Real-time displacement measurement using a pattern correlationsystem incorporating an ultra-high-speed shutter camera and parallelaligned nematic liquid crystal spatial light modulators (PAL-SLMs)

摘要

PIV (Particle Image Velocimetry) system has been composed of anultra-high-speed shutter camera and optical correlator for real-time(frame-rate) operation. The ultra-high-speed shutter camera has severalfunctions such as optical amplification (typically×104), high speed shuttering (100 nsec-1 msec), andmulti-shuttering (1, 2, 4, and 8 times) for forming a double-exposurepattern of an object image, in order to measure the displacement of theflow. The optical correlator is a joint transform correlator (JTC) usingtwo PAL-SLMs, which are optically addressed spatial light modulatorswith phase only modulating function, for real-time analysis of thedouble-exposure pattern. It is demonstrated that the system can measurevelocity of a random-dot pattern on a side of a rotating disk withframe-rate response. The performance of the system is shown anddiscussed