Distance and size dependence of detections by different algorithm and parameter combinations for all 1385 OCs in all studied fields, plotted against the reported size and distance of the OCs in the literature. OC candidates not passing the criterion in Sect. 4.2 and with a CST of less than 3σ were discarded. HDBSCAN detects the most OCs, especially at nearby distances. GMMs only perform well at detecting well populated OCs. While individual DBSCAN results at different ϵ values do not detect especially many OCs, combining them all together nearly matches the performance of HDBSCAN – even exceeding it slightly at large distances.