Apparatus and method for eliminating artifacts in active pixel sensor (APS) imagers
First Claim
Patent Images
1. An active pixel sensor comprising:
- at least one pixel comprising a photodetector that outputs an output level indicative of incoming light;
a storage element, electrically connected to the photodetector, operating to store said output level during a photodetector readout operation;
a comparison element electrically connected to said storage element operating to compare said output level and an adjusted saturation voltage; and
an output selector electrically connected to said comparison element, operating to output an adjusted maximum voltage during pixel readout operation in response to the comparison element determining that said adjusted saturation voltage exceeds said output level.
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Abstract
An active pixel sensor (APS) that includes circuitry to eliminate artifacts in digital images. The APS includes a comparator for comparing a signal level from a pixel to an adjusted saturation voltage to determine if the pixel is saturated. If the pixel is saturated, the signal output from the pixel is replaced with an analog voltage having a maximum value corresponding to a brightest pixel in the image.
57 Citations
14 Claims
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1. An active pixel sensor comprising:
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at least one pixel comprising a photodetector that outputs an output level indicative of incoming light;
a storage element, electrically connected to the photodetector, operating to store said output level during a photodetector readout operation;
a comparison element electrically connected to said storage element operating to compare said output level and an adjusted saturation voltage; and
an output selector electrically connected to said comparison element, operating to output an adjusted maximum voltage during pixel readout operation in response to the comparison element determining that said adjusted saturation voltage exceeds said output level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method comprising:
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storing an output level indicative of incoming light output from a photodetector during a photodetector readout operation;
comparing said output level to an adjusted saturation voltage;
outputting an adjusted maximum voltage during a pixel readout operation in response to said adjusted saturation voltage exceeding said output level;
storing a reset level from the photodetector during the photodetector readout operation;
calculating a difference voltage from said output level and said reset level; and
outputting said difference voltage during the pixel readout operation in response to said output level exceeding said adjusted saturation voltage. - View Dependent Claims (13, 14)
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Specification