Automatic Fringe Analysis (FRAN)

FRAN (Fringe Analysis) : The Latest Release: version for Windows 95

FRAN is a piece of software which automatically unwraps fringe images. Example images have been created to show how it can operate. Click on the thumbnail to view.

You can download FRAN here, and the documentation is available here (Download - PDF or Word document formats).

FRAN can either automatically unwrap data using a Fourier transform algorithm using one image as the following example shows:

Or it can use three or more phase steps to unwrap the image.

FRAN has now been recompiled in full 32 bit form for Windows 95. FRAN is a self standing program and needs no extra boards, accelerators or adds-ons to perform an accurate unwrapping operation. FRAN has no security keys, fixes or limitations. It just works. The average time FRAN takes to completely process a 512x512 image automatically is less than 20 seconds (on a Pentium 90).

Our intention is To create a FRAN user base. In order to achieve this we have decided to supply FRAN as low cost software solution and offer support from our Web site.

FRAN started life in 1990 as part of the PhD study of Dr.T.Judge (ref.(1)). The objective at the time was to 'unwrap' a complex interferometric image of a gas flame (ref.(2)). The project evolved in two stages. The first was its ability to compute a tan wrapped map. This can be achieved in two ways, either by using a Fourier transform approach or by Phase stepping (ref.(3)). The next step was to then unwrap the tan map automatically. This approach was based upon a well known computer science algorithm know as the 'travelling salesman' algorithm. FRAN allows the user to perform a complete unwrapping process automatically. A detailed description of the fringe unwrapping process was given in a recent paper published in the journal Optics & Lasers in Engineering (ref.(4)).

The first generation of FRAN was UNIX based, and has been used extensively by British Aerospace BAe. The new version is a self standing Windows 95 package. We have been also been using FRAN extensively in our work at the OEL, it forms the backbone of all our fringe analysis work and, therefore, is thoroughly tested and bug free.

References

1. Judge, T.R., PhD Thesis, "The Application of Digital Imaging to Fringe Analysis and PIV (Particle Image Velocimetry)", Engineering Department, Warwick University, December, 1991.
2. Parker, S.C.J., Holden, C.M.E., Bryanston-Cross, P.J.,"The Study of Transonic Flows by Quantitative Holographic Interferometry", Proceedings of the Institute of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 1994, Vol.208, No.2, pp.91-97 IS: 0954-4100 (Awarded prize for the best Aerospace Engineering paper by the Institute of Mechanical Engineers April 1995 and the Mechanical Engineering Thomas Hawksley medal for the 'best original paper published in 1994').
3. Towers, D.P., Judge, T.R. & Bryanston-Cross, P.J., "Automatic Interferogram Analysis applied to Quasi-heterodyne Holography and ESPI", Invited paper, Optics and Lasers in Engineering. 1991 Vol.14. pp 239- 281. IS: 0143-8166
4. Judge, T.R. & BryanstonCross, P.J., "A Review of Phase Unwrapping Techniques in Fringe Analysis Optics and Lasers in Engineering, Vol.21, No.4, p.199-239, 1994.

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Page last modified: November 26, 2002