An optical touch panel and a detection method thereof are provided. A receiving bay in the casing receives slide-in parts of the power tool and of a recharging stand, to retain the battery pack. A user separation weight computation unit finds a user separation vector on the basis of the direction vectors. A stroke recognition device includes a stroke sensing area. These images are generally generated without any specific reference markers in the image for determining the distortion caused by an optical system. A store clerk passes the prints to the user.