Event-based sensor and event-based sensing method

• US 10,516,838 B2
• Filed: 06/20/2017
• Issued: 12/24/2019
• Est. Priority Date: 12/14/2016
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Suh, Yun Jae, Kim, Sung Ho, Kim, Jun Seok, Ryu, Hyun Surk
• Primary Examiner(s): Hsu, Amy R
• Application Number:
  US15/627,555
• Publication Number:
  US 20180167570A1
• Time in Patent Office: 917 Days
• CPC Class Codes: H04N 25/40 Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components

Abstract

An event-based sensor includes: a pixel array configured to output activation signals in response to an input to the pixel array; and a controller configured to output a control signal for supplying a first photocurrent generated in a first pixel of the pixel array to a second pixel of the pixel array.

Claims

1. An event-based sensor comprising:

a pixel array configured to output activation signals in response to an input to the pixel array; and

a controller configured to output a control signal for supplying a first photocurrent generated in a first pixel of the pixel array to a second pixel of the pixel array.

2. The event-based sensor of claim 1, wherein the second pixel is configured to output an activation signal based on the first photocurrent and a second photocurrent generated in the second pixel.

3. The event-based sensor of claim 2, wherein the first pixel comprises a plurality of pixels included in the pixel array, and

wherein a number of the plurality of pixels is determined to allow a sum of the first photocurrent and the second photocurrent to be equal to or greater than a predetermined threshold.

4. The event-based sensor of claim 3, wherein the predetermined threshold is determined based on a magnitude of noise generated in inverse proportion to an amount of an input current, comprising the first photocurrent and the second photocurrent, applied to a pixel circuit configured to generate the activation signal in the second pixel.

5. The event-based sensor of claim 2, wherein the second pixel is configured to output the activation signal based on a voltage corresponding to a sum of the first photocurrent and the second photocurrent, and a threshold adjusted according to the supply of the first photocurrent to the second pixel.

6. The event-based sensor of claim 2, wherein the second pixel is configured to output the activation signal based on a voltage corresponding to an average of the first photocurrent and the second photocurrent, and a predetermined threshold.

7. The event-based sensor of claim 1, wherein the controller is configured to output the control signal to supply the first photocurrent generated in the first pixel which is in an inactive state to the second pixel which is in an active state, in a subsampling mode in which at least a portion of a plurality of pixels included in the pixel array is inactive.

8. The event-based sensor of claim 1, further comprising:

a signal line to transfer the first photocurrent to the second pixel; and

a control line to transfer the control signal to an internal switching circuit of the first pixel, and an external switching circuit between the first pixel and the second pixel.

9. The event-based sensor of claim 8, wherein the pixel array comprises a plurality of pixels, comprising the first pixel and the second pixel, which are arranged in a matrix form,

wherein the signal line comprises a first signal line for transferring the first photocurrent in a row direction of the matrix, and a second signal line for transferring the first photocurrent in a column direction of the matrix, and

wherein the control line comprises a first control line for selecting a pixel in the row direction, and a second control line for selecting a pixel in the column direction, among the plurality of pixels.

10. The event-based sensor of claim 9, wherein, in response to the first control line being selected, the second signal line is blocked,

wherein, in response to the second control line being selected, the first signal line is blocked, and

wherein, in response to both the first control line and the second control line being selected, a photodiode of the first pixel and a pixel circuit of the first pixel are connected to each other.

11. The event-based sensor of claim 9, wherein, in response to the first control line not being selected, the second signal line is connected,

wherein, in response to the second control line not being selected, the first signal line is connected, and

wherein, in response to at least one of the first control line and the second control line not being selected, a connection between a photodiode of the first pixel and a pixel circuit of the first pixel is blocked.

12. An event-based sensor comprising:

a plurality of pixels configured to generate respective photocurrents in response to input light; and

a controller configured to select one or more pixels to generate and supply a photocurrent to a given pixel, among the plurality of pixels, based on a noise level of the given pixel, so that the given pixel generates an activation signal based on the photocurrent.

13. The event-based sensor of claim 12, wherein the given pixel is configured to generate another photocurrent, and generate the activation signal based on a sum or an average of the photocurrent and the other photocurrent.

14. The event-based sensor of claim 13, wherein the controller is configured to select the one or more pixels such that the sum or the average of the photocurrent and the other photocurrent exceeds a predetermined threshold which is set based on the noise level.

15. The event-based sensor of claim 13, further comprising:

at least one dummy pixel disabled to sense input light and configured to generate a dark current; and

a current mirror configured to mirror the dark current so that the given pixel deducts a current component, corresponding to the dark current, from the other photocurrent generated in the given pixel.

16. The event-based sensor of claim 12, wherein the controller is configured to select the one or more pixels set to an inactive state and the given pixel set to an active state.

17. A pixel in an event-based sensor comprising:

a photodiode configured to generate a photocurrent based on incident light;

a pixel circuit configured to output an activation signal based on the photocurrent; and

a switching circuit configured to control connection between the photodiode and the pixel circuit depending on a control signal,

wherein the photocurrent is supplied to a pixel circuit of another pixel, depending on an operation of the switching circuit.

18. The pixel in an event-based sensor of claim 17, wherein the other pixel outputs another activation signal based on the photocurrent and another photocurrent generated in a photodiode of the other pixel.

19. The pixel in an event-based sensor of claim 17, wherein the pixel circuit is configured to covert the photocurrent to a voltage, and compare information about the voltage to a predetermined threshold to output the activation signal based on a result of the comparison.