>Psychtoolbox>PsychGLImageProcessing

AddImageUndistortionToGLOperator(gloperator, exampleImage, calibrationStructureOrFile [, showCalibOutput=0][, varargin])

Add a geometric undistortion operation to a given imaging pipeline image
processing operator ‘gloperator’. ‘gloperator’ is the operator to add to.
‘exampleImage’ is a texture- or offscreen window handle to a texture or
offscreen window which has exactly the color depths and size of the input
images you want to geometrically undistort (and scale) later on. The
created operator will be adapted to only work correctly on input images
of that size! ‘calibrationStructureOrFile’ Either the file name to a
geometric calibration file, as created by, e.g.,
DisplayUndistortionBezier.m or DisplayUndistortionBVL.m, or a struct with
the neccessary information as created, e.g., by CreateDisplayWarp().
‘showCalibOutput’ optional flag: If set to non-zero value, the routine
will plot some debug output to the console or into figure windows.
‘varargin’ may contain optional parameters that will be passed to the
routine CreateDisplayWarp() as optional arguments (see help
CreateDisplayWarp)).

This routine can be used if you have geometrically distorted images from
some source (movie file, video capture, etc.), given as textures or
offscreen windows. It allows to define an operator that applies some
geometric correction to that images and returns corrected versions of
that images.

A typical way of using this:

a) Create an “undistortion definition file” by use of the interactive
display calibration routines, e.g., DisplayUndistortionBezier.m or
DisplayUndistortionBVL.m, and save it somewhere.

b) In your script, call this routine, passing the filename of that
calibration file, and an ‘exampleImage’ of the size and format of the
input images to undistort, to create a suitable gloperator.

c) In your code, apply the operator to distorted images by use of the
Screen(‘TransformTexture’) function, e.g.:

correctedImage = Screen(‘TransformTexture’, distortedImage, gloperator);

An example of this procedure can be seen in the demo
“ImageUndistortionDemo”.