Static and dynamic spatial resolution in image coding: an investigation of eye movements

Abstract
Large savings in bandwidth can be achieved when an image is displayed at full resolution at the center of gaze, and at lower resolution outside this central area. However, these savings require real-time monitoring of the observer's eye-position and real-time processing of the image. Hence, such techniques are limited to a single viewer. It would be useful if a reduction in bandwidth similar to that obtained with a single viewer could be achieved with multiple viewers, and without real- time monitoring of eye-movements. It is clear that this technique would be feasible only if different viewers looked at the same part of an image at the same time. In the present research, twenty-four observers viewed 15 forty-five-second clips of NTSC video while their direction of gaze was monitored. The goal of the research was to assess whether information about viewing behavior could be used for image coding. Our analysis of the viewing behavior showed that there was a substantial degree of agreement among viewers in terms of where they looked. We conclude that incorporating information about viewing behavior into video coding schemes may result in appreciable bandwidth savings.