Patent ID: 7972018
Filing Date: 2011-07-05
Classification: G03B,H04N

Abstract:
1. An image projection system comprising: a projector comprising a light projecting unit constructed to emit light in accordance with image data, a projection lens constructed to image light emitted by the light projecting unit onto a projection screen, and a focus adjusting mechanism constructed for controllable adjustment of focus of the projection lens; a capture device constructed to capture an image of the image projected onto the projection screen by the projection lens; and a control unit constructed to control the projector to project an asymmetrically focused pattern, and to control the capture device to capture an image of the asymmetrically focused pattern, wherein the asymmetrically focused pattern is imaged by the projection lens onto the projection screen with a focus at one position on the projection screen that differs from focus at another position thereof, wherein the control unit is further constructed to calculate a focus adjustment direction by using asymmetrical aspects of the captured image of the asymmetrically focused pattern and to control the projector to drive the focus adjustment mechanism in the calculated focus adjustment direction so as to move from an out-of-focus state of the projection lens toward an in-focus state.