add ability to retrieve ROI names in a case insensitive way

[raffaelespinoni]

No description provided.

[raffaelespinoni]

issue targeted by the PR: link

[awtkns]

Thanks for this @raffaelespinoni!

@asim-shrestha this LGTM! I added a couple tests for this, one of which is currently failing until my comment below is resolved (NPE issue).

[awtkns]

    def get_roi_mask_by_name(self, name: str) -> np.ndarray:
        """
        Returns the 3D binary mask of the ROI with the given input name
        """
        name = name.casefold() if type(name) is str else name

        for structure_roi in self.ds.StructureSetROISequence:
            if structure_roi.ROIName.casefold() == name:
                contour_sequence = ds_helper.get_contour_sequence_by_roi_number(
                    self.ds, structure_roi.ROINumber
                )
                return image_helper.create_series_mask_from_contour_sequence(
                    self.series_data, contour_sequence
                )

        raise RTStruct.ROIException(f"ROI of name `{name}` does not exist in RTStruct")

It may be safer to check that name is not none before calling .casefold() as shown above.

[asim-shrestha]

We should make this an optional function in get_roi instead of the default. I imagine there may be other existing rt_structs that are sensitive in regards to naming. Do we know if thats allowed by the dicom standards?

[awtkns]

@asim-shrestha thoughts on either merging this or closing?