I am using the IPP (3.0) rotate and resize functions and have wondered about the specific implementation of the IPP_INTER_SUPER supersampling mode. What pixel neighbourhoods are used for computing the output pixel, and is for an e.g. resize operation the interpolation dependent on the resize factors?
Take downsizing an image as an example: if the original image was sampled according to the Nyquist condition, correctly downsizing it would really require a spatial lowpass filter (to avoid aliasing) prior to interpolation. This could be implemented by evaluating a pixel neighbourhood and using pixel weights based on the distance from the sample location to each contributing pixel. For larger neighbourhoods this would probably be a costly operation, but it would permit to implement an arbitrary spatial frequency transfer function of the lowpass.
But perhaps "supersampling interpolation" means something quite different after all...
Thanks for all replies,