def nonzero_pixels(self):
        """ Return an array of the nonzero pixels.

        Returns
        -------
        :obj:`numpy.ndarray`
             Nx2 array of the nonzero pixels
        """
        nonzero_px = np.where(np.sum(self.raw_data, axis=2) > 0)
        nonzero_px = np.c_[nonzero_px[0], nonzero_px[1]]
        return nonzero_px