Perception...again

I've already mentioned that the use of human visual perception concepts is a growing trend this year at Siggraph. Today's technical papers session entitled "Perception, presence and animation" just confirmed to me the strength of that trend.

Two of the papers presented dealt with identifying what details of a visual scene can be discarded without affecting the quality and the readability of the rendered images. This is exactly what visual artists have always been doing, that is, avoiding to render what is not needed to tell the story. And it is especially true for animators who have had to find ways to maintain the amount of drawing required to a reasonable level. In "Fool me twice: Exploring and exploiting error tolerance in physics-based animation", authors investigate our tolerance to different kinds of errors in the accuracy of physical simulations. The goal is to reduce computation times of such simulations. In "Seeing is Believing: Body Motion Dominates in Multisensory Conversations", authors explore visual and auditory elements of a conversation between a group of people that make it believable for an external observer. Using this information, they hope to be able to automatically animate a crowd with a sound using a very small amount of example data.

In "Using Blur to Affect Perceived Distance and Size", depth perception principles are used to enhance a rendered image by exploring the relationship between depth perception and image blurring. The results from this paper reminded me of a question that I've always asked myself: Is there a relation between the perceptual correctness of an image and its aesthetic qualities. I don't have an answer, but I feel it is the case. At the end of his talk, the presenter added a comment about how his work could be extended to stereo images. He shows how stereo disparity is directly correlated to blurring, which means that stereoscopic filmakers must be very careful to vary these 2 parameters in a coherent way. It immediately reminded me of some of the barely watchable live action shots in "Facing Champlain", a stereoscopic movie I worked on 2 years ago at the National Film Board. This must have been the problem.

It would be interesting to put together vision scientists and renown animators to analyze the techniques used by those animators from the point of view of the science of human visual perception. I think both fields would benefit from that collaboration.

Tomorrow, more papers related to human visual perception in a session entitled "Perceptual rendering methods".