Use of Two Radiation Sources in Speckle Interferometer Optical Arrangement at Turbo-Machine Parts Deformation and Vibration Investigation

Two independent coherent radiation sources with wave length of 632.8 nm are simultaneously used in speckle interferometer optical arrangement with combined beams and speckle-modulated background wave. This permitted to reduce low-frequency noise related to non-uniform light pattern of the surface of the object under investigation. Moreover, measurements performed showed speckle-noise dispersion reduction. The developed method application allows increasing of interference fringes visibility in speckle-interferograms that is required to increase measurement accuracy of vibration and static displacement orthogonal to the surface of the part under investigation.