Lecture 7

Question 1

Image registration

Answer 1

The changing of images such that both images are part of the same coordinative systems

• Aligning for colocalization
• Fixating cells
• Mosaicking
• Multimodal fusion
• Longitudianal analysis

Question 2

Aligning for colocalization

Answer 2

Can be used for chomatic aberration. Less double and more clear

Question 3

Fixating cells

Answer 3

Makes it easier to study their internal changes like shape and position. You can segment them out and map them on a grid

Question 4

Mosaicking

Answer 4

Enlarge the field of view. This way you can see a large picture. You need them to overlap

Question 5

Multimodal fusion

Answer 5

This can help with joint analysis. For example fluorescence and electron microscopy mixing

Question 6

Longtitudinal analysis

Answer 6

Can compare different time points. Need to be stacked in the same positional state

Question 7

Extrinsic vs intrinsic information

Answer 7

Extrinsic if the images are very different from one another. Need external markers to allign the images. Otherwise intrinsic information can be used. Look at the Pearson’s correlation coefficient

Question 8

landmarks

Question 9

intensity differences

Answer 9

Can be improved by extracting common image features such as edges or ridges

Question 10

Joint histogram

Answer 10

To look at intesity differenes

Question 11

Similarity measures

Answer 11

• Normalized cross-correlation
• Sum of squared differences
• Mutual information

Question 12

Normalized cross-correlation

Question 13

Sum of squared differences

Question 14

Mutual information

Question 15

Geometric image transformations

Answer 15

• Rigid transformations
• Affine transformations
• grid based nonrigid transformations

Question 16

Rigid transformations

Answer 16

• Translation

- Rotation

Question 17

Affine transformations

Answer 17

Perserves points, straight lines and parallelism between straight lines.

• Shearing
• Scaling
• Identity
• Translation
• Rotation

Question 18

Grid based non rigid transformations

Answer 18

• Random
• Elastic
  Define a coarse grid of control points and estimate the local displacements. Smoothly interpolate estimated displacements to all coordinates and apply.

Question 19

Optimization

Answer 19

• Iterative
• Brute force
• Gradient based
• Quadratic
• Multiscale optimization

Question 20

Iterative optimization

Answer 20

Step size is important, determines the accuracy.

Question 21

Brute force

Answer 21

Simply try all possible parameter values within certain limits.

Question 22

Gradient based

Answer 22

Move toward the optimum of a local quadratic approcimation of M

Question 23

Quadratic optimization

Answer 23

Move toward the optimum of a local quadratic approximation of M

Question 24

Multiscale optimization

Answer 24

Iterative registration from low to original imare resolution. More efficient, but more robust.

Question 25

Interpolation methods

Answer 25

• Nearest-Neighbor
• Linear
• Cubic interpolation

Question 26

Atlas based registration

Answer 26

Minimize overlap error of full skeleton, then do this for all bones seperately. Now normalize the poster to comper the structure to other posters