We consider the general problem of the quantum noise in a multipixel measurement of an optical image. We first give a precise criterium in order to characterize intrinsic single mode and multimode light. Then, using a transverse mode decomposition, for each type of possible linear combination of the pixels' outputs we give the exact expression of the detection mode, i.e. the mode carrying the noise. We give also the only way to reduce the noise in one or several simultaneous measurements.
@article{arxiv.quant-ph/0407246,
title = {Quantum Noise in Multipixel Image Processing},
author = {Nicolas Treps and Vincent Delaubert and Agnes Maitre and Jean-Michel Courty and Claude Fabre},
journal= {arXiv preprint arXiv:quant-ph/0407246},
year = {2009}
}