Algorithm for dynamic Speckle pattern processing. (July 2016)

• Record Type: Journal Article
• Authors: Cariñe, J.; Guzmán, R.; Torres-Ruiz, F.A.
• Is Part Of: Optics and lasers in engineering. Volume 82(2016)
• Page Start: 56
• Page End: 61
• Publication Date: 2016-07
• Subjects: Laser speckle -- Processing speckle pattern -- Determination of surface activity; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2016.02.001
• Languages: English
• ISSNs: 0143-8166

Abstract

Abstract: In this paper we present a new algorithm for determining surface activity by processing speckle pattern images recorded with a CCD camera. Surface activity can be produced by motility or small displacements among other causes, and is manifested as a change in the pattern recorded in the camera with reference to a static background pattern. This intensity variation is considered to be a small perturbation compared with the mean intensity. Based on a perturbative method we obtain an equation with which we can infer information about the dynamic behavior of the surface that generates the speckle pattern. We define an activity index based on our algorithm that can be easily compared with the outcomes from other algorithms. It is shown experimentally that this index evolves in time in the same way as the Inertia Moment method, however our algorithm is based on direct processing of speckle patterns without the need for other kinds of post-processes (like THSP and co-occurrence matrix), making it a viable real-time method. We also show how this algorithm compares with several other algorithms when applied to calibration experiments. From these results we conclude that our algorithm offer qualitative and quantitative advantages over current methods. Abstract : Highlights: Our algorithm is suitable for real-time speckle interferometry. The computational implementation is fast and straightforward. Faster performance and comparable results with Inertia Moment based on THSP. Less computational resources demanding algorithm. Suitable for speckle field analysis among other applications.