A method and apparatus for real-time tracking of a non-rigid target. In addition, a liquid crystal display device is provided with corrected data generating means for generating corrected data by correcting the current image data input to the image data inputting means, on the basis of previous image data stored in the image data memory. The bearing devices each have a lever which is attached to both the guide element and the sunroof in a pivot bearing, whereby the pivot bearing on the sunroof end has a bearing axle which protrudes at its one end into a control path. This provides support to the heel cup and the foot A heel cushion is secured to said structural gel in a heel cushion area defined by the structural gel on the bottom surface of the heel cup.