SYNCHRONIZING DYNAMIC BACKLIGHT ADAPTATION

• US 20090002404A1
• Filed: 06/24/2008
• Published: 01/01/2009
• Est. Priority Date: 06/26/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chen, Wei, Barnhoefer, Ulrich T., Corlett, Barry J., Yao, Wei H.
• Granted Patent: US 8,629,830 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2310/0232 Special driving of display border areas
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: Y10S 348/913 Letterbox, e.g. display 16:9 aspect ratio image on 4:3 screen

Abstract

Embodiments of a system that includes one or more integrated circuits are described. During operation, the system receives a sequence of video images and a brightness setting of a light source which is configured to illuminate a display that is configured to display the video images, where the sequence of video images includes video signals. Then, the system determines an intensity setting of the light source on an image-by-image basis for the sequence of video images, where the intensity of a given video image is based on the brightness setting and brightness information contained in the video signals associated with the given video image. Next, the system synchronizes the intensity setting of the light source with a current video image to be displayed.

Claims

1. A system, comprising one or more integrated circuits, wherein the one or more integrated circuits include:

an input interface configured to receive video signals associated with a sequence of video images and a brightness setting of a light source which is configured to illuminate a display that is configured to display the video images;

an intensity circuit electrically coupled to the input interface, the intensity analysis circuit configured to determine an intensity setting of the light source on an image-by-image basis for the sequence of video images, wherein the intensity of a given video image is based on the brightness setting and brightness information contained in the video signals associated with the given video image; and

a buffer electrically coupled to the intensity circuit, the buffer configured to synchronize the intensity setting of the light source with a current video image to be displayed.

2. The system of claim 1, wherein the given video image includes a frame of video.

3. The system of claim 1, wherein the determined intensity setting of the light source reduces power consumption of the light source.

4. The system of claim 1, wherein the light source comprises a light emitting diode.

5. The system of claim 1, wherein the light source comprises a fluorescent lamp.

6. The system of claim 1, wherein the one or more integrated circuits further include an extraction circuit electrically coupled to the input interface and the intensity circuit, the extraction circuit operative to calculate a brightness metric associated with the given video image in the sequence of vide images based on the received video signals;

and

wherein the brightness metric corresponds to the brightness information.

7. The system of claim 6, wherein the brightness metric includes a histogram of brightness values in the given video image.

8. The system of claim 6, wherein the one or more integrated circuits further include a scaling circuit electrically coupled to the input interface, the extraction circuit and the intensity circuit,

wherein the scaling circuit is configured to scale the given video signal based on the brightness metric.

9. The system of claim 8, wherein the scaling is based on a dynamic range of a mechanism that attenuates coupling of light from the light source to the display that is configured to display the sequence of video images.

10. The system of claim 8, wherein the scaling is based on a mapping function associated with a portion of the brightness metric.

11. The system of claim 10, wherein a distortion metric is associated with the mapping function.

12. The system of claim 11, wherein the intensity setting of the light source is based on the distortion metric.

13. The system of claim 1, wherein the one or more integrated circuits further include a filter electrically coupled to the intensity circuit and the buffer;

and

wherein the filter is configured to filter a change in intensity settings between adjacent video images in the sequence of video images.

14. A method for synchronizing an intensity setting of a light source and a current video image to be displayed, comprising:

receiving a sequence of video images and a brightness setting of the light source which is configured to illuminate a display that is configured to display the video images, wherein the sequence of video images includes video signals;

determining an intensity setting of the light source on an image-by-image basis for the sequence of video images, wherein the intensity of a given video image is based on the brightness setting and brightness information contained in the video signals associated with the given video image; and

synchronizing the intensity setting of the light source with the current video image to be displayed.

15. A computer-program product for use in conjunction with a computer system, the computer-program product comprising a computer-readable storage medium and a computer-program mechanism embedded therein for synchronizing an intensity setting of a light source and a video image to be displayed, the computer-program mechanism comprising:

instructions for receiving a sequence of video images and a brightness setting of the light source which is configured to illuminate a display that is configured to display the video images, wherein the sequence of video images includes video signals;

instructions for determining an intensity setting of the light source on an image-by-image basis for the sequence of video images, wherein the intensity of a given video image is based on the brightness setting and brightness information contained in the video signals associated with the given video image; and

instructions for synchronizing the intensity setting of the light source with the current video image to be displayed.

16. An integrated circuit, comprising one or more sub-circuits, wherein the one or more sub-circuits are configured to:

receive a sequence of video images and a brightness setting of a light source which is configured to illuminate a display that is configured to display the video images, wherein the sequence of video images includes video signals;

determine an intensity setting of the light source on an image-by-image basis for the sequence of video images, wherein the intensity of a given video image is based on the brightness setting and brightness information contained in the video signals associated with the given video image; and

synchronize the intensity setting of the light source with a current video image to be displayed.

17. An integrated circuit, comprising:

an input interface configured to receive video signals associated with a sequence of video images and a brightness setting of a light source which is configured to illuminate a display that is configured to display the video images;

an intensity circuit electrically coupled to the input interface, the intensity analysis circuit configured to determine an intensity setting of the light source on an image-by-image basis for the sequence of video images, wherein the intensity of a given video image is based on the brightness setting and brightness information contained in the video signals associated with the given video image; and

a buffer electrically coupled to the intensity circuit, the buffer configured to synchronize the intensity setting of the light source with a current video image to be displayed.

18. A computer system to determine an intensity setting of a light source, comprising:

a processor;

memory;

a program module, wherein the program module is stored in the memory and configurable to be executed by the processor, the program module comprising;

instructions for receiving a sequence of video images and a brightness setting of a light source which is configured to illuminate a display that is configured to display the video images, wherein the sequence of video images includes video signals;

instructions for determining an intensity setting of the light source on an image-by-image basis for the sequence of video images, wherein the intensity of a given video image is based on the brightness setting and brightness information contained in the video signals associated with the given video image; and

instructions for synchronizing the intensity setting of the light source with a current video image to be displayed.

19. A computer system configured to execute instructions to determine an intensity setting of a light source, comprising:

a processor;

a memory;

an instruction fetch unit within the processor configured to fetch;

instructions for receiving a sequence of video images and a brightness setting of a light source which is configured to illuminate a display that is configured to display the video images, wherein the sequence of video images includes video signals;

instructions for determining an intensity setting of the light source on an image-by-image basis for the sequence of video images, wherein the intensity of a given video image is based on the brightness setting and brightness information contained in the video signals associated with the given video image; and

instructions for synchronizing the intensity setting of the light source with a current video image to be displayed; and

an execution unit within the processor configured to execute the instructions for receiving the sequence of video images, the instructions for determining the intensity setting of the light source, and instructions for synchronizing the intensity setting of the light source with the current video image to be displayed.

20. A portable device, comprising:

a display;

a light source configured to output light based on an intensity setting;

an attenuation mechanism configured to modulate the output light incident on the display, wherein the display is configured to display a sequence of video images; and

one or more integrated circuits, wherein the one or more integrated circuits include;

an input interface configured to receive video signals associated with a sequence of video images and a brightness setting of a light source which is configured to illuminate a display that is configured to display the video images;

an intensity circuit electrically coupled to the input interface, the intensity analysis circuit configured to determine an intensity setting of the light source on an image-by-image basis for the sequence of video images, wherein the intensity of a given video image is based on the brightness setting and brightness information contained in the video signals associated with the given video image; and

a buffer electrically coupled to the intensity circuit, the buffer configured to synchronize the intensity setting of the light source with a current video image to be displayed.