Light montage for perceptual image enhancement

• Published in: Computer graphics forum Vol. 33; no. 2; pp. 185 - 194
• Main Authors: Hosu, Vlad, Lan Ha, Mai, Sim, Terence
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.05.2014
• Subjects: Analysis; Artists; Categories and Subject Descriptors (according to ACM CCS); Computer graphics; Cues; I.3.3 [Computer Graphics]: Picture/Image Generation-Viewing; I.4.3 [Image Processing and Computer Vision]: Enhancement; Illumination; Light; Montage; Photography; Reflectance; Reflectivity; Studies; Surface layer; Texture
• ISSN: 0167-7055; 1467-8659
• DOI: 10.1111/cgf.12292

Recent photography techniques such as sculpting with light show great potential in compositing beautiful images from fixed‐viewpoint photos under multiple illuminations. The process relies heavily on the artists’ experience and skills using the available tools. An apparent trend in recent works is to facilitate the interaction making it less time‐consuming and addressable not only to experts, but also novices. We propose a method that automatically creates enhanced light montages that are comparable to those produced by artists. It detects and emphasizes cues that are important for perception by introducing a technique to extract depth and shape edges from an unconstrained light stack. Studies show that these cues are associated with silhouettes and suggestive contours which artists use to sketch and construct the layout of paintings. Textures, due to perspective distortion, offer essential cues that depict shape and surface slant. We balance the emphasis between depth edges and reflectance textures to enhance the sense of both shape and reflectance properties. Our light montage technique works perfectly with a few to hundreds of illuminations for each scene. Experiments show great results for static scenes making it practical for small objects, interiors and small‐scale outdoor scenes. Dynamic scenes may be captured using spatially distributed light setups such as light domes. The approach could also be applied to time‐lapse photos, with the sun as the main light source.