A high-speed acquisition and processing system of the laser speckle signal on the magnetic fluid

In order to achieve the dynamical detection and real-time analysis of the movement status of the magnetic fluid, according to the difficulties of the detection of the magnetic fluid, established a high-speed acquisition and processing system of laser speckle signal on the magnetic fluid. First of all, the FPGA (EP2C8T144C8N) drived the linear array CCD(TCD1501D) to scan in the corresponding time sequence given by the computer, collected the laser speckle interferometric image in rapid change on the surface of the magnetic fluid, which followed the movement of the magnetic fluid, and the signal collected by CCD was converted into the digital data through the high-speed A/D convertor and stored into the internal buffer FIFO of the FPGA, whose width and depth were designed by the user as required. Then, the FPGA sent the digital signal of the laser speckle interferometric images into the computer through the USB2.0 highspeed differential bus, whose transmission rate can reach 480Mb/s in theory. Finally, the distribution of the laser speckle on the magnetic fluid was messy and random, which carried certain information about the surface of the magnetic fluid, based on the theories of the statistic correlation and the subdivision of images, analysing and processing the laser speckle interferometric images, indirectly got the movement status of the magnetic fluid under the electromagnetic field. The experimental results show that: the High Speed Acquisition and Processing System has the advantage of full-court, non-contact, non-invasive, high-precision and high reliability and so on. The detection resolution of high speed acquisition and processing system is superior to 1m and the sample rate is 3Msps, which basically meets the requirements of the magnetic fluid movement state detection.