Stochastic transfer function: application to fluorescence microscopy.

We develop the concept of the stochastic transfer function (STF) and its application to high-resolution fluorescence microscopy. The STF is directly related to the conventional optical transfer functions but incorporates a probability density function at each spatial frequency. The mean of the STF yields the conventional transfer function; the variance of the STF gives a measure of the noise associated at each spatial frequency. The STF thus provides a more complete picture of the microscope performance in comparison with conventional transfer functions. Here we present the STF for a wide-field fluorescent microscope using both Monte Carlo simulation and probability theory.