Imaging systems with column randomizing circuits
First Claim
1. An image sensor comprising:
- an array of image sensing pixels arranged in rows and columns;
a plurality of image readout circuits;
data output circuitry;
a first multiplexer having inputs and outputs, wherein each of the inputs of the first multiplexer is coupled to a respective one of the columns of the array and wherein each of the outputs of the first multiplexer is coupled to a respective one of the image readout circuits;
a plurality of bias circuits, each of which provides a bias voltage; and
a second multiplexer that connects each of the bias circuits to a randomly-selected and different one of the columns of image sensing pixels in the array.
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Accused Products
Abstract
An imaging system may include an image sensor array and column randomizing multiplexers. The imaging system may include a data output circuit and image readout circuitry such as analog amplifiers, analog-to-digital converters, and memory circuits. The column randomizing multiplexers may include a first column randomizing multiplexer between the image sensor array and at least some of the image readout circuitry. The first column randomizing multiplexer may randomly connect columns of the image sensor array to the image readout circuitry. The connections made by the first column randomizing multiplexer may be randomized as each row of the image sensor array is read out. The column randomizing multiplexers may include a second column randomizing multiplexer between at least some of the image readout circuitry and the data output circuit. The second column randomizing multiplexer may reorder image data for the image readout circuitry.
35 Citations
17 Claims
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1. An image sensor comprising:
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an array of image sensing pixels arranged in rows and columns; a plurality of image readout circuits; data output circuitry; a first multiplexer having inputs and outputs, wherein each of the inputs of the first multiplexer is coupled to a respective one of the columns of the array and wherein each of the outputs of the first multiplexer is coupled to a respective one of the image readout circuits; a plurality of bias circuits, each of which provides a bias voltage; and a second multiplexer that connects each of the bias circuits to a randomly-selected and different one of the columns of image sensing pixels in the array. - 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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an array of image sensing pixels arranged in rows and columns; a plurality of bias circuits, wherein each of the bias circuits comprises a plurality of transistors and wherein, when one of the transistors is turned on, that transistor provides a bias voltage; and circuitry that turns on a random one of the transistors in each of the bias circuits. - View Dependent Claims (17)
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12. An image sensor comprising:
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an array of image sensing pixels arranged in rows and columns; a plurality of analog-to-digital converters; a first multiplexer having inputs and outputs, wherein each of the inputs of the first multiplexer is coupled to a respective one of the columns of the array and wherein each of the outputs of the first multiplexer is coupled to a respective one of the analog-to-digital converters; an output buffer; a second multiplexer having inputs and outputs, wherein each of the inputs of the second multiplexer is coupled to a respective one of the analog-to-digital converters and wherein the outputs of the second multiplexer are coupled to the output buffer; and a plurality of bias circuits, wherein each of the bias circuits comprises a plurality of transistors and wherein, when one of the transistors is turned on, that transistor provides a bias voltage; and circuitry that turns on a random one of the transistors in each of the bias circuits. - View Dependent Claims (13)
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14. A method of reducing fixed pattern column noise in images captured by an imager, wherein the imager comprises a pixel array including image sensing pixels arranged in rows and columns, a switching array, a data output circuit, and image readout circuits coupled between the pixel array and the data output circuit, the method comprising:
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enabling column randomizing functions that utilize the switching array; while the column randomizing functions are enabled, reading image data associated with a first image from the image sensing pixels in the pixel array; disabling the column randomizing functions; and while the column randomizing functions are disabled, reading image data associated with a second image from the image sensing pixels in the pixel array, wherein the imager further comprises circuitry that detects lower-light-flux conditions and that detects higher-light-flux conditions, wherein enabling the column randomizing functions comprises enabling the column randomizing functions in response to the circuitry detecting the lower-light-flux-conditions, and wherein disabling the column randomizing functions comprises disabling the column randomizing functions in response to the circuitry detecting the higher-light-flux-conditions. - View Dependent Claims (15, 16)
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Specification