def extract_slitlet2d(self, image_2k2k):
        """Extract slitlet 2d image from image with original EMIR dimensions.

        Parameters
        ----------
        image_2k2k : numpy array
            Original image (dimensions EMIR_NAXIS1 * EMIR_NAXIS2)

        Returns
        -------
        slitlet2d : numpy array
            Image corresponding to the slitlet region defined by its
            bounding box.

        """

        # protections
        naxis2, naxis1 = image_2k2k.shape
        if naxis1 != EMIR_NAXIS1:
            raise ValueError('Unexpected naxis1')
        if naxis2 != EMIR_NAXIS2:
            raise ValueError('Unexpected naxis2')

        # extract slitlet region
        slitlet2d = image_2k2k[(self.bb_ns1_orig - 1):self.bb_ns2_orig,
                               (self.bb_nc1_orig - 1):self.bb_nc2_orig]

        # transform to float
        slitlet2d = slitlet2d.astype(np.float)

        # display slitlet2d with boundaries and middle spectrum trail
        if abs(self.debugplot) in [21, 22]:
            self.ximshow_unrectified(slitlet2d)

        # return slitlet image
        return slitlet2d