def get_qpimage_raw(self, idx=0):
        """Return QPImage without background correction"""
        # Load experimental data
        with SingleTifPhasics._get_tif(self.path) as tf:
            # page 0 contains intensity
            # page 1 contains phase in nm
            # page 2 contains phase in wavelengths
            # Intensity:
            inttags = tf.pages[0].tags
            imin = inttags["61243"].value
            imax = inttags["61242"].value
            isamp = inttags["max_sample_value"].value
            blc = INTENSITY_BASELINE_CLAMP
            inten = tf.pages[0].asarray() * (imax - imin) / isamp + imin - blc
            inten[inten < 0] = 0
            # Phase
            # The SID4Bio records two phase images, one in wavelengths and
            # one in nanometers. Surprisingly, these two phase images are
            # not derived from the same recording. The first image (pages[1])
            # (in wavelengths) matches the intensity image (pages[0]). The
            # second image (pages[2]) is recorded at a different time point.
            # Initially, I thought it would be best to compute the phase
            # directly from the measured value in nanometers (pages[2]) using
            # the known wavelength given by the qpformat user. However, since
            # phase and amplitude won't match up in that case, the wavelength
            # phase image (pages[1]) has to be used. Since phasics uses its own
            # wavelength (set by the user in the acquisition/extraction
            # software) which might be wrong, I decided to first compute
            # the phase in nanometers from tf.pages[1] using the phasics
            # wavelength and then proceed as before, computing the phase
            # in radians using the correct, user-given wavelength.
            wl_phasics = self._get_wavelength(self.path)
            if not np.isnan(wl_phasics):
                # proceed with phase in wavelengths
                phaid = 1
            else:
                # proceed with phase in nanometers
                phaid = 2
            phatags = tf.pages[phaid].tags
            pmin = phatags["61243"].value
            pmax = phatags["61242"].value
            psamp = phatags["max_sample_value"].value
            if psamp == 0 or pmin == pmax:
                # no phase data
                pha = np.zeros_like(inten)
            else:
                # optical path difference
                opd = tf.pages[phaid].asarray() * (pmax - pmin) / psamp + pmin
                if phaid == 1:  # convert [wavelengths] to [nm]
                    assert not np.isnan(wl_phasics)
                    opd *= wl_phasics * 1e9
                # convert from [nm] to [rad]
                pha = opd / (self.meta_data["wavelength"] * 1e9) * 2 * np.pi

        meta_data = copy.copy(self.meta_data)
        if "time" not in meta_data:
            meta_data["time"] = self.get_time()
        qpi = qpimage.QPImage(data=(pha, inten),
                              which_data="phase,intensity",
                              meta_data=meta_data,
                              h5dtype=self.as_type)
        # set identifier
        qpi["identifier"] = self.get_identifier()
        return qpi
Return QPImage without background correction