Specifications

Geometric Transforms
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Internally, all geometric transformation functions handle regions of interest
(ROIs) with the following sequence of operations:
• transform the rectangular ROI of the source image to a quadrangle in
the destination image
• find the intersection of this quadrangle and the rectangular ROI of the
destination image
• update the destination image in the intersection area, taking into
account mask images (if any).
The source and destination images must be different; that is, in-place
operations are not supported. The coordinates in the source and destination
images must have the same origin.
Most of the geometric transformation functions have to interpolate the
pixel values of the source image in order to compute the pixel values of the
destination image. The Image Processing Library supports several
interpolation algorithms. For more information on the algorithms supported
in the library, see Appendix B.
Changing the Image Size
This section describes the functions that scale the input image in the x-or
y-directions, without changing the image orientation.
These functions perform image resampling by using various kinds of
interpolation algorithms: nearest neighbor, linear interpolation, cubic
interpolation, and super-sampling.