.. _`Active contour segmentation`:

.. _`com.sympathyfordata.imageanalysis.active_contours`:

Active contour segmentation
```````````````````````````

.. image:: image_active_contour.svg
   :width: 48


Takes a starting contour (snake) and uses active contours to
optimise its shape. Takes a table(s) with coordinates of the initial contour, returns a table(s) with coordinates of optimised contour.





Definition
::::::::::


Input ports
...........

    **source**  image
        Source image

    **contours**  table
        Starting contour


Output ports
............

    **result**  table
        Resulting contour




Configuration
.............

    **X or R column** (X)
        Column names with contour X coordinates
    **Y or C column** (Y)
        Column names with contour Y coordinates
    **Length parameter** (alpha)
        Snake length shape parameter. Higher values makes snake contract faster.
    **Smoothness parameter** (beta)
        Snake smoothness shape parameter. Higher values makes snake smoother.
    **Boundary condition** (boundary_condition)
        Boundary conditions for worm (first and last point). Periodic attaches the two ends, fixed holds them in place and free allows them to move.
    **Convergence** (convergence)
        Convergence criteria.
    **Coordinates type** (coordinates)
        Coordinate tpes for the input columns
    **Gamma parameter** (gamma)
        Controls attraction to edges. Use negative values to repel snake from edges.
    **Max iterations** (max_iterations)
        Maximum number of iterations
    **Max move** (max_px_move)
        Maximum distance in number of pixels to move per iteration.
    **Edge parameter** (w_edge)
        Controls attraction to edges. Use negative values to repel snake from edges.
    **Brightness parameter** (w_line)
        Controls attraction to brightness. Use negative values to attract to dark regions.







Examples
........

* :download:`Snake_contours.syx </Examples/Image Analysis/Snake_contours.syx>`




Implementation
..............

.. automodule:: node_contours
    :noindex:

.. class:: ActiveContourSegmentation
    :noindex: