Method and apparatus for detecting low light levels

This application relates in general to measurement and sensing of low power signals. More particularly, the invention relates to the sensing, amplification and measurement of a low power, light-based signal. A method and apparatus for measuring very low light signals including integrating a signal from a photo diode, avalanche photo diode, photomultiplier tube or the like, digitally sampling the integrator output more than two times during each integration period, fitting a curve to the multiple digitized readings to calculate the integration slope for each integration period and determining the original signal from the calculated integration slope.