Conveying Shape and Features

with Image-Based Relighting

 

David Akers

Stanford University

Frank Losasso

Stanford University

Jeff Klingner

Stanford University

Maneesh Agrawala

Microsoft Research

John Rick

Stanford University

Pat Hanrahan

Stanford University

 

Published in IEEE Visualization 2003

 

Paper

PDF (11 MB)

 

Video (interface demonstration)

QuickTime (50 MB)

 

Abstract

 

Hand-crafted illustrations are often more effective than photographs for conveying the shape and important features of an object, but they require expertise and time to produce. We describe an image compositing system and user interface that allow an artist to quickly and easily create technical illustrations from a set of photographs of an object taken from the same point of view under variable lighting conditions. Our system uses a novel compositing process in which images are combined using spatially-varying light mattes, enabling the final lighting in each area of the composite to be manipulated independently. We describe an interface that provides for the painting of local lighting effects (e.g. shadows, highlights, and tangential lighting to reveal texture) directly onto the composite. We survey some of the techniques used in illustration and lighting design to convey the shape and features of objects and describe how our system can be used to apply these techniques.

 

 

 

Figure 1: Above: A photograph of a human skull, followed by an artist's handmade drawing of the same skull [Hodges 1989]. Arrows in the drawing indicate variance in the local lighting direction that the artist used to emphasize the shape and texture of the skull. Below: A photograph of a baboon skull, followed by a composite image we generated from a set of many photographs taken under different lighting directions. (Top row images are used by permission of John Wiley & Sons, Inc.)

 

 

 

Figure 5: Above: Twelve photographs of the moon taken on consecutive nights during the waxing portion of the lunar cycle. Below, from left to right: a) An unmodified photograph of a full moon. b) A set of control arrows used to define a field of incident lighting directions that lie tangent to the moon's surface across its breadth. c) The resulting composite photograph, which combines surface detail from the terminator zones of each of the input photographs. The disk's flat appearance results from the loss of large scale shading variation during composition. Source moon photographs (c) 2002-2003 Tom Talbott (http://www.blarg.net/~thomast/).
Jeff Klingner | Last updated 18 Aug 2003