Optical detection of geometric configurations
First Claim
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1. A spatial filter for detecting and locating a selected object configuration from background noise in a recorded image comprising:
- (a) an amplitude filter that is a (photographic) negative of the Fourier transform of an object corresponding to said selected object configuration and(b) a phase filter that provides π
phase reversals for alternate amplitude waves of said Fourier transform.
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Abstract
The specification discloses an optical technique for retrieving images of geometric shapes from a cluttered background in a photographic record by means of amplitude and phase filters configured according to the particular shape sought to be retrieved. A Fourier transform of the record is filtered with filters of both types and light representing the desired shape, if present, is brought to a focus in an image plane.
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Citations
9 Claims
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1. A spatial filter for detecting and locating a selected object configuration from background noise in a recorded image comprising:
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(a) an amplitude filter that is a (photographic) negative of the Fourier transform of an object corresponding to said selected object configuration and (b) a phase filter that provides π
phase reversals for alternate amplitude waves of said Fourier transform. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A process for locating selected objects of predetermined configurations from an original image comprising:
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(a) coherently illuminating said image in the object plane of an optical system; (b) spatial filtering said image in a Fourier transform plane of said system with a filter that has the inverse transform function relative to said selected objects both as to amplitude and phase; and (c) forming an image in a retransform plane of said system in which light representative of said selected objects is focussed to small spots while all other light is distributed and attenuated. - View Dependent Claims (8, 9)
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Specification