This document discusses using glyphs in layered 2D medical visualizations. It covers combining glyphs with other visual representations, positioning glyphs, and considerations for emphasizing glyphs. Examples of using glyphs in diffusion tensor imaging and CMR visualization are provided. The conclusion notes that layered visualizations remain an unsolved problem and questions whether benefits outweigh challenges given limited visual channels.

1. GLYPHS IN LAYERED 2D
MEDICALVISUALISATIONS
Simon Walton

2. THEMES
• Glyphs in medical visualisation, generally
• Combining glyphs with other types of visual representations

3. GLYPHS IN MEDICALVIS
• Glyphs in both research and clinical settings
• Clinicians still want numbers
• Perceptual bias is an issue
• Large variance in accuracy of perception
• Laying out glyphs can be an issue

4. POSITIONING GLYPHS
• Do we allow overlaps?
• What is the significance of each
glyph’s position?
• Strategies (Ward)
• Data-driven
• Structure-driven

5. POSITIONING GLYPHS

6. OTHER CONSIDERATIONS
• Do we want some glyphs
to pop out?
• Can emphasise using
visual perception theory
• What parameter mapping
function is used?
• Continuous or discrete?

7. DIFFUSIONTENSOR IMAGING
Eigenvectors
Ellipse

8. DIFFUSIONTENSOR IMAGING

9. DIFFUSIONTENSOR IMAGING

10. CMRVISUALISATION

11. CMRVISUALISATION

13. raw heatmap
vector glyph

15. NEW DIFFICULTY
=>
LUT

17. CAN WE DO BETTER?
Spatial
frequency
Density of
coverage
Transparency
Colour
important?
Heart Low High No Yes
Heatmap Low Low Variable No
Vector High Low Variable No
Glyphs High Low No Yes

20. CONCLUSION
• Layered visualisations largely an unsolved problem
• Do the benefits for the application outweigh the
challenges?
• A layered visualisation can be `modulated’ to assist user’s
visual decomposition of each layer
• How many visual channels can we use before the
visualisation becomes useless?