The OPERA experiment, designed to conclusively prove the existence of νμ→ντ oscillations in the atmospheric sector, makes use of a massive lead-nuclear emulsion target to observe the appearance of ντ's in the CNGS νμ beam. The location and analysis of the neutrino interactions in quasi real-time required the development of fast computer-controlled microscopes able to reconstruct particle tracks with sub-micron precision and high efficiency at a speed of ∼20 cm2/h. This paper describes the performance in particle track reconstruction of theEuropean Scanning System, a novel automatic microscope for the measurement of emulsion films developed for OPERA.