Device, system and method to provide an auto-focus capability based on object distance information

Patent metadata

Field	Value
Publication number	US-10027879-B2
Application number	US-201615352503-A
Country	US
Kind code	B2
Filing date	Nov 15, 2016
Priority date	Nov 15, 2016
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

Techniques and mechanisms for determining a configuration of the lens system. In an embodiment, respective distances from a reference are determined for each of a plurality of objects that are observable via the lens system. Based on the object distances, counts of in-focus objects are determined, each for a corresponding focal configuration of the lens system. Each such count of in-focus objects represents a total number of objects that are (or would be) in focus during the corresponding focal configuration, wherein a respective one of the plurality of objects is at a near depth of field of the corresponding focal configuration. In another embodiment, a preference of one focal configuration over another focal configuration is determined based on the counts of in-focus objects.

First claim

What is claimed is:

1. A device comprising:
a lens system to receive light from an environment external to the device;
distance evaluation circuitry configured to identify respective distances to each of a plurality of objects including a first object and a second object;
selection circuitry coupled to the distance evaluation circuitry to determine a focus of the lens system, the selection circuitry including logic that when executed causes the device to perform operations including:
adjusting the lens system to have a first focal configuration and a first aperture in which the first object is at a first near depth of field;
determining a first count of any of the plurality of objects to be in focus, while the first object is at the first near depth of field, due to the first focal configuration and to the first aperture, wherein the first count represents a number of objects in focus while the first object is at the first near depth of field;
adjusting the lens system to have a second focal configuration and the first aperture in which the second object is at a second near depth of field;
determining a second count of any of the plurality of objects to be in focus, while the second object is at the second near depth of field, due to the second focal configuration and to the first aperture, wherein the second count represents a number of objects in focus while the second object is at the second near depth of field;
comparing a first score based on the first count that results from the first focal configuration and a second score based on the second count that results from the second focal configuration, to identify a preference between the first focal configuration and the second focal configuration based on which focal configuration provides a larger number of in-focus objects; and
providing, based on the comparing of the first score and the second score, a signal which indicates the preference between the first focal configuration and the second focal configuration based on which focal configuration provides a larger number of in-focus objects;

a focus controller coupled to adjust the lens system based on the signal; and
an image sensor optically coupled to capture an image received with the lens system after the lens system has been adjusted based on the signal.

2. The device of claim 1 , wherein the selection circuitry is configured to cause the device to generate the signal which indicates the preference between the first focal configuration and the second focal configuration independent of the device performing any count of objects being in focus while all of the plurality of objects are offset from a near depth of field for a present focal configuration.

3. The device of claim 1 , wherein the selection circuitry is configured to cause the device to determine one or more other focuses of the lens system, each of the one or more of the other focuses due in part to a respective aperture other than the first aperture.

4. The device of claim 1 , wherein the signal indicates the preference for the first focal configuration, and an object other than the first object, of the plurality of objects, is a closest object to the lens array while the lens system has the first focal configuration.

5. The device of claim 1 , wherein the selection circuitry is configured to cause the device to calculate the first score based on a first weight value assigned to an object based on a location of the object in the field of view.

6. The device of claim 5 , wherein the location of the object in the field of view is relative to a reference point or a reference line of the field of view.

7. The device of claim 6 , wherein the reference point is a center of the field of view.

8. The device of claim 5 , wherein the location of the object in the field of view is relative to another object of the plurality of objects.

9. The device of claim 5 , wherein the first score includes a number other than any integer.

10. The device of claim 1 , wherein selection circuitry is configured to cause the device to calculate the first score based on a first weight value assigned to an object based on an object type of the object.

11. The device of claim 10 , wherein the object type includes a human face object type.

12. A non-transitory computer-readable storage medium having stored thereon instructions which, when executed by one or more processing units, cause the one or more processing units to perform a method comprising:
identifying respective distances to each of a plurality of objects in a field of view of a lens system, the plurality of objects including a first object and a second object;
determining a focus of the lens system, including:
adjusting the lens system to have a first focal configuration and a first aperture in which the first object is at a first near depth of field;
determining a first count of any of the plurality of objects to be in focus, while the first object is at the first near depth of field, due to the first focal configuration and to the first aperture, wherein the first count represents a number of objects in focus while the first object is at the first near depth of field;
adjusting the lens system to have a second focal configuration and the first aperture in which the second object is at a second near depth of field;
determining a second count of any of the plurality of objects to be in focus, while the second object is at the second near depth of field, due to the second focal configuration and to the first aperture, wherein the second count represents a number of objects in focus while the second object is at the second near depth of field;
comparing a first score based on the first count that results from the first focal configuration and a second score based on the second count that results from the second focal configuration, to identify a preference between the first focal configuration and the second focal configuration based on which focal configuration provides a larger number of in-focus objects; and
providing, based on the comparing of the first score and the second score, a signal which indicates the preference between the first focal configuration and the second focal configuration based on which focal configuration provides a larger number of in-focus objects;

adjusting the lens system based on the signal; and
capturing an image received with the lens system after the lens system has been adjusted based on the signal.

13. The non-transitory computer-readable storage medium of claim 12 , wherein the signal which indicates the preference between the first focal configuration and the second focal configuration is generated independent of performing any count of objects being in focus while all of the plurality of objects are offset from a near depth of field for a present focal configuration.

14. The non-transitory computer-readable storage medium of claim 12 , the method further comprising determining one or more other focuses of the lens system, each of the one or more of the other focuses due in part to a respective aperture other than the first aperture.

15. The non-transitory computer-readable storage medium of claim 12 , wherein the signal indicates the preference for the first focal configuration, and an object other than the first object, of the plurality of objects, is a closest object to the lens array while the lens system has the first focal configuration.

16. The non-transitory computer-readable storage medium of claim 12 , the method further including calculating the first score based on a first weight value assigned to an object based on a location of the o

Assignees

• Google Llc

Inventors

• Passarella Katrina
• Cardei Vlad

Classifications

• H04N23/671 Primary

  in combination with active ranging signals, e.g. using light or sound signals emitted toward objects · CPC title

• H04N23/54 Primary

  Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils · CPC title

• H04N23/55

  Optical parts specially adapted for electronic image sensors; Mounting thereof · CPC title

• H04N23/611

  where the recognised objects include parts of the human body · CPC title

• G02B7/28 Primary

  Systems for automatic generation of focusing signals · CPC title