def _Pcn_crp(x, dsz, Nv, dimN=2, dimC=1):
    """
    Projection onto dictionary update constraint set: support
    projection and normalisation. The result is cropped to the
    support of the largest filter in the dictionary.

    Parameters
    ----------
    x  : array_like
       Input array
    dsz : tuple
      Filter support size(s), specified using the same format as the
      `dsz` parameter of :func:`bcrop`
    Nv : tuple
      Sizes of problem spatial indices
    dimN : int, optional (default 2)
      Number of problem spatial indices
    dimC : int, optional (default 1)
      Number of problem channel indices

    Returns
    -------
    y : ndarray
      Projection of input onto constraint set
    """

    return normalise(bcrop(x, dsz, dimN), dimN + dimC)