Returns:
            pandas.DataFrame: Output a dataframe with regions and region sizes

def get_measured_regions(self):
        """
        Returns:
            pandas.DataFrame: Output a dataframe with regions and region sizes
        """
        mergeon = ['project_id','project_name',
                'sample_id','sample_name',
                'frame_id','frame_name',
                ]
        temp = self.loc[:,mergeon+['regions']].\
            set_index(mergeon)['regions'].apply(json.dumps).\
            reset_index().drop_duplicates()
        temp['regions'] = temp['regions'].apply(json.loads)
        rows = []
        for i,r in temp.iterrows():
            for label in r['regions']:
                a = list(r.index)
                b = list(r.values)
                a = a+['region_label','region_area_pixels']
                b = b+[label,r['regions'][label]]
                rows.append(dict(zip(a,b)))
        rows = pd.DataFrame(rows).drop(columns='regions').\
            drop_duplicates()[mergeon+['region_label','region_area_pixels']]
        #rows = rows.loc[rows['region_area_pixels']>0].copy()
        return rows