Defective pixel signal substitution in thermal imaging systems
First Claim
1. An apparatus for defective pixel signal substitution in a thermal imaging system, the thermal imaging system having a focal plane array with at least three pixels, the apparatus comprising:
- addressing circuitry operable to address a signal produced by at least one of the pixels;
a reference generator operable to generate a reference value for the pixel;
a subtractor having a first input coupled to the addressing circuitry and a second input coupled to the reference generator, the subtractor operable to output an error value representing a comparison of the produced signal and the reference value;
a comparator coupled to the subtractor and operable to compare the error value to a predetermined threshold and to generate a substitution flag if the error value exceeds the predetermined threshold; and
a substitutor coupled to the comparator and operable to substitute the produced signal of the pixel with a selected signal in response to the substitution flag.
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Accused Products
Abstract
Thermal imaging system (10) includes a focal plane array (18) having pixels (20). Signals produced by pixels (20) are addressed by integrated circuit substrate (22) and passed to video processor (24). Video processor (24) includes, among other modules, a detection and substitution module (28) that detects defective pixels (21) and substitutes the signals produced by defective pixels (21). The detection and substitution of signals produced by defective pixels (21) may be performed while viewing the thermal scene (12) or while stimulating pixels (20) with a stimulus. A thermal stimulus may be generated by a thermoelectric cooler (50) thermally coupled to integrated circuit substrate (22) and focal plane array (18). An electrical stimulus to identify defective pixels (21) may also be delivered to pixels (20) of focal plane array (18).
69 Citations
20 Claims
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1. An apparatus for defective pixel signal substitution in a thermal imaging system, the thermal imaging system having a focal plane array with at least three pixels, the apparatus comprising:
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addressing circuitry operable to address a signal produced by at least one of the pixels; a reference generator operable to generate a reference value for the pixel; a subtractor having a first input coupled to the addressing circuitry and a second input coupled to the reference generator, the subtractor operable to output an error value representing a comparison of the produced signal and the reference value; a comparator coupled to the subtractor and operable to compare the error value to a predetermined threshold and to generate a substitution flag if the error value exceeds the predetermined threshold; and a substitutor coupled to the comparator and operable to substitute the produced signal of the pixel with a selected signal in response to the substitution flag. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for post-delivery defective pixel signal substitution in a thermal imaging system having a focal plane with at least three pixels, for at least one of the pixels, the method comprising:
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addressing a signal produced by the pixel; generating a reference value for the pixel; generating an error value that represents a comparison of the produced signal to the reference value; generating a substitution flag if the error value exceeds a predetermined threshold; and substituting the produced signal of the pixel with a selected signal in response to the substitution flag. - View Dependent Claims (10, 11, 12, 13)
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14. A thermal imaging system having a post-delivery defective pixel signal substitution system, comprising:
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a focal plane array having at least three pixels; an integrated circuit substrate coupled to the focal plane array, the integrated circuit substrate operable to address a signal produced by at least one of the pixels of the focal plane array; and substitution circuitry coupled to the integrated circuit substrate, the substitution circuitry further comprising; a reference generator operable to generate a reference value for the pixel; a subtractor having a first input coupled to the integrated circuit substrate and a second input coupled to the reference generator, the subtractor operable to output an error value representing a comparison of the produced signal and the reference value; a comparator coupled to the subtractor and operable to compare the error value to a predetermined threshold and to generate a substitution flag if the error value exceeds the predetermined threshold; and a substitutor coupled to the comparator and operable to substitute the produced signal of the pixel with a selected signal in response to the substitution flag. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification