Patent ID: 7528354
Filing Date: 2009-05-05
Classification: G01S,G02B,G03B

Abstract:
1. An imaging system comprising: an image sensor located at an image plane; at least a lens element for projecting an image on the image sensor, the lens element defining an optical axis; a driving mechanism, operatively connected to the lens element, for shifting the lens element relative to the image sensor in a direction substantially parallel to the optical axis; a light source for providing a light beam to illuminate a spot on a surface of the lens element so as to produce a reflected light beam from the spot on said surface, wherein the light source is so positioned that the reflected light beam is arranged to encounter the image sensor at a location on the image sensor; and a processor, operatively connected to the image sensor, for determining the encountering location, wherein when the lens element is shifted by a shifting distance, said encountering location is moved within the image sensor by a moving distance, the processor is configured to compute the shifting distance of the lens element based on the moving distance of the encountering location.