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US 8,619,168 B2Granted
Image sensor with high dynamic range imaging and integrated motion detection
AssigneeRegents of the University of Minnesota
InventorsJaehyuk Choi, Euisik Yoon
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Abstract
This disclosure describes: (1) two different schemes to enhance dynamic range, (2) a new motion detection scheme using in-pixel digital storage, and (3) the motion detection in high illumination for CMOS image sensors. The schemes may be implemented in a small pixel size and easily incorporated in simple column-level circuits for existing CMOS image sensor systems.
Claims20
An image sensor comprising:
- an array of pixels to capture an image, the array of pixels arranged as a plurality of pixel groups, each of the pixel groups having a two or more pixels, each of the pixels having a floating diffusion node for outputting an image signal;
- and
- control logic to store digital reset information within the floating diffusion nodes of each pixel group,
- wherein the digital reset information comprises a multi-bit digital value for each of the pixel groups that indicates a point in time when one or more of the pixels of the pixel group was reset during a previous integration period and represents an illumination level for the pixel group during the previous integration period.
1 more element
An image sensor comprising:
- an array of pixels to capture an image, the array of pixels arranged as a plurality of pixel groups, each of the pixel groups having a two or more pixels, each of the pixels having a floating diffusion node for outputting an image signal, wherein each pixel comprises a first photodiode with a high sensitivity and a second photodiode with a sensitivity lower than the sensitivity of the first diode;
- and
- control logic to, for each of the pixel groups, trigger a conditional reset during an integration period for the pixel group to reset collection of illumination of the first photodiode of one or more of the pixels of the pixel group when illumination of the second photodiode for the one of the pixels of the pixel group reaches a specified threshold.
An image sensor comprising:
- an array of pixels to capture an image, the array of pixels arranged as a plurality of pixel groups, each of the pixel groups having a two or more pixels, each of the pixels having a floating diffusion node for outputting an image signal;
- and
- control logic to store digital reset information within the floating diffusion nodes of each pixel group,
- wherein the digital reset information comprises a multi-bit digital value for each of the pixel groups, and
- wherein each of the floating diffusion nodes for the pixels of each of the pixel groups stores one bit of the digital reset information for the pixel group.
2 more elements
A video capture device comprising:
- an image sensor, the image sensor comprising:
- an array of pixels to capture an image, the array of pixels arranged as a plurality of pixel groups, each of the pixel groups having a two or more pixels, each having a floating diffusion node for outputting an image signal;
- and
- control logic to store digital reset information within the floating diffusion nodes of each pixel group, wherein the digital reset information for each pixel group indicates a point in time when one or more of the pixels of the pixel group was reset during a previous integration period and indicates an illumination level for the pixel group during the previous integration period;
- a motion detection unit that identifies a region of interest by comparing the digital reset information computed for a current frame with the stored digital reset information and provides an address for the region of interest to the image sensor;
- a signal processing unit that receives a motion signal based on the region of interest and an image signal based on the captured image from the image sensor and generates a merged output signal based on the motion signal and image signal;
- and
- a display unit that receives the merged output signal and displays the merged output signal to a user.
5 more elements
A method, comprising:
- storing multi-bit digital reset information within a group of pixels within an image sensor, wherein the digital reset information for each pixel group indicates a point in time when one or more of the pixels of the pixel group was reset during an integration period, wherein each of the pixels stores one bit of the multi-bit digital reset information for the pixel group in a floating diffusion node of the pixel;
- and
- outputting illumination values for the pixels computed from image signals read from the pixels and the multi-bit digital reset information.
Dependencies are inferred from the claim text.