Feature detecting vision sensor

• US 7,652,754 B2
• Filed: 10/04/2007
• Issued: 01/26/2010
• Est. Priority Date: 10/04/2007
• Status: Expired due to Fees

• Current Assignee: Geoffrey L. Barrows
• Original Assignee: Geoffrey L. Barrows
• Inventors: Barrows, Geoffrey L.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Ratcliffe; Luke D
• Application Number:
  US11/905,851
• Publication Number:
  US 20090168046A1
• Time in Patent Office: 845 Days
• Field of Search: 356 301- 315, 356 401- 41, 356 501- 515, 356 6- 22
• US Class Current: 356/28
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/46 by combining or binning pixels
• CPC Class Codes: H04N 25/707 Pixels for event detection
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/767 Horizontal readout lines, multiplexers or registers
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components
• CPC Class Codes: H04N 3/155 Control of the image-sensor operation, e.g. image processing within the image-sensor

Abstract

A visual sensor for generating an array of binarized feature signals based on a visual field is provided. The visual sensor comprises an array of photoreceptor circuits capable of generating photoreceptor signals based on the visual field, an array of feature detectors capable of generating feature signals based on the photoreceptor signals, and a reconfigurable binary generator array capable of generating binarized feature signals based on the feature signals.

Claims

1. A visual sensor, comprising:

a set of first circuits configured in parallel to generate a plurality of analog signals based on information observed from a visual field;

a set of second circuits configured in parallel to generate a plurality of analog feature signals based on the plurality of analog signals;

a third circuit capable of generating a plurality of binarized feature signals based on the plurality of analog feature signals and in accordance with a function selected from a plurality of possible functions based on a plurality of switch signals, wherein

the third circuit comprises a plurality of binary generators configured in parallel to generate a plurality of binary values based on the plurality of analog feature signals and the selected function,

each of the plurality of binary generators generates at least one of the plurality of binary values based on at least two of the plurality of analog feature signals, and

the third circuit generates the plurality of binarized feature signals based on the plurality of binary values, wherein

the plurality of analog signals relate to photo perception,

the third circuit is reconfigurable.

2. The visual sensor of claim 1, wherein the set of first circuits, the set of second circuits, and the third circuit is implemented in an integrated circuit.

3. The visual sensor of claim 1, wherein

values of the switch signals are set according to a need of an application deploying he visual sensor;

and

each combination of the values of the switch signals as set corresponds to a selectable function.

4. The visual sensor of claim 1, wherein each of the plurality of binary generators comprises at least one switched capacitor circuit.

5. The visual sensor of claim 4, wherein the set of first circuits, the set of second circuits, and the third circuit is implemented in an integrated circuit.

6. The visual sensor of claim 1, further comprising a processor capable of generating an optical flow measurement based on the plurality of binarized feature signals.

7. The visual sensor of claim 1, wherein the set of second circuits is associated with a plurality of time domain filters.

8. The visual sensor of claim 1, wherein the set of second circuits is associated with a plurality of active load circuits.

9. The visual sensor of claim 8, wherein the set of second circuits is further associated with a plurality of time domain filters.

10. The visual sensor of claim 1, wherein the set of first circuits is associated with a plurality of photoconductive elements.

11. The visual sensor of claim 10, wherein the set of first circuits is further associated with a plurality of transduction circuits.

12. The visual sensor of claim 1, further comprising a processor configured for generating an output based on at least one of the plurality of analog signals, the plurality of analog feature signals, and the plurality of binarized feature signals.

13. A visual sensor, comprising:

a focal plane circuit capable of generating a plurality of analog feature signals based on information observed from the visual field, comprising;

a plurality of photoreceptor circuits configured in parallel to generate a plurality of photoreceptor signals based on the information observed from a visual field, and

a plurality of feature detector circuits configured in parallel to generate the plurality of analog feature signals based on the plurality of photoreceptor signals and in accordance with a feature function, wherein

each of the plurality of feature detector circuits receives as input at least two of the plurality of photoreceptor signals, and

each of the plurality of analog feature signals is generated based on the at least two of the plurality of photoreceptor signals; and

a binarization circuit capable of generating a plurality of binarized feature signals based on the plurality of analog feature signals and in accordance with a binarization function selectable from a plurality of possible functions based on a plurality of switch signals, wherein

the binarization circuit comprises a plurality of binary generators configured in parallel to generate a plurality of binary values based on the plurality of analog feature signals,

each of the plurality of binary generators generates at least one of the plurality of binary values based on at least two of the plurality of analog feature signals and the binarization function, and

the binarization circuit generates the plurality of binarized feature signals based on the plurality of binary values.

14. The visual sensor of claim 13, wherein each of the plurality of binary generators is capable of computing a comparison based on whether a first function of the at least two of the plurality of analog feature signals is greater than a second function of the at least two analog feature signals, and

each of the plurality of binary generators is capable of generating the corresponding binary value based on the computed comparison.

15. The visual sensor of claim 14, further comprising a processor capable of generating an optical flow measurement based on the plurality of binarized feature signals.

16. The visual sensor of claim 13, wherein the feature function is based on a substantially linear feature function.

17. The visual sensor of claim 13, wherein each of the plurality of binary generators comprises:

a capacitor having a first side and a second side;

a plurality of switches, wherein

the first side of each switch is connected to the first side of the capacitor and the second side of each switch is connected to one of the plurality of analog feature signals,

each switch connects to a different analog feature signal, and

the plurality of switches may be operated to electrically connect the first side of the capacitor to any of the corresponding analog feature signals electrically connectable through the plurality of switches;

an amplifying circuit connected to the second side of the capacitor;

wherein

the amplifying circuit comprises a circuit selected from the group consisting of an amplifier and an inverter;

the amplifying circuit generates an amplified signal; and

the binary signal generator generates the corresponding binary value based on the amplified signal.

18. The visual sensor of claim 17, further comprising a processor capable of generating an optical flow measurement based on the plurality of binarized feature signals.

19. The visual sensor of claim 13, wherein each of the plurality of binary generators comprises:

an amplifying circuit;

a plurality of switches, wherein

the first side of each switch is connected to the amplifying circuit and the second side of each switch is connected to one of the plurality of analog feature signals,

each switch is connected to a different analog feature signal, and

the plurality of switches may be operated to electrically connect the first side of the capacitor to any of the corresponding analog feature signals electrically connectable through the plurality of switches;

wherein

the amplifying circuit generates an amplified signal; and

the binary generator generates the corresponding binary value based on the amplified signal.

20. A visual sensor, comprising:

a focal plane circuit capable of generating a plurality of analog row signals based on information observed from the visual field, comprising;

a plurality of photoreceptor circuits configured in parallel to generate a plurality of photoreceptor signals based on the information observed from a visual field, and

a plurality of feature detector circuits configured in parallel to generate a plurality of analog feature signals based on the plurality of photoreceptor signals and in accordance with a feature function, wherein

each of the plurality of feature detector circuits receives as input at least two of the plurality of photoreceptor signals,

each of the plurality of analog feature signals is generated based on the at least two of the plurality of photoreceptor signals, and

the focal plane circuit is capable of generating the plurality of analog row signals based on the plurality of analog feature signals and based on a selection signal; and

a binarization circuit capable of generating a plurality of binarized feature signals based on the plurality of analog row signals and in accordance with a binarization function, wherein

the binarization circuit comprises a plurality of binary generators configured in parallel to generate a plurality of binary values based on the plurality of analog row signals,

each of the plurality of binary generators generates at least one of the plurality of binary values based on at least two of the plurality of analog row signals and the binarization function, and

the binarization circuit generates the plurality of binarized feature signals based on the plurality of binary values.

21. The visual sensor of claim 20, wherein each of the plurality of binary generators is capable of computing a comparison based on whether a first function of the at least two of the plurality of analog row signals is greater than a second function of the at least two analog row signals, and

each of the plurality of binary generators is capable of generating the corresponding binary value based on the computed comparison.

22. The visual sensor of claim 20, wherein each of the plurality of binary generators comprises:

an amplifying circuit;

a plurality of switches, wherein

the first side of each switch is connected to the amplifying circuit and the second side of each switch is connected to one of the plurality of analog row signals,

each switch is connected to a different analog row signal, and

the plurality of switches may be operated to electrically connect the first side of the capacitor to any of the corresponding analog row signals electrically connectable through the plurality of switches;

wherein

the amplifying circuit generates an amplified signal; and

the binary generator generates the corresponding binary value based on the amplified signal.