TU Wien:Visualisierung medizinischer Daten 2 VU (Raidou)/Quiz 2022

Quiz 1: Vector and Flow Vis

1. One way to visualize vector (and, thus, flow) fields is to use vector decomposition to reduce a vector field to scalar quantities. Discuss how this is done theoretically (decomposition AND visualization) and mention at least three disadvantages of this approach.
2. Mention four disadvantages/limitations of using vector glyphs for the representation of vector fields (no need for details, just: A,B,C,D).
3. Give the definition of a streamline and mention the most common type of error that they suffer from (no details needed).

Quiz 2: Tensor Visualization

1. How do we derive diffusion measures from the diffusion tensor? Name the four most important measures and explain briefly their physical meaning.
2. Name one advantage and one disadvantage for each of these approaches for tensor visualization:
   1. Derive several diffusion measures from the tensor and use color encoding on 2D slices.
   2. Derive several diffusion measures from the tensor and do a volume/surface rendering thereof.
   3. Use of superquadric glyphs.
   4. Use of ellipsoid glyphs.
   5. Use of streamlines for fiber tracking.

Quiz 3: Advanced Illumination and Illustrative Visualization

1. What is streamline-based illustrative rendering and when it is used?
2. What is a silhouette and how we compute it? (NOTE: I do not want the mathematical definition, just an explanation of the term)
3. In each of these three cases, what would you use: gradient-based illumination approach (GI) or local ambient occlusion (LOA)? And why? (NOTE: you can use only one of these two and your explanation should be max one line)
   1. In a volume rendering of the folds of the brain
   2. In a volume rendering of the upper abdomen, which focuses on the structure of the rib cage
   3. In a volume rendering of the heart, which focuses on the representation of the coronary veins (the veins adjacent to the outer surface of the heart)
   4. In a volume rendering of the heart, which focuses on the representation of the coronary veins, based on a high-resolution dataset

Quiz 4: Vascular Visualization

1. Mention the two most commonly used methods for the segmentation of vessels, and describe with few details how ONE of them works.
2. What are the three graphics primitives used in model-based vessel visualization and how they are used?
3. What is the unwanted blending effect of implicit methods for vessel visualization and how to solve it?

Quiz 5: Endoscopy, Surgery and Education

1. What is path planning in virtual endoscopy, and how is it computed?
2. How do we balance between artifacts and loss of details in indirect volume rendering for virtual endoscopy?
3. Give a brief example of augmentation in computer assisted surgery.

Quiz 6: Visual Analytics in Healthcare

1. What is effectiveness, expressiveness, and appropriateness in visual analytics?
2. Why do we need both visualization and automated approaches in visual analytics?
3. Describe briefly the nested model of Tamara Munzner for validation (3-4 sentences).

Quiz 7: Visual Analytics for BioMedical Applications

1. From all the examples you saw in class, give YOUR interpretation of how visual analytics can support user within the context of a biomedical application.
2. Give TWO examples of interaction strategies that are commonly used in visual analytics applications.