Thomas J Willett

49881892, Jan 29, 1991

Oct 8, 1981

6/309864

Richard F. Kroupa - Lansdowne MD
Thomas J. Willett - Baltimore MD
Glenn E. Tisdale - Severna Park MD

Westinghouse Electric Corp. - Pittsburgh PA

G01C 308

356 4

A passive ranging system functions in conjunction with an electro-optical imaging system to compute a range measurement based on determined changes of the image of a designated object or objects or image features representative thereof in the scene of an image sensor which is transported from one position to another with respect to the designated objects. In the present embodiment, the image sensor generates frames of image information corresponding to the one and another positions thereof while maintaining substantially a common image scene in its field of view. Image features representative of the designated image objects are extracted from at least a selected portion of the two frames for registration in accordance with a predetermined matching criteria. The variations in the geometric relationship of common image features of the registered selected portions of the two frames caused by the image sensor positioning are determined and used together with the one and another image sensor positions, measured with respect to the designated objects, for computing the range measurement in question.