Context : Small-scale magnetic fields in the solar photosphere can be identified in high-resolution magnetograms or in the G-band as magnetic bright points ( MBPs ) .
Rapid motions of these fields can cause magneto-hydrodynamical waves and can also lead to nanoflares by magnetic field braiding and twisting .
The MBP velocity distribution is a crucial parameter for estimating the amplitudes of those waves and the amount of energy they can contribute to coronal heating .

Aims : The velocity and lifetime distributions of MBPs are derived from solar G-band images of a quiet sun region acquired by the Hinode/SOT instrument with different temporal and spatial sampling rates .

Methods : We developed an automatic segmentation , identification and tracking algorithm to analyse G-Band image sequences to obtain the lifetime and velocity distributions of MBPs .
The influence of temporal/spatial sampling rates on these distributions is studied and used to correct the obtained lifetimes and velocity distributions for these digitalisation effects .

Results : After the correction of algorithm effects , we obtained a mean MBP lifetime of ( 2.50 \pm 0.05 ) min and mean MBP velocities , depending on smoothing processes , in the range of ( 1 - 2 ) \mathrm { km~ { } s ^ { -1 } } .
Corrected for temporal sampling effects , we obtained for the effective velocity distribution a Rayleigh function with a coefficient of ( 1.62 \pm 0.05 ) \mathrm { km~ { } s ^ { -1 } } .
The x - and y - components of the velocity distributions are Gaussians .
The lifetime distribution can be fitted by an exponential function .

Conclusions :