.. _`Edge detection`:

.. _`syip.edge_detection`:

Edge detection
~~~~~~~~~~~~~~

.. image:: image_edges.svg
   :width: 48


Detects edges in the incoming image

*Algorithms*:


  - `canny`_

    Canny edge detection.

    **sigma:**
      Standard deviation of gaussian kernel (default 1.0)


  - `laplace`_

    Find edges using the Laplace operator.

    **kernel size:**
      Kernel size of the discrete Laplacian operator


  - `prewitt`_

    Find edges using the Prewitt transform as one of, or combination of horizontal and vertical prewitt convolutions

    **horizontal/vertical:**
      Select orientation for transform, if both then mean square of both will be used


  - `roberts`_

    Find edges using Robert's cross operator.

    **positive/negative diagonal:**
      Select orientation for transform


  - `scharr`_

    Find edges using the Scharr transform as one of, or combination of horizontal and vertical prewitt convolutions.

    The Scharr operator has a better rotation invariance than other edge filters such as the Sobel or the Prewitt operators

    **horizontal/vertical:**
      Select orientation for transform, if both then mean square of both will be used


  - `sobel`_

    Find edges using the Sobel transform as one of, or combination of horizontal and vertical prewitt convolutions.

    **horizontal/vertical:**
      Select orientation for transform, if both then mean square of both will be used


.. _canny: http://scikit-image.org/docs/0.13.x/api/skimage.feature.html#skimage.feature.canny
.. _laplace: http://scikit-image.org/docs/0.13.x/api/skimage.filters.html#skimage.filters.laplace
.. _prewitt: http://scikit-image.org/docs/0.13.x/api/skimage.filters.html#skimage.filters.prewitt_h
.. _roberts: http://scikit-image.org/docs/0.13.x/api/skimage.filters.html#skimage.filters.roberts_pos_diag
.. _scharr: http://scikit-image.org/docs/0.13.x/api/skimage.filters.html#skimage.filters.scharr_h
.. _sobel: http://scikit-image.org/docs/0.13.x/api/skimage.filters.html#skimage.filters.sobel_h

*Input ports*:
    **source** : image

        source image to filter

*Output ports*:
    **result** : image

        result after filtering



*Configuration*:
    **Algorithm** (algorithm)
        (no description)
    **horizontal/vertical** (horizontal/vertical)
        (no description)
    **kernel size** (kernel size)
        (no description)
    **positive/negative diagonal** (positive/negative diagonal)
        (no description)
    **sigma** (sigma)
        (no description)

.. automodule:: node_detection_filters

.. class:: EdgeDetection