Download presentation

Presentation is loading. Please wait.

Published bySeth St. ives Modified over 2 years ago

1
John Brosz & Faramarz Samavati University of Calgary Shape Modeling International – June 2010 1

2
Outline 1. Scenario/Motivation 2. Goals 3. Related Work 4. Observations 5. Projection Surface Formulation 6. Rendering 7. Applications 2

3
3

4
Figure from Transformations & Projection in Computer Graphics, Salomon, Springer, 2006 4

5
5 i = R Figure from Transformations & Projection in Computer Graphics, Salomon, Springer, 2006

6
6 z j = + ( i, j ) = ( R,, + ) Figure from Transformations & Projection in Computer Graphics, Salomon, Springer, 2006

7
7

8
8

9
Spherical Projection Equation 9 ( i, j ) =

10
10

11
11

12
12

13
13

14
14

15
Goals Create panoramas that: 1. Allow for exploration & customization 2. Are defined by modeling 3. Build on existing intuition 4. Allow for visual understanding Single Viewpoint: no “slit cameras”. 15

16
Related Work Panoramas from Perspective Images Image from http://www.cirq.de/mosaicing.html Image from Szeliski & Shum, Creating full view panoramic image mosaics and environment maps, Siggraph 1997 16

17
Related Work Correcting Distortion Images from Carrol, Agrawala & Agarwala, Optimizing Content-Preserving Projections for Wide-Angled Images, Siggraph 2009 17

18
Related Work Single-Center Projections Images from Trapp & Döllner, Generalization of Single-Center Projections Using Projection Tile Screens, VISIGRAPP, 2008 Normal Map Panorama 18

19
19

20
Common Panoramas 20

21
Observations 1. Shapes are associated with panoramas 21

22
Observations 1. Shapes are associated with panoramas 2. Angular change 22

23
Observations 1. Shapes are associated with panoramas 2. Angular Change 3. Parameterization is important 23 ( i, j ) = ( R,, + ) ( i, j ) =

24
Shape Defined Panoramas Defined by two curves 1. Outline: closed, controls horizontal sampling 24

25
Shape Defined Panoramas Defined by two curves 1. Outline: closed, controls horizontal sampling 25

26
Shape Defined Panoramas Defined by two curves 1. Outline: closed, controls horizontal sampling 2. Profile: open, controls vertical sampling 26

27
Shape Defined Panoramas Defined by two curves 1. Outline: closed, controls horizontal sampling 2. Profile: Open, controls vertical sampling Curves parameterized by arc-length 27

28
Shape Defined Panoramas Mix between surface of revolution and surface extrusion Profile Outline Extrusion Surface 28

29
Shape Defined Panoramas Mix between surface of revolution and surface extrusion Profile Outline Panorama Surface 29

30
Example 1 Profile Outline 30

31
Example 2 31 Outline

32
Example 2 Before After 32

33
Shape Defined Panoramas Multiple Profiles 33

34
Shape Defined Panoramas Multiple Profiles 34

35
35

36
Rendering Ray-tracing Image Re-sampling Nonlinear Projection on GPU 36

37
Rendering Ray-tracing x x 37

38
Rendering Image Re-sampling 38

39
Rendering Nonlinear Projection on GPU 1. Find projection equation 2. Project vertices with equation on GPU 3. Be careful with seams 39

40
Find Projection Equation World Coordinates Normalized Device Coordinates 40

41
Find Projection Equation Only surfaces that map onto spherical coordinates. Projection Surface: Q(u,v) = (x,y,z) Projection Volume: t (0,0,0) + (1-t) Q(u,v) 1. Find spherical coordinates of p = (x,y,z) 2. Search for u,v s.t. Q(u,v) with same spherical coords. 3. t = || p || || Q(u,v) || 41

42
Find Projection Equation Search for u,v s.t. Q(u,v) with same spherical coords. 42

43
Project Vertices with GPU Override projection matrix with nonlinear projection equation. This only moves vertices! Triangles are filled as if linearly projected. Nonlinearly Projected Triangle Triangle w/ Linear Fill Algorithm 43

44
Seams 44

45
Seams 45

46
Rendering Performance Single pass algorithm 60 fps with 100K polygons on NVIDIA 8800 GTS 46

47
Application: Custom Panorama 47

48
Application: Re-projecting Panoramas 48

49
Application: Animated Projection 49

50
Application: Interactive Local Editing 50

51
Application: Interactive Local Editing 51

52
Conclusions Use of modeling to define a projection. Use of Arc-length to dictate parameterization. Visual means for creating panoramas. Realtime GPU based rendering of panoramas. 52

53
THANK-YOU 53

Similar presentations

OK

Real-Time Rendering TEXTURING Lecture 02 Marina Gavrilova.

Real-Time Rendering TEXTURING Lecture 02 Marina Gavrilova.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on sectors of indian economy Ppt on mobile phones operating systems Ppt on varactor diode circuit Converter pub to ppt online templates Ppt on self management skills Ppt on game theory prisoner's dilemma Ppt on tsunami 2004 in india Ppt on minimum wages act 2015 Ppt on grooming and etiquettes meaning Ppt on indian textile industries in tanzania