AUTO WHITE BALANCE SYSTEM FOR IMAGE SENSOR AND AUTO WHITE BALANCE METHOD

• US 20090079846A1
• Filed: 06/06/2008
• Published: 03/26/2009
• Est. Priority Date: 09/24/2007
• Status: Active Grant

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd.
• Inventors: CHOU, CHIEH-MIN
• Granted Patent: US 8,013,908 B2
• Time in Patent Office: Days
• US Class Current: 348/223.100
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: H04N 23/88 for colour balance, e.g. white-balance circuits or colour temperature control

Abstract

An exemplary auto white balance system for an image sensor includes a global positioning system (GPS) receiver, a memory, a setting determining unit, and a white balance unit. The GPS receiver is configured for receiving signals from a satellite, and calculating its position and local time using signals received from at least four satellites. The memory is configured for storing a number of white balance settings. The setting determining unit is configured for determining which one of the white balance settings is suitable for the current ambient light conditions based on the received signal of the global positioning system receiver. The whit balance unit is configured for adjusting the color temperature of a current image captured by the image sensor using the determined white balance setting.

Claims

1. An auto white balance system for an image sensor, comprising:

a global positioning system receiver capable of positioning itself and acquiring local time using signals received satellites;

a memory capable of storing a plurality of white balance settings;

a setting determining unit capable of determining which one of the white balance settings stored in the memory is suitable for a current ambient light conditions based on received signals of the global positioning system receiver; and

a white balance unit capable of adjusting the color temperature of a current image captured by the image sensor using the determined white balance setting.

2. The auto white balance system as claimed in claim 1, wherein the white balance settings comprises an indoor setting that is suitable for an indoor scene.

3. The auto balance system as claimed in claim 1, wherein the white balance setting comprises an outdoor setting for use in case the global positioning system receiver fails to acquire signals from satellites.

4. The auto balance system as claimed in claim 1, wherein the white balance setting comprises a plurality of open-air settings each corresponding to a predetermined region, season and local time.

5. The auto white balance system as claimed in claim 1, wherein the setting determining unit determines which one of the white balance settings is suitable for the current ambient light conditions by judging whether the intensity of the received signal of the global positioning system receiver exceeds a predetermined threshold.

6. The auto white balance system as claimed in claim 5, wherein the predetermined threshold is about −

145 dbm.

7. An auto white balance method for an auto white balance system, the auto white balance system comprising a global positioning system receiver, and a memory configured for storing a plurality of white balance settings, the global positioning system receiver being configured for positioning itself and acquiring local time using signals received from satellites, the white balance settings comprising an indoor setting for use in an indoor conditions, a first outdoor setting for use in an outdoor obstruction conditions, and a plurality of second outdoor settings each corresponding to a predetermined region, seasons and local time, the auto white balance method comprising:

judging whether the intensity of the received signals of the global positioning system receiver exceeds a predetermined threshold;

adjusting the color temperature of a current image captured by an image sensor using the indoor setting if the intensity of the received signals of the global positioning system receiver is below the predetermined threshold;

judging whether the global positioning system receiver has positioned itself, if the intensity of the received signals of the global positioning system receiver exceeds the predetermined threshold;

adjusting the color temperature of the current image captured by the image sensor using the first outdoor setting if the global positioning system receiver fails to position itself and if the intensity of the received signals of the global positioning system receiver exceeds the predetermined threshold;

determining which one of the second outdoor settings is suitable for the current ambient light conditions based on the received signals of the global positioning system receiver if the global positioning system receiver has positioned itself and if the intensity of the received signals of the global positioning system receiver exceeds the predetermined threshold; and

adjusting the color temperature of the current image captured by the image sensor using the determined second outdoor setting.

8. The auto white balance method as claimed in claim 7, further comprising:

detecting whether the global positioning system receiver is functioning and receiving satellite signals, if not, stopping the flow of the method.

9. The auto white balance method as claimed in claim 7, wherein the predetermined threshold is about −

145 dbm.