.. _`Perspective Transform`:

.. _`com.sympathyfordata.imageanalysis.perspective_transform`:

Perspective Transform
`````````````````````

.. image:: image_perspective_transform.svg
   :width: 48


Performs a perspective transform in an image by mapping four points (atleast 3 non-colinear) in the input image to specific corresponding points in the output image




Documentation
:::::::::::::

Performs a perspective transform in an image by mapping four points
(atleast 3 non-colinear) in the input image to specific corresponding
points in the output image.

The input table should have exactly four rows and four columns. Two of
the columns give the XY coordinates of an input point and the other two
columns the corresponding point in the output image.

The result is an image after applying the perspective transform implied by
the given points.


Definition
::::::::::


Input ports
...........

    **image**  image
        image to transform

    **coords**  table
        Table mapping four coordinates


Output ports
............

    **result**  image
        Result




Configuration
.............

    **X column after** (xafter)
        Column containing X coordinates after transform
    **X column before** (xbefore)
        Column containing X coordinates before transform
    **Y column after** (yafter)
        Column containing Y coordinates after transform
    **Y column before** (ybefore)
        Column containing Y coordinates before transform









Implementation
..............

.. automodule:: node_perspective
    :noindex:

.. class:: PerspectiveTransform
    :noindex: