Subject tracking device, subject tracking method, subject tracking program product and optical device

• US 8,433,097 B2
• Filed: 12/12/2011
• Issued: 04/30/2013
• Est. Priority Date: 03/15/2006
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Muramatsu, Keiko
• Primary Examiner(s): Lu, Tom Y
• Application Number:
  US13/316,686
• Publication Number:
  US 20120087544A1
• Time in Patent Office: 505 Days
• Field of Search: 382/103, 348/345
• US Class Current: 382/103
• CPC Class Codes: G03B 15/16 for photographing the track of moving objects high-speed photography G03B39/00
• CPC Class Codes: G03B 39/00 High-speed photography
• CPC Class Codes: H04N 23/611 where the recognised objects include parts of the human body
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene

Abstract

A subject tracking device includes: a tracking zone setting unit that sets an area where a main subject is present within a captured image as a tracking zone; a tracking unit that tracks the main subject based upon an image output corresponding to the tracking zone; and an arithmetic operation unit that determines through arithmetic operation image-capturing conditions based upon an image output corresponding to a central area within the tracking zone.

Claims

1. A subject tracking device, comprising:

a tracking zone setting unit that initially sets an area where a main subject is present within a captured image as a tracking zone;

a tracking unit that detects a new area, where the main subject is present and which corresponds to the tracking zone set by the tracking zone setting unit, within a next captured image based upon an image output corresponding to the tracking zone, and sets the detected new area as a new tracking zone; and

an arithmetic operation unit that determines through arithmetic operation image-capturing conditions based upon an image output corresponding to a central area that is within the set new tracking zone and smaller than the set new tracking zone.

2. A subject tracking device according to claim 1, further comprising:

a converting unit that converts a captured image data to be reduced and outputs a converted image data, wherein;

the tracking unit detects the new area by using the converted image data.

3. A subject tracking device according to claim 1, wherein:

the tracking zone setting unit initially sets the area corresponding to the main subject present at a center of the captured image as the tracking zone.

4. An optical device, comprising:

a subject tracking device according to claim 1.

13. A subject tracking device according to claim 1, further comprising:

a focus detection calculation unit that executes focus detection calculation through a phase detection method for the focus detection area closest to the center of the set new tracking zone among a plurality of focus detection areas that are provided for the phase detection method in a screen corresponding to the captured image.

14. A subject tracking device according to claim 13, further comprising:

a display unit that turns on a focus detection area closest to a center of the tracking zone among the plurality of focus detection areas.

15. A subject tracking device according to claim 1, wherein:

the tracking unit sequentially sets a plurality of equal-size areas which are each equal in size to the tracking zone within the next captured image and compares the image output corresponding to the tracking zone with an other image output corresponding to the sequentially set equal-size area, and detects an equal-size area of the plurality of equal-size areas judged to be most similar to the tracking zone as the new area.

5. A subject tracking method, comprising:

setting initially an area where a main subject is present within a captured image as a tracking zone;

detecting a new area, where the main subject is present and which corresponds to the set tracking zone, within a next captured image based upon an image output corresponding to the set tracking zone;

setting the detected new area as a new tracking zone; and

determining through arithmetic operation image-capturing conditions based upon an image output corresponding to a central area that is within the set new tracking zone and smaller than the set new tracking zone.

6. A non-transitory computer-readable medium having contained therein a subject tracking program that enables a computer to execute a subject tracking method according to claim 5.

7. A subject tracking device, comprising:

a tracking unit that designates image data in an area where a subject is present within a first image as a first tracking zone and tracks the subject by detecting a new area where image data corresponding to the image data in the first tracking zone are present, in a second image obtained after the first image, and designating the detected new area as a second tracking zone; and

an arithmetic operation unit that determines through arithmetic operation image-capturing conditions by using information corresponding to a central area that is within the second tracking zone and smaller than the second tracking zone.

8. A subject tracking device according to claim 7, wherein:

the arithmetic operation unit executes exposure calculation by using image data over the central area of the second tracking zone.

9. A subject tracking device according to claim 7, wherein:

the arithmetic operation unit includes a focus detection calculation unit that executes focus detection through a contrast detection method by using the image data over the central area within the second tracking zone.

16. A subject tracking device according to claim 7, wherein:

the tracking unit sequentially sets a plurality of equal-size areas which are each equal in size to the first tracking zone within the second image and compares the image data in the first tracking zone with image data in the plurality of equal-size areas, and detects an equal-size area of the plurality of equal-size areas judged to be most similar to the first tracking zone as the second tracking zone.

10. A subject tracking method, comprising:

designating image data in an area where a subject is present within a first image as a first tracking zone;

tracking the subject by detecting a new area where image data corresponding to the image data in the first tracking zone are present in a second image obtained after the first image and designating the new detected area as a second tracking zone; and

determining through arithmetic operation image-capturing conditions by using information corresponding to a central area that is within the second tracking zone and smaller than the second tracking zone.

11. A subject tracking method according to claim 10, wherein:

exposure calculation is executed by using image data over the central area of the second tracking zone.

12. A subject tracking method according to claim 10, wherein:

focus detection is executed through a contrast detection method by using image data over the central area within the second tracking zone.

17. A subject tracking device, comprising:

an image sensor that captures an image and outputs an image capturing signal;

a plurality of focus detection areas provided at intervals at predetermined positions in the captured image;

a tracking zone setting unit that sets an area where a main subject is present within the captured image as a tracking zone;

a tracking unit that tracks the main subject using a signal of an area corresponding to the tracking zone of the image capturing signal;

a focus adjusting control unit that performs focus adjusting control using a focus detection area selected among focus detection areas included in the tracking zone; and

a display unit that displays within the captured image a mark indicating a position corresponding to the focus detection area, wherein;

the display unit displays a focus detection area closest to a center of the tracking zone of the captured image even if the focus detection area closest to the center of the tracking zone is not selected by the focus adjusting control unit.

18. A subject tracking device according to claim 17, wherein:

the focus adjusting control unit selects the focus detection area to be used for focus adjusting control while weighting a distance from the center of the tracking zone.

19. A subject tracking device according to claim 17, further comprising:

a converting unit that converts a captured image data to be reduced and outputs a converted image data, wherein

the tracking unit tracks movement of the main subject by using the converted image data.

20. A subject tracking device according to claim 17, wherein:

the tracking zone setting unit sets an area corresponding to a subject existing at a central area of the captured image as the tracking zone.

21. A subject tracking device, comprising:

an image sensor that captures an image and outputs an image capturing signal;

a plurality of focus detection areas provided at intervals at predetermined positions in the captured image;

a tracking zone setting unit that sets an area where a main subject is present within the captured image as a tracking zone;

a tracking unit that tracks the main subject based upon an image output corresponding to the tracking zone;

an exposure arithmetic operation unit that calculates exposure conditions based upon an image output corresponding to a central area within the tracking zone;

a focus detection arithmetic operation unit that calculates a focus adjustment quantity by using a focus detection signal corresponding to a focus detection area closest to a center of the tracking zone among focus detection areas existing in the tracking zone; and

a display unit that displays within the captured image a mark indicating a position corresponding to the focus detection area, wherein

the display unit displays within the captured image a mark indicating the focus detection area in the tracking zone.