A system for the automatic evaluation of interference patterns has been developed. After digitizing the interferograms from classical and holografic interferometers with a television digitizer and performing different picture enhancement operations the fringe loci are extracted by use of a floating-threshold method. The fringes are numbered using a special scheme after the removal of any fringe disconnections which might appear if there was insufficient contrast in the interferograms. The reconstruction of the object function from the numbered fringe field is achieved by a local polynomial least-squares approximation. Applications are given, demonstrating the evaluation of interferograms of supersonic flow fields and the analysis of holografic interferograms of car-tyres.
[1]
D. H. McLain,et al.
Drawing Contours from Arbitrary Data Points
,
1974,
Comput. J..
[2]
M. Schlüter.
Analysis of holographic interferograms with a tv picture system
,
1980
.
[3]
Jumpei Tsujiuchi,et al.
Hybrid Holographic Interferometer For Measuring Three-Dimensional Deformations
,
1981
.
[4]
Urs Ramer,et al.
An iterative procedure for the polygonal approximation of plane curves
,
1972,
Comput. Graph. Image Process..
[5]
O. E. Toler,et al.
Interferogram Evaluation Program For The HP-9825A Calculator
,
1979,
Photonics West - Lasers and Applications in Science and Engineering.