System and method for redeye strobe mode control

• US 20040150743A1
• Filed: 01/31/2003
• Published: 08/05/2004
• Est. Priority Date: 01/31/2003
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Schinner, Charles E.
• Granted Patent: US 7,180,545 B2
• Time in Patent Office: Days
• US Class Current: 348/371
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means

Abstract

A method and apparatus for controlling a flash that automatically selects between normal flash mode and redeye reduction flash mode is disclosed. The apparatus measures the light in the scene, and based on this measurement, chooses between the redeye reduction flash mode and the normal flash mode. The apparatus may also measure the distance to the object and use this information to help chooses which flash mode to use.

Claims

1. A digital imaging device comprising:

a photo-sensor configured to capture images of a scene;

a processor configured to measure the brightness of the scene using the captured images;

a flash, the flash being used in at least two modes;

the first flash mode configured to reduce redeye artifacts, the second flash mode configured to flash normally;

the processor configured to automatically use the first flash modes when the brightness of the scene falls below a predetermined threshold and to use the second flash mode when the brightness of the scene is equal to or above the predetermined threshold.

2. The digital imaging device of claim 1 where the predetermined threshold is set between an EV of 4 and an EV of 7.

3. The digital imaging device of claim 1 where the processor is configured to not use the flash when the brightness of the scene is above a second threshold, the second threshold indicating a scene brighter than the first threshold.

4. The digital imaging device of claim 3 where the second threshold is set approximately at an EV of 9.5.

5. A method of controlling a flash, comprising:

measuring the illumination level in a scene;

automatically using the flash in a redeye reduction mode when the illumination level is below a first threshold;

automatically using the flash in a normal mode when the illumination level is above or equal to the first threshold.

6. The method of claim 5 where the predetermined threshold is set between an EV of 4 and an EV of 7.

7. The method of claim 5 further comprising:

turning the flash off when the illumination level is above a second threshold, the second threshold being higher than the first threshold.

8. The method of claim 7 where the second threshold is set approximately at an EV of 9.5.

9. The method of claim 5 where the flash is used with a digital camera.

10. The method of claim 5 where the flash is used with a film camera.

11. A digital imaging device, comprising:

a means for measuring the brightness of a scene;

a means for automatically adding illumination to the scene without inducing redeye when the brightness of the scene falls below a first threshold and a means for normally adding illuminating to the scene when the brightness of the scene is above or equal to the first threshold.

12. A method of controlling a flash, comprising:

measuring the distance to an object in a scene;

when the distance is greater than predetermined distance then measuring the illumination level in a scene;

setting the flash to a redeye reduction mode when the illumination level is below a threshold.

13. The method of claim 12 where the threshold is set between an EV of 4 and an EV of 7.

14. The method of claim 13 where the predetermined distance is set such that when an object is at the predetermined distance, the angle made between a line between a lens optical axis and the object and a line between a flash and the object is approximately 2.5°

.

15. The method of claim 13 further comprising:

using the flash in a normal mode when the object is closer than the predetermined distance.

16. A digital imaging device comprising:

a photo-sensor configured to capture images of a scene;

a processor configured to measure the brightness of the scene using the captured images;

the processor configured to measure a distance to an object in the scene;

a flash;

the processor configured to fire the flash using a redeye reduction mode when the brightness of the scene is below a threshold and the distance to the object is greater than a predetermined distance.

17. A film camera, comprising:

a photo-sensor configured to measure the brightness of a scene;

a flash, the flash having at least two modes;

the first flash mode configured to reduce redeye, the second flash mode configured to conserve energy;

the camera configured to automatically use the first flash modes when the brightness of the scene falls below a predetermined threshold and otherwise use the second flash mode.