From: "Colin Godfrey" Subject: *CAL* SIGGRAPH/Boston at MERL, Wed. June 6 Date: Thursday, May 31, 2001 2:58 PM SIGGRAPH/Boston Meeting Announcement A Physically-Based Night Sky Model Fredo Durand Image-Based Modeling and Photo-Editing Byong Mok Oh Place: Mitsubishi Electric Research Laboratory 201 Broadway, Cambridge MA 02139 8th Floor Time: Wednesday June 6th 2001 Networking time will start around 6:15pm. The feature presentations should start around 7:30 - 7:45. A Physically-Based Night Sky Model Fredo Durand MIT Lab for Computer Science Joint work with Henrik Wann Jensen, Michael M. Stark, Simon Premoze, Julie Dorsey, and Peter Shirley This paper presents a physically-based model of the night sky for realistic image synthesis. We model both the direct appearance of the night sky and the illumination coming from the Moon, the stars, the zodiacal light, and the atmosphere. To accurately predict the appearance of night scenes we use physically-based astronomical data, both for position and radiometry. The Moon is simulated as a geometric model illuminated by the Sun, using recently measured elevation and albedo maps, as well as a specialized BRDF. For visible stars, we include the position, magnitude, and temperature of the star, while for the Milky Way and other nebulae we use a processed photograph. Zodiacal light due to scattering in the dust covering the solar system, galactic light, and airglow due to light emission of the atmosphere are simulated from measured data. We couple these components with an accurate simulation of the atmosphere. To demonstrate our model, we show a variety of night scenes rendered with a Monte Carlo ray tracer. Fredo Durand is a post-doc in the MIT LCS Graphics Group. He received his PhD in computer Science from Grenoble University, France. His research interests include visibility and real-time display, realistic and physically-based rendering, application of visual perception, tone mapping, image-based modeling and rendering, non-photorealistic rendering, interaction between visual arts and perception. ====================================================================== Image-Based Modeling and Photo-Editing Byong Mok Oh Ph.D. candidate, MIT Computer Graphics Group. We present an image-based modeling and editing system that takes a single photo as input. We represent a scene as a layered collection of depth images, where each pixel encodes both color and depth. Starting from an input image, we employ a suite of user-assisted techniques, based on a painting metaphor, to assign depths and extract layers. We introduce two specific editing operations. The first, a "clone brushing tool", permits the distortion-free copying of parts of a picture, by using a parameterization optimization technique. The second, a "texture-illuminance decoupling filter", discounts the effect of illumination on uniformly textured areas, by decoupling large- and small-scale features via bilateral filtering. Our system enables editing from different viewpoints, extracting and grouping of image-based objects, and modifying the shape, color, and illumination of these objects. Directions to Mitsubishi Electric Research Labs, 201 Broadway: Via T Get off the T at the Kendall Square stop on the Red Line. Exit from the subway and then walk directly into the lobby of the Marriott hotel, which is on a courtyard adjacent to the subway exit. Walk straight through the lobby and out the opposite side of the building. The street you are facing is Broadway. Turn left. Walk through 3 traffic lights. 201 broadway is the first building on your right after the third light. We are on the 8th floor. Driving From the intersection of Storrow Drive and Cambridge Street, take the Longfellow bridge over the Charles river to Cambridge. Drive straight on away from the river. You are on Broadway. Go through one traffic light (the Marriot hotel is now on your left). Continue straight through two more traffic lights (you are now passing over some railroad tracks). (Between the first and second of these traffic lights is a parking garage open to the public. Depending on the time of day there may also be on street parking availabe near MERL.) Continue straight through one more light (Mitsubishi is the first building on your right after this light). It says 201 in large numbers on the corner of the building. MERL is on the eighth floor. ************************************************************************ SIGGRAPH/Boston Contacts WWW: http://www.siggraph.org/chapters/boston SIGGRAPH/Boston maintains a mailing list for e-mail announcements of meetings. Send e-mail to siggraphdistrib-request@cs.umb.edu if you want be added or dropped from this list.