From: Hendrik-Jan van Veen Subject: TECH: Color Correction of Real Images Date: 10 Jul 1996 15:41:31 GMT Message-ID: <4s0ivb$vqa@newsserv.zdv.uni-tuebingen.de> Organization: Max-Planck-Institut fuer Biologische Kybernetik We are building a photorealistic computer graphics model of a local town for use in Virtual Reality applications. The ultimate goal of this is to run experiments with human subjects to address their navigation behaviour. To approach photrealism we need to make thousands of pictures of buildings in the town. These pictures have to be scanned and perspectively corrected before they can be used as textures on the walls of our (computer-) model houses. We have some methoids to get this part working. The current problem is the following: Making this amount of pictures means that the illumination conditions vary a lot. Also, due to shadows and interreflections one part of a house can have a quite diffent illumination than other parts. We obviously need to do some sort of color/contrast/luminance-correction to avoid artifacts in the computer model afterwards. But how to do this? Of course we can use photoshop or something else to do these corrections by hand (and eye!), but this will mean an awful lot of work and probably a lot of variability due to the judgment variability of human observers. Questions: : Is there any way in which we could use the color histogram of each picture and the grand average histogram to equalize the colors over all pictures? Similarly for contrast and luminance? : Can anyone think of a different approach? : Is there anyone around who has experience with similar problems? : Are there any publications on this topic? We have high-performance Silicon Graphics machines, PowerMacs and if necessary we could buy WindowsPc's as well. Any input is highly appreciated. Please send your comments to my personal email address as well. -- Dr. Hendrik-Jan van Veen Max-Planck-Institut fur Biologische Kybernetik Spemannstrasse 38 -- 72076 Tuebingen -- GERMANY E-MAIL: veen@mpik-tueb.mpg.de FAX: +49-7071-601-616 WEB: http://www.mpik-tueb.mpg.de/people/personal/veen/veen.html