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Proceedings Paper

Passive range measurement through wavefront coding
Author(s): Steven A. Lis
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Paper Abstract

Through the introduction of a simply designed phase mask at the pupil of a conventional imaging system, the range to objects in view can be precisely determined. The mask allows for roughly 50% light transmission, and is segmented to introduce a 1/4 wave phase shift into half of the transmitted light. The resulting point spread function is highly sensitive to object range and is incorporated into the resultant image. Through comparison of the wavefront coded image with a conventional image of the same scene, the precise range to the object can be determined. The range measurement precision obtained is directly related to image contrast. For objects having a simple linear edge possessing a contrast of 32 gray levels above noise, range can be measured to 1% precision. While based on an interference effect, wide-band polychromatic light can be used to determine object range. No actively moving components in the optical system are required for operation. The resultant approach allows for imaging and range determination simultaneously. Based on a fundamental interference phenomenon, this approach is applicable to all passive optical imaging systems ranging from the UV to the infrared. Both a theoretical analysis and an experimental verification of the approach showing the expected performance is provided.

Paper Details

Date Published: 12 October 2006
PDF: 11 pages
Proc. SPIE 6382, Two- and Three-Dimensional Methods for Inspection and Metrology IV, 63820A (12 October 2006); doi: 10.1117/12.682025
Show Author Affiliations
Steven A. Lis, LightLine Technologies, Inc. (United States)

Published in SPIE Proceedings Vol. 6382:
Two- and Three-Dimensional Methods for Inspection and Metrology IV
Peisen S. Huang, Editor(s)

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