getRectSubPix and borderInterpolate in OpenCV

Question

The documentation for OpenCVs getRectSubPix() function:

C++: void getRectSubPix(InputArray image, Size patchSize, 
Point2f center, OutputArray patch, int patchType=-1 )

contains the statement:

While the center of the rectangle must be inside the image, parts of the rectangle may be outside. In this case, the replication border mode (see borderInterpolate() ) is used to extrapolate the pixel values outside of the image.

But I can't see a way to set the borderInterpolate mode in getRectSubPix. Many other OpenCV functions (boxFilter, copyMakeBorder, ...) allow you to pass in the borderInterpolate enum, but not getRectSubPix.

Is this just a documentation error?

Answer 1

The statement "replication border mode (see borderInterpolate() ) is used to extrapolate the pixel values", clearly states that it uses a predefined mode known as BORDER_REPLICATE to estimate the pixels outside the image boundary, You cannot use other Border methods like BORDER_REFLECT, BORDER_WRAP, BORDER_CONSTANT, etc.