| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Research Abstract |
Holographic particle image velocimetry systems use high-quality information and allow the recording of an instantaneous three-dimensional velocity field illuminated by only one beam line. However, this method takes up most of the process time in image reconstruction. It is also difficult to use it to capture the time evolution of a particle image by single frame recording of instantaneous particles dispersed in a flow field. In contrast, digital holographic techniques can easily capture the time evolution of particles using a digital camera. Therefore, we have studied a complete digital holographic particle tracking velocimetry (DHPTV) system by a high speed digital camera. However, this method requires a high-performance computational power to reconstruct particle location. Although the high-speed reconstruction of a particle field has been performed by use of Fast Fourier Transform (FFT), it is not sufficient. To overcome the computational cost, we studied the special-purpose computer system.
We developed two special-purpose computers. First computer was designed and built with a large-scale FPGA (Field Programmable Gate Array) board and showed the effectiveness of this study. However, it limited a calculation domain of FFT, which was an important role on this system, to 256^*256 since we developed the hardware surely. The limitation was caused by the capacity of internal memory of the FPGA chip.
Next step, we designed and built developed the second computer which expanded a calculation domain of FFT to 1,024^*1,024. We changed the hardware design to use not only the internal memory of FPGA but also the external memory. We have used a CCD camera with the resolution of 1,024^*1,024 in our experimental setup. Therefore, the second special-purpose computer can calculate data of our experimental result directly. The special-purpose computer system was 10 times faster than a PC (Personal Computer) and showed that the system was suitable for HPTV method.
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