Theory for Off-Specular Reflection From Roughened Surfaces*

Torrance, K. E.; Sparrow, E. M.

doi:10.1364/josa.57.001105

Cited by 1,626 publications

(864 citation statements)

References 9 publications

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“…Combined with a laser range scanned model of the subject under study, dense measurements of the BRDF could be made. Georghiades [79] incorporated the Torrance and Sparrow [80] model of reflectance into an extended uncalibrated photometric stereo algorithm. This allowed accurate shape and reflectance parameters to be recovered from multiple images of various objects, including faces.…”

Section: Inverse Renderingmentioning

confidence: 99%

Inverse Rendering of Faces with a 3D Morphable Model

Aldrian

Smith

2013

IEEE Trans. Pattern Anal. Mach. Intell.

176

160

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In this thesis, we present a complete framework to inverse render faces with a 3D Morphable Model. By decomposing the image formation process into a geometric and photometric part, we are able to state the problem as a multilinear system which can be solved accurately and efficiently. As we treat each contribution as independent, the objective function is convex in the parameters and a globally optimal solution can be found. We start by recovering 3D shape using a novel algorithm which incorporates generalisation errors of the model obtained from empirical measurements. The algorithm is extended so it can efficiently deal with mixture distributions. We then describe three methods to recover facial texture, and for the second and third, diffuse lighting, specular reflectance and camera properties from a single image. These methods make increasingly weak assumptions and can all be solved in a linear fashion. We further modify our framework so it accounts for global illumination effects. This is achieved by incorporating statistical models for ambient occlusion and bent normals into the image formation model. We show that solving for ambient occlusion and bent normal parameters as part of the fitting process improves the accuracy of the estimated texture map and illumination environment. We present results on challenging data, rendered under complex natural illumination with both specular reflectance and occlusion of the illumination environment. We evaluate our findings on publicly available datasets, where we are able to obtain state-ofthe-art results. Finally, we present a practical method to synthesise a larger population from a small training-set and show how the new instances can be used to build a flexible PCA model.

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Section: Inverse Renderingmentioning

confidence: 99%

Inverse Rendering of Faces with a 3D Morphable Model

Aldrian

Smith

2013

IEEE Trans. Pattern Anal. Mach. Intell.

176

160

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“…We computed the radiance distribution on a specular hemisphere for different scattering angles, using the Torrance-Sparrow reflectance model [14] (see Appendix A for the derivation of radiance). The hemisphere is illuminated and viewed orthographically from the same direction (top).…”

Section: Specularitiesmentioning

confidence: 99%

“…Point p receives illumination from a single diffuser strip parallel to the x-axis. According to the Torrance-Sparrow reflectance model [14], the radiance due to a single infinitesimal diffuser element corresponding to the incidence angle α is given as: dL(θ, φ) = C F . G .…”

Section: A Derivation Of Radiancementioning

confidence: 99%

Diffuse structured light

Nayar

Gupta

2012

2012 IEEE International Conference on Computational Photography (ICCP)

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Today, structured light systems are widely used in applications such as robotic assembly, visual inspection, surgery, entertainment, games and digitization of cultural heritage. Current structured light methods are faced with two serious limitations. First, they are unable to cope with scene regions that produce strong highlights due to specular reflection. Second, they cannot recover useful information for regions that lie within shadows. We observe that many structured light methods use illumination patterns that have translational symmetry, i.e., two-dimensional patterns that vary only along one of the two dimensions. We show that, for this class of patterns, diffusion of the patterns along the axis of translation can mitigate the adverse effects of specularities and shadows. We show results for two applications -3D scanning using phase shifting of sinusoidal patterns and separation of direct and global components of light transport using highfrequency binary stripes.

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“…The Torrance-Sparrow model [34] derives the specular component by assuming the reflecting surface to be composed of microfacets based on a gaussian distribution. It includes a Fresnel term for off-specularity and also accounts for shadowing and masking with respect to the microfacet distribution.…”

Section: Physically-based Modelsmentioning

confidence: 99%

BRDF Acquisition with Basis Illumination

Ghosh

Achutha

Heidrich

et al. 2007

2007 IEEE 11th International Conference on Computer Vision

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To create a realistic image we need to characterize how light reflects off a surface.In optics terminology, the complete Bidirectional Reflectance Distribution Function is needed. At a given point on a surface the BRDF is a function of two directions, one toward the light and one toward the viewer. Any device for measuring the 4D reflectance data has to obtain measurements over the hemisphere of incident and exitant directions which can be quite tedious if done using the brute-force approach.In this thesis, we describe an efficient image-based acquisition setup that has no moving parts and can acquire reflectance data in a matter of a few minutes. We make this possible by using curved reflective surfaces that eliminate the need to move either the camera or the light source. The acquisition speedup mostly comes from the way we optically sample the BRDF data into a suitable basis. This also saves us the postprocess compression of data. We then encode the data into a compact form that is suitable for use in various rendering systems. ContentsAbstract .

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Theory for Off-Specular Reflection From Roughened Surfaces*

Cited by 1,626 publications

References 9 publications

Inverse Rendering of Faces with a 3D Morphable Model

Inverse Rendering of Faces with a 3D Morphable Model

Diffuse structured light

BRDF Acquisition with Basis Illumination

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