Westinghouse Electric Corporation

Glenn E Tisdale

Richard F Kroupa

Thomas J Willett

Harley B Lindemann

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.

Passive ranging system especially for use with an electro-optical

A passive electro-optical target recognition system which utilizes additional signature measurements of an active nature to enhance the discrimination of desired targets from detected candidate targets in the field of view thereof is disclosed. Candidate targets are detected by the passive target recognition system from passive image radiation received from the field of view of its one or more passive sensors. A laser beam generated substantially at a predetermined wavelength is positioned to illuminate individually each of the detected candidate targets. An active sensor tuned to the predetermined wavelength receives the active laser radiation separately reflected from the individually illuminated candidate targets. An active signature is derived for each of the detected candidate targets from its received active image radiation. Accordingly, a desired target is discriminated from the detected candidate targets in the field of view of the passive sensor based on the derived active target signatures thereof. To further enhance this discrimination process, polarizing properties of the laser beam may be used as an additional measurement for each candidate target beyond the derived active target signatures thereof.

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Severna Park, MD, United States of America

Glenn E Tisdale