<title>Phase-shifted double single-pulse additive stroboscopic TV holography for the measurement of high-frequency vibrations using low-bandwidth phase-modulation devices</title>

Abstract

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.

A systematic approach to TV holography

“…Standard double exposure. Two pulses with different delays t p1,n and t p2,n are fired within each oscillation cycle ( figure 10(b)) or two bursts, with the same number of single light pulses but different delays, are fired alternately within the integration period of the camera [139]…”

“…and the intensity of the primary correlogram, according to expression (4.7), is 10(b)) or two bursts, with the same number of single light pulses but different delays, are fired alternately within the integration period of the camera [139]. The resulting fringe function is…”