Visualization Techniques: Scalar Field

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Visualization TechniquesScalar Field
Day 2
Raphael Grasset
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Topics

• Color/Colour Mapping
• Contour/Contouring
• Isosurface
• Surface Rendering

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Last Lecture

• Visualization Terminology, Concept and
  Applications
• Importance of Perception
• Visualization Model The Visualization Pipeline
• Dataset and Data Transformations
• Dataset structure attributes

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Visualization Pipeline

• From Raw Data to Data to Visualize

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Classification

• Different techniques for different attributes
• Scalar Visualization Techniques
• Vector Visualization Techniques
• Tensor Visualization Techniques
• (Modelling Visualization Techniques)
• Remark Dimensionality of the structure can be
  1D, 2D, 3D ( of Dimensionality of Attributes)

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Classification

• Different techniques for different attributes
• Scalar Visualization Techniques
• Color Mapping
• Contouring
• Isosurfaces
• Volume Rendering (course tomorrow)
• Vector Visualization Techniques
• Tensor Visualization Techniques
• Modelling Visualization Techniques

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Remark

• The Following slides are largely based on the
  slides from
• Taku Komura
• Institute for Perception, Action Behaviour
• The University of Edinburgh, UK

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Colour Mapping
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Colour Mapping
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Colour Mapping Basic Example
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Colour Mapping Examples
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Colour Mapping Examples
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Colour Map

• Also defined as
• Colour Scheme
• Colour Ramp
• Lot of viz software have
• predefined colour maps

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Colour Data Model?

• Previously presented perception of colour
• Representation of Colour for the Computer
• Colour Data Model
• Colour Data Model representation of the colour
  to a format understandable by the computer
• Some Colour Models
• RGB
• HSV
• ..

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Color Space Demo

• http//hydra.nac.uci.edu/wiedeman/cspace/me/rgbci
  eyiqhsv.html

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Contouring Isosurface
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Iso-..
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Slow!!!
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Summary

• Different types of scalar viz techniques
• Colour Mapping Scalar Value to Colour
• Contouring Scalar variation to Colour
• Isosurfaces Contouring in 3D

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Modelling Techniques General Surface Rendering
and Implicit Modelling Representation
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MRI
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Surface Rendering

• In some cases you just want to visualize your
  dataset structure (your mesh) without any
  attributes (existent or not)
• In some case (as previously) you want to
  visualize a 3D reconstruction of a segmented
  scalar volume
• General Computer Graphics Rendering (not really
  scalar visualization techniques)

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Basic Graphics Rendering

• You have a structure (geometry topology)
• What is the best representation for it?
• How I can visualize it?

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3D Computer Graphics in a Nutshell
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Summary

• Modelling Algorithms
• Polygonal Representation
• Implicit Representation
• Basic Computer Graphics
• Polygonal Mesh, Lighting, Shading, Camera