MSU Graphics & Media Lab ReportĀ #6 onĀ stereo films quality assessment

One of the common issues with stereo 3D (S3D) movies is the presence of stereo-window violations. A stereo-window violation can be defined as a contradiction between two different depth cues where an object on the side of the image is partly hidden by a border of the frame but, owing to its parallax, appears closer than the border (Image #1). As with other contradictions, this situation can cause serious discomfort because it almost never occurs under viewing conditions in a real environment. However, it often receives surprisingly little attention during both production and screening of S3D movies. The Graphics & Media Lab CMC of Lomonosov Moscow State University decided to investigate this problem.


Image #1: Example of a stereo-window violation


Image #2: Example of a stereo-window violation fixed by means of the floating window technique

In most cases the stereo-window violation issue can be fixed by means of the floating-window technique. A floating window is simply a black stripe added to the edge of one of the views to cover window-violating content (Image #2). A lot of different strategies can be employed in using this technique, including static, dynamic, slant or even curved floating windows (Images #3-5)


Image #3: Example of a slant floating window


Image #4: Example of a curved floating window


Image #5: Example of a dynamic floating window

The sixth report is dedicated to the analysis of stereo-window violation issue and use of floating windows in various S3D movies. It addresses 10 different S3D films, both natively captured and post-converted:

The report presents per-frame charts that enable the analysis of floating window behaviour with respect to disparity of the closest object near the edge of the frame (Image #6). The charts are accompanied by visualizations of the most noticeable window violations.

Image #6: Example of a per-frame analysis chart

The report also presents an overall comparison of films in terms of quality of stereo window violation handling.

One may notice that more recent movies tend to have better stereo-window violation handling (Image #7)

Image #7: Stereo Window Violation vs. Release Date

Naturally, films with heavy use of floating windows tend to have less stereo-window violations. However, some films achieve low stereo-window violation number with virtually no floating windows across the whole film (Image #8)

Image #8: Stereo Window Violation vs. Floating Window Usage Intensity

This fact can be explained by looking at the average disparities of the closest object near the edge of the screen (Image #9). In fact, The Three Musketeers has the highest average positive disparity value, indicating that, indeed, floating windows are not required to achieve low stereo window violation level in this film.

Image #9: Stereo Window Violation vs. Closest Object Disparity

Acknowledgements

We would like to thank the following people for providing valuable comments, opinions and feedback, which helped to improve this report:

A key motive of our reports is to improve the stereo quality and therefore to reduce eyestrain and headache. The Graphics & Media Lab hopes that a high 3D video quality would contribute to a continually increasing number of people, leaving the modern theaters without annoyance and with good impressions from the image quality and storytelling.

We are always interested in feedback from professionals in film-production industry. We have already collaborated with more than 20 stereographers who provided us valuable comments which were inserted in our reports. If you would like to participate in the next reports, please feel free to contact us: 3dmovietest@graphics.cs.msu.ru.

Reports overview

Stereo-analysis project description

Report 1 (S3D shooting quality analysis of 5 movies) Download
(Additional info for bloggers and press)
Pages: 246
Figures: 295
Report 2 (S3D shooting quality analysis of 5 movies) Download
(Additional info for bloggers and press)
Pages: 342
Figures: 442
Report 3 (2D-3D conversion quality analysis of 5 movies) Download
(Additional info for bloggers and press)
Pages: 305
Figures: 336
Report 4 (S3D shooting quality analysis of 5 movies) Download Pages: 301
Figures: 402
Report 5 (2D-3D conversion quality analysis of 5 movies) Download
(Additional info for bloggers and press)
Pages: 384
Figures: 404
Report 6 (Stereo Window analysis of 10 movies) Download
(Additional info for bloggers and press)
Pages: 415
Figures: 455
Report 7 (Stereo Window analysis of 10 movies) Download
(Additional info for bloggers and press)
Pages: 333
Figures: 348
Report 8 (Rotate Analysis, Temporal Shift, Channels Swap, Zoom Mismatch in 25 movies) Download
(Additional info for bloggers and press)
Pages: 366
Figures: 361
Report 9 (Temporal Shift, Stuck-to-Background Objects, 2D to S3D conversion in Captured Films) Download
(Additional info for bloggers and press)
Pages: 467
Figures: 529
Report 10 (Overall analysis of 105 movies) Download Pages: 211
Figures: 270

Report 11 (Overall analysis of 10 selected Chinese movies)

Approximate release date: 2021

Contacts

For questions and proposition please contact us 3dmovietest@graphics.cs.msu.ru

22 Oct 2014
See Also
MSU Deinterlacer Benchmark 2020
MSU 3D-video Quality Analysis. Report 10
Detection of stereo window violation
How to find objects that are present only in one view?
Depth continuity estimation in S3D video
How smooth is the depth transition between scenes?
Detection of 3D movie scenes shot on converged axes
Another cause of headaches when watching 3D movies.
Parallax range estimation in S3D video
The parallax range should be both comfortable and entertaining for spectators.
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