Abstract
In the information society of the 21st century, it is important that human beings comfortably coexist with information systems through visual human interface. To realize better human interface in next generation information systems, this paper proposes as a basic theory for human interface and communication a new type of size called Subjective Size which measures the apparent size of an object in relation to different viewing distances. In this paper, human interface means the bridge between the real world and imagery information space, which is the structure of information in human brains induced from the real world through human senses. We applied a psychophysical approach in estimating the relationship between subjective size (i.e., apparent size) and viewing distance by measuring the apparent size of an object in relation to viewing distances. For this, we measured the apparent size of an object from various viewing distances using discs and spheres as stimuli, and proposed a model that relates viewing distance to apparent size. Finally, we tested the validity of the model (i.e., Subjective Size Function) by an experiment that compared perspective images of real space through the subjective size function with actual images of real space.
