title: Optimal re-referencing rate for in-plane dynamic speckle interferometry.
abstract: We investigate experimentally the optimal rate at which the reference speckle pattern should be updated when dynamic speckle interferometry is used to measure transient in-plane displacement fields. Images are captured with a high-speed camera and phase shifting and phase unwrapping are done temporally. For a wide range of in-plane velocities, up to a maximum of 40% of the Nyquist limit, the random errors in the calculated displacement field are minimized by updating the reference speckle pattern after a speckle displacement of 1/10 of the pixel spacing. The technique is applied to measurements of microscale deformation fields within an adhesive joint in a carbon-fiber epoxy composite.
authors.affiliation: Luleå University of Technology, Division of Experimental Mechanics, 97187 Luleå, Sweden.
authors.forename: Angelica
authors.initials: A
authors.lastname: Svanbro
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Huntley
authors.forename: Abundio
authors.initials: A
authors.lastname: Davila