Electronic camera

• US 6,906,744 B1
• Filed: 02/15/2000
• Issued: 06/14/2005
• Est. Priority Date: 09/28/1999
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Takeshita, Tetsuya, Hoshuyama, Hideo
• Primary Examiner(s): Ho, Tuan
• Assistant Examiner(s): AGGARWAL, YOGESH K
• Application Number:
  US09/503,917
• Time in Patent Office: 1,946 Days
• Field of Search: 3482231-2281, 348/655, 348/603, 348/650, 348/652, 348/229.1, 348/665, 382/164, 382/190, 382/194, 382/293, 358515-518
• US Class Current: 348/223.1
• CPC Class Codes: H04N 23/88 for colour balance, e.g. white-balance circuits or colour temperature control

Abstract

An electronic camera is provided with an image-capturing device for photographing (73, 26) that captures an image of a subject image passed through a taking lens and outputs image data, an image-capturing device for scene analysis (86) that is provided at a position conjugate with the position of the image-capturing device for photographing relative to the taking lens and outputs scene analysis image data by receiving the light of the subject image and a scene detection processing circuit (35) that determines a white balance adjustment gains based upon the scene analysis image data output by the analytical image-capturing device. Using the white balance adjustment gains determined by the scene detection processing circuit, white balance adjustment is performed on the image data output by the image-capturing device for photographing.

Claims

1. An electronic camera comprising:

an image-capturing device for photographing that captures an image of a subject image passing through a taking lens and outputs image data;

an image-capturing device for scene analysis that is provided at a position conjugate with said image-capturing device for photographing relative to said taking lens and receives light from the subject image to output scene analysis image data;

a gain calculation unit that calculates gain by using at least either image data corresponding to a large area of said image-capturing device for scene analysis or image data corresponding to a small area of said image-capturing device for scene analysis; and

a gain adjustment unit that performs gain adjustment by applying said gain calculated at said gain calculation unit to the image data output by said image-capturing device for photographing.

2. An electronic camera according to claim 1, wherein:

said large area is constituted of a plurality of first areas obtained by dividing the image-capturing area of said image-capturing device for scene analysis, into a unit area including a first specific number of pixels; and

said small area is constituted of a plurality of second areas achieved by dividing the image-capturing area of said image-capturing device for scene analysis into a unit area including a second specific number of pixels which is smaller than the first specific number.

3. An electronic camera according to claim 1, wherein:

said gain calculation unit selects image data of either said large area or said small area in correspondence to the type of subject and calculates gain based on the image data in the selected area.

4. An electronic camera according to claim 2, further comprising:

a decision-making unit that makes a decision as to whether or not there is an area having image data that are judged to indicate an achromatic color among said plurality of first areas and further makes a decision as to whether or not there is an area having image data judged to indicate skin color among said plurality of second areas if it is decided that there is no area with image data judged to indicate an achromatic color, wherein;

if said decision-making unit decides that there is an area having image data that are judged to indicate an achromatic color, said gain calculation unit calculates gain based upon the image data in said area having the image data judged to indicate an achromatic color; and

if said decision-making unit decides that there is an area having image data that are judged to indicate skin color, said gain calculation unit calculates gain based upon the image data in said area having the image data indicating skin color.

5. An electronic camera comprising:

an image-capturing device for photographing that captures an image of a subject image passing through a taking lens and outputs image data;

an image-capturing device for scene analysis that is provided at a position conjugate with said image-capturing device for photographing relative to said taking lens and receives light from the subject image to output scene analysis image data;

a detection unit that detects an area having image data that are judged to indicate a predetermined color in image data corresponding to a predetermined area of said image-capturing device for scene analysis;

a gain calculation unit that calculates gain based upon a color indicated by the image data in said area detected by said detection unit; and

a gain adjustment unit that performs gain adjustment by applying said gain calculated by said gain calculation unit to the image data output by said image-capturing device for photographing.

6. An electronic camera according to claim 5, wherein:

said detection unit detects;

(1) presence of an area having image data judged to indicate an achromatic color among a plurality of first areas achieved by dividing an image-capturing area of said image-capturing device for scene analysis into a unit area including a first specific number of pixels; and

(2) presence of an area having image data judged to indicate skin color among a plurality of second areas achieved by dividing the image-capturing area of said image-capturing device for scene analysis into a unit area including a second specific number of pixels which is smaller than the first specific number.

7. An electronic camera according to claim 6, wherein:

said detection unit performs detection for an area having image data that are judged to indicate skin color if an area having image data that are judged to indicate an achromatic color cannot be detected.

8. An electronic camera according to claim 5, further comprising:

a selection unit that selects either a first photographing mode suited to white balance adjustment performed by using an achromatic color or a second photographing mode suited to white balance adjustment performed by using skin color, wherein;

a color to be detected by said detection unit is selected in correspondence to a photographing mode selected by said selection unit and gain is calculated by using image data indicating the selected color.

9. An electronic camera according to claim 5, further comprising:

a selection unit that selects, at least, a landscape photographing mode, wherein;

if the landscape photographing mode has been selected by said selection unit, said detection unit detects, at least, an area having image data that are judged to indicate an achromatic color; and

said gain calculation unit calculates gain based upon the image data in said area having the image data judged to indicate an achromatic color.

10. An electronic camera according to claim 5, further comprising:

a selection unit that selects, at least, a portrait photographing mode, wherein;

if said portrait photographing mode has been selected by said selection unit, said detection unit detects, at least, an area having image data judged to indicate skin color; and

said gain calculation unit calculates gain based upon the image data in said area having the image data judged to indicate skin color.

11. An electronic camera comprising:

an image-capturing device for photographing that captures an image of a subject image passing through a taking lens and outputs image data;

an image-capturing device for scene analysis that is provided at a position conjugate with said image-capturing device for photographing relative to said taking tens and receives light from the subject image to output scene analysis image data;

a conversion unit that converts image data in a predetermined area of said image-capturing device for scene analysis to color data in either a first color-related coordinate system or a second color-related coordinate system;

a gain calculation unit that calculates gain based upon the color data resulting from conversion performed by said conversion unit; and

a gain adjustment unit that performs gain adjustment by applying said gain calculated by said gain calculation unit to the image data output by said image-capturing device for photographing.

12. An electronic camera according to claim 11, wherein:

said conversion unit converts;

(1) image data in a plurality of first areas achieved by dividing an image-capturing area of said image-capturing device for scene analysis into a unit area including to a first specific number of pixels, to color data in the first coordinate system; and

(2) converts image data in a plurality of second areas achieved by dividing the image-capturing area of said image-capturing device for scene analysis into a unit area including a second specific number of pixels that is smaller than the first specific number, to color data in the second coordinate system.

13. An electronic camera according to claim 11, further comprising:

a selection unit that selects either a first photographing mode suited to white balance adjustment performed by using an achromatic color or a second photographing mode suited to white balance adjustment performed by using skin color, wherein;

said conversion unit converts the image data in the predetermined area of said image-capturing device for scene analysis to color data in the first coordinate system or the second coordinate system in correspondence to the photographing mode selected by said selection unit.

14. An electronic camera according to claim 11, further comprising:

a selection unit that selects, at least, a landscape photographing mode, wherein;

if the landscape photographing mode has been selected by said selection unit, said conversion unit converts the image data in the predetermined area of the image-capturing device for scene analysis to color data in the first coordinate system.

15. An electronic camera according to claim 11, further comprising:

a selection unit that selects, at least, a portrait photographing mode, wherein;

if said portrait photographing mode has been selected by said selection unit, said conversion unit converts the image data in the predetermined area of said image-capturing device for scene analysis to color data in the second coordinate system.

16. An electronic camera comprising:

an image-capturing device for photographing that captures an image of a subject image passing through a taking lens and outputs image data;

an image-capturing device for scene analysis that is provided at a position conjugate with said image-capturing device for photographing relative to said taking lens and receives light from the subject image to output scene analysis image data;

a conversion unit that converts image data in a plurality of first areas achieved by dividing an image-capturing area of said image-capturing device for scene analysis into a unit area including a first specific number of pixels, to color data in a first color-related coordinate system or converts image data in a plurality of second areas achieved by dividing the image-capturing area of said image-capturing device for scene analysis into a unit area including a second specific number of pixels that is smaller than the first specific number, to color data in a second color-related coordinate system;

a gain calculation unit that calculates gain using the color data in the first coordinate system or the second coordinate system resulting from conversion performed by said conversion unit; and

a gain adjustment unit that performs gain adjustment by applying said gain calculated by said gain calculation unit to the image data output by said image-capturing device for photographing.

17. An electronic camera according to claim 16, further comprising:

a selection unit that selects either a first photographing mode suited to white balance adjustment performed by using an achromatic color or a second photographing mode suited to white balance adjustment performed by using skin color, wherein;

said conversion unit converts said scene-analysis image data to color data in the first coordinate system or the second coordinate system in correspondence to the photographing mode selected by said selection unit.

18. An electronic camera according to claim 16, further comprising:

a selection unit that selects, at least, a landscape photographing mode, wherein;

if the landscape photographing mode has been selected by said selection unit, said conversion unit converts said scene-analysis image data to color data in the first coordinate system.

19. An electronic camera according to claim 16, further comprising:

a selection unit that selects, at least, a portrait photographing mode, wherein;

if said portrait photographing mode has been selected by said selection unit, said conversion unit converts said scene-analysis image data to color data in the second coordinate system.

20. An electronic camera comprising:

an image-capturing device that captures an image of a subject image passing through a taking lens and outputs image data;

a color temperature detection unit that is provided at a position conjugate with said image-capturing device relative to the taking lens and receives light of the subject image to detect color temperature information;

a gain calculation unit that detects skin color based on the color temperature information detected by said color temperature detection unit for a predetermined area in a photographic field to calculate gain by using the skin color; and

a gain adjustment unit that performs gain adjustment by applying said gain calculated at said gain calculation unit to the image data output by said image-capturing device.

21. An electronic camera according to claim 20, further comprising:

a focal point detection unit that detects a focal adjustment state of the taking lens in a plurality of areas within the photographic field;

a focal point detection area selection unit that selects a detection area in which detection is performed by said focal point detection unit among the plurality of areas; and

a lens drive unit that drives the taking lens to a focus position based upon the focal adjustment state detected by said focal point detection unit, wherein;

said gain calculation unit detects skin color based on the color temperature information detected by the color temperature detection unit for the detection area selected by said focal point detection area selection unit to calculate gain using the skin color.

22. An electronic camera according to claim 21, wherein:

said gain calculation unit calculates gain by using the skin color detected at a point in time at which said lens drive unit completes the focal adjustment drive and said gain adjustment unit performs gain adjustment by applying the gain to the image data output by said image-capturing device.

23. An electronic camera according to claim 20, further comprising:

a photometering unit that detects a brightness level of the subject image in a plurality of areas in the photographic field; and

a photometering area selection unit that selects a photometering area where a photometering operation is to be performed by said photometering unit among the plurality of areas, wherein;

said gain calculation unit detects skin color based on the color temperature information detected by said color temperature detection unit for the photometering area selected by said photometering area selection unit to calculate gain using the skin color.

24. An electronic camera according to claim 20, wherein:

said gain calculation unit calculates gain based upon a predetermined color if the skin color cannot be detected.