Contour Visualization Using Coherent Optical Systems

TL;DR: Wertheimer and Givens as discussed by the authors discussed two optical process-ing systems for the rapid extraction of con-tours from a pair of stereo transparencies, where the stereo images of all points at a given elevation have the same value of x-parallax.

Abstract: CONTOUR VISUALIZATION USING COHERENT OPTICAL SYSTEMSAlan WertheimerLeeds g Northrup Co.North Wales, Pa. 19454andM. Parker GivensThe Institute of OpticsRochester, N.Y. 14627IntroductionThis paper discusses two optical process-ing systems for the rapid extraction of con-tours from a pair of stereo transparencies.For a given x- parallax, these systems pro-vide a display of all contours present at theelevation corresponding to the parallax set-ting.Two assumptions form the basis for theapproaches described here. The first is thatthe photography is taken vertically, or hasbeen rectified to a vertical orientation, sothe stereo images of all points at a givenelevation have the same value of x- parallax.Accordingly, when the stereo transparenciesare overlapped and registered properly, imagecoincidence occurs for all areas at one spe-cific elevation. The task, then, is to lo-cate these regions of image coincidence andisolate them from the rest of the scene.The Positive -Negative SystemOne technique for defining the areas ofmatching imagery is to make a positive trans-parency from one input photograph and a neg-ative transparency from the other. A simpli-fying assumption is that the copies are madewithin the straight line portion of the H & Dcurve, where the slope is defined as the con-stant, y. With T1 (x,y) and T2 (x,y) repre-senting the intensity transmittances of theinputs, the copies TA and TB, may be expressed