def _parse_calibration_files(self):
        """Build calibration table from dataset.
        Calibration details here:
        https://github.com/NVIDIA/DIGITS/blob/v4.0.0-rc.3/digits/extensions/data/objectDetection/README.md

        Returns
        -------
        calibration_table: dict, default: None
            Calibration table used for looking up sample-level calibration.
            >>> (K, pose_0S) = self.calibration_table[(calibration_key, datum_name)]

            Calibration key is string filename prefix. (i.e. 007431)
        """
        calibration_files = [
            os.path.join(self.root_dir, f"{MV3D_SPLIT_KITTI_3D_REMAP[self._mv3d_split]}", "calib", f"{sample}.txt")
            for sample in self._split
        ]

        with Pool(min(cpu_count(), 4)) as _proc:
            per_sample_calibrations = itertools.chain.from_iterable(
                (_proc.map(self._read_calibration_file, calibration_files))
            )

        return OrderedDict(per_sample_calibrations)
Build calibration table from dataset.
        Calibration details here:
        https://github.com/NVIDIA/DIGITS/blob/v4.0.0-rc.3/digits/extensions/data/objectDetection/README.md

        Returns
        -------
        calibration_table: dict, default: None
            Calibration table used for looking up sample-level calibration.
            >>> (K, pose_0S) = self.calibration_table[(calibration_key, datum_name)]

            Calibration key is string filename prefix. (i.e. 007431)
        
tridet/data/datasets/kitti_3d/build.py