Estimating Lighting Direction and Classifying Textures
نویسندگان
چکیده
The appearance of a rough surface is affected by the direction from which it is lit and texture classifiers should account for this. We propose a classifier that is robust to lighting direction—even when the direction is unknown. An existing model of the dependency of texture features on lighting direction is used to develop a probabilistic model. Given a feature set, the algorithm estimates the most likely illumination direction for each texture class. The likelihoods of each candidate (with their estimated lighting) are compared to classify the sample. The ability of the classifier to identify illuminant direction, and to assign the correct class, was tested on 25 real texture samples. The classifier was able to accurately estimate both the azimuth and the zenith of the light source for most textures and gave a 98% classification rate.
منابع مشابه
Multiple-cue Illumination Estimation in Textured Scenes
In this paper, we present a method that integrates cues from shading, shadow and specular reflections for estimating directional illumination in a textured scene. Texture poses a problem for lighting estimation, since texture edges can be mistaken for changes in illumination condition, and unknown variations in albedo make reflectance model fitting inpractical. Unlike previous works which all a...
متن کاملAnalyzing mental dimensions and investigating the effects of lighting on the improvement of urban settlements (Case study: Tehran Metropolis)
Light and lighting encompass different dimensions of urban life, thus the harmony and coordination of this process with environment and urban space is of great importance. Due to the importance of mental patterns in urban planning, present article analyzes the relation between mental dimensions of lighting and the spatial improvement of Tehran metropolis. The present article is developmental an...
متن کاملThe influence of shape cues on the perception of lighting direction.
Three scene properties determine the luminances in the image of a shaded object: the material reflectance, the illuminant position, and the object's shape. Because all three properties determine the image, one cannot solve for any one property without knowing the other two. Nevertheless, people perceive consistent 3D shape and consistent lighting in shaded images; they must therefore be making ...
متن کاملAugmenting Deformable Objects in Real-Time
We present a real-time system that can draw virtual patterns or images on deforming real objects by estimating both the deformations and the shading parameters. We show that this is what is required to render the virtual elements so that they blend convincingly with the surrounding real textures. The whole process of uncompressing the video stream, measuring the deformations, estimating the lig...
متن کاملEstimating changes in lighting direction in binocularly viewed three-dimensional scenes.
We examine human ability to detect changes in scene lighting. Thirteen observers viewed three-dimensional rendered scenes stereoscopically. Each scene consisted of a randomly generated three-dimensional "Gaussian bump" surface rendered under a combination of collimated and diffuse light sources. During each trial, the collimated source underwent a small, quick change of position in one of four ...
متن کامل