Snakes: Active Contour Models - Banff International Research ...

Snakes: Active Contour Models - Banff International Research ...

Incorporating Global Information into Active Contour Models Anthony Yezzi Georgia Institute of Technology Snakes: Active Contour Models Snakes or Active Contours pose the segmentation as an energy minimization problem. Kass, Witkins & Terzopoulos. ESnake Eext dp Eint dp

C Initialization C Final Segmentation Local Minima One major drawback of Active Contour model is the tendency to get stuck in Local minima caused by subtle irrelevant edges and image features. Initialization

Final Segmentation Avoiding Local Minima Balloon Force: (Cohen) EBal Eds ds C Makes assumption about the initialization. Biased final segmentation result.

Region-based Energy: EReg inside C C Fin dA

( I in ) 2 outside C Fout dA 2 ( I ) out

Makes Strong assumptions about the image. Image Domain Global minimum of Edge-based Energy: EEdge ( s)ds C Global minimal path for open curves/geodesics. (Cohen & Kimmel) Not suitable for closed curves (Geodesic Active Contours used instead) Active Geodesics Region-based active contour

segmentation with a Global Edgebased Constraint Edge-based Segmentation Globally Optimal Geodesic Active Contours (GOGAC) Appleton B. and Talbot H. Introduce an artificial cut in the image domain and search for an optimal open geodesic with end points on either side of the cut. Test Image

GOGAC Propagating Fronts Purely Region-Based Segmentation Region-based energy minimization. Chan-Vese Model (Mumford-Shah special case) EReg

inside C ( I in ) 2 dA Initialization outside C ( I out ) 2 dA Final Segmentation Incorporating Region-based

Energy in Edge-based Segmentation Test Image Propagating Fronts Closed Curve with least Region-based Energy Saddle Points Associated Closed Curves Active Geodesics

Reverse roles of Source/saddle point Initialization away from object boundary Minimize the region-based energy and restrict evolution to a single local degree of freedom: translation of saddle point in the normal direction to the curve at that point. p EReg FRe g ds C Continuum of Closed geodesics 1/(|| I || 1)

Test Image Propagating Fronts Segmentation Region-based Evolution Move Saddlepoint New Source Propagating Fronts Segmentation after 3rd iteration

Segmentation after 2nd iteration Evolution (Left Ventricle Segmentation) Iterations 4 to 18 Right Ventricle Segmentation User can interact with the segmentation algorithm by adding poles and zeros, to attract and repel the contour towards desired edges.

Red X Additional Pole (Repeller) Green X Additional Zero (Attractor) Initial Right Ventricle Segmentation with Active Geodesics Segmentation after adding a repeller Final segmentation with 2 repellers and 1 attractor Cell Segmentation Active geodesic-based segmentation with three different initializations

Edge-based GOGAC segmentation for three different initializations Nuclei Segmentation Nuclei segmentation with same initialization as the previous slide Region-based Chan-Vese segmentation for nucleus segmentation

Recently Viewed Presentations

  • VWF Electronic Database 2002

    VWF Electronic Database 2002

    29 consanguineous families from Eastern Turkey having type 1 and type 3 VWD were supplied by Dr. J. Ingerslev, Denmark and Dr. T. Gürsel, Turkey. One patient was homozygous. Gene deletion exons 26-34 New mutation, decreased large multimers. Ware et...
  • Radioactive equations

    Radioactive equations

    Mole Maze. Stoichiometry. Learning Target: I can work in pairs to practice stoichiometry problems through a calculation maze. February 26, 2018. Do Now (4 min) Learning target: I can work in pairs to practice stoichiometry problems through a calculation maze.
  • BIRTH  2013 The McGraw-Hill Companies, Inc. All rights

    BIRTH 2013 The McGraw-Hill Companies, Inc. All rights

    Late first stage (transition stage) - Cervix is fully dilated and the amniotic sac has ruptured, releasing amniotic fluid. Second stage - Birth of the infant. ... Mother adjusts physically and psychologically to process of childbearing. Lasts about six weeks.
  • Tiny House - fcs246 Visual Communication for Interior Design

    Tiny House - fcs246 Visual Communication for Interior Design

    -seating area use a drop down table to create an eating area-Be sure to add wheels or felt to the legs of. furniture for mobility
  • Session 6: Major and Minor Changes

    Session 6: Major and Minor Changes

    Corporate body as uniform title qualifier. ... Serials issued in multiple languages often change the order of the titles so that no one language predominates. In most cases, such changes are considered to be minor and a note may be...
  •  Tim,  My mums birthday is 13th July. Lilys

    Tim, My mums birthday is 13th July. Lilys

    Unit title: 爱好 Hobbies LO: Learn the words for some hobbies Talk about what you do and don't do in your free time Use the correct sentence structure with time phrases Hobbies 爱好 ài hào Hobbies 看书 kàn shū 看...
  • Éthique et communication avec les personnes âgées

    Éthique et communication avec les personnes âgées

    Bande dessinée destinée aux novices afin de les sensibiliser aux difficultés éthiques et aux risques de violence dans les soins des personnes âgées et de leur faire réaliser la nécessité de mieux répondre à leurs besoins fondamentaux et de leur...
  • Editorial Speeches - Mrs. Baione-Doda's English Classes

    Editorial Speeches - Mrs. Baione-Doda's English Classes

    Editorial speeches. Your primary purpose is to persuade! Take a stand on an issue. If you cannot take a clear stand, you do not have a good editorial. ... Step 3: Outline Your Supporting Ideas. Consider the opposition's argument to...