Visualisatie BMT Introduction, visualization, visualization - - PowerPoint PPT Presentation

1

Visualisatie

BMT

Introduction, visualization, visualization pipeline Arjan Kok Huub van de Wetering (h.v.d.wetering@tue.nl)

2

Lecture overview

• Goal
• Summary
• Study material
• What is visualization
• Examples
• Visualization pipeline

3

Goal

• Provide theoretical and practical knowledge in:
• Data visualization
• Data representation
• Computer graphics
• Data processing in Java
• Visualization in MayaVi

4

Summary (1)

• Introduction
• What is visualization
• Related disciplines
• Fields of applications
• The visualization pipeline
• Definition
• Data enrichment, mapping, rendering

5

Summary (2)

• Basic data representation
• Datasets
• Sampling
• Interpolation
• Graphics rendering
• Rendering process
• Color
• Lighting, shading

6

Summary (3)

• Algorithms
• Scalar algorithms
• Vector algorithms
• Tensor algorithms
• Modeling algorithms
• Volume visualization
• Ray tracing, ray sampling
• Volume interpolation
• …

7

Study material

• Theory
• Book
• Slides
• Practice
• MayaVi (visualization tool)
• Jaspis

(java programming tool)

• Assignments

8

Book

• The Visualization Toolkit –An Object-Oriented Approach

to 3D Graphics

• W. Schroeder, K. Martin, B. Lorensen

Prentice Hall

• Book contains a lot more than the

course does (course will address specific parts/chapters)

• Book contains software (VTK) we shall

not (directly) use

9

Slides

• Slides used in lectures will be available at:

http://www.win.tue.nl/~wstahw/2Z860

10

Visualization

11

What do we visualize?

12

Visualization

The purpose of computing is insight, not numbers

• Richard Hamming

13

Visualization - insight in data

14

From data to pictures

• Attributes of Visualization
• Making abstract data visible (complex, many)
• Forming a mental image of something abstract
• Using the abilities of human vision and interaction

DATA VISUALIZATION PICTURES

12.4556 34.442

• 22.2000E+11 0.3324

a: 27.3099 b: 43.3 C:33.323 34.445

15

Scientific visualization

• The use of computer imaging techniques as a tool for

comprehending data obtained by simulation or physical measurements

• The techniques that allow scientists and engineers to extract

knowledge from the results of simulations and computations

16

Goals in visualization

• Exploration of data and information
• Enhancing understanding of concepts and processes
• Gaining new (unexpected) insight
• Making invisible visible
• Effective presentation of significant features
• Quality control of simulations and measurements
• Increasing scientific production

17

Visualization challenges

• Getting usable data
• Parsable
• Visualizable
• Defining your goal
• What is the focus of attention or primary features
• Who is the audience
• What is the message
• Choosing meaningful/compelling visual representations

18

Graphs

2 4 6 8 10 12 14 16 18 20 1 2 3 4 5 6 7 8 9 10

19

Complex data

• We are interested in more complex data
• Multi-dimensional
• Complex geometry
• Computed or collected
• Simulations
• MRI, CT, ..
• Microscopic to galactic data collections

20

Some examples

21

Related disciplines

SIGNAL PROCESSING COMPUTER GRAPHICS COMPUTER AIDED DESIGN PERCEPTUAL PSYCHOLOGY GEOMETRIC MODELING IMAGE PROCESSING V I S U A L I Z A T I O N USER INTERFACE STUDIES

22

Imaging, graphics, visualization

• Imaging
• The study of 2D images

(transformations, enhancement, information extraction)

• Graphics
• Creating images using a computer

(2D drawing techniques, 3D rendering techniques)

• Visualization
• Exploring, transforming, and viewing data as images

23

Imaging, graphics, visualization

• Visualization uses computer graphics and imaging as tools

for the higher level goal of getting insight into data

• Graphics and imaging are particular forms of visualization

…

24

Imaging, graphics, visualization

any data image 2D/3D object image image image Data transformation nD 2D, 3D 2D Data dimensionality Visualization Graphics Imaging

25

Applications

26

Applications

• Biochemistry
• Molecular modeling/dynamics
• Industrial research on molecular structures
• Drug design

DATA VISUALIZATION PICTURES

molecule structures

27

Molecular visualization

28

Molecular visualization

29

Applications

• Mathematics
• Understanding complex concepts

(functions, surfaces, fields, ..)

DATA VISUALIZATION PICTURES

functions f(x,y,z)

function plot

30

Mathematics

z = F(x,y) = e-rcos(10r) saddle quadric surface F(x,y,z) = 0 nested implicit functions

31

Applications

• Medicine
• Diagnosis
• Treatment planning
• Education
• Research

DATA VISUALIZATION PICTURES

2D/3D scan data surfaces/ slices

32

Medicine

33

Examples

• Geosciences
• Weather forecast
• Topography
• Geology

DATA VISUALIZATION PICTURES

surface/ volume data surfaces/ height plots

34

Geosciences

Ocean surface height during the El Nino event Rain during summer 2004

35

Applications

• Space sciences
• Astronomy
• Astrophysics
• Remote sensing

36

Space sciences

Orion Nebula as seen from a virtual spacecraft

37

Applications

• Engineering and physics
• Computational fluid dynamics
• Fluid flow simulation
• Surface modeling
• Finite element simulations
• Physical processes

(strength, elasticity, flow, ..)

38

Computational fluid dynamics

air pressure on a plane wing velocity of a turbulent jet flow internal waves inside the ocean

39

Finite element methods

pressure on a plane wing 2D flow past a cylinder

40

Applications

• Architecture
• Simulations of:
• Indoor lighting
• Sound
• Heath
• Air

41

Architecture

Simulation of light in a theatre

42

Applications

• Visualization is applicable in any research or engineering

field

DATA VISUALIZATION PICTURES

12.4556 34.442

• 22.2000E+11 0.3324

a: 27.3099 b: 43.3 C:33.323 34.445

43

Visualization pipeline

• Describes the steps to transform “raw” data into displayable

images

• Goal of these steps is to convert the information to a format

amenable to understanding by the human perceptual system while maintaining the integrity of information

44

Visualization pipeline

Raw Data Derived Data Abstract Visualization Object Displayable Image Data Enrichment/Enhancement Visualization Mapping Rendering

45

Getting the data

Simulation data Measured data Data formats HDF, NetCDF, XDR, Dicom, …. Data compression RLE, Fractal methods, …. my own format

Visualization internal data (ready for the pipeline)

46

Step 1: Data enrichment

• Data enrichment
• Interpolation
• Filtering and smoothing
• Selection
• Merging
• Format conversion
• 2D and 3D conversions (rotation, translation)

data object(s) data enrichment (filter object) data object(s)

47

Step 2: Mapping

• Mapping
• Generating displayable data (2D and 3D objects) whose

shape, dimensions and color represent the enriched data

• Abstract visualization objects
• The 2D and 3D objects resulting from the mapping stage

(graphical primitives)

data object(s) mapping (mapper object) abstract visualization objects

48

Step 3: Rendering

• Rendering
• Produces an image (view) of the 2D/3D abstract

visualization objects

• Several rendering parameters

(lighting, shadows, reflections, etc)

abstract visualization objects rendering image(s)

49

Step 3: Rendering

• Rendering
• Special rendering techniques such as volume rendering

for non-opaque data

data object(s) volume rendering image(s)

50

Example

51

Example pipeline

surface data

polydata

data

polydata

data

• str. pnts

surfaces lines image

• utline

filter geometry filter reader render mapper mapper mapper

52

Visualization and interaction

Raw Data Derived Data Abstract Visualization Object Displayable Image Data Enrichment/Enhancement Visualization Mapping Rendering u s e r i n p u t

53

Visualization and research process

• Visualization plays a large role in forming the link between

hypothesis and experiment, and between insight and new hypothesis

54

Visualization and research process

55

Visualization pipeline (revisited)

Raw Data Derived Data Abstract Visualization Object Displayable Image Data Enrichment/Enhancement Visualization Mapping Rendering