ExTrack parameter fitting. (a) 3D maps of the mean error on extracted parameters from simulations similar to those in Fig. 1, of two-state models with one immobile and one diffusive state as a function of diffusion length d^∗, unbinding rate k_u, and binding rate k_b. Errors are obtained from five replicates. Errors are indicated as absolute or relative errors, as indicated. ExTrack settings: no sub-steps, window length = 7. (b and c) Heat maps of mean relative error on extracted parameters from the same simulations as in Fig. 1, but inferred with no sub-steps. ExTrack settings: no sub-steps, window length = 10 (b) or 3 (c). (d) Computation time of ExTrack fitting module applied to 1,000 tracks of 100 positions each with 200 iterations (typical number of iterations needed for the fit of a two-state model) depending on the window length m (without sub-steps or with two sub-steps; left) or depending on the number of states N (without sub-steps; right), using seven cores of a Intel Core i7-9700 processor. For details see Materials and methods, Implementation and computation time.