High-dynamic-range imaging devices
First Claim
1. A method for capturing high-dynamic-range image data with an image pixel, wherein the image pixel comprises a photosensor, a first charge storage region, a second charge storage region, a charge readout circuit coupled between the second charge storage region and an output line, a first transistor coupled between the photosensor and the first charge storage region, and a second transistor coupled between the first charge storage region and the second charge storage region, the method comprising:
- accumulating a first amount of charge with the photosensor;
transferring the first amount of charge from the photosensor to the second charge storage region using the first and second transistors;
while the first amount of charge is stored on the second charge storage region, accumulating a second amount of charge with the photosensor; and
while the first amount of charge is stored on the second charge storage region, transferring the second amount of charge from the photosensor to the first charge storage region with the first transistor without disturbing the first amount of charge stored on the second charge storage region, wherein accumulating the first amount of charge comprises accumulating charge for a first time period, wherein accumulating the second amount of charge comprises accumulating charge for a second time period, and wherein the first time period is shorter than the second time period, and wherein accumulating the charge for the second time period comprises;
accumulating charge for a third time period;
after accumulating the charge, partially resetting the photosensor; and
after partially resetting the photosensor, accumulating additional charge for a fourth time period that is shorter than the third time period.
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Accused Products
Abstract
High-dynamic-range images may be produced by combining multiple integration periods of varying duration, wherein each integration is obtained using a global shutter operation. Charge accumulated during a first integration period may be stored on a first storage node while charge accumulated during a second and third integration time are carried out. Storage of charges accumulated during the second and third integration periods on a second storage node within a pixel while charge is stored on the first storage node allows capture of a global-shutter-based, high-dynamic-range image. A global-shutter-based image capture base on at least three integration time periods may provide enhanced dynamic range.
44 Citations
14 Claims
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1. A method for capturing high-dynamic-range image data with an image pixel, wherein the image pixel comprises a photosensor, a first charge storage region, a second charge storage region, a charge readout circuit coupled between the second charge storage region and an output line, a first transistor coupled between the photosensor and the first charge storage region, and a second transistor coupled between the first charge storage region and the second charge storage region, the method comprising:
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accumulating a first amount of charge with the photosensor; transferring the first amount of charge from the photosensor to the second charge storage region using the first and second transistors; while the first amount of charge is stored on the second charge storage region, accumulating a second amount of charge with the photosensor; and while the first amount of charge is stored on the second charge storage region, transferring the second amount of charge from the photosensor to the first charge storage region with the first transistor without disturbing the first amount of charge stored on the second charge storage region, wherein accumulating the first amount of charge comprises accumulating charge for a first time period, wherein accumulating the second amount of charge comprises accumulating charge for a second time period, and wherein the first time period is shorter than the second time period, and wherein accumulating the charge for the second time period comprises; accumulating charge for a third time period; after accumulating the charge, partially resetting the photosensor; and after partially resetting the photosensor, accumulating additional charge for a fourth time period that is shorter than the third time period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for capturing high-dynamic-range image data with an image pixel array using a global shutter scheme, wherein the image pixel array comprises a plurality of image pixels, wherein each image pixel comprises a photosensor, a first charge storage region, a second charge storage region, a charge readout circuit, and a reset transistor, the method comprising:
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asserting a global reset signal to reset the photosensor in each image pixel; for a first time period, accumulating a first amount of charge with the photosensor in each image pixel; storing the first amount of charge on the second charge storage region in each image pixel; for a second time period, accumulating a second amount of charge with the photosensor in each image pixel; and while the first amount of charge is stored on the second charge storage region, storing the second amount of charge on the first charge storage region in each image pixel without disturbing the first amount of charge stored on the second charge storage region of each image pixel, wherein accumulating the second amount of charge with the photosensor in each image pixel comprises; accumulating charge with the photosensor in each image pixel for a third time period; after accumulating the charge with the photosensor in each image pixel, draining excess charge accumulated during the third time period from the photosensor of each image pixel through the reset transistor of each image pixel; and after draining the excess charge, accumulating additional charge for a fourth time period, wherein the fourth time period is shorter than the third time period, and wherein the fourth time period is longer than the first time period. - View Dependent Claims (11, 12)
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13. A method for capturing high-dynamic-range images using a global shutter scheme with an electronic device, wherein the electronic device comprises an image pixel array, control circuitry, and processing circuitry, wherein the image pixel array comprises a plurality of image pixels arranged in rows and columns, and wherein each image pixel comprises a photosensor, a first charge storage region, a second charge storage region, and a charge readout circuit the method comprising:
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with the control circuitry, asserting a global reset signal to reset the image pixel array; during a first integration time period, storing a first image on the first charge storage regions of the image pixels; and storing a second image on the second charge storage regions of the image pixels without disturbing the first image stored on the first charge storage regions of the image pixels, wherein storing the second image on the second charge storage regions comprises; during a second integration time period, accumulating charge with the photosensor in each of the plurality of image pixels; partially resetting the photosensor in each of the plurality of image pixels to an intermediate voltage; during a third integration time period, accumulating charge with the photosensor in each of the plurality of image pixels; and transferring the charge accumulated during the second and third integration time periods to the second storage regions of the image pixels, wherein the second integration time period is longer than the third integration time period, and wherein the third integration time period is longer than the first integration time period. - View Dependent Claims (14)
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Specification