Method for evaluating quality of image on display device

• US 6,859,192 B1
• Filed: 03/27/2000
• Issued: 02/22/2005
• Est. Priority Date: 03/26/1999
• Status: Expired due to Fees

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Ogawa, Eiji
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): Sajous, Wesner
• Application Number:
  US09/534,578
• Time in Patent Office: 1,793 Days
• Field of Search: 345616-618, 345/440, 345/440.1, 345690-691, 345/694, 345/698, 345/699, 345/208, 345/10, 345/12, 345/13, 345/20, 345/77, 345/94, 345/428, 345/581, 345/588, 345/589, 382/2.1, 382161-162, 382/165, 382/168, 382/169, 382/170, 382171-172, 382/181, 382/254, 382255-256, 382/264, 382/266, 382/267, 382/269, 382274-276, 382/112
• US Class Current: 345/77
• CPC Class Codes: G06T 2207/30168 Image quality inspection
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309

Abstract

The method for evaluating a quality of an image on a display device displays a test pattern having different contrast intensities on a display screen of the display, then determines a contrast intensity at which the test pattern is visually discernible and uses the thus determined contrast intensity as a value for evaluation of granularity on the display device. The method is optimal for achieving quantitative and objective visual evaluation of image quality, particularly, its granularity.

Claims

1. A method for evaluating a quality of a display device, comprising the steps of:

displaying a test pattern having different contrast intensities on a display screen of the display device;

determining a contrast intensity at which said test pattern is visually discernible; and

using the thus determined contrast intensity as a value for evaluation of granularity of said display device.

2. The method according to claim 1, wherein said test pattern having different contrast intensities contains areas having different contrast intensities.

3. The method according to claim 1, wherein said test pattern having different contrast intensities is such that test patterns each of which has a single contrast intensity are sequentially presented on the display screen of the display device to produce varying contrast intensity with time.

4. The method according to claim 1, wherein said test pattern having different contrast intensities varies in amplitude but has a generally constant amplitude center.

5. The method according to claim 1, wherein said test pattern having different contrast intensities is white noise.

6. The method according to claim 1, wherein said test pattern having different contrast intensities has different frequencies for the respective contrast intensities.

7. The method according to claim 1, wherein said value for evaluation of granularity is compared with a value preliminarily acquired by said display device and an amount of the difference between the two values is output.

8. The method according to claim 1, wherein a test pattern includes a plurality of patterns having disparate intensity levels placed adjacent to each other in space, and determining a contrast intensity at which said test pattern is visually discernible comprises selecting one of said plurality of patterns having disparate intensity levels among said plurality of patterns.

9. The method of claim 8, wherein evaluation of granularity comprises using said selected test pattern, and varying said test pattern over a range of frequencies.

10. The method of claim 9, further comprising evaluating quality of an image for a second device by displaying said test pattern having different contrast intensities on a display screen of the second device;

determining a second contrast intensity at which said test pattern is visually discernible on said second device; and

using the second contrast intensity as a value for evaluation of granularity of the second device; and

comparing granularity of the first device and the second device.

11. The method of claim 8, wherein the plurality of test patterns comprise a plurality of white noise patterns.

12. The method of claim 11, wherein the evaluation of granularity follows said determination of contrast intensity.

13. The method according to claim 1, wherein a test pattern includes a plurality of patterns having disparate intensity levels placed adjacent to each other in time, and determining a contrast intensity at which said test pattern is visually discernible comprises selecting one of said plurality of patterns having disparate intensity levels among said plurality of patterns, wherein said plurality of patterns comprise white noise patterns.

14. The method of claim 13, wherein evaluation of granularity comprises using said selected test pattern, and varying said test pattern over a range of frequencies.

15. The method of claim 1, wherein determining the contrast intensity at which said test pattern is discernible comprises selection of a single contrast intensity level.

16. The method of claim 1, further comprising evaluating quality of an image for a second device by displaying said test pattern having different contrast intensities on a display screen of the second device;

determining a second contrast intensity at which said test pattern is visually discernible on said second device; and

using the second contrast intensity as a value for evaluation of granularity of the second device; and

comparing granularity of the first device and the second device.