Systems and methods of selective output for reducing power

• US 9,967,500 B2
• Filed: 04/04/2015
• Issued: 05/08/2018
• Est. Priority Date: 09/29/2014
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ovsiannikov, Ilia, Wang, Hongyu
• Primary Examiner(s): Wang, Xi
• Application Number:
  US14/678,965
• Publication Number:
  US 20160094768A1
• Time in Patent Office: 1,130 Days
• Field of Search: 382293, 382232, 348 36
• CPC Class Codes: H04N 25/47 Image sensors with pixel address output; Event-driven image sensors; Selection of pixels to be read out based on image data
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array

Abstract

An embodiment includes a system, comprising: a buffer configured to store a plurality of events, each event including a plurality of bits; an output circuit configured to output events from the buffer; and a controller coupled to the buffer and the output circuit and configured to: cause the output circuit to output a first event from the buffer; and select a second event from the buffer to be output by the output circuit after the first event based on bits associated with the first event.

Claims

1. A system, comprising:

a dynamic vision sensor comprising a plurality of pixels, the dynamic vision sensor generating a plurality of events, each event being based on a pixel of the dynamic vision sensor sensing a change of illumination of the pixel, each pixel having an address, each event sensed by a pixel including a plurality of bits representing an address of the pixel, and each event having a temporal relationship to other events;

a buffer configured to store the plurality of events;

an output circuit configured to output the plurality of bits of each event from the buffer; and

a controller coupled to the buffer and the output circuit and configured to;

cause the output circuit to output the bits of a first event from the buffer;

determine a Hamming distance between the bits of the first event and bits of other events in the buffer; and

select a second event from the other events in the buffer to be output by the output circuit after the first event such that among the other events, the bits of the second event have a lowest hamming distance to the bits of the first event.

2. The system of claim 1, wherein the dynamic vision sensor is coupled to the buffer and configured to generate the plurality of events to be stored in the buffer.

3. The system of claim 2, wherein

the plurality of bits of each event further represent a value associated with a change in illumination sensed by the pixel sensing the event.

4. The system of claim 3, wherein the address of the pixel sensing the event are encoded to reduce a Hamming distance between addresses of substantially adjacent pixels.

5. The system of claim 4, wherein addresses of the pixels of the dynamic vision sensor are encoded using a grey code.

6. The system of claim 1, wherein the controller is configured to select the second event such that output of the second event by the output circuit after output of the first event uses a minimum of energy relative to other events stored in the buffer.

7. The system of claim 1, wherein the buffer has a depth of at least eight events.

8. The system of claim 1, wherein controller comprises:

a comparator configured to compare the first event with at least two events stored in the buffer to determine the second event;

a multiplexer configured to select the second event as the event to be output by the output circuit; and

a demultiplexer configured to select a location in the buffer to store a new event in response to the comparator.

9. The system of claim 1, wherein:

the controller comprises a comparator configured to compare the first event with at least two entries stored in the buffer to determine the second event; and

the buffer is configured to shift entries of the events in response to the comparator.

10. A system, comprising:

a dynamic vision sensor comprising a plurality of pixels, the dynamic vision sensor generating a plurality of events, each event being based on a pixel of the dynamic vision sensor sensing a change of illumination of the pixel, each pixel having an address, each event sensed by a pixel including a plurality of bits representing an address of the pixel, and each event having a temporal relationship to other events;

a buffer configured to store the plurality of events;

an output circuit configured to output the plurality of events in the buffer; and

a controller coupled to the buffer and the output circuit and configured to;

select a first event of the plurality of events stored in the buffer to be output from the output circuit, the first event having a minimum number of bit transitions from a previous event output from the output circuit of the plurality of events stored in the buffer,

shift the first event to the output circuit to be output by the output circuit and so that the buffer may receive another event, and

select a second event of the plurality of events stored in the buffer to be output from the output circuit, the second event having a minimum number of bit transitions from the first event of the plurality of events stored in the buffer.

11. A method, comprising:

generating a plurality of events by a dynamic vision sensor, the dynamic vision sensor comprising a plurality of pixels, each event being based on a pixel of the dynamic vision sensor sensing a change of illumination of the pixel, each pixel having an address, each event sensed by the pixel including a plurality of bits comprising the address of the pixel, and each event having a temporal relationship to other events;

storing the plurality of events in a buffer;

outputting a first event of the plurality of events stored in the buffer from an output circuit, the first event having a lowest Hamming distance from an event previously output from the output circuit;

storing in the buffer another event generated by the dynamic vision sensor;

selecting a second event of the plurality of events stored in the buffer to be output based on the first event; and

outputting the second event from the output circuit;

wherein selecting the second event of the plurality of events stored in the buffer comprises;

determining a Hamming distance between bits of the first event and bits of other events stored in the buffer; and

selecting the second event to have a lowest Hamming distance to the bits of the first event.

12. The method of claim 11, wherein the plurality of bits of an event further comprising a value of the change of illumination sensed by the pixel sensing the change of illumination.

13. The method of claim 12, further comprising encoding addresses of pixels of the dynamic vision sensor to reduce a Hamming distance between addresses of substantially adjacent pixels of the dynamic vision sensor.