Overview of our approach

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Input images

Light probe, gray card

Point cloud and camera position

Multiviewstereo

User intervention

Aligned, calibratedenvironment map and sun

Sun illuminationno visibility

Sky illumination

Indirect illumination

Visibility initialization Candidatere!ectances

Sun visibility

Optimization

Re!ectance Total illumination

Sun illumination

Sky illumination

Indirect illumination

(a) Capture (b) 3D reconstruction,callibration

(c) Geometry-basedcomputation

(d) Sun visibility estimation

(e) Image-guided propagation,light source separation

Colored proxy

Total illumination

Users capture a small set of pictures of the scene along with an environment map (a). We use multi-view stereo to reconstruct a 3D point cloud of the scene and a coarse geometry (b). We use the 3D reconstruction to compute sun, sky and indirect lighting over the point cloud (c). We then introduce an iterative optimization to estimate sun visibility at every point, despite the lack of precise geometry (d). The "nal step of our method consists in propagating the illumination values computed at 3D points to every pixel in the image (e). We decompose the propagated illumination into the sun, sky and indirect lighting components.

For more details, please refer to our publication in IEEE Transactions on Visualization and Computer Graphics, 2012.

Intrinsic images aim at separating an image into re!ectance (e) and illumination layers (f-h) to facilitate analysis or manipulation. Most successful methods rely on user indications, precise geometry, or need multiple images from the same viewpoint and varying lighting to solve this severely ill-posed problem. We propose a method to estimate intrinsic images from multiple views of an outdoor scene at a single time of day without the need for precise geometry and with little manual calibration. Each intrinsic component can then be manipulated independently for advanced image editing applications (b-d).

Rich Intrinsic Image Decomposition of Outdoor Scenes from Multiple Views

(a) Input photographs (b) Edited Re!ectance (d) Sunset relighting

(f ) Sun Illumination (h) Indirect Illumination(g) Sky Illumination

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(c) Virtual object

(e) Re!ectance

We acknowledge the generous support of Autodesk (software donation) and Adobe (research donation). This work was partly supported by the EU FP7 IP project VERVE (www.verveconsortium.eu)

Pierre-Yves La#ont, Adrien Bousseau, George Drettakis

REVES / Inria Sophia-AntipolisWe will also present this work in the “Image Playground” sessionThursday 3:45 pm- 5:15 pm, Room 408A