CAMERA FLASH FOR IMPROVED COLOR BALANCE

• US 20120262571A1
• Filed: 03/20/2012
• Published: 10/18/2012
• Est. Priority Date: 04/12/2011
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: WANG, Qian, CHOI, Yun Seok, TOWNSEND, Graham Charles, TANG, Sui Tong
• Granted Patent: US 9,681,058 B2
• Time in Patent Office: Days
• US Class Current: 348/135
• CPC Class Codes: H04N 2101/00 Still video cameras
• CPC Class Codes: H04N 23/10 for generating image signals from different wavelengths
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 23/88 for colour balance, e.g. white-balance circuits or colour temperature control
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A camera unit and method of control are described. The camera unit has a camera flash sub-unit configurable to emit flash light having an adjustable characteristic. A camera sensor sub-unit generates raw color data when exposed to light for processing into a digital image. The camera unit also includes a camera controller for coordinating operation of the camera flash sub-unit and the camera sensor sub-unit. The camera controller monitors one or more ambient light characteristics in a vicinity of the camera unit. Prior to receiving a command instructing the camera unit to generate the digital image, the camera controller repeatedly configures the camera flash sub-unit based on the monitored ambient light characteristics to adjust the characteristics of the emitted flash light. Once the camera controller receives the command, the camera sensor sub-unit is instructed to expose an image sensor using the pre-adjusted camera flash light to increase illumination.

Claims

1. A method for controlling a camera unit to generate a digital image, the camera unit comprising a camera flash sub-unit for emitting flash light, the method comprising:

monitoring one or more characteristics of ambient light in a vicinity of the camera unit;

receiving a command for instructing the camera unit to generate the digital image;

prior to receiving the command, repeatedly configuring the camera flash sub-unit based on the monitored characteristic of the ambient light to adjust one or more characteristics of the flash light emitted by the camera flash sub-unit; and

after receiving the command, exposing an image sensor of the camera unit to generate raw color data for processing into the digital image using the adjusted flash light emitted by the camera flash sub-unit to increase illumination.

2. The method of claim 1, wherein the configuring the camera flash sub-unit based on the monitored one or more characteristics of the ambient light comprises matching the one or more characteristics of the flash light to the monitored one or more characteristics of the ambient light.

3. The method of claim 1, further comprising:

prior to receiving the command, selecting an algorithm based on the monitored one or more characteristics of the ambient light for performing color balancing; and

after receiving the command, processing the raw color data using the selected color balancing algorithm.

4. The method of claim 1, wherein the monitoring one or more characteristics of ambient light comprises:

prior to receiving the command, repeatedly pre-exposing the image sensor to generate pre-image data; and

processing the pre-image data to determine the monitored one or more characteristics of the ambient light.

5. The method of claim 4, wherein the processing the pre-image data to determine the monitored characteristic of the ambient light comprises, for each pre-exposure of the image sensor:

determining one or more new values based on the pre-image data, each new value being representative of one of the one or more characteristics of the ambient light; and

updating one or more old values with the one or more new values, each old value being representative of the one of the one or more characteristics of the ambient light for a previous pre-exposure of the image sensor.

6. The method of claim 1, wherein the monitoring one or more characteristics of ambient light and the configuring the camera flash sub-unit are performed in real time over a time period occurring prior to receipt of the command.

7. The method of claim 1, wherein the monitoring one or more characteristics of ambient light and the configuring the camera flash sub-unit are performed at discrete intervals over a time period occurring prior to receipt of the command.

8. The method of claim 7, wherein the discrete intervals are substantially equally spaced in time.

9. The method of claim 1, further comprising displaying one or more values on a user interface of the camera unit prior to receiving the command, each value being representative of one of the monitored one or more characteristics of ambient light.

10. The method of claim 9, further comprising receiving input at the user interface to adjust the configuration the camera flash sub-unit.

11. The method of claim 1, wherein the monitored one or more characteristics of the ambient light comprises a color temperature of the ambient light and the adjusted one or more characteristics of the flash light comprises a color temperature of the flash light.

12. A camera unit for generating a digital image, the camera unit comprising:

a camera flash sub-unit comprising a plurality of emissive light sources arranged to emit flash light having an adjustable characteristic;

a camera sensor sub-unit comprising an image sensor configured to generate raw color data when exposed for processing into the digital image; and

a camera controller coupled to the camera flash sub-unit and the camera sensor sub-unit for coordinating operation thereof, the camera controller configured to;

monitor one or more characteristics of ambient light in a vicinity of the camera unit;

receive a command for instructing the camera unit to generate the digital image;

prior to receiving the command, repeatedly configure the plurality of emissive sources in the camera flash sub-unit based on the monitored one or more characteristics of the ambient light to adjust one or more characteristics of the flash light emitted by the camera flash sub-unit; and

after receiving the command, instruct the camera sensor sub-unit to expose the image sensor using the adjusted flash light emitted by the camera flash sub-unit to increase illumination.

13. The camera unit of claim 12, wherein the camera controller is configured to control the plurality of emissive sources in the camera flash sub-unit to match the one or more characteristics of the flash light to the monitored one or more characteristics of the ambient light.

14. The camera unit of claim 12, wherein the camera sensor sub-unit further comprises an image sensor processor coupled to the image sensor and configured to process the raw color data generated by the image sensor into the digital image.

15. The camera unit of claim 14, wherein the camera controller is configured to:

prior to receiving the command, instruct the image sensor processor to select an algorithm based on the monitored one or more characteristics of the ambient light for performing color balancing; and

after receiving the command, instruct the image sensor processor to process the raw color data using the selected color balancing algorithm.

16. The camera unit of claim 14, wherein the camera controller is configured to monitor the one or more characteristics of the ambient light by instructing the camera sensor sub-unit to:

prior to receiving the command, repeatedly pre-expose the image sensor to generate pre-image data; and

process the pre-image data using the image sensor processor to determine the monitored one or more characteristics of the ambient light.

17. The camera unit of claim 16, wherein the image sensor processor is configured to process the pre-image data to determine the monitored one or more characteristics of the ambient light by, for each pre-exposure of the image sensor:

determining one or more new values based on the pre-image data, each new value being representative of one of the one or more characteristics of the ambient light; and

updating one or more old values with the one or more new values, each old value being representative of the one of the one or more characteristics of the ambient light for a previous pre-exposure of the image sensor.

18. The camera unit of claim 12, wherein the camera controller is configured to monitor the one or more characteristics of ambient light and to configure the plurality of emissive sources in the camera flash sub-unit in real time over a time period occurring prior to receipt of the command.

19. The camera unit of claim 12, wherein the camera controller is configured to monitor the one or more characteristics of ambient light and to configure the plurality of emissive sources in the camera flash sub-unit at discrete intervals over a time period occurring prior to receipt of the command.

20. The camera unit of claim 19, wherein the discrete intervals are substantially equally spaced in time.

21. The camera unit of claim 12, further comprising a user interface for displaying one or more values prior to the camera controller receiving the command, each value being representative of one of the monitored one or more characteristics of ambient light.

22. The camera unit of claim 21, wherein the user interface is configured to receive input to adjust the configuration of the camera flash sub-unit.

23. The camera unit of claim 12, wherein the monitored one or more characteristics of the ambient light comprises a color temperature of the ambient light and the adjusted one or more characteristics of the flash light comprises a color temperature of the flash light.

24. The camera unit of claim 12, wherein the camera unit is included in a mobile communication device.

25. A non-transitory computer-readable storage medium storing instructions executable by one or more processors coupled to the storage medium, the stored instructions for programming the one or more processors when executed to control a camera unit to generate a digital image, the camera unit comprising a camera flash sub-unit for emitting flash light, and the stored instructions comprising:

monitoring one or more characteristics of ambient light in a vicinity of the camera unit;

receiving a command for instructing the camera unit to generate the digital image;

prior to receiving the command, repeatedly configuring the camera flash sub-unit based on the monitored one or more characteristics of the ambient light to adjust one or more characteristics of the flash light emitted by the camera flash sub-unit; and

after receiving the command, exposing an image sensor of the camera unit to generate raw color data for processing into the digital image using the adjusted flash light emitted by the camera flash sub-unit to increase illumination.