Realistic perspective projections for virtual objects and environments

Abstract

Computer graphics systems provide sophisticated means to render virtual 3D space to 2D display surfaces by applying planar geometric projections. In a realistic viewing condition the perspective applied for rendering should appropriately account for the viewer's location relative to the image. As a result, an observer would not be able to distinguish between a rendering of a virtual environment on a computer screen and a view “through” the screen at an identical real-world scene. Until now, little effort has been made to identify perspective projections which cause human observers to judge them to be realistic. In this article we analyze observers' awareness of perspective distortions of virtual scenes displayed on a computer screen. These distortions warp the virtual scene and make it differ significantly from how the scene would look in reality. We describe psychophysical experiments that explore the subject's ability to discriminate between different perspective projections and identify projections that most closely match an equivalent real scene. We found that the field of view used for perspective rendering should match the actual visual angle of the display to provide users with a realistic view. However, we found that slight changes of the field of view in the range of 10-20% for two classes of test environments did not cause a distorted mental image of the observed models.