This paper describes a numerical method applied to speckle photography to measure the in-
plane displacement field on a thin film and specially adapted to microtensile test. Speckle
photography is chosen to avoid touching and stressing the specimen. A Spectral Phase
Algorithm particularly useful in the case of small displacement or/and strain is compared with
the Intercorrelation and Double FFT methods. A final algorithm using first the
Intercorrelation method without interpolation and secondly the Spectral Phase Algorithm is
then adopted to estimate with good accuracy the in-plane displacement field in quasi-real time
during the microtensile tests.
A first application of the method to the tensile tests performed on thin films of electroplated
copper of 18, 35 and 70 μm of thickness is then presented.