MOTION-SENSOR DEVICE HAVING MULTIPLE LIGHT SOURCES

• US 20150292884A1
• Filed: 03/19/2014
• Published: 10/15/2015
• Est. Priority Date: 04/01/2013
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Fuchikami, Ryuji
• Granted Patent: US 10,473,461 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/62 Control of parameters via user interfaces
• CPC Class Codes: H04N 23/63 by using electronic viewfinders

Abstract

A motion sensor device according to an embodiment of the present disclosure includes an image sensor (101) and LED light sources (102, 103). Using an image captured by the image sensor (101) when both of the LED light sources (102, 103) are turned ON and an image captured by the image sensor (101) when only the LED light source (103) is turned ON, the distance to an object is estimated based on the luminance ratio of the object.

Claims

1. A motion sensor device comprising:

an image sensor;

a plurality of light sources including first, second and third light sources, the first light source being arranged at a first distance from the image sensor in a first direction, the second light source being arranged at a second distance from the image sensor in a second direction, the third light source being arranged at a third distance from the image sensor in a third direction; and

a controller configured to control the image sensor and the plurality of light sources,

wherein the controller is configured to;

make the image sensor capture a first frame with light emitted from the first light source at a first time;

make the image sensor capture a second frame with light emitted from the second light source at a second time;

make the image sensor capture a third frame with light emitted from the third light source at a third time;

obtain information about a distance to an object based on a plurality of images which have been gotten by capturing the first, second and third frames;

obtain multiple pieces of information about an estimated distance to the object based on information representing a direction of the object derived from at least one of the plurality of images and a luminance of the object derived from each of the plurality of images; and

determine the information about the distance based on the multiple pieces of estimated distance information, and

the second and third directions are different from each other, and

the first and second distances are different from each other.

3. The motion sensor device of claim 1, wherein the controller is configured to calculate at least two luminance ratios based on a first luminance of the object in a first image gotten by capturing the first frame, a second luminance of the object in a second image gotten by capturing the second frame, and a third luminance of the object in a third image gotten by capturing the third frame, and obtain the multiple pieces of estimated distance information based on the information representing the direction of the object and the at least two luminance ratios.

4. The motion sensor device of claim 1, wherein the image sensor captures the first, second and third frames in this order continuously so that a period between a starting point of the first frame and an end point of the third frame becomes equal to or shorter than three milliseconds.

14. An electronic device comprising:

the motion sensor device of claim 1; and

a display which changes what to present thereon in response to a motion of the object detected by the motion sensor device.

15. An integrated circuit for use in the motion sensor device of claim 1, the integrated circuit comprising:

a timing controller which is connected to the image sensor and the light sources to control timings of exposure and light emission;

an extreme value searching section which processes image capturing data to search an area with a relatively high luminance;

a coordinate memory which stores the coordinates and luminance of the area that has been searched by the extreme value searching section; and

a distance calculating section which calculates estimated distance information based on a luminance ratio by choosing frames that have been shot in the same area under different conditions from data in the coordinate memory.

16. A distance estimating method to be performed by the motion sensor device of claim 1, the method comprising:

searching for an extreme value by extracting selectively a range with a relatively high light intensity from data of captured frames and by calculating its coordinates and light intensity;

calculating the ratio of luminances that have been extracted in the extreme value searching step and that have been selected from among luminances of frames shot under different conditions; and

converting the luminance ratio calculated in the luminance ratio calculating step and the coordinates searched for in the extreme value searching step into a distance.

17. A computer readable storage medium storing a computer program which is defined to make the motion sensor device of claim 1 perform:

searching for an extreme value by extracting selectively a range with a relatively high light intensity from data of captured frames and by calculating its coordinates and light intensity;

calculating the ratio of luminances that have been extracted in the extreme value searching step and that have been selected from among luminances of frames shot under different conditions; and

converting the luminance ratio calculated in the luminance ratio calculating step and the coordinates searched for in the extreme value searching step into a distance.

2. (canceled)

5. A motion sensor device comprising:

an image sensor;

a plurality of light sources including first and second light sources, the first light source being arranged at a first distance from the image sensor in a first direction, the second light source being arranged at a second distance from the image sensor in a second direction; and

a controller configured to control the image sensor and the plurality of light sources,

wherein the controller is configured to;

make the image sensor capture a first frame with light emitted from the first light source at a first time;

make the image sensor capture a second frame with light emitted from both of the first and second light sources at a second time; and

obtain information about an estimated distance to an object based on a plurality of images which have been gotten by capturing the first and second frames, and

the first and second directions are different from each other and/or the first and second distances are different from each other.

6. (canceled)

7. A motion sensor device comprising:

an image sensor;

a plurality of light sources including first and second light sources, the first light source being arranged at a first distance from the image sensor in a first direction, the second light source being arranged at a second distance from the image sensor in a second direction; and

a controller configured to control the image sensor and the plurality of light sources,

wherein the controller is configured to;

make the image sensor capture a first frame with light emitted from the first light source at a first time;

make the image sensor capture a second frame with light emitted from the second light source at a second time; and

obtain information representing a direction of the object based on a plurality of images which have been gotten by capturing the first and second frames, obtain a first piece of information about an estimated distance to the object based on a luminance of the object derived from each of the plurality of images, obtain a second piece of information about an estimated distance to the object by another method of measuring the distance, and obtain information about the distance to the object based on the first and second pieces of information about the estimated distance, and

the first and second directions are different from each other and/or the first and second distances are different from each other.

9. The motion sensor device of claim 7, wherein the controller is configured to determine the degree of reliability of the first piece of information about the estimated distance by reference to the information representing the direction of the object, and either discard the first piece of information about the estimated distance as erroneous information or correct the first piece of information based on the second piece of information about the estimated distance according to the degree of reliability.

10. The motion sensor device of claim 9, wherein the controller corrects the degree of reliability based on a difference in coordinate between the plurality of images in an area with a relatively high luminance.

11. The motion sensor device of claim 9, wherein the controller calculates the second piece of information about the estimated distance based on at least one of a difference in coordinate between the plurality of images in an area with a relatively high luminance, the width of the area with the relatively high luminance, and the luminance.

12. The motion sensor device of claim 9, wherein the controller calculates the second piece of information about the estimated distance based on a time delay caused by light reflected from the object.

13. The motion sensor device of claim 12, wherein the controller measure the time delay caused by the reflected light measured by the light sources and the image sensor.

8. (canceled)