# Computing Local Surface Orientation and Shape From Texture for Curved Surfaces

### Jitendra Malik and Ruth Rosenholtz

###
EECS Department

University of California, Berkeley

Technical Report No. UCB/CSD-93-775

1993

### http://www.eecs.berkeley.edu/Pubs/TechRpts/1993/CSD-93-775.pdf

Shape from texture is best analyzed in two stages, analogous to steropsis and structure from motion: (a) Computing the 'texture distortion' from the image, and (b) Interpreting the 'texture distortion' to infer the orientation and shape of the surface in the scene. We model the texture distortion for a given point and direction on the image plane as an affine transformation and derive the relationship between the parameters of this transformation and the shape parameters. We have developed a technique for estimating affine transforms between nearby image patches which is based on solving a system of linear constraints derived from a differential analysis. One need not explicitly identify texels or make restrictive assumptions about the nature of the texture such as isotropy. We use non-linear minimization of a least squares error criterion to recover the surface orientation (slant and tilt) and shape (principal curvatures and directions) based on the estimated affine transforms in a number of different directions. A simple linear algorithm based on singular value decomposition of the linear parts of the affine transforms provides the initial guess for the minimization procedure. Experimental results on both planar and curved surfaces under perspective projection demonstrate good estimates for both orientation and shape. A sensitivity analysis yields predictions for both computer vision algorithms and human perception of shape from texture.

BibTeX citation:

@techreport{Malik:CSD-93-775, Author = {Malik, Jitendra and Rosenholtz, Ruth}, Title = {Computing Local Surface Orientation and Shape From Texture for Curved Surfaces}, Institution = {EECS Department, University of California, Berkeley}, Year = {1993}, URL = {http://www.eecs.berkeley.edu/Pubs/TechRpts/1993/6294.html}, Number = {UCB/CSD-93-775}, Abstract = {Shape from texture is best analyzed in two stages, analogous to steropsis and structure from motion: (a) Computing the 'texture distortion' from the image, and (b) Interpreting the 'texture distortion' to infer the orientation and shape of the surface in the scene. We model the texture distortion for a given point and direction on the image plane as an affine transformation and derive the relationship between the parameters of this transformation and the shape parameters. We have developed a technique for estimating affine transforms between nearby image patches which is based on solving a system of linear constraints derived from a differential analysis. One need not explicitly identify texels or make restrictive assumptions about the nature of the texture such as isotropy. We use non-linear minimization of a least squares error criterion to recover the surface orientation (slant and tilt) and shape (principal curvatures and directions) based on the estimated affine transforms in a number of different directions. A simple linear algorithm based on singular value decomposition of the linear parts of the affine transforms provides the initial guess for the minimization procedure. Experimental results on both planar and curved surfaces under perspective projection demonstrate good estimates for both orientation and shape. A sensitivity analysis yields predictions for both computer vision algorithms and human perception of shape from texture.} }

EndNote citation:

%0 Report %A Malik, Jitendra %A Rosenholtz, Ruth %T Computing Local Surface Orientation and Shape From Texture for Curved Surfaces %I EECS Department, University of California, Berkeley %D 1993 %@ UCB/CSD-93-775 %U http://www.eecs.berkeley.edu/Pubs/TechRpts/1993/6294.html %F Malik:CSD-93-775