The Robotics Institute

Carnegie Mellon Robotics Institute

Copyright notice: This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. These works may not be reposted without the explicit permission of the copyright holder.

Abstract

Webcams placed all over the world observe and record the visual appearance of a variety of outdoor scenes over long periods of time. The recorded time-lapse image sequences cover a wide range of illumination and weather conditions -- a vast untapped resource for creating visual realism. In this work, we propose to use a large repository of webcams as a "clip art" library from which users may transfer scene appearance (objects, scene backdrops, outdoor illumination) into their own time-lapse sequences or even single photographs. The goal is to combine the recent ideas from data-driven appearance transfer techniques with a general and theoretically-grounded physically-based illumination model. To accomplish this, the paper presents three main research contributions: 1) a new, high-quality outdoor webcam database that has been calibrated radiometrically and geometrically; 2) a novel approach for matching illuminations across different scenes based on the estimation of the properties of natural illuminants (sun, sky, weather and clouds), the camera geometry, and illumination-dependent scene features; 3) a new algorithm for generating physically plausible high dynamic range environment maps for each frame in a webcam sequence.

Notes

Associated Center(s) / Consortia: Vision and Autonomous Systems Center

Associated Lab(s) / Group(s): Illumination and Imaging Lab and Computer Graphics Lab

Number of pages: 9

Note: For more details, see our project webpage.

Text Reference

Jean-Francois Lalonde, Alexei A. Efros, and Srinivasa G. Narasimhan, "Webcam Clip Art: Appearance and Illuminant Transfer from Time-lapse Sequences," ACM Transactions on Graphics (SIGGRAPH Asia 2009), Vol. 28, No. 5, December, 2009

BibTeX Reference

@article{Lalonde_2009_6482,
   author = "Jean-Francois Lalonde and Alexei A. Efros and Srinivasa G Narasimhan",
   title = "Webcam Clip Art: Appearance and Illuminant Transfer from Time-lapse Sequences",
   journal = "ACM Transactions on Graphics (SIGGRAPH Asia 2009)",
   month = "December",
   year = "2009",
   volume = "28",
   number = "5",
   Notes = "For more details, see our project webpage."
}

The Robotics Institute

Menu