  The Electron Multiplying Charge Coupled Devices (EMCCD), owing to their high
quantum efficiency and spatial resolution, are widely used to study typical
quantum optical phenomena and related applications. Researchers have already
developed a procedure that enables one to statistically determine whether a
pixel detects a single photon, based on whether its output is higher or lower
than the estimated noise level. However, these techniques are feasible at
extremely low photon numbers (about 0.15 mean number of photons per pixel per
exposure), allowing for at most one photon per pixel. This limitation
necessitates a very large number of frames required for any study. In this
work, we present a method to estimate the mean rate of photons per pixel per
frame for arbitrary exposure time. Subsequently, we make a statistical estimate
of the number of photons (greater than or equal to 1) incident on each pixel.
This allows us to effectively utilize the EMCCD as a photon number resolving
device. This immediately augments the acceptable light levels in the
experiments, leading to significant reduction in the required experimentation
time. As evidence of our approach, we quantify contrast in quantum correlation
exhibited by a pair of spatially entangled photons generated by Spontaneous
Parametric Down Conversion process. In comparison to conventional methods, our
method realizes an enhancement in the signal to noise ratio by about a factor
of 3 for half the data collection time. This SNR can be easily enhanced by
minor modifications in experimental parameters such as exposure time etc.
