Layered Texture Matting 葉展岱 范智勝

Outline  Introduction  Implementation Overview  Current Work  Reference

Introduction  Our goal Doing texture synthesis on various objects with an irregular shape. Without losing the 3D property in vision.  ( differ from texture transfer) Preserving the property of texture by using the layered texture synthesis.  E.g., leaves, hair

Implementation Overview  Shape from Shading - 葉展岱  (Patch Orientation)  Texture Synthesis - 范智勝  (Layered Texture Synthesis)

Shape from Shading(1)  Normal Recovery Related parameters  S ： a unit vector toward a sufficiently distant point light source  I(x,y) ： intensity of pixel at (x,y).  Imin ： minimum intensity ambient light in the scene  Imax ： maximum intensity faces the light source

Shape from Shading(2)  c(x,y) = (I(x,y)−Imin)/(Imax −Imin) cosine of the angle of incidence at (x,y).  s(x,y) = sqrt(1−c(x,y)^2) sine of the angle of incidence at (x,y).  G(x,y) = ▽ I(x,y)−( ▽ I(x,y) · S)S ▽ I(x,y) is the image gradient.  N(x,y) = c(x,y)*S+s(x,y)*G(x,y)/||G(x,y)|| So, what we need is ‘ S ’.

Shape from Shading(3)  How to estimate S ? N(x i,y i ) ． S = (I(x i,y i ) – Imin)/(Imax - Imin) (xi,yi): on the boundary of the object ’ s projection N(xi,yi): the gradient of (xi,yi) The source vector S is the least-squares solution to the over constrained linear system

Shape from Shading(2)  Surface Segmentation Cluster with the pixels with similar normals. Use Watershed as cluster method.

Texture Synthesis  Image Quilting Procedure Define similarity using L2-norm applied to every pixel/color in block. Optimize overlap region using minimum error boundary cut.

Texture Synthesis (without cluster)

Current Work(1)  Original Image & texture

Current Work(2)  Cut out the target image Use Matting

Current Work(3)  Normal Recovery Translate N(x,yz) to (R,G,B)

Current Work(4)  Patch Cluster Use Watershed as cluster method

Current Work(5)  Texture Synthesis Obey the normals and intensity

Reference  [1] H. Fang and JC. Hart. Texture Synthesis as Photograph Editing SIGGRAPH  [2] A. A. Efros and WT. Freeman. Image Quilting for Texture Synthesis and Transfer. SIGGRAPH  [3] A. Levin, D. Lischinski, and Y. Weiss. A Closed Form Solution to Natural Image Matting. CVPR 2006.