Method and apparatus for correcting offsets of two detectors using respective functions of a difference
First Claim
1. A dithered offset correction method comprising the steps of:
- (a) providing an array of detectors;
(b) viewing a scene with said detectors at a first time and providing an output from each of said detectors relating to a portion of said scene;
(c) viewing said scene with said detectors at a second time after said first time with each said portion of said scene detected by one of the detectors of said array other than the detector viewing said portion of said scene at said first time and providing an output from each of said detectors relating to the portion of the scene detected;
(d) determining a difference in outputs of first and second said detectors viewing the same portion of said scene respectively at said first time and said second time and offsetting one of the first and second detectors having a higher output with a first function of said difference and offsetting the other of the first and second detectors having a lower output with a second function of said difference different from said first function.
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Abstract
A dithered offset correction method wherein, according to a first embodiment, updates are made of the offset correction during each iteration and, after four iterations, the offset for each pixel or detector element is updated from all of its neighbors to provide faster convergence than is obtainable by the prior art. In accordance with a second embodiment, the offset for each detector element is updated for every iteration and, for each update, the update is made with information from an entire row or an entire column of data. After four iterations, each offset has been updated with information from every detector element in the focal plane array. This provides even more rapid convergence compared to the prior art.
21 Citations
28 Claims
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1. A dithered offset correction method comprising the steps of:
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(a) providing an array of detectors; (b) viewing a scene with said detectors at a first time and providing an output from each of said detectors relating to a portion of said scene; (c) viewing said scene with said detectors at a second time after said first time with each said portion of said scene detected by one of the detectors of said array other than the detector viewing said portion of said scene at said first time and providing an output from each of said detectors relating to the portion of the scene detected; (d) determining a difference in outputs of first and second said detectors viewing the same portion of said scene respectively at said first time and said second time and offsetting one of the first and second detectors having a higher output with a first function of said difference and offsetting the other of the first and second detectors having a lower output with a second function of said difference different from said first function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A dithered offset correction system comprising:
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(a) an array of detectors for viewing a scene with said detectors at a first time and providing an output from each of said detectors relating to a portion of said scene and viewing said scene with said detectors at a second time after said first time with each said portion of said scene detected by one of the detectors of said array other than the detector viewing said portion of said scene at first time and providing an output from each of said detectors relating to the portion of the scene detected; (b) circuitry for determining a difference in outputs of first and second said detectors viewing the same portion of said scene respectively at said first time and said second time and offsetting one of the first and second detectors having a higher output with a first function of said difference and offsetting the other of the first and second detectors having a lower output with a second function of said difference different from said first function. - View Dependent Claims (20, 21)
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22. A dithered offset correction method, comprising the steps of:
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viewing a scene at a first time with a detector array which includes first, second and third detectors, wherein the scene includes first, second, third and fourth portions which are different, and wherein said first, second and third detectors respectively detect the first, second and third portions of the scene at said first time, and respectively provide first, second and third outputs respectively relating to the first, second and third portions of the scene at said first time; viewing the scene with said detector array at a second time after said first time, wherein said first, second and third detectors respectively detect the second, third and fourth portions of the scene at said second time, and respectively provide fourth, fifth and sixth outputs respectively relating to the second, third and fourth portions of the scene at said second time; determining a difference between said second and fourth outputs; and adjusting an offset of said first detector by using said difference according to a respective one of first and second functions when said fourth output is respectively larger and smaller than said second output, and adjusting an offset of said second detector by using said difference according to a respective one of said first and second functions when said fourth output is respectively smaller and larger than said second output, said first function being different from said second function. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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Specification