We have applied the graphics processing unit (GPU) to computer generated holograms (CGH) to overcome the high computational cost of CGH and have compared the speed of a GPU implementation to a standard CPU implementation. The calculation speed of a GPU (GeForce 6600, nVIDIA) was found to be about 47 times faster than that of a personal computer with a Pentium 4 processor. Our system can realize real-time reconstruction of a 64-point 3-D object at video rate using a liquid-crystal display of resolution 800x600.
Diffraction calculations, such as the angular spectrum method, and Fresnel
diffractions, are used for calculating scalar light propagation. The
calculations are used in wide-ranging optics fields: for example, computer
generated holograms (CGHs), digital holography, diffractive optical elements,
microscopy, image encryption and decryption, three-dimensional analysis for
optical devices and so on. However, increasing demands made by large-scale
diffraction calculations have rendered the computational power of recent
computers insufficient. We have already developed a numerical library for
diffraction calculations using a graphic processing unit (GPU), which was named
the GWO library. However, this GWO library is not user-friendly, since it is
based on C language and was also run only on a GPU. In this paper, we develop a
new C++ class library for diffraction and CGH calculations, which is referred
as to a CWO++ library, running on a CPU and GPU. We also describe the
structure, performance, and usage examples of the CWO++ library.Comment: 18 page
We developed the HORN-6 special-purpose computer for holography. We designed and constructed the HORN-6 board to handle an object image composed of one million points and constructed a cluster system composed of 16 HORN-6 boards. Using this HORN-6 cluster system, we succeeded in creating a computer-generated hologram of a three-dimensional image composed of 1,000,000 points at a rate of 1 frame per second, and a computer-generated hologram of an image composed of 100,000 points at a rate of 10 frames per second, which is near video rate, when the size of a computer-generated hologram is 1,920 x 1,080. The calculation speed is approximately 4,600 times faster than that of a personal computer with an Intel 3.4-GHz Pentium 4 CPU.
In electroholography, a real-time reconstruction is one of the grand challenges. To realize it, we developed a parallelized high performance computing board for computer-generated hologram, named HORN-5 board, where four large-scale field programmable gate array chips were mounted. The number of circuits for hologram calculation implemented to the board was 1,408. The board calculated a hologram at higher speed by 360 times than a personal computer with Pentium4 processor. A personal computer connected with four HORN-5 boards calculated a hologram of 1,408 x 1,050 made from a three-dimensional object consisting of 10,000 points at 0.0023 s. In other words, beyond at video rate (30 frames / s), it realized a real-time reconstruction.
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