.. auto-generated by script ../../../../utils/nxdl2rst.py from the NXDL source NXdistortion.nxdl.xml

.. index::
    ! NXdistortion (base class)
    ! distortion (base class)
    see: distortion (base class); NXdistortion

.. _NXdistortion:

============
NXdistortion
============

**Status**:

  base class, extends :ref:`NXobject`

**Description**:

  Subclass of NXprocess to describe post-processing distortion correction.

**Symbols**:

  The symbols used in the schema to specify e.g. dimensions of arrays

  **nsym**: Number of symmetry points used for distortion correction

  **ndx**: Number of points of the matrix distortion field (x direction)

  **ndy**: Number of points of the matrix distortion field (y direction)

**Groups cited**:
  none

**Structure**:

  .. _/NXdistortion/last_process-field:

  .. index:: last_process (field)

  **last_process**: (optional) :ref:`NX_CHAR <NX_CHAR>`

    Indicates the name of the last operation applied in the NXprocess sequence.

  .. _/NXdistortion/applied-field:

  .. index:: applied (field)

  **applied**: (optional) :ref:`NX_BOOLEAN <NX_BOOLEAN>`

    Has the distortion correction been applied?

  .. _/NXdistortion/symmetry-field:

  .. index:: symmetry (field)

  **symmetry**: (optional) :ref:`NX_INT <NX_INT>` {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}

    For `symmetry-guided distortion correction`_,
    where a pattern of features is mapped to the regular geometric structure
    expected from the symmetry. Here we record the number of elementary symmetry
    operations.

       .. _symmetry-guided distortion correction: https://www.sciencedirect.com/science/article/abs/pii/S0304399118303474?via%3Dihub

  .. _/NXdistortion/original_centre-field:

  .. index:: original_centre (field)

  **original_centre**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` (Rank: 1, Dimensions: [2]) {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}

    For symmetry-guided distortion correction. Here we record the coordinates of the
    symmetry centre point.

  .. _/NXdistortion/original_points-field:

  .. index:: original_points (field)

  **original_points**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` (Rank: 2, Dimensions: [nsym, 2]) {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}

    For symmetry-guided distortion correction. Here we record the coordinates of the
    relevant symmetry points.

  .. _/NXdistortion/cdeform_field-field:

  .. index:: cdeform_field (field)

  **cdeform_field**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` (Rank: 2, Dimensions: [ndx, ndy]) {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}

    Column deformation field for general non-rigid distortion corrections. 2D matrix
    holding the column information of the mapping of each original coordinate.

  .. _/NXdistortion/rdeform_field-field:

  .. index:: rdeform_field (field)

  **rdeform_field**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` (Rank: 2, Dimensions: [ndx, ndy]) {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}

    Row deformation field for general non-rigid distortion corrections. 2D matrix
    holding the row information of the mapping of each original coordinate.

  .. _/NXdistortion/description-field:

  .. index:: description (field)

  **description**: (optional) :ref:`NX_CHAR <NX_CHAR>`

    Description of the procedures employed.


Hypertext Anchors
-----------------

List of hypertext anchors for all groups, fields,
attributes, and links defined in this class.


* :ref:`/NXdistortion/applied-field </NXdistortion/applied-field>`
* :ref:`/NXdistortion/cdeform_field-field </NXdistortion/cdeform_field-field>`
* :ref:`/NXdistortion/description-field </NXdistortion/description-field>`
* :ref:`/NXdistortion/last_process-field </NXdistortion/last_process-field>`
* :ref:`/NXdistortion/original_centre-field </NXdistortion/original_centre-field>`
* :ref:`/NXdistortion/original_points-field </NXdistortion/original_points-field>`
* :ref:`/NXdistortion/rdeform_field-field </NXdistortion/rdeform_field-field>`
* :ref:`/NXdistortion/symmetry-field </NXdistortion/symmetry-field>`

**NXDL Source**:
  https://github.com/nexusformat/definitions/blob/main/base_classes/NXdistortion.nxdl.xml