Patent ID: 6911642

Claim:
A method of object presence detection, by using a detection device of the type mounted to a motor vehicle, said vehicle having at least one blind spot, where said detection device is for detecting an object such as an approaching vehicle situated in said blind spot, comprising: (a) a receiver ( 7 ) for detecting electromagnetic waves, said receiver ( 7 ) comprising a focusing device, and a light detector including a set of active photosensor elements that converts said electromagnetic waves into electrical signals, said light detector defining an image surface, (b) an electronic circuit ( 9 ) converting said electrical signals into digitized signals, (c) a logic circuit ( 15 ) analyzing said digitized signals to analyze the presence of objects in said at least one blind spot which are moving relative to said vehicle, and generating variable output alarm signals depending on the result of said analysis, and (d) indicator members activated by said output signals, said detection device being adapted to distinguish a vehicle from other objects, wherein said distinguishing is effected by recognizing arrises, clearly marked on at least a first portion of said image surface of interest in vertical and/or horizontal directions on a road surface and the follow-up of the movement of said arrises through various successive images to calculate a relative speed of a detected object providing said arrises.