The properties of the phase-gradient algorithm for retrieving the Fourier phase from stellar speckle images are examined with respect to random image motion, centroiding, photon noise, and stray photons. The phase gradient is found to be immune to the degradation from image motion and distortions at low photon levels that occur in the Knox–Thompson process. The signal-to-noise ratios of the two methods are found to be comparable. Bias terms that are due to stray photons caused by background light or detector noise are derived.
© 1989 Optical Society of America
Original Manuscript: April 18, 1988
Manuscript Accepted: August 18, 1988
Published: January 1, 1989
R. Johnson and G. J. M. Aitken, "Statistical properties of the photon-address, phase-gradient algorithm," J. Opt. Soc. Am. A 6, 56-61 (1989)