%GETRECTSUBPIX  Retrieves a pixel rectangle from an image with sub-pixel accuracy
%
%     dst = cv.getRectSubPix(src, patchSize, center)
%     dst = cv.getRectSubPix(..., 'OptionName',optionValue, ...)
%
% ## Input
% * __src__ Source image, 8-bit integer or 32-bit floating-point, 1- or
%   3-channels.
% * __patchSize__ Size of the extracted patch `[w,h]`.
% * __center__ Floating-point coordinates of the center of the extracted
%   rectangle within the source image. The center `[x,y]` must be inside the
%   image.
%
% ## Output
% * __dst__ Extracted patch that has the size `PatchSize`, the same number of
%   channels as `src`, and the specified type in `PatchType`.
%
% ## Options
% * __PatchType__ Depth of the extracted pixels. By default (-1), they have
%   the same depth as `src`. Supports either `uint8` or `single`.
%
% The function cv.getRectSubPix extracts pixels from `src`:
%
%     dst(x,y) = src(x + center(1) - (size(dst,2)-1)*0.5,
%                    y + center(2) - (size(dst,1)-1)*0.5)
%
% where the values of the pixels at non-integer coordinates are retrieved
% using bilinear interpolation. Every channel of multi-channel images is
% processed independently. Also the image should be a single channel or three
% channel image. While the center of the rectangle must be inside the image,
% parts of the rectangle may be outside. In this case, the pixel values
% outside of the image are extrapolated.
%
% See also: cv.Rect.crop, cv.warpAffine, cv.warpPerspective
%
