Chromatic balancer for flash cameras

• US 5,749,002 A
• Filed: 02/28/1997
• Issued: 05/05/1998
• Est. Priority Date: 03/01/1996
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Iwasaki, Hiroyuki
• Primary Examiner(s): Perkey, W. B.
• Application Number:
  US08/807,272
• Time in Patent Office: 431 Days
• Field of Search: 396/225, 396/155, 396/159, 396/161, 348/224, 348/370, 348/371
• US Class Current: 396/161
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 7/18 in accordance with light-reducing "factor" of filter or other obturator used with or on the lens of the camera

Abstract

A chromatic balancer determines an optimal chromatic balance between strobe illumination and light illumination during balance synchro photography. A photometric detector measures the amount of light from one or more regions in the scene to be photographed. A chromatic balance calculator determines the chromatic balance of the photograph scene. A background exposure correction value calculator determines a background light exposure correction value. A flash level correction value calculator determines a flash level correction value.

Claims

1. A chromatic balancer, comprising:

a photometric detector which measures light from at least one of a plurality of regions of a photograph scene and which generates corresponding photometric data;

a chromatic balance calculator which determines a first chromatic balance and a second chromatic balance of the photograph scene based on the photometric data from the photometric detector;

a background exposure correction value calculator which determines a background light exposure correction value based on the first chromatic balance determined by the chromatic balance calculator; and

a flash level correction value calculator which generates a flash level correction value based on the second chromatic balance determined by the chromatic balance calculator.

2. The chromatic balancer of claim 1, wherein the chromatic balance calculator determines the chromatic balance of the photograph scene based on photometric data from a portion of the photograph scene.

3. The chromatic balancer of claim 1, wherein the chromatic balance calculator determines the chromatic balance of the photograph scene based on photometric data from the entire photograph scene.

4. The chromatic balancer of claim 1, wherein the photometric detector comprises a CCD array.

5. The chromatic balancer of claim 1, further comprising a position sensor for determining an orientation of the photometric detector.

6. The chromatic balancer of claim 1, wherein the photometric detector separately measures blue, green and red chromatic components in the photograph scene.

7. The chromatic balancer of claim 6, wherein the background exposure correction value determined by the background exposure correction value calculator adjusts a background light exposure towards underexposure when the green chromatic components in the photograph scene exceed a predetermined level.

8. The chromatic balancer of claim 6, wherein the flash level correction value determined by the flash level correction value calculator adjusts a flash illumination level towards a brighter level when the green chromatic components in the photograph scene exceed a predetermined level.

9. The chromatic balancer of claim 6, wherein the background exposure correction value adjusts a background light exposure towards overexposure when the red chromatic components in the photograph scene exceed a predetermined level.

10. The chromatic balancer of claim 6, wherein the flash level correction value adjusts a flash illumination level towards a dimmer level when the red chromatic components in the photograph scene exceed a predetermined level.

11. The chromatic balancer of claim 6, wherein the background exposure correction value adjusts a background light exposure towards underexposure when the blue chromatic components in the photograph scene exceed a predetermined level.

12. The chromatic balancer of claim 6, wherein the flash level correction value adjusts a flash illumination level towards a brighter level when the blue chromatic components in the photograph scene exceed a predetermined level.

13. The chromatic balancer of claim 1, wherein the chromatic balance calculator, background exposure correction value calculator and flash level correction value calculator comprise a single device.

14. A camera having a chromatic balance control, comprising:

a flash illuminator which illuminates a photograph scene;

an image recording medium which records the photograph scene;

a photometric detector which measures light from at least one of a plurality of regions of the photograph scene and which generates corresponding photometric data;

a chromatic balance calculator which determines a first chromatic balance and a second chromatic balance of the photograph scene based on the photometric data from the photometric detector;

an exposure calculator which determines a background light exposure value based on the photometric data from the photometric detector;

a background exposure correction value calculator which determines a background light exposure correction value based on the first chromatic balance determined by the chromatic balance calculator;

an exposure controller which controls an exposure of the image recording medium based on the background light exposure correction value and the background light exposure value;

a flash level calculator which determines a flash illumination level based on the photometric data from the photometric detector;

a flash level correction value calculator which generates a flash level correction value based on the second chromatic balance determined by the chromatic balance calculator;

a flash controller which controls the flash illuminator based on the flash level correction value and flash illumination level.

15. The camera of claim 14, further comprising a shutter, and wherein the exposure controller controls the opening and closing of the shutter.

16. The camera of claim 14, wherein the chromatic balance calculator determines the chromatic balance of the photograph scene based on photometric data from a portion of the photograph scene.

17. The camera of claim 14, wherein the chromatic balance calculator determines the chromatic balance of the photograph scene based on photometric data from the entire photograph scene.

18. The camera of claim 14, wherein the photometric detector comprises a CCD array.

19. The camera of claim 14, further comprising a position sensor for determining an orientation of the camera.

20. The camera of claim 14, wherein the photometric detector separately measures blue, green and red chromatic components in the photograph scene.

21. The camera of claim 20, wherein the background exposure correction value determined by the background exposure correction value calculator adjusts a background light exposure towards underexposure when the green chromatic components in the photograph scene exceed a predetermined level.

22. The camera of claim 20, wherein the flash level correction value determined by the flash level correction value calculator adjusts a flash illumination level towards a brighter level when the green chromatic components in the photograph scene exceed a predetermined level.

23. The camera of claim 20, wherein the background exposure correction value adjusts a background light exposure towards overexposure when the red chromatic components in the photograph scene exceed a predetermined level.

24. The camera of claim 20, wherein the flash level correction value adjusts a flash illumination level towards a dimmer level when the red chromatic components in the photograph scene exceed a predetermined level.

25. The camera of claim 20, wherein the background exposure correction value adjusts a background light exposure towards underexposure when the blue chromatic components in the photograph scene exceed a predetermined level.

26. The camera of claim 20, wherein the flash level correction value adjusts a flash illumination level towards a brighter level when the blue chromatic components in the photograph scene exceed a predetermined level.

27. The camera of claim 14, wherein the chromatic balance calculator, background exposure correction value calculator and flash level correction value calculator comprise a single device.