.. _`Threshold image`:

.. _`syip.threshold`:

Threshold image
~~~~~~~~~~~~~~~

.. image:: image_threshold.svg
   :width: 48


Applies a threshold to an image giving a boolean output

:Algorithms:


  - `adaptive`_

    Applies an adaptive threshold to an array.



    Also known as local or dynamic thresholding where the threshold value is the weighted mean for the local neighborhood of a pixel subtracted by a constant.

    **threshold method:**
      Method used for calculating adaptive threshold

    **kernel size:**
      Size of blocks used during threshold check.

      Must be an odd number. (default 3)

    **offset:**
      Constant subtracted from weighted mean of neighborhood to calculate the local threshold value. (default 0.0)

    **sigma:**
      Standard deviation of gaussian kernel when method gaussian is used.


  - `automatic`_

    Performs global thresholding based a selection of automatic algorithms with none or few parameters

    **auto threshold method:**
      Method used for calculating threshold


  - *basic*

    Compares each channel with a threshold

    **threshold:**
      Threshold value to compare with


.. _adaptive: http://scikit-image.org/docs/0.13.x/api/skimage.filters.html#skimage.filters.threshold_local
.. _automatic: http://scikit-image.org/docs/0.13.x/api/skimage.filters.html

:Inputs:
    **source** : image

        source image to filter

:Outputs:
    **result** : image

        result after filtering

*Ports*:

    **Inputs**:

        :source: image

            source image to filter

    **Outputs**:

        :result: image

            result after filtering

*Configuration*:

    **algorithm**
        (no description)
    **threshold method**
        (no description)
    **auto threshold method**
        (no description)
    **offset**
        (no description)
    **threshold**
        (no description)
    **kernel size**
        (no description)
    **sigma**
        (no description)

.. automodule:: node_threshold

.. class:: ThresholdImage