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Proceedings Paper

Optical rangefinding from image focus
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Paper Abstract

A method for gauging the distance from a video camera to an object of interest is described. By using a calibrated camera-lens system, range was related to focus of a selected object. Optimum focus of the image was determined by maximizing the high-frequency content of the Fourier transform of the object image. The Walsh- Hadamard transform was investigated as an alternative focusing function. Software was developed to determine optimum image focus and control a motorized camera lens. Range values from the video camera to target objects were calculated by the system. Calculated values were compared with measured distances. For any given distance, the difference between calculated and actual distance averaged less than 1.2%. Distance values calculated using the Walsh-Hadamard transform differed from values calculated with the Fourier transform by less than 1%.

Paper Details

Date Published: 1 January 1990
PDF: 11 pages
Proc. SPIE 1260, Sensing and Reconstruction of Three-Dimensional Objects and Scenes, (1 January 1990); doi: 10.1117/12.19999
Show Author Affiliations
Paul R. Weckler, Virginia Polytechnic Institute (United States)
Glenn A. Kranzler, Oklahoma State Univ. (United States)


Published in SPIE Proceedings Vol. 1260:
Sensing and Reconstruction of Three-Dimensional Objects and Scenes
Bernd Girod, Editor(s)

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