radiometric_normalization是一个图形转换工具（normalizingacandidateimagetotime-invariantfeaturesinasetofreferenceimagescoveringatimeseries）。具有以下功能：generatingatime-invariantreferenceimagefromatimestackidentifyingfeatures calculatingalinearreference_image = time_stack.generate(    reference_paths,    method='