Inter-car distance detecting device for tracking a car running ahead

Claim 1

An inter-car distance detecting device installed on a first car for tracking a second car running ahead of said first car, said inter-car distance detecting device comprising: a pair of image sensors each for picking up an image of objects including said second car and background; window setting means for setting a plurality of distance measuring windows in predetermined positions in the image picked up by one of said image sensors, respectively; distance detecting means for comparing the image contained within each of said distance measuring windows with a corresponding image picked up by the other of said image sensors, to detect distances from said first car to parts of said objects contained within each of said distance measuring windows; window selecting means for selecting said distance measuring windows which contain the image of said second car according to a detection value of said distance detecting means; tracking window setting means for automatically setting a tracking window for tracking the image of said second car with reference to said distance measuring windows selected by said window selecting means; and tracking distance detecting means for detecting a distance to said second car in the image contained within said tracking window, wherein said window selecting means compares said distances detected by said distance detecting means with each other to select said distance measuring windows which are adjacent to one another and contain the image of the second car having distances which are equal and shorter than those of nonselected distance measuring windows.