Motivation

1. Motivation • Microtubules (MT) are filamentous cytoskeleton structures composed of tibulin protein subunits. • Quantitative analysis of MT dynamics in live cell is necessary • Growth and shortening events of MT by considering only the MT tip position is not a valid approximation if MT follow non-linear paths • Reliable tracing of MT body is required

2. Challenges • Intersecting and overlapping MT regions appear brighter due to additive florescence • Typical binarization methods yields gaps

3. Tip Detection • MT image is filtered by second derivative of Gaussian filter with different orientations to reveal curvilinear structures. • Binary mask obtained by thresholding the filter response is then further skeletonized to have B(x,y) • The candidate tip positions are marked by finding the line ends in B(x,y)

4. Methodology • Use estimated tip positions as starting points • Apply fast marching to extract all possible paths starting with tip position and end points s.t. • Calculate the support of the path p • Select the path that maximizes the support

5. Results Results of the Geodesic Paths Results of the Proposed Algorithm