layered texture matting 9562631 葉展岱 9565524 范智勝. outline introduction implementation...
Post on 19-Dec-2015
240 views
TRANSCRIPT
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(xi,yi) . S = (I(xi,yi) – 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 th
e 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 er
ror boundary cut.