A study on local photometric models and their application to robust tracking

• Published in: Computer vision and image understanding Vol. 116; no. 8; pp. 896 - 907
• Main Authors: Gouiffès, M., Collewet, C., Fernandez-Maloigne, C., Trémeau, A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01-08-2012; Elsevier
• Subjects: Algorithms; Applied sciences; Artificial intelligence; Automatic Control Engineering; Computer Science; Computer science; control theory; systems; Computer vision; Estimating; Exact sciences and technology; Illumination; Lighting; Local photometric models; Mathematical models; Pattern recognition. Digital image processing. Computational geometry; Robust feature point tracking; Tracking; Computer vision; Local photometric models; Robust feature point tracking; Light source; Tracking; Image processing; Measurement sensor; Local theory; Rough surface; Modeling; Light sources; Lighting; Specular reflection; Robustness; Localization; Photometry; ROBUST FEATURE POINT TRACKING; COMPUTER VISION; LOCAL PHOTOMETRIC MODELS
• ISSN: 1077-3142; 1090-235X
• DOI: 10.1016/j.cviu.2012.04.002

► Explanation of some local photometric models which are often used without knowing the assumptions on which they rely. ► Proposition of two photometric models. ► Study on the validity of the models according to the acquisition conditions. ► A differential feature point tracker (KLT). ► A comparison between our method and existing KLT-like methods.
Since modeling reflections in image processing is a difficult task, most computer vision algorithms assume that objects are Lambertian and that no lighting change occurs. Some photometric models can partly answer this issue by assuming that the lighting changes are the same at each point of a small window of interest. Through a study based on specular reflection models, we explicit the assumptions on which these models are implicitly based and the situations in which they could fail.
This paper proposes two photometric models, which compensate for specular highlights and lighting variations. They assume that photometric changes vary smoothly on the window of interest. Contrary to classical models, the characteristics of the object surface and the lighting changes can vary in the area being observed. First, we study the validity of these models with respect to the acquisition setup: relative locations between the light source, the sensor and the object as well as the roughness of the surface. Then, these models are used to improve feature points tracking by simultaneously estimating the photometric and geometric changes. The proposed methods are compared to well-known tracking methods robust to affine photometric changes. Experimental results on specular objects demonstrate the robustness of our approaches to specular highlights and lighting changes.