Abstract
Todya "videophone" and "videoconference via internet" have been used as important tools for communications via network. However viewing line of a sender who sends his or her facial image to another person will not meet with a receiver's viewing line due to the constraint of the camera's position. We can communicate effectively without feeling mental stress if eye contact is established. This work presents experimental results for permissible viewing angle deviations for "eye contact" and verified the influence of the resolution of images. It was clarified that we are able to percept subtle movements of iris, i.e., 0.96mm on display or 3 pixels, it corresponds to the receiver's viewing angle of 0.055 degrees.
