CMOS image sensor with noise cancellation
First Claim
1. An image sensor, comprising:
- a pixel; and
, a control circuit that is connected to said pixel and causes said pixel to provide in order a sampled first reference output signal, a sampled reset output signal, a sampled light response output signal and a sampled second reference output signal.
1 Assignment
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Accused Products
Abstract
An image sensor that has one or more pixels within a pixel array. The pixel array may be coupled to a control circuit and one or more subtraction circuits. The control circuit may cause each pixel to provide a first reference output signal and a reset output signal. The control circuit may then cause each pixel to provide a light response output signal and a second reference output signal. The light response output signal corresponds to the image that is to be captured by the sensor. The subtraction circuit may provide a difference between the reset output signal and the first reference output signal to create a noise signal that is stored in memory. The subtraction circuit may also provide a difference between the second reference output signal and the light response output signal to create a normalized light response output signal. The noise signal may then be subtracted from the normalized light response output signal to generate the output data of the sensor. The second reference output signal is the same as the first reference output signal so that the process in essence subtracts the reset noise from the light response signal.
94 Citations
51 Claims
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1. An image sensor, comprising:
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a pixel; and
,a control circuit that is connected to said pixel and causes said pixel to provide in order a sampled first reference output signal, a sampled reset output signal, a sampled light response output signal and a sampled second reference output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An image sensor, comprising:
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a pixel; and
,control means for causing said pixel to provide in order a sampled first reference output signal, a sampled reset output signal, a sampled light response output signal and a sampled second reference output signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for canceling noise in an image sensor, comprising:
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sampling a first reference output signal from a pixel;
sampling a reset output signal from the pixel after sampling the first reference output signal;
generating a difference between the reset output signal and the first reference output signal to create a noise signal;
sampling a light response output signal from the pixel after sampling the reset output signal;
sampling a second reference output signal from the pixel after sampling the light response output signal;
generating a difference between the second reference output signal and the light response output signal to create a normalized light response signal; and
,subtracting the noise signal from the normalized light response signal. - View Dependent Claims (22, 23)
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24. An image sensor, comprising:
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a pixel;
a control circuit that is connected to said pixel and causes said pixel to provide a sampled first reference output signal, a sampled reset output signal, a sampled light response output signal and a sampled second reference signal, said sampled first reference output signal having the same voltage as said sampled second reference output signal;
a first subtraction circuit that provides a difference between said sampled reset output signal and said sampled first reference output signal to create a noise signal, and provides a difference between said sampled second reference output signal and said sampled light response output signal to create a normalized light response signal; and
,a second subtraction circuit that subtracts said noise signal from said normalized light response signal. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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31. An image sensor, comprising:
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a pixel;
control means for causing said pixel to provide a sampled first reference output signal, a sampled reset output signal, a sampled light response output signal and a sampled second reference signal, said sampled first reference output signal having the same voltage as said sampled second reference output signal;
first subtraction means for providing a difference between said sampled reset output signal and said sampled first reference output signal to create a noise signal, and providing a difference between said sampled second reference output signal and said sampled light response output signal to create a normalized light response signal; and
,second subtraction means for subtracting said noise signal from said normalized light response signal. - View Dependent Claims (32, 33, 34, 35, 36, 37)
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38. A method for canceling noise in an image sensor, comprising:
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sampling a first reference output signal from a pixel;
sampling a first output signal from the pixel;
generating a difference between the reset output signal and the first reference output signal to create a noise signal;
sampling a light response output signal from the pixel;
sampling a second reference output signal from the pixel, the first reference output signal having the same voltage as the second reference output signal;
generating a difference between the second reference output signal and the light response output signal to create a normalized light response signal; and
,subtracting the noise signal from the normalized light response signal. - View Dependent Claims (39)
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40. An image sensor, comprising:
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a pixel;
a control circuit that is connected to said pixel and causes said pixel to provide a sampled first reference output signal, a sampled reset output signal, a sampled light response output signal and a sampled second reference signal; and
,a first subtraction circuit that provides a difference between said sampled reset output signal and said sampled first reference output signal to create a noise signal, and provides a difference between said sampled second reference output signal and said sampled light response output signal to create a normalized light response signal, said first subtraction circuit includes a capacitor that stores at least one of said sampled output signals. - View Dependent Claims (41, 42, 43, 44, 45)
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46. An image sensor, comprising:
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a pixel;
control means for causing said pixel to provide a sampled first reference output signal, a sampled reset output signal, a sampled light response output signal and a sampled second reference signal; and
,first subtraction means for providing a difference between said sampled reset output signal and said sampled first reference output signal to create a noise signal, and providing a difference between said sampled second reference output signal and said sampled light response output signal to create a normalized light response signal, said first subtraction means includes a capacitor that stores at least one of said sampled output signals. - View Dependent Claims (47, 48, 49, 50, 51)
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Specification