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At LatinDisplay / IDRC 2012, which was held from November 26  to November 30 at the Universidade Presbiteriana Mackenzie in Sao Paulo, Brazil, coordinated papers from visual scientists on two continents, presented ideas that have  interesting ramifications for video-signal compression strategy.

The papers were “The Aesthetic Side of Visual Quality” (Judith Redi, Delft University)  and “Incorporating Visual Attention Models into Visual Quality Metrics” ( Mylene Farias and Wellington Akamine, University of Brasilia).  One of the concepts discussed in both papers was “saliency maps.”  The maps, based on eye-tracking measurements of subjects, show where in an image subjects direct their attention.  One example used in the papers (which had been coordinated with each other) was an image  of a group of boatmen in a long canoe navigating the rapids in a river.  In this complicated image, viewers consistently focused on the faces of the boatmen, and virtually ignored the non-central areas of the image that portrayed the forested riverbank.

Clearly, providers of video content could compress these low-saliency areas with impunity since viewers pay almost no attention to them.  The problem is that the most accurate saliency maps are currently created with painstaking research on human subjects.  There are computational models that generate approximations of the experimentally derived saliency maps, but the different models produce maps that differ significantly from each other.  Although they are different, could some version of these models be accurate enough to compress video data streams more efficiently and (we hope) less objectionably?  We would need to predict the saliency of image areas in real time and use that information compress the pixel map selectively.  That’s a roadmap that could begin driving development strategies in the foreseeable future.

Ken Werner is Principal of Nutmeg Consultants, specializing in the display industry, display manufacturing, display technology, and display applications.  You can reach him at kwerner@nutmegconsultants.com.

Posted by Pete Putman, December 5, 2012 11:32 AM

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About Pete Putman

Peter Putman is the president of ROAM Consulting L.L.C. His company provides training, marketing communications, and product testing/development services to manufacturers, dealers, and end-users of displays, display interfaces, and related products.

Pete edits and publishes HDTVexpert.com, a Web blog focused on digital TV, HDTV, and display technologies. He is also a columnist for Pro AV magazine, the leading trade publication for commercial AV systems integrators.