  Imaging atmospheric Cherenkov telescopes, such as the VERITAS array, are
subject to the Night Sky Background (NSB) and electronic noise, which
contribute to the total signal of pixels in the telescope camera. The
contribution of noise photons in event images is reduced with the application
of image cleaning methods. Conventionally, high thresholds must be employed to
ensure the removal of pixels containing noise signal. On that account,
low-energy gamma-ray showers might be suppressed during the cleaning. We
present here the application of an optimised next neighbour image cleaning for
the VERITAS array. With this technique, differential noise rates are estimated
for each individual observation and thus changes in the NSB and afterpulsing
are consistently being accounted for. We show that this method increases the
overall rate of reconstructed gamma-rays, lowers the energy threshold of the
array and allows the reconstruction of low energy (E > 70 GeV) source events
which were suppressed by the conventional cleaning method.
