Patent ID: 6788289
Filing Date: 2004-09-07
Classification: G06F

Abstract:
A pointed position detection system which detects a position pointed by a pointer within a predetermined image display region, the system comprising:image pick-up means for picking up an image of the image display region; means for storing an image for differential image generation which is generated by picking up an image of the image display region on which a uniform image is displayed; differential image extraction means for extracting a differential image based on the image for differential image generation and a pointing image which is generated by picking up an image of the image display region in which a pointing action is performed based on a cast shadow; and means for detecting a pointed position in the pointing image based on the extracted differential image, wherein the means for detecting the pointed position detects change of environment effect on the image display region even when the pointing action is in a halted state, and substitutes a new image for differential image generation in place of the image for differential image generation when the detected change based on a calculated dispersion of pixels is equal to or greater than a predetermined amount.