  We propose the use of Flat Metric to assess the performance of reconstruction
methods for single-molecule localization microscopy (SMLM) in scenarios where
the ground-truth is available. Flat Metric is intimately related to the concept
of optimal transport between measures of different mass, providing solid
mathematical foundations for SMLM evaluation and integrating both localization
and detection performance. In this paper, we provide the foundations of Flat
Metric and validate this measure by applying it to controlled synthetic
examples and to data from the SMLM 2016 Challenge.
