1 / 14

Quality Assessment for Digital Cinema: Test Materials & Metrics for Compression

Quality Assessment for Digital Cinema: Test Materials & Metrics for Compression. Charles Fenimore Convergent Information Systems Division, NIST Digital Cinema 2001 Conference January 12, 2001. Quality Assessment. Tests - subjective and objective

luisa
Télécharger la présentation

Quality Assessment for Digital Cinema: Test Materials & Metrics for Compression

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Quality Assessment for Digital Cinema: Test Materials & Metrics for Compression Charles Fenimore Convergent Information Systems Division, NIST Digital Cinema 2001 Conference January 12, 2001

  2. Quality Assessment • Tests - subjective and objective • Display matters in compression tests - strategy for complex systems • Video and cinema: materials and metrics • Conclusions

  3. Quality measurement in video • Compression in digital cinema. • Subjective testing is the gold standard, • objective testing is a useful adjunct • Selection of test materials • Qualification of the test system • Test methods smorgasbord: ITU-R Rec 500

  4. Goals of Testing • Characterize for a range of typical materials • OR • Stress the system, to see where it breaks • Compression or decompression testing. • Threshold vs. Wide Range Tests.

  5. Qualifying the system • Resolution and sharpness. • Spot-size: trade flicker for resolution • Motion rendition and flicker, image stability • Dynamic range, tone • Brightness and contrast • Viewer background: golden eyes/naive • Visual acuity of the viewers

  6. SMPTE RP 133 – resolution pattern

  7. Selection of subjective test materials • Desired attributes include a range of: • resolution and detail patterns, • image and camera motion, • luminance, • color saturation and hue, • skin tones, • noise, and • graphics and titles. • A sense of presence, reality, and depth.

  8. Skin Tones

  9. Selection of subjective test materials • Experience with DV provides surprises in coding difficulty. • Range of image detail, motion, color and luminance. • Criticality: a computable measure of image detail and motion in electronic imagery.

  10. Surprisingly tough to compress

  11. Synthetic test patterns • Used in engineering evaluation of imaging systems. • SMPTE color bars, other color patterns • SMPTE Rec. 133 Resolution Chart. • Sarnoff, AT&T, many other contributors • NIST spinning wheel (blocking) and moving spirals (mosquito noise) patterns.

  12. Impairment specific detectors • FLAT: • an 8  8 block of pixels having constant luma, Y'0, inside the block in either row, column, or both directions and • at least one pixel exceeds a threshold value, T, across the block boundary. • Detect those flats with high local contrast ---

  13. Conclusions • There is a need for both subjective and objective metrics & materials for imaging system evaluation. • Properly designed d-cinema testing: • Know your users, what are needs and goals. • Translate user needs to engineering requirements (subjective and objective criteria, resolution and sharpness, color characteristics), • Specify measurement protocol to test requirements: metrics and materials.

More Related