This is the header of the function vil_crop, in the file vil_crop.h:

//: Create a view which is a cropped version of src.
// Doesn't modify underlying data. O(1).
// \relates vil_image_view
// \return an n_i x n_j window of im with offset (x0,y0)
template<class T>
inline vil_image_view<T> vil_crop(const vil_image_view<T> &im, unsigned i0,
                                  unsigned n_i, unsigned j0, unsigned n_j)

Shouldn't the last documentation line end with "offset (i0, j0)"?

Crístian Deives dos Santos Viana [aka CD1]
Google Talk: cristiandeives@gmail.com