What is a “virtual” image? At its most basic, a virtual image is an image that is projected into space. Typical devices that produce virtual images include corrective eye ware, binoculars, magnifying
glasses, microscopes, telescopes, rifle scopes, near-eye displays, and heads-up displays. Each of these devices forms a near-field image that is viewed with the eye and adapted to the distance based upon the design of the instrument. In creating a “virtual image,” luminance and color measurement are key factors. Both of these are impacted by the fixed physical entrance size of the pupil.