Backlight control method and apparatus for high brightness contrast images

1. A method for determining characteristics of an image to be displayed on a display device, the method comprising:

determining a pixel intensity distribution of the image;

determining a first intensity characteristic of the image from the pixel intensity distribution, wherein determining the first intensity characteristic comprises:

defining a bright region of the pixel intensity distribution of the image; and

determining a lowest brightness level corresponding with the bright region of the pixel intensity distribution, wherein the first intensity characteristic is the lowest brightness level;

determining a second intensity characteristic of the image from the pixel intensity distribution;

determining a difference between the first and second intensity characteristics; and

if the difference is greater than or equal to a threshold value, classifying the image as a high brightness contrast image.

2. The method of claim 1 wherein the determining the second intensity characteristic includes determining an average brightness level of the image from the pixel intensity distribution of the image.

3. The method of claim 1 wherein:

the image includes a plurality of pixels, each of the plurality of pixels being associated with a brightness level; and

the determining the pixel intensity distribution of the image includes determining a number of pixels associated with each brightness level.

4. The method of claim 3 wherein:

the determining the first intensity characteristic includes determining a first ratio; and

the determining the second intensity characteristic includes determining a second ratio.

5. The method of claim 4 wherein the first ratio include the determined lowest brightness level corresponding with the bright region of the pixel intensity distribution as a brightness percentage.

6. The method of claim 4 wherein the determining the second ratio includes determining an average brightness level of the image from the pixel intensity distribution of the image, thereby determining an average brightness percentage of the image.

7. The method of claim 1 including:

if the image is a high brightness contrast image, generating a backlight control signal that corresponds with the first and second intensity characteristics; and

if the image is not a high brightness contrast image, generating a backlight control signal that corresponds with the second intensity characteristic.

8. A method comprising:

determining a pixel intensity distribution of an image to be displayed on a display device that includes a backlight section;

determining a first intensity characteristic of the image from the pixel intensity distribution, wherein determining the first intensity characteristic comprises:

defining a bright region of the pixel intensity distribution of the image; and

determining a lowest brightness level corresponding with the bright region of the pixel intensity distribution, wherein the first intensity characteristic is the lowest brightness level;

determining a second intensity characteristic of the image from the pixel intensity distribution;

determining a difference between the first and second intensity characteristics;

if the difference is less than a threshold value, generating a backlight control signal, such that the backlight section outputs light according to the backlight control signal; and

if the difference is equal to or greater than the threshold value, generating an adjusted backlight control signal, such that the backlight section outputs light according to the adjusted backlight control signal.

9. The method of claim 8 wherein:

the image includes a plurality of pixels, each of the plurality of pixels being associated with a brightness level; and

the determining the pixel intensity distribution of the image includes determining a number of pixels associated with each brightness level.

10. The method of claim 8 wherein the determining the second intensity characteristic includes determining an average brightness level of the image from the pixel intensity distribution of the image.

11. The method of claim 10 wherein the determining the difference between the first and second intensity characteristics includes determining a difference between the lowest brightness level corresponding with the bright region and the average brightness level.

12. The method of claim 11 wherein the generating the adjusted backlight control signal includes generating a backlight dimming ratio corresponding with the difference and the average brightness level.

13. The method of claim 12 wherein the generating the backlight dimming ratio corresponding with the difference and the average brightness level includes:

determining an adjustment amount based on the difference and an adjustment level;

and generating a backlight dimming ratio based on the adjustment amount and the average brightness level.

14. The method of claim 11 wherein the generating the backlight control signal includes generating a backlight dimming ratio corresponding with the average brightness level.

15. The method of claim 8 wherein:

the first intensity characteristic is a first dimming ratio and the second intensity characteristic is a second dimming ratio;

the determining the difference between the first and second intensity characteristics includes determining a difference between the first and second dimming ratios;

the generating the backlight control signal includes generating a backlight dimming ratio corresponding with the second dimming ratio; and

the generating the adjusted backlight control signal includes generating a backlight dimming ratio corresponding with the first and second dimming ratios.

16. The method of claim 15 wherein the generating the backlight dimming ratio corresponding to the first and second dimming ratios includes:

determining an adjustment ratio based on an difference ratio and the difference between the first and second dimming ratios; and

adding the adjustment ratio to the second dimming ratio to determine the generated backlight dimming ratio.

17. The method of claim 15 wherein the generating the backlight dimming ratio corresponding with the second dimming ratio includes setting the generated backlight dimming ratio to the second dimming ratio.

18. An apparatus comprising:

a display section for displaying an image;

a backlight section for outputting light to the display section; and

a backlight control section in communication with the backlight section, such that the output of light from the backlight section is according to a backlight control signal, wherein the backlight control section is configured to:

determine a first intensity characteristic of the image to be displayed on the display device, wherein the first intensity characteristic is a lowest brightness level in a defined bright region in a pixel intensity distribution of the image,

determine a second intensity characteristic of the image from the pixel intensity distribution,

determine a difference between the first and second intensity characteristics,

if the difference is less than the threshold value, generate a backlight control signal, such that the backlight section outputs light according to the backlight control signal, and

if the difference is equal to or greater than a threshold value, generate an adjusted backlight control signal, such that the backlight section outputs light according to the adjusted backlight control signal.

19. The apparatus of claim 18 wherein:

the first intensity characteristic is a first dimming ratio and the second intensity characteristic is a second dimming ratio;

the determining the difference between the first and second intensity characteristics includes determining a difference between the first and second dimming ratios;

the generating the backlight control signal includes generating a backlight dimming ratio corresponding with the second dimming ratio; and

the generating the adjusted backlight control signal includes generating a backlight dimming ratio corresponding with the first and second dimming ratios.