Section: Research Program

The photometry component

In addition to the geometry (of scene and cameras), the way an image looks like depends on many factors, including illumination, and reflectance properties of objects. The reflectance, or “appearance”, is the set of laws and properties which govern the radiance of the surfaces . This last component makes the connections between the others. Often, the “appearance” of objects is modeled in image space, e.g. by fitting statistical models, texture models, deformable appearance models (...) to a set of images, or by simply adopting images as texture maps.

Image-based modelling of 3D shape, appearance, and illumination is based on prior information and measures for the coherence between acquired images (data), and acquired images and those predicted by the estimated model. This may also include the aspect of temporal coherence, which becomes important if scenes with deformable or articulated objects are considered.

Taking into account changes in image appearance of objects is important for many computer vision tasks since they significantly affect the performances of the algorithms. In particular, this is crucial for feature extraction, feature matching/tracking, object tracking, 3D modelling, object recognition etc.