Image measurement of body position during side-approach transfer motion

In order to clarify the side-transfer ability of spinal cord injury (SCI) patients, it is necessary to analyse the side-transfer motion of SCI patients. This study describes a method for easy detection of the body position during the transfer motion using a simple human body model and side- and front-view images taken by using two charge-coupled device (CCD) cameras. The proposed simple human body model consists of five cuboids, nine columns and two elliptical cylinders. First, the wheelchair size was measured at the 11 points on its right side using a side-view image. Next, the wheelchair position was detected from the centre position of the right back wheel, and the gap angle between the platform and the wheelchair was detected from the edge position of both back wheels on the side- and front-view images. The positions of the 11 parts of the body model were estimated by matching each part to the side- and front-view images, and then the gravity centre of the body was calculated. Finally, the two images and the centre of gravity calculated every 1 s during the transfer motion were used to realise the movement of the body during the transfer motion.