Display unit, image processing unit, and display method for improving image quality

• US 9,940,870 B2
• Filed: 05/21/2013
• Issued: 04/10/2018
• Est. Priority Date: 06/14/2012
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yano, Tomoya, Nakagawa, Makoto, Asano, Mitsuyasu, Inoue, Yasuo, Araki, Shoji, Shimizu, Hidehisa
• Primary Examiner(s): Mummalaneni, Nalini
• Application Number:
  US13/899,030
• Publication Number:
  US 20130335457A1
• Time in Patent Office: 1,785 Days
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2360/147 the originated light output being determined for each pixel
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]

Abstract

An image processing unit includes: a gain calculating section obtaining, based on first luminance information for each pixel, a first gain, in which the first gain is configured to increase with an increase in pixel luminance value in a range where the pixel luminance value is equal to or larger than a predetermined luminance value, and in which the pixel luminance value is derived from the first luminance information; and a determination section determining, based on the first luminance information and the first gain, second luminance information for each of the pixels.

Claims

1. A display unit, comprising:

a gain calculating section configured to;

calculate a first gain based on a first gain parameter and a second gain parameter,

wherein the first gain parameter is calculated based on first luminance information of each pixel of a first image,

wherein the first gain is configured to increase with an increase in pixel luminance value in a range where the pixel luminance value is equal to or larger than a luminance value, and the pixel luminance value is derived from the first luminance information,

wherein the first luminance information includes multiple pieces of sub luminance information,

wherein the second gain parameter is configured to increase with a decrease in an area of a plurality of regions within the first image, and

wherein the plurality of regions within the first image have the pixel luminance value equal to or larger than the luminance value, and

correct the calculated first gain by reduction in the first gain based on an increase in average value of the multiple pieces of sub luminance information of the first luminance information;

a determination section configured to determine second luminance information for each pixel of the first image based on multiplication of each of the multiple pieces of sub luminance information with the first gain; and

a display section configured to display a second image that is generated from the first image based on the second luminance information.

2. The display unit according to claim 1, wherein

the gain calculating section is further configured to obtain the first gain parameter based on a gain function that represents a relationship between the pixel luminance value and the first gain parameter, and

the first gain parameter is further configured to increase at a gradient with the increase in the pixel luminance value equal to or larger than the luminance value, in the gain function.

3. The display unit according to claim 1, wherein the luminance value is configured to increase with an increase in average of the first luminance information in the first image.

4. The display unit according to claim 1, wherein the pixel luminance value corresponds to a value of Value information in an HSV color space.

5. The display unit according to claim 1, wherein

the display section comprises a plurality of display pixels, and

each of the plurality of display pixels comprises a first sub-pixel, a second sub-pixel, a third sub-pixel, and a fourth sub-pixel,

wherein the first sub-pixel, the second sub-pixel, and the third sub-pixel are associated with respective wavelengths that are different from one another, and

wherein the fourth sub-pixel is configured to emit color light different from corresponding color light emitted by each of the first sub-pixel, the second sub-pixel, and the third sub-pixel.

6. The display unit according to claim 5, wherein the first luminance information comprises three pieces of first sub luminance information, wherein the respective three pieces of first sub luminance information corresponds to the first sub-pixel, the second sub-pixel, and the third sub-pixel.

7. The display unit according to claim 5, further comprising a conversion section configured to generate, based on the second luminance information, third luminance information that comprises four pieces of third sub luminance information,

wherein the second luminance information comprises three pieces of second sub luminance information,

wherein the respective three pieces of second sub luminance information corresponds to the first sub-pixel, the second sub-pixel, and the third sub-pixel,

wherein the respective four pieces of third sub luminance information correspond to the first sub-pixel, the second sub-pixel, the third sub-pixel, and the fourth sub-pixel, and

wherein the display section is further configured to display the second image based on the third luminance information.

8. The display unit according to claim 7, wherein the conversion section is further configured to convert color gamut based on the second luminance information, and generate the third luminance information based on the second luminance information subjected to the color gamut conversion.

9. The display unit according to claim 7, further comprising a correction section configured to:

calculate a second gain for each of the respective three pieces of third sub luminance information that corresponds to the first sub-pixel, the second sub-pixel, and the third sub-pixel among the four pieces of third sub luminance information of the third luminance information, based on the respective three pieces of third sub luminance information; and

generate fourth luminance information based on the respective three pieces of third sub luminance information and a second gain that corresponds to the fourth luminance information,

wherein the fourth luminance information comprises three pieces of fourth sub luminance information that correspond to the first sub-pixel, the second sub-pixel, and the third sub-pixel, and the third sub luminance information that corresponds to the fourth sub pixel, and

wherein the display section is further configured to display the second image based on the fourth luminance information.

10. The display unit according to claim 9,

wherein the second gain is configured to decrease with an increase in luminance level in a range where the luminance level is equal to or larger than a value, and

wherein the luminance level is represented by the corresponding one of the pieces of third sub luminance information.

11. The display unit according to claim 7, further comprising a correction section configured to:

calculate a second gain for each pixel based on a largest luminance level among the three pieces of third sub luminance information that correspond to the first sub-pixel, the second sub-pixel, and the third sub-pixel among the four pieces of third sub luminance information of the third luminance information; and

generate, based on the four pieces of third sub luminance information and the second gain, fourth luminance information that comprises four pieces of fourth sub luminance information,

wherein the four pieces of fourth sub luminance information correspond to the first sub-pixel, the second sub-pixel, the third sub-pixel, and the fourth sub pixel, and

wherein the display section is further configured to display the second image based on the fourth luminance information.

12. The display unit according to claim 5, wherein

the first sub-pixel, the second sub-pixel, and the third sub-pixel are configured to emit red color light, green color light, and blue color light, respectively, and

the color light emitted by the fourth sub-pixel has a luminosity factor substantially equal to or higher than a luminosity factor for the green color light emitted by the second sub-pixel.

13. The display unit according to claim 12, wherein the fourth sub-pixel is configured to emit white color light.

14. The display unit according to claim 1,

wherein the gain calculating section is further configured to calculate the first gain based on a value (V) for each pixel in HSV color space corresponding to the first image and an average luminance level (APL) of a frame image, and

wherein the value V and the APL are calculated based on each of the multiple pieces of sub luminance information of the first luminance information.

15. The display unit according to claim 1,

wherein the second gain parameter is calculated based on a first map generated based on average values of the first luminance information of a plurality of block regions within the first image,

wherein a second map is generated based on an average values of first luminance information of a plurality of block regions in the first map, and

wherein a third map is generated by scaling the second map from a map in block units to a map in pixel information units.

16. The display unit according to claim 15, wherein the second gain parameter is calculated for each of the pixel information units based on individual data of the third map.

17. The display unit according to claim 15, wherein the average values of the first luminance information of the plurality of block regions within the first image increase with an increase in the area of the region within the first image with the pixel luminance value equal to or larger than the luminance value.

18. The display unit according to claim 1, wherein each of the multiple pieces of sub luminance information corresponds to a sub-pixel of the respective pixel of the first image.

19. The display unit according to claim 1,

wherein the first gain decreases with the increase in the area of the plurality of regions within the first image, and

wherein the plurality of regions within the first image have the pixel luminance value equal to or larger than the luminance value.

20. An image processing unit, comprising:

a gain calculating section configured to;

calculate a first gain based on a first gain parameter and a second gain parameter,

wherein the first gain parameter is calculated based on first luminance information of each pixel of an image,

wherein the first gain is configured to increase with an increase in pixel luminance value in a range where the pixel luminance value is equal to or larger than a luminance value, and the pixel luminance value is derived from the first luminance information,

wherein the first luminance information comprises multiple pieces of sub luminance information,

wherein the second gain parameter is configured to increase with a decrease in an area of a plurality of regions within the image,

wherein the plurality of regions within the image have the pixel luminance value equal to or larger than the luminance value, and

correct the calculated first gain by reduction in the calculated first gain based on an increase in average value of the multiple pieces of sub luminance information of the first luminance information; and

a determination section configured to determine second luminance information for each pixel of the image based on multiplication of each of the multiple pieces of sub luminance information with the first gain.

21. A display method, comprising:

calculating a first gain based on a first gain parameter and a second gain parameter,

wherein the first gain parameter is calculated based on first luminance information of each pixel of a first image,

wherein the first gain is configured to increase with an increase in pixel luminance value in a range where the pixel luminance value is equal to or larger than a luminance value, and the pixel luminance value is derived from the first luminance information,

wherein the first luminance information includes multiple pieces of sub luminance information,

wherein the second gain parameter is configured to increase with a decrease in an area of a plurality of regions within the first image,

wherein the plurality of regions within the first image have the pixel luminance value equal to or larger than the luminance value,

correcting the calculated first gain by reduction in the calculated first gain based on an increase in average value of the multiple pieces of sub luminance information of the first luminance information;

determining second luminance information for each pixel of the first image based on multiplication of each of the multiple pieces of sub luminance information with the first pain; and

displaying a second image that is generated from the first image based on the second luminance information.