Selection Dialog
================
.. index:: Selection Dialog

The `Selection Dialog` selects a region based on a given threshold value or method.
The `Method` and `Comparison` combo-boxes selects the method for creating the thresholding value and
to compare the data to it.
As an example, if the `Method` produces a value of 1 and the `Comparison` is '>' then all values greater
than 1 will be selected.

Checking `Limit selection to current selection` will select the intersection (:math:`A \cap B`)
with the previously selected area.

Checking `Limit thresholding to selected value` will pass only currently selected values
to the thresholding method.

.. figure:: ../images/tutorial_selection_otsu.png
    :width: 400px
    :align: center

    Extraction of tissue from background using the `Selection Dialog` and Otsu's method.

.. seealso::
   :ref:`Example: Mean of a region`.
    Example using selections.