25 April 1990 Stabilized And Accelerated Speckle Strain Gauge
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We have improved stability and temporal response of the laser speckle strain gauge. In the gauge a narrow laser beam is incident on a diffuse surface and speckle patterns appearing in the light scattered to certain directions are detected by linear image sensors. The correlator computes the correlation peak between the current frame and a reference one of the sensor which is driven at 1000 frames per second. The reference frame is fixed until the correlation peak becomes lower than a threshold. By employing a pair of the correlators and a laser of output power of a few tens of mW, we could measure dynamic strain of polymer films, between a fraction of Hertz and one hundred Hertz. The resolution of the gauge which only depends on geometry of the optical system and the sensor pitch, is a few tens of microstrains. The upper limit of the measurement can be extended arbitrarily much because small incremental strain is integrated.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ichirou Yamaguchi, Ichirou Yamaguchi, Tamiki Takemori, Tamiki Takemori, Koichi Kobayashi, Koichi Kobayashi, } "Stabilized And Accelerated Speckle Strain Gauge", Proc. SPIE 1162, Laser Interferometry: Quantitative Analysis of Interferograms: Third in a Series, (25 April 1990); doi: 10.1117/12.962746; https://doi.org/10.1117/12.962746


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