.. _`Filter image`:

.. _`syip.general_filters`:

Filter image
~~~~~~~~~~~~

.. image:: image_filtering.svg
   :width: 48


Applies simple filtering or scaling algorithms on an image. For more complex operations see the more specialized image manipulation nodes

:Algorithms:


  - *abs*

    Computes absolute value or complex magnitude of image


  - *angle*

    Gives the phase angle of a complex image


  - *center image*

    Shifts image so that center of mass lies in center of image


  - *clamp*

    Restricts the output values to a given maximum/minimum

    **minimum:**
      The minimum output value that can be passed through

    **maximum:**
      The maximum output value that can be passed through


  - `gaussian`_

    Two-dimensional Gaussian filter

    **sigma-x:**
      Standard deviation of gaussian filter along X-axis

    **sigma-y:**
      Standard deviation of gaussian filter along Y-axis

    **border mode:**
      Determines how the array borders are handled

    **k:**
      Value outside image borders when method constant is used.


  - `hessian determinant`_

    Computes an approximation of the determinant of the hessian matrix for each pixel.

    **sigma:**
      Standard deviation of gaussian kernel (default 3.0) used for calculating Hessian.

      Approximation is not reliable for sigma < 3.0


  - *imag*

    Gives the imaginary part of a complex image


  - `integral image`_

    Creates the integral image of the input.

    An integral image contains at coordinate (m,n) the sum of all values above and to the left of it.

       S(m,n) = sum(im[0:m, 0:n])


  - *normalize*

    Adds a (positive) scale and offset so that smallest/highest value in image becomes 0 and 1 respectively.

     Operates on each channel separately

    **minimum:**
      Minimum value after normalization

    **maximum:**
      Maximum value after normalization


  - *real*

    Gives the real valued part of a complex image


  - *scale/offset*

    Adds a scale and/or an offset to each channel equally

    **scale:**
      Scale factor applied to image before offset

    **offset:**
      Offset applied to image after scale


  - *to integer*

    Converts all channels into integer data


.. _gaussian: http://scikit-image.org/docs/0.13.x/api/skimage.filters.html#skimage.filters.gaussian
.. _hessian determinant: http://scikit-image.org/docs/0.13.x/api/skimage.feature.html#skimage.feature.hessian_matrix_det
.. _integral image: http://scikit-image.org/docs/0.13.x/api/skimage.feature.html#skimage.feature.hessian_matrix_det

: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)
    **scale**
        (no description)
    **k**
        (no description)
    **sigma-y**
        (no description)
    **sigma-x**
        (no description)
    **maximum**
        (no description)
    **border mode**
        (no description)
    **minimum**
        (no description)
    **offset**
        (no description)
    **sigma**
        (no description)

.. automodule:: node_general_filters

.. class:: GeneralImageFiltering