We report the measurement of transient bending waves with double-pulsed-subtraction TV holography. The correlation fringe patterns are automatically quantitatively analyzed by the application of Fourier methods. A novel optical setup with two different object-beam optical paths is demonstrated for the generation of carrier fringes. The proposed system is highly immune to environmental disturbances because the optical setup imposes no lower limit on the time separation between laser pulses. One removes the linear phase distribution due to the spatial carrier in the spatial domain by subtracting the phase of the undeformed carrier fringes from the phase of the modulated fringes. Experimental results obtained with an aluminum plate excited by the impact of a piezoelectric translator are presented.

A phase-evaluation method of multiple-beam Fizeau patterns that combines two-beam phase-stepping algorithms with the moiré effect was previously reported [Appl. Opt. 34, 3639-3643(1995)]. The method is based on a multiplicative moiréimage-formation process obtained by the direct superposition of high-frequency multiple-beam Fizeau carrier fringes upon a transmission grating (working as a phase modulator). We present a comparison between this multiplicative moiré two-beam phase-stepping method and the well-known Fourier-transform method for the topographic measurement of an undoped silicon wafer. The discrepancy between the two methods yields a rms phase-difference value of the order of(~2pi/90).

We present a novel technique for the application of stroboscopic additive TV-Holography (also known as ESPI) to the measurement of vibrations using temporal phase-shifting. Based on a previous concept contrived and developed by the same authorslvz that used two illumination pulses within each vibration cycle and interpulse phase modulation at the same rate that the vibration of the object, this new technique implements an analogous phase modulation scheme but between two swiftly alternating bursts of single pulses with different phases within each video frame, rather than using true double-pulses, thus allowing quantitative measurements to be performed with stroboscopic illumination keeping the characteristics of stability and temporal resolution of the double-pulse additive stroboscopic technique but with the additional bene t of reaching high vibration frequencies with low bandwidth phase modulators.

In this paper we demonstrate the feasibility of impact-induced transient deformations measurement by singlepulsed subtraction TV holography and the Fourier transform method with contouring fringes as spatial carrier. Fringe formation in single-pulsed subtraction TV holography and phase demodulation by the Fourier transform method are described. Contouring fringes are probed to be well suited for introducing spatial carrier in the correlation fringe patterns. Experimental results are presented. Finally, the degree of immunity to environmental disturbances of this technique is discussed and improvements are proposed.

Two TV-Holographic techniques to detect cracks in mechanical elements are demonstrated. One of them employs continuous illumination and is based in the modal analysis of the part. The other one consists in the study by pulsed TV-Holography of transient waves induced in the part.