Determining the velocity of a moving object from a series of photon-limited frames using a temporal Fourier transform

We propose a technique to obtain directly from a series of photon-limited frames, the spectrum of an object moving with constant velocity. Instead os averaging statistical functions as the auto or triple correlations or their Fourier transforms, our method averages the series of frame spectra once the phase factor due to the movement has been removed. Two different procedures to obtain this phase factor are studied: the temporal derivative of the spectrum logarithm and the temporal Fourier transform of the series of spatial spectra. The latter method involves a larger number of calculations but it produces much better results, especially when only a small number of frames are available. Finally, the recovery technique is checked for a simulated experiment in which a one-dimensional object is reconstructed from a short series of photon-limited frames.