on Commodity Graphics Hardware

sizzlepictureΛογισμικό & κατασκευή λογ/κού

2 Δεκ 2013 (πριν από 3 χρόνια και 7 μήνες)

79 εμφανίσεις

Multi
-
resolution Real
-
time Stereo
on Commodity Graphics Hardware


12


組員

吳冠璋

家庭自動化實驗室

Author:

Ruigang Yang and Marc Pollefeys

Publication:

IEEE Computer Society
Conference on Computer Vision and
Pattern Recognition, 2003

Introduction


Real
-
time stereo vision


2 parallel camera


Optimized algorithm with hardware acceleration


Correlation
-
based stereo algorithms


Assembly
-
level optimization


MMX


Multi
-
processor PC


Graphic Processing Unit

Method


SSD



(I’
x,y



I
x,y
)
2



I’
x,y

and I
x,y

denote pixels in two images


For parallel camera, no more image processing is
need.

SSD on GPU







The same as standard SSD, but window size is limited



n = support size (2
a

* 2
b
)



a, b = any GPU supported size



x, y = center coordinate of texture



p, q = pixel on texture

SSD on GPU


For SSD


Large windows the curves mostly only have a single
strong minimum


Small windows the minima are typically well localized


Combine the global characteristics of the large
windows with the well
-
localized minima of the
small windows


Sum up multi
-
level mipmap SSD


Computer Graphic Basic


Mipmap


Multi
-
texture


Pixel Shader

Mipmap (1/2)


A set of texture that


Pre
-
generated


Multiple resolution


Linear interpolated


Mipmap generation






i = Mipmap level



u, v = Texture coordinate



p, q = support size (2
n

* 2
n
)

Mipmap (2/2)


Paper said that mipmap

generation is fast on GPU,

with some ext. supported

With mipmap


Without mipmap

gluBuild2DMipmaps
(…)

/* Get generated map size


at level n */

glGetTexLevelParameteriv
(…)

malloc(…)

/* Copy texture
from graphic


memory to system memory

*/

glGetTexImage
(…)

/* Select a texture stage */

glActiveTextureARB(…)

glEnable(GL_TEXTURE_2D)

glBindTexture(…)

/* Copy texture
from system


memory to graphic memory

*/

glTexImage2D(…)

Multi
-
texture


Apply two or more distinct textures to a single
fragment


Pixel Shader


Replace standard multi
-
texture processing order


Programmable


ARB_multitexture


GL Shading Language


OpenGL 2.0

Vertex

Shader

Pixel

Shader

Object space

Window space

Framebuffer

IN

OUT

Textures

Multi
-
mipmap SSD


Compute SSD and sum them up on GPU


GPU SSD, pixel
-
by
-
pixel


Special scoring and the selection method [1]


SSD score is computed on CPU, pixel
-
by
-
pixel (My impl.)

My Result (100 steps)


CPU: T2500 (1 core) GPU: Intel 940gm graphic



4 sec : 0.25 fps


CPU: Althon X2 4200+ GPU: GeForce 6150



1 sec : 1 fps

Result in Paper



4 MML






0 MML + texture shift

Reference


[1] R. Yang, G. Welch, and G. Bisop. Real
-
Time Consensus
-
Based Scene Reconstruction
Using Commodity Graphics Hardware. In Proceedings of Pacific Graphics 2002, pages 225

234, Beijing, China, October 2002.


End of Slides







Thank you