  In atmospheric \v{C}erenkov technique $\gamma-$rays are detected against
abundant background produced by hadronic showers. In order to improve signal to
noise ratio of the experiment, it is necessary to reject a significant fraction
of hadronic showers. The temporal and spectral differences, the lateral
distributions and density fluctuations of \v{C}erenkov photons generated by
$\gamma-$ray and hadron primaries are often used for this purpose. Here we
study the differences in \v{C}erenkov photon density fluctuations at the
observation level based on Monte Carlo simulations. Various types of density
fluctuations like the short range (or local), medium range fluctuations and
flatness parameter are studied. The estimated quality factors reflect the
efficiencies with which the hadrons can be rejected from the data. It has been
found that we can reject around 80% of proton showers while retaining about 70%
of $\gamma-$ray showers in the data, based only on the differences in the
flatness parameter. Density fluctuations particularly suited for wavefront
sampling observations seem to be a good technique to improve the signal to
noise ratio.
