20. The gesture recognition method according to claim 17 , wherein a skin part is filtered from the color digital image by using a skin processing method, the skin part is then converted into a gray-scale image, and the skin edge of the skin part is found out with an edge detection filter.
20. The gesture recognition method according to claim 17 , wherein a skin part is filtered from the color digital image by using a skin processing method, the skin part is then converted into a gray-scale image, and the skin edge of the skin part is found out with an edge detection filter. 21. The gesture recognition method according to claim 20 , wherein sets of the edge pixels within the same angle ranges are respectively found out from the edge pixels constituting the skin edge, then stored as the edge parts, and further classified into the edge parts of different angle classes according to the angles of the edge pixels contained in the edge parts.