Image sensor artifact elimination
First Claim
1. A method of correcting errors in an active pixel sensor that generates an output indicative of illumination intensity, the method comprising:
- determining the output from the active pixel sensor;
comparing the output with a threshold value;
if the output is lower than the threshold value identifying an erroneous output and storing a value in a latching device in response thereto;
generating a maximum value based upon the value stored in the latching device and correcting the erroneous output by replacing the erroneous output with the maximum value; and
controlling the latching device with a latch control signal so that a select signal output therefrom is used to determine whether an analog-to-digital converter (ADC) selectively outputs one of the maximum value and a converted output from the active pixel sensor.
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Accused Products
Abstract
The method and circuit corrects errors in an active pixel sensor which generates an output indicative of illumination intensity and which may experience an error in the output as a result of artifacts which produce an erroneous output. The approach includes determining the output from the pixel, comparing the output with a threshold value, and if the output is lower that the threshold value identifying the existence of an erroneous output and storing a value in a latching device in response thereto. A maximum value is generated in response to the latching device to replace the erroneous output, thereby correcting the error. The present invention switches the system from the analog to digital domain with respect to the issue of artifacts by using a latch to store a value which is then used to replace the actual output if the output is wrong.
29 Citations
20 Claims
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1. A method of correcting errors in an active pixel sensor that generates an output indicative of illumination intensity, the method comprising:
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determining the output from the active pixel sensor; comparing the output with a threshold value; if the output is lower than the threshold value identifying an erroneous output and storing a value in a latching device in response thereto; generating a maximum value based upon the value stored in the latching device and correcting the erroneous output by replacing the erroneous output with the maximum value; and controlling the latching device with a latch control signal so that a select signal output therefrom is used to determine whether an analog-to-digital converter (ADC) selectively outputs one of the maximum value and a converted output from the active pixel sensor. - View Dependent Claims (2, 3, 4, 5)
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6. A method of correcting errors in an array of active pixel sensors for forming an image, wherein each pixel generates an output indicative of illumination intensity thereon which contributes to the image, the method comprising, for each active pixel sensor in the array:
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determining the output from the active pixel sensor; comparing the output with a threshold value; if the output is lower than the threshold value identifying an erroneous output and storing a value in a latching device in response thereto; and generating a maximum value based upon the value stored in the latching device and correcting the erroneous output by replacing the erroneous output with the maximum value; and controlling the latching device with a latch control signal so that a select signal output therefrom is used to determine whether an analog-to-digital converter (ADC) selectively outputs one of the maximum value and a converted output from the active pixel sensor. - View Dependent Claims (7, 8, 9)
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10. An active pixel sensor comprising:
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a pixel section which is responsive to illumination thereon to produce an output; a sampling section for sampling outputs from the pixel section to determine the output; a correction section for identifying if the output is an erroneous output and replacing the erroneous output with a maximum output value; the correction section including a comparator to compare the output with a threshold value and generate a value based thereon, and a latch to store the value if the output is below the threshold; the maximum output value being based on the value stored in the latch; and an analog-to-digital converter (ADC) configured to selectively output one of the maximum value and a converted output from the pixel section based upon a select signal output from the latch. - View Dependent Claims (11, 12, 13, 14)
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15. An imaging device comprising:
array of active pixel sensors for forming an image, wherein each active pixel sensor generates an output indicative of illumination intensity thereon which contributes to the image, each active pixel sensor including a pixel section which is responsive to illumination thereon to produce an output, a sampling section for sampling outputs from the pixel section to determine the output, a correction section for identifying if the output is an erroneous output and replacing the erroneous output with a maximum output value, the correction section including a comparator to compare the output with a threshold value and generate a value based thereon, and a latch to store the value if the output is below the threshold, the maximum output value being based on the value stored in the latch; and an analog-to-digital converter (ADC) configured to selectively output one of the maximum value and a converted output from the pixel section based upon a select signal output from the latch. - View Dependent Claims (16, 17, 18, 19, 20)
Specification