Optimising and comparing source-extraction tools using objective segmentation quality criteria Caroline Haigh, Nushkia Chamba, Aku Venhola, Reynier Peletier, Lars Doorenbos, Matthew Watkins and Michael H. F. Wilkinson A&A, 645 (2021) A107 Published online: 22 January 2021 DOI: 10.1051/0004-6361/201936561