Correspondence in pictorial space under isoluminance conditions

Abstract

We have previously studied correspondences of points on photographs of an object in different poses. When the object has no (or few) surface landmarks the observer has to perform the correspondence task in pictorial (3D) space. Thus the ability to establish such correspondences derives from monocular stereopsis. Question: Isoluminant rendering is generally supposed to destroy both binocular and monocular stereopsis. Can observers establish correspondences between photographs of an object in different poses when the pictures are rendered isoluminant? Method: The motion stand-still method was used to find the isoluminant setting for each observer. Isoluminant renderings were put on a screen and observers had to match a few hundred positions in one picture to those in another. Poses differed by 45 degrees in either direction. Result: Observers performed equally well in Monochrome-Monochrome (thus not isoluminant), and Monochrome-Red/Green, Monochrome-Green/Red and Red/Green-Green/Red isoluminant conditions.