiChen, 陳昭瑋
• Other Authors: Yung-Nien Sun
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/46212117066803937298

碩士 === 國立成功大學 === 資訊工程學系碩博士班 === 98 === In the kinematic assessment and clinical application, the kinematic evaluations for rehabilitation and therapeutic are necessary. Thus, the approaches of measurement based on skin-attached markers for motion analyses have been widely applied. However, one of the major facts that cause the measurement error of kinematic parameters is the skin elastic-deformation and sliding that produces the relative displacements of the attached markers with respect to the underlying bones. It implies that bony motion can not be solely represented by the markers. This thesis provides new ideas to measure the skin movements and also give credible conclusions by the experimental results. The proposed skin-movement measurement is based on integrating the camera images, fluoroscopy and magnetic resonance imaging technologies. First of all, the specific grid drawn on skin surface was adopted to represent the skin patch of interest. The motion of the three-dimensional grid model associated with this skin-drawn grid will be reconstructed by camera tracking system from multiple-view grid images. Next, the bone images captured by planar fluoroscopy system simultaneously were correlated to the corresponding motion of grid model. Thus, the two-dimensional (2-D) skin movement projected on the fluoroscopy plane can also be measured. However, the actual three-dimensional (3-D) movements were still not available. To this end, the three-dimensional bony hand model must be found by using the additionally magnetic resonance imaging (MRI). After registering the bony hand model to fluoroscopy images, the three-dimensional bony hand motion could be simulated in terms of the inter-poses transformations. Finally, the three-dimensional skin movements with respect to the MRI bony finger can be obtained based on the spatial information from the three systems. In the experiments, we compared the tracking results with the ground truth given by experts, and obtained very small tracking errors (less than 1 pixel). Moreover, in the skin movement, the PIP joint of index and middle finger were investigated for skin movements with 10 healthy-hand subjects. The measurement results showed that the skin slide with respect to the underlying bone segment toward the joint center in finger flexion. This information can be used in kinematic compensation, and also available to assist skin surgical judgments.