Communications of the ACM
Perfecting Digital Imaging
The subtleties in these computer-generated images of translucent materials are important. Texture, color, contrast, and sharpness combine to create a realistic image.
Credit: Ioannis Gkioulekas and Shuang Zhao
Harvard University researchers say they are developing computer graphics tools that narrow the gap between "virtual" and "real." One project tries to find better ways to mimic the appearance of a translucent object. The project examines how humans perceive and recognize real objects and how software can exploit the details of that process to make the most realistic computer-rendered images possible. The project's approach focuses on translucent materials' phase function, part of a mathematical description of how light refracts or reflects inside an object, which determines how people see it. The researchers first rendered thousands of computer-generated images of one object with different computer-simulated phase functions. A program then compared each image's pixel colors and brightness to another image in the space and determined how different the two images were.
"This study, aiming to understand the appearance space of phase functions, is the tip of the iceberg for building computer-vision systems that can recognize materials," says Harvard researcher Todd Zickler.
Another study investigates a type of screen hardware that displays different images when lit or viewed from different directions. The research demonstrates that interference effects can be exploited to control reflection from a screen at micron scales using well-known photolithographic techniques. A third project addressed the problem of color grading in digital film editing.
From Harvard University
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