Meeting Minutes

Date:	February 17, 2010
Location:	DC 1304
Time:	1:30
Chair:	Matthew Kay

1. Attendance

* Elodie Fourquet * Eugene Greene * Marshall Hahn * Jingyuan Huang * Tiffany Inglis * Craig Kaplan * Philippe Lamoureux * Xinling * Stephen Mann * Zainab Meraj * Alex Pytel * Maxime Quiblier * Matthew Thorne * Matthew Kay * Ben Lafreniere

2. Coffee Hour

Coffee hour last week:: Philippe- thanks!
Coffee hour this week:: Andrew
Coffee hour next week:: Matei

3. Forthcoming

Date:	February 24, 2010	March 3, 2010	March 10, 2010	March 17, 2010
Location:	DC 1304 1:30	DC 1304 1:30	DC 1304 1:30	DC 1304 1:30
Chair:	Ben Lafreniere	Philippe Lamoureux	Stephen Mann	Zainab Meraj
Technical Presentation:	Craig Kaplan	Matthew Kay	Ben Lafreniere	Philippe Lamoureux

4. Technical Presentation

Tiffany Inglis	Title : Multilevel image segmentation Abstract: A multilevel aggregation method is applied to the problem of segmenting live cell bright field microscope images. The method employed is a variant of the so-called `Segmentation by Weighted Aggregation' technique, which itself is based on Algebraic Multigrid methods. The variant of the method used is described in detail, and it is explained how it is tailored to the application at hand. In particular, a new scale-invariant `saliency measure' is proposed for deciding when aggregates of pixels constitute salient segments that should not be grouped further. It is shown how segmentation based on multilevel intensity similarity alone does not lead to satisfactory results for bright field cells. However, the addition of multilevel intensity variance (as a measure of texture) to the feature vector of each aggregate leads to correct cell segmentation. Preliminary results are presented for applying the multilevel aggregation algorithm in space-time to temporal sequences of microscope images, with the goal of obtaining space-time segments (`object tunnels') that track individual cells. The advantages and drawbacks of the space-time aggregation approach for segmentation and tracking of live cells in sequences of microscope images are presented, followed by a discussion of how this approach may be used in future work as a building block in a complete and robust segmentation and tracking system.

Tiffany Inglis

Title : Multilevel image segmentation
Abstract:
A multilevel aggregation method is applied to the problem of segmenting live cell bright field microscope images. The method employed is a variant of the so-called `Segmentation by Weighted Aggregation' technique, which itself is based on Algebraic Multigrid methods. The variant of the method used is described in detail, and it is explained how it is tailored to the application at hand. In particular, a new scale-invariant `saliency measure' is proposed for deciding when aggregates of pixels constitute salient segments that should not be grouped further. It is shown how segmentation based on multilevel intensity similarity alone does not lead to satisfactory results for bright field cells. However, the addition of multilevel intensity variance (as a measure of texture) to the feature vector of each aggregate leads to correct cell segmentation. Preliminary results are presented for applying the multilevel aggregation algorithm in space-time to temporal sequences of microscope images, with the goal of obtaining space-time segments (`object tunnels') that track individual cells. The advantages and drawbacks of the space-time aggregation approach for segmentation and tracking of live cells in sequences of microscope images are presented, followed by a discussion of how this approach may be used in future work as a building block in a complete and robust segmentation and tracking system.

5. Discussion Items

None so far...

6. Action Items

We need a new CGL poster to replace the ancient one.
Thurs Feb 25 lab tours
March break lab tours

7. Conferences and Special Journal Issues

Recent Additions

Upcoming Deadlines

Feb 24, 2010: PCG2010 Paper submission
Mar 01, 2010: GMP 2010 Camera ready paper
Mar 01, 2010: Bridges 2010 Workshop paper submissions

8. Directors' Meeting

9. Seminars and Events

    * 2010 Feb 17, 10:30 - Computer Science Seminar
      Rafae Bhatti, Oracle, U.S.A.
      Security and Privacy For Healthcare Applications: Does Policy mean Protection?
    * 2010 Feb 18, 13:00 - Computer Systems Group PhD Thesis Defence
      Rolando Maldonado Blanco, PhD candidate, David R. Cheriton School of Comp. Sci., Univ. Waterloo
      Process Models for Distributed Event-Based Systems
    * 2010 Feb 26, 13:30 - Cryptography, Security, and Privacy (CrySP) Group Seminar
      Rosario Gennaro (IBM Research)
      Non-Interactive Verifiable Computing: Outsourcing Computation to Untrusted Workers

Also see other Math and CS postings.