IMAGE PROCESSING APPARATUS, IMAGE PROCESSING METHOD, AND STORAGE MEDIUM

• US 20140333649A1
• Filed: 05/07/2014
• Published: 11/13/2014
• Est. Priority Date: 05/08/2013
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tatsumi, Eisaku
• Granted Patent: US 9,799,108 B2
• Time in Patent Office: Days
• US Class Current: 345/589
• CPC Class Codes: G06T 5/92 based on global image properties
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/08 Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165
• CPC Class Codes: G09G 5/003 Details of a display terminal, the details relating to the control arrangement of the display terminal and to the interfaces thereto specific for a CRT G09G1/165; for a flat panel G09G3/2092

Abstract

An image processing apparatus can correct the influence of contrast caused by a difference between a photopic vision and a scotopic vision to provide an image excellent in image quality. An averaged within-visual-field luminance calculation unit calculates a luminance value in the visual field based on at least one of environmental luminance in the visual field and luminance in a screen on which image data can be displayed. A reverse gamma conversion processing unit corrects the contrast of the image data based on the obtained luminance value in the visual field.

Claims

1. An image processing apparatus comprising:

an image acquisition unit configured to acquire image data;

a brightness acquisition unit configured to acquire at least one of first brightness information relating to brightness of the image data and second brightness information relating to ambient brightness of a display area in which an image can be displayed based on the image data;

a control unit configured to control contrast of the image data acquired by the image acquisition unit, based on the brightness information acquired by the brightness acquisition unit; and

a display control unit configured to display an image based on the image data whose contrast has been controlled by the control unit.

2. The image processing apparatus according to claim 1, wherein if the brightness indicated by the brightness information acquired by the brightness acquisition unit is lower than a predetermined brightness level, the control unit controls the contrast of the image data so as to enhance the contrast compared to a case where the brightness indicated by the brightness information is higher than the predetermined brightness level.

3. The image processing apparatus according to claim 1, wherein the control unit is configured to control the contrast of the image data based on the first brightness information, the second brightness information, and size of the display area in which the image can be displayed based on the image data.

4. The image processing apparatus according to claim 1, wherein the brightness acquisition unit is configured to acquire the second brightness information from an illuminance sensor.

5. The image processing apparatus according to claim 1, wherein the control unit is configured to control the contrast of the image data acquired by the image acquisition unit by controlling a value relating to gamma correction.

6. The image processing apparatus according to claim 1, wherein the brightness acquisition unit is configured to acquire an averaged luminance value of a plurality of image frames acquired by the image acquisition unit, as the first brightness information.

7. The image processing apparatus according to claim 1, wherein the brightness acquisition unit is configured to acquire the first brightness information based on a display mode of the display control unit so as to enhance the brightness indicated by the first brightness information when the display control unit is operating in a first display mode, compared to a case where the display control unit is operating in a second display mode.

8. The image processing apparatus according to claim 1, further comprising:

a table configured to associate the brightness information acquired by the brightness acquisition unit with a parameter relating to a control amount of the contrast, and

wherein the control unit is configured to control the contrast by referring to the table.

9. The image processing apparatus according to claim 1, wherein when the control unit performs a control to enhance the contrast of the image frame, a ratio between a maximum luminance value and a minimum luminance value in the controlled image frame becomes greater, compared to a case where the control unit does not perform the control to enhance the contrast of the image frame.

10. A method for causing an image processing apparatus to perform image processing, the method comprising:

acquiring image data;

acquiring at least one of first brightness information relating to brightness of the image data and second brightness information relating to ambient brightness of a display area in which an image can be displayed based on the image data;

controlling contrast of the acquired image data based on the acquired brightness information; and

displaying an image based on the image data whose contrast has been controlled.

11. The image processing method according to claim 10, wherein if the brightness indicated by the acquired brightness information is lower than a predetermined brightness level, the contrast of the image data is controlled so as to enhance the contrast compared to a case where the brightness indicated by the brightness information is higher than the predetermined brightness level.

12. The image processing method according to claim 10, wherein the contrast of the image data is controlled based on the first brightness information, the second brightness information, and size of the display area in which the image can be displayed based on the image data.

13. The image processing method according to claim 10, wherein the acquired contrast of the image data is controlled by controlling a value relating to gamma correction.

14. The image processing method according to claim 10, wherein an averaged luminance value of a plurality of acquired image frames is acquired as the first brightness information.

15. A storage medium storing a computer-readable program that causes a computer to perform a method comprising:

acquiring image data;

acquiring at least one of first brightness information relating to brightness of the image data and second brightness information relating to ambient brightness of a display area in which an image can be displayed based on the image data;

controlling contrast of the acquired image data based on the acquired brightness information; and

displaying an image based on the image data whose contrast has been controlled.

16. The storage medium according to claim 15, wherein if the brightness indicated by the acquired brightness information is lower than a predetermined brightness level, the contrast of the image data is controlled so as to enhance the contrast compared to a case where the brightness indicated by the brightness information is higher than the predetermined brightness level.

17. The storage medium according to claim 15, wherein the contrast of the image data is controlled based on the first brightness information, the second brightness information, and size of the display area in which the image can be displayed based on the image data.

18. The storage medium according to claim 15, wherein the acquired contrast of the image data is controlled by controlling a value relating to gamma correction.

19. The storage medium according to claim 15, wherein an averaged luminance value of a plurality of acquired image frames is acquired as the first brightness information.