In recent years the realisation has been growing within the computer graphics community of the advantages to be gained by using knowledge of human perception. This Campfire will bring together researchers from the fields of computer graphics and visualisation, psychology, eye-movement analysis, and other related fields to discuss how such knowledge may be exploited to enhance the realism of computer-generated scenes, animations, and virtual environments.

There were many hard problems to solve in the field of Computer Graphics during the second half of the last century, and the challenges posed were sufficient to keep a large number of researchers very busy. For a long time, the emphasis was on producing physically valid representations of objects, lighting and motion, and on improving the efficiency of such algorithms. To enhance real-time performance, techniques which traded accuracy for speed were developed, rendering objects and animations at variable levels of detail in order to keep a high and constant frame-rate. In more recent years, the computer graphics community has started asking itself questions such as: How do I know how real an image is? What parts of the image can be rendered at a lower level of detail, or even eliminated, without the change being perceptible to the viewer? People are extremely sensitive to tiny anomalies in certain types of simulation (such as facial animation) and will barely notice significant inaccuracy in others (such as a tree blowing in the wind). Why is this, what factors influence it, and how can it be quantified and exploited? In the field of Virtual Reality, what will enhance the feeling of immersion in a virtual world?

Meanwhile, psychologists studying aspects of the Human Visual System (HVS), from both the neurological and psychophysical points of view, have made significant progress, but there is still much to learn. Many of the functions of the human brain, including the visual system, still remain a mystery. Therefore, there is no complete and rigorous theory that the computer graphics community can study and apply. Some computational models of different visual functions have been developed, but they rarely generalise to handle the complex visual tasks typical in graphical scenes and simulations. Most psychophysical experiments consider only one property of the visual system in isolation, (such as Vernier Acuity: the ability to detect whether two lines are displaced or not), and these experiments are often conducted in restrictive laboratory conditions e.g. with reduced lighting, monochrome display, fixed head position and restricted yes-no responses. Neurological investigations reduce even further, to the reaction of a single brain cell to simple stimuli. Natural, higher level tasks need to be devised, that more truly reflect the situations being simulated.

We can see that there is a wonderful opportunity for the psychological community and the graphics community to co-operate and learn new truths about human perception. Semir Zeki, one of the world's foremost researchers into the visual functions of the brain, has written: "I hope that no one will be deterred from asking new questions and suggesting new experiments simply because they are not specialists in brain studies." The questions asked by CG practitioners when trying to reproduce reality often leave psychologists scratching their heads, thus potentially triggering new directions of research for them. Together, exciting experiments can be designed that provide deep insights into the higher-level processes involved in visual processing: Scenarios which would be almost impossible to set up in the real world are easily simulated and controlled using computer graphics, and psychological expertise is imperative to ensure the robustness of experiments and the validity of conclusions drawn.