The use of laser speckle for displacement and deformation measurement has found wide applications in mechanics and metrology. Traditionally, a deterministic approach has been adopted to analyze the process. In this paper a statistical approach is utilized, resulting in a better understanding of the limitations and potentials of one-beam subjective laser-speckle interferometry (or speckle photography). We find that the amplitude modulation of the information-carrying cosine fringes is controlled by three factors: a decorrelation factor γ, a displacement factor Ω, and a displacement-gradient factor ψ. We introduce the concept of an ambiguity factor that sets a critical value for the product γΩψ. We then propose a criterion for fringe discernibility from which the upper limit of measurement is established.
© 1985 Optical Society of America
D. W. Li, J. B. Chen, and F. P. Chiang, "Statistical analysis of one-beam subjective laser-speckle interferometry," J. Opt. Soc. Am. A 2, 657-666 (1985)