Tracking a selected point in vector field

Liefei (Lucy) XuOct 2008

1234

1 2 3 4

Track a point:

Select a point

Find the most similar point in later slices (how?)

Tracking a point through time

Measure similarity between points

1. Extract attributes of each point- Vector Spin image

2. Compute similarity based on the attributes- χ2 statistic distance

Test and adjustment

• We test and adjust our algorithm on below parameters:– Different types of selected point:

singularities, ridges, regular points

– Different attributes for spin image: vector direction, vector magnitude, strength of rotation, strength of dilation, strength of stretch, direction of stretch, tensor magnitude

– Different radius of spin image: 2*20, 5*60, 8*120

Selected Result tracking a singularity

1

2

3

4

Vector Direction Strength of dilation Tensor magnitude

Selected Result tracking a regular point

Vector Direction Strength of dilation Tensor magnitude

1

2

3

4

Selected Result tracking a point on ridge

Vector Direction Strength of dilation Tensor magnitude

1

2

3

Uniqueness and Strength

Topological method Our Statistic method

A lot of research has been done

A novel method

Depends on singularities Works for both singularity and non-singularity vector field

Sensitive to noise Robust to noise

Ambiguity Avoids the ambiguity problem