## 1 Introduction  
Telemedicine and home-care systems have become the trend because of the integration of technology into the practice of medicine [1; 2; 3; 4; 5]. Some medical care can be applied at home using some simple system. If technology products are easy to operate, then patients or caregivers can conveniently perform daily self-care activities at home by themselves. This can improve the time spent on patient care, the quality of care, and the therapeutic benefits of care. Telemedicine and home care systems can also reduce the costs and time associated with transportation between the hospital and home for follow-up care or treatment [6; 7; 8; 9]. In rehabilitation, the person receiving treatment exhibits impaired mobility. Treatment typically takes a long time to achieve a positive effect, and if the treatment is stopped or interrupted, then a functional decline or reversal of progress may occur [10; 11]. Therefore, rehabilitation is a very lengthy process that takes a heavy psychological, physical, and economic toll on the patients and families of patients [12]. If an efficient rehabilitation system can be designed for use at home that helps patients to perform the movements that they must perform repeatedly every day to maintain their mobility and physical function, then with such a system, transportation challenges and costs are eliminated. Moreover, infection risks for patients with weakened immune systems can be avoided because frequent hospital stays are eliminated too. A home-based rehabilitation program can also make rehabilitation more flexible and enables more frequent exercise. In sum, transportation burdens are reduced, families have more time, and exercises can be more frequently performed. Rehabilitation involves the use of repetitive movements for maintaining or improving physical or motor functions [10]. After receiving a professional evaluation and a recommended exercise regimen to perform at home, a patient may only need to be observed and recorded by a rehabilitation supporting instrument during the basic training sections performed at home. A professional demonstrates an action or use of an instrument, and the patient can then operate a quality monitoring system or review visual feedback provided by a home rehabilitation system for quality self-monitoring of the motions performed during the daily rehabilitation training at home [13]. Some somatosensory games claim that they can achieve the effects of sports and entertainment, and some of these have been used for physical training and physical rehabilitation [14; 15; 16]. However, these games are usually designed to involve whole body activities, and most require a standing position [17; 18; 19; 20; 21] often in front of a camera at a distance of at least 100 cm. Beside most of those somatosensory games and human pose estimation are focus on whole body pose discrimination [22] neither pay attention on changes of range of motion of joints nor think about how muscles works in those poses. Nowadays, there are many human pose estimation systems that extract skeletons or skeleton points from depth sensors [18; 19; 20; 21; 22; 23]. However, determining the joint movements (include directions and angles) are necessary for rehabilitation applications. In [18; 19; 20], they derive a unified gaussian kernel correlation (GKC) representation and develop an articulated GKC and articulated pose estimation for both the full body and the hands. That study can achieve effective human pose estimation and tracking, but may have limitations in single joint movement determination, such as shoulder rotation, wrist pronation. In [21], the input depth map is extracted to match with a set of pre-captured motion exemplars to generate a body configuration estimation, as well as semantic labeling of the input point cloud, but as we know that body figure can be shown or defined as a point cloud but the real body skeletons is segmental, each movement comes from the angle change of the key joint rather than each point cloud of the body.