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Holographic projection that utilizes holography to record and reconstruct images to be projected is an attractive technique because it inherently requires no lenses, which could lead to the development of an ultra-small projector. In addition, holographic projection has unique functions that are difficult to perform on other projections: multi-projection that projects a multi-image on plural screens (which are also applicable on tilted screens) and projection on arbitrary surface screens; however, holographic projection has considerable problems: speckle noise, hologram calculation time and zoom without using a zoom lens. In this paper, we begin with basics of holographic projection (how to calculate holograms and reconstruct the projected images, and why we need a random phase), and then describe our latest results: the speckle reduction technique, which is referred to as random phase-free method; multi-projection, and real-time holographic projection with the random phase-free method. In addition, our holographic projection is capable of performing the zoom function without using a zoom lens, using a numerical method called scaled diffraction which can calculate diffraction at different sampling rates on a projected image and hologram.

We propose an aerial projection system for reconstruction of floating 3D images based on computer-generated image holograms (CGIHs). The proposed system consists of a spatial light modulator (SLM) and two concave mirrors. The SLM displays CGIHs, and a reconstructed 3D image is formed near the SLM plane. Because the two concave mirrors are set face to face, the floating image of the reconstructed 3D image can be projected at the hole of upper concave mirror. The system can reconstruct and project not only still 3D images but also 3D motion pictures by switching CGIHs.

We report a high-speed parallel phase-shifting digital holography system using a special-purpose computer for image reconstruction. Parallel phase-shifting digital holography is a technique capable of single-shot phase-shifting interferometry. This technique records information of multiple phase-shifted holograms required for calculation of phase-shifting interferometry with a single shot by using space-division multiplexing. This technique needs image-reconstruction process for a huge amount of recorded holograms. In particular, it takes a long time to calculate light propagation based on fast Fourier transform in the process and to obtain a motion picture of a dynamically and fast moving object. Then we designed a special-purpose computer for accelerating the image-reconstruction process of parallel phase-shifting digital holography. We developed a special-purpose computer consisting of VC707 evaluation kit (Xilinx Inc.) which is a field programmable gate array board. We also recorded holograms consisting of 128 × 128 pixels at a frame rate of 180,000 frames per second by the constructed parallel phase-shifting digital holography system. By applying the developed computer to the recorded holograms, we confirmed that the designed computer can accelerate the calculation of image-reconstruction process of parallel phase-shifting digital holography ~50 times faster than a CPU.

Computer-Generated Holograms (CGHs) can be generated by superimposing zoneplates. A zoneplate is a grating that can concentrate an incident light into a point. Since a zoneplate has a circular symmetry, we reported an algorithm that rapidly generates a zoneplate by drawing concentric circles using computer graphic techniques. However, random memory access was required in the algorithm and resulted in degradation of the computational efficiency. In this study, we propose a fast CGH generation algorithm without random memory access using run-length encoding (RLE) based recurrence relation. As a result, we succeeded in improving the calculation time by 88 %, compared with that of the previous work.

Our proposed method of random phase-free holography using virtual convergence light can obtain large reconstructed images exceeding the size of the hologram, without the assistance of random phase. The reconstructed images have low-speckle noise in the amplitude and phase-only holograms (kinoforms); however, in low-resolution holograms, we obtain a degraded image quality compared to the original image. We propose an iterative random phase-free method with virtual convergence light to address this problem.

Computer Generated Holograms (CGH) are generated on computers; however, a great deal of computational power is required because the quality of the image is proportional to the number of point light sources of a 3D object. The Wavefront Recording Plane (WRP) method is an algorithm that enables reduction of the amount of calculations required. However, the WRP method also has a defect; it is not effective in the case of a 3D object with a deep structure. In this study, we propose two improved WRP methods: "Least Square Tilted WRP method" and "RANSAC Multi-Tilted WRP method."

In this study, we propose and experimentally demonstrate a volumetric display system based on quantum dots (QDs) embedded in a polymer substrate. Unlike conventional volumetric displays, our system does not require electrical wiring; thus, the heretofore unavoidable issue of occlusion is resolved because irradiation by external light supplies the energy to the light-emitting voxels formed by the QDs. By exploiting the intrinsic attributes of the QDs, the system offers ultrahigh definition and a wide range of colours for volumetric displays. In this paper, we discuss the design, implementation and characterization of the proposed volumetric display's first prototype. We developed an 8 × 8 × 8 display comprising two types of QDs. This display provides multicolour three-type two-dimensional patterns when viewed from different angles. The QD-based volumetric display provides a new way to represent images and could be applied in leisure and advertising industries, among others.

We propose an algorithm for calculating computer-generated holograms without the trigonometric functions using linear interpolation and a recurrence relation. As a result, we improved the calculation time about 5 times faster than the conventional method.

We report the aerial projection system based on electro-holography with two parabolic mirrors. We succeeded in reconstructing a three-dimensional motion picture at the rate of 29 frames per second by a graphics processing unit.

Addition of random phase to the object light is required in computer-generated holograms (CGHs) to widely diffuse the object light and to avoid its concentration on the CGH; however, this addition causes considerable speckle noise in the reconstructed image. For improving the speckle noise problem, techniques such as iterative phase retrieval algorithms and multi-random phase method are used; however, they are time consuming and are of limited effectiveness. Herein, we present a simple and computationally inexpensive method that drastically improves the image quality and reduces the speckle noise by multiplying the object light with the virtual convergence light. Feasibility of the proposed method is shown using simulations and optical reconstructions; moreover, we apply it to lens-less zoom-able holographic projection. The proposed method is useful for the speckle problems in holographic applications.

We designed and built a special-purpose computer for holography, HORN-4 (HOlographic ReconstructioN) using PLD (Programmable Logic Device) technology. HORN computers have a pipeline architecture. We use HORN-4 as an attached processor to enhance the performance of a general-purpose computer when it is used to generate holograms using a “recurrence formulas” algorithm developed by our previous paper. In the HORN-4 system, we designed the pipeline by adopting our “recurrence formulas” algorithm which can calculate the phase on a hologram. As the result, we could integrate the pipeline composed of 21 units into one PLD chip. The units in the pipeline consists of one BPU (Basic Phase Unit) unit and twenty CU (Cascade Unit) units. These CU units can compute twenty light intensities on a hologram plane at one time. By mounting two of the PLD chips on a PCI (Peripheral Component Interconnect) universal board, HORN-4 can calculate holograms at high speed of about 42 Gflops equivalent. The cost of HORN-4 board is about 1700 US dollar. We could obtain 800×600 grids hologram from a 3D-image composed of 415 points in about 0.45 sec with the HORN-4 system.

We designed and developed a control circuit for a three-dimensional (3-D) light-emitting diode (LED) array to be used in volumetric displays exhibiting full-color dynamic 3-D images. The circuit was implemented on a field-programmable gate array; therefore, pulse-width modulation, which requires high-speed processing, could be operated in real time. We experimentally evaluated the developed system by measuring the luminance of an LED with varying input and confirmed that the system works appropriately. In addition, we demonstrated that the volumetric display exhibits different full-color dynamic two-dimensional images in two orthogonal directions. Each of the exhibited images could be obtained only from the prescribed viewpoint. Such directional characteristics of the system are beneficial for applications, including digital signage, security systems, art, and amusement.

We propose a simple gradation representation method for a reconstructed three-dimensional (3-D) image without controlling the brightness of the reference light. In the proposed method, we use multiple bit planes comprised of binary-weighted computer-generated holograms (CGHs) with various light transmittances. Binary-weighted CGH is generated by changing the white in the conventional binary CGH to gray. The light transmittance of a binary-weighted CGH is less than that of a conventional binary CGH. The object points of a 3-D object are assigned to multiple bit planes according to the gray level of the object points. The multiple bit planes are displayed sequentially in a time-division multiplex manner. Consequently, the proposed method realizes a gradation representation of a reconstructed 3-D object.

Computer-generated holograms (CGHs) are generated by superimposing complex amplitudes emitted from a number of object points. However, this superposition process remains very time-consuming even when using the latest computers. We propose a fast calculation algorithm for CGHs that uses a wavelet shrinkage method, eliminating small wavelet coefficient values to express approximated complex amplitudes using only a few representative wavelet coefficients.

We demonstrate fast time-division color electroholography using a multiple-graphics-processing-unit (GPU) cluster system with a spatial light modulator and a controller to switch the color of the reconstructing light. The controller comprises a universal serial bus module to drive the liquid crystal optical shutters. By using the controller, the computer-generated hologram (CGH) display node of the multiple-GPU cluster system synchronizes the display of the CGH with the color switching of the reconstructing light. Fast time-division color electroholography at 20 fps is realized for a three-dimensional object comprising 21,000 points per color when 13 GPUs are used in a multiple-GPU cluster system.

We propose a real-time spatiotemporal division multiplexing electroholography utilizing the features of movies. The proposed method spatially divides a 3-D object into plural parts and periodically selects a divided part in each frame, thereby reconstructing a three-dimensional (3-D) movie of the original object. Computer-generated holograms of the selected part are calculated by a single graphics processing unit and sequentially displayed on a spatial light modulator. Visual continuity enables a reconstructed movie of the original 3-D object. The proposed method realized a real-time reconstructed movie of a 3-D object composed of 11,646 points at over 30 frames per second (fps). We also displayed a reconstructed movie of a 3-D object composed of 44,647 points at about 10 fps.

We report frequency estimation of loudspeaker diaphragm vibrating at high speed by parallel phase-shifting digital holography which is a technique of single-shot phase-shifting interferometry. This technique records multiple phaseshifted holograms required for phase-shifting interferometry by using space-division multiplexing. We constructed a parallel phase-shifting digital holography system consisting of a high-speed polarization-imaging camera. This camera has a micro-polarizer array which selects four linear polarization axes for 2 × 2 pixels. We set a loudspeaker as an object, and recorded vibration of diaphragm of the loudspeaker by the constructed system. By the constructed system, we demonstrated observation of vibration displacement of loudspeaker diaphragm. In this paper, we aim to estimate vibration frequency of the loudspeaker diaphragm by applying the experimental results to frequency analysis. Holograms consisting of 128 × 128 pixels were recorded at a frame rate of 262,500 frames per second by the camera. A sinusoidal wave was input to the loudspeaker via a phone connector. We observed displacement of the loudspeaker diaphragm vibrating by the system. We also succeeded in estimating vibration frequency of the loudspeaker diaphragm by applying frequency analysis to the experimental results.

We developed a 24-bit color volumetric display based on light emitting diode (LED). This volumetric display consists of 8 × 8 × 8 LEDs array and can represent 24-bit color three-dimensional images. The light intensity of the LEDs is gradated by the pulse width modulation method. We designed a control circuit of the volumetric display with the field programmable gate array. We succeeded in displaying 24-bit color three-dimensional moving image.

We developed " Loop architecture " which can perform different length FFT without changing fundamental circuit composition. In order to perform FFT effectively, we adopted Mixed-radix FFT algorithm with radix-2 and radix-4 butterfly calculation. Furthermore, we developed " Pipelined butterfly calculation system" and "5-bank memory architecture" in order to perform Mixed-radix FFT effectively. As a result, we succeeded to develop the versatile FFT processing system with small circuit area and low latency. In addition, we implemented our circuit to Spartan-6 FPGA board and developed sound analysis system via USB.

In high-speed 3D imaging by using parallel phase-shifting digital holography, there is a problem that the computational cost is very huge. Therefore, we have studied and developed special purpose computers for accelerating the calculation of parallel phase-shifting digital holography to solve the problem. However, the computational circuit for parallel phase-shifting interferometry and the special-purpose computer for light propagation have been independently designed. In this paper, we aim to connect them in order to realize high-precision and high-speed 3D imaging system by parallel phase-shifting digital holography.

We designed and developed a special-purpose computer named FFT-HORN for high-speed imaging by digital holography. We demonstrated the developed FFT-HORN accelerated the computational time of reconstruction processing in digital holography.

Computer based holography such as electro-holography and digital holography advances because the resolution of an imaging display and a sensing device such as a liquid crystal display (LCD) and a charge coupled device (CCD) becomes higher. A higher resolution of imaging device requires the more powerful computing system. On the other hand, a solid state drive (SSD) develops as a storage device of computers. We studied the effectiveness of SSD for a large-scale digital holography calculation. When the calculation data scale exceeds the main memory capacity, the SSD system showed better performance compared with the hard disk drive (HDD) system at computational speed and stability. Full Text: PDF References M. Stanley et al., "100-megapixel computer-generated holographic images from Active Tiling: a dynamic and scalable electro-optic modulator system", Proc. SPIE 5005, Practical Holography XVII and Holographic Materials IX, 247 (2003) CrossRef H. Sasaki, K. Yamamoto, Y. Ichihashi, T. Senoh, "Large size three-dimensional video by electronic holography using multiple spatial light modulators", Scientific Reports 4, Article number 04000 (2014) CrossRef T. Kozacki, G. Finke, P. Garbat, W. Zaperty, M. Kujawinska, "Wide angle holographic display system with spatiotemporal multiplexing", Opt. Express 20, 27473-27481 (2012) CrossRef T. Shimobaba et al., "In-line digital holographic microscopy using a consumer scanner", Scientific Reports 3, Article number 02664 (2013). CrossRef S.O.Isikman, A.Greenbaum, W.Luo,A.F.Coskun, A.Ozcan, "Giga-Pixel Lensfree Holographic Microscopy and Tomography Using Color Image Sensors", PloS one, 7(9), e45044 (2012) CrossRef T. Shimobaba et al., "Computational wave optics library for C++: CWO++ library", Comput. Phys. Commun. 183, 1124-1138 (2012) CrossRef

In a three-dimensional display by a computer-generated hologram?(CGH), fast computation of CGH is required. In this paper, in order to accelerate CGH generation, the following two methods are used; the first method is band-limited double-step Fresnel diffraction. Compared with the convolution-based diffraction, such as angular spectral method, the proposed method requires less computational time and memory. The second method is a wavefront recording plane (WRP) method which reduces the calculation amount by placing WRPs in the vicinity of the object. We succeeded in speeding up CGH calculation by combining the two methods. Full Text: PDF References T. C. Poon (Ed.), "Digital holography and three-dimensional display: Principles and Applications", Springer (2006). CrossRef S. C. Kim and E. S. Kim, "Effective generation of digital holograms of three-dimensional objects using a novel look-up table method", Appl. Opt. 47, D55–D62 (2008) . CrossRef K. Matsushima, H. Shimmel, and F. Wyrowski, "Fast calculation method for optical diffraction on tilted planes by use of the angular spectrum of plane waves", J. Opt. Soc. Am. A. 20, 1755-1762 (2003). CrossRef M. Yamaguchi, H. Hoshino, T. Honda, and N. Ohyama, "Phase-added stereogram: calculation of hologram using computer graphics technique", Proc. SPIE 1914, 25-31 (1993). CrossRef N. Okada, T. Shimobaba, Y. Ichihashi, R. Oi, K. Yamamoto, M. Oikawa, T. Kakue, N. Masuda, and T. Ito, "Band-limited double-step Fresnel diffraction and its application to computer-generated holograms", Opt. Express 21, 9192-9197 (2013). CrossRef F. Zhang, I. Yamaguchi, and L. P. Yaroslavsky, "Algorithm for reconstruction of digital holograms with adjustable magnification", Opt. Lett. 29, 1668-1670 (2004). CrossRef T. Shimobaba, N. Masuda and T. Ito, "Simple and fast calclulation algorithm for computer-generated hologram with wavefront recording plane", Opt. Lett. 34, 3133-3135 (2009). CrossRef T. Shimobaba, H. Nakayama, N. Masuda and T. Ito, "Rapid calculation of Fresnel computer-generated-hologram using look-up table and wavefront-recording plane methods for three-dimensional display", Opt Express 18 19504-19509 (2010). CrossRef J. Weng, T. Shimobaba, N. Okada, H. Nakayama, M. Oikawa, N. Masuda and T. Ito, "Generation of real-time large computer generated hologram using wavefront recording method", Opt. Express 20, 4018-4023 (2012). CrossRef T. Shimobaba, T. Kakue, N. Masuda, Y. Ichihashi, K. Yamamoto and T. Ito, "Computer holography using wavefront recording method", Digital Holography and Three-Dimensional Imaging(DH) DH2013, DTu1A. 2 (2013). CrossRef A. -H. Phan, M. -l. Piao, S. -K. Gil, and N. Kim, "Generation speed and reconstructed image quality enhancement of a long-depth object using double wavefront recording planes and a GPU," Appl. Opt. 53, 4817-4824 (2014). CrossRef P. Tsang, W. -K. Cheung, T. -C. Poon, and C. Zhou, "Holographic video at 40 frames per second for 4-million object points," Opt. Express 19, 15205-15211 (2011). CrossRef

This paper numerically investigates the feasibility of lensless zoomable holographic multiple projections to tilted planes. We have already developed lensless zoomable holographic single projection using scaled diffraction, which calculates diffraction between parallel planes with different sampling pitches. The structure of this zoomable holographic projection is very simple because it does not need a lens; however, it only projects a single image to a plane parallel to the hologram. The lensless zoomable holographic projection in this paper is capable of projecting multiple images onto tilted planes simultaneously.

We have developed an algorithm which can record multiple two-dimensional (2-D) gradated projection patterns in a single three-dimensional (3-D) object. Each recorded pattern has the individual projected direction and can only be seen from the direction. The proposed algorithm has two important features: the number of recorded patterns is theoretically infinite and no meaningful pattern can be seen outside of the projected directions. In this paper, we expanded the algorithm to record multiple 2-D projection patterns in color. There are two popular ways of color mixing: additive one and subtractive one. Additive color mixing used to mix light is based on RGB colors and subtractive color mixing used to mix inks is based on CMY colors. We made two coloring methods based on the additive mixing and subtractive mixing. We performed numerical simulations of the coloring methods, and confirmed their effectiveness. We also fabricated two types of volumetric display and applied the proposed algorithm to them. One is a cubic displays constructed by light-emitting diodes (LEDs) in 8×8×8 array. Lighting patterns of LEDs are controlled by a microcomputer board. The other one is made of 7×7 array of threads. Each thread is illuminated by a projector connected with PC. As a result of the implementation, we succeeded in recording multiple 2-D color motion pictures in the volumetric displays. Our algorithm can be applied to digital signage, media art and so forth.

We propose acceleration of color computer-generated holograms (CGHs) from three-dimensional (3D) scenes that are expressed as texture (RGB) and depth (D) images. These images are obtained by 3D graphics libraries and RGB-D cameras: for example, OpenGL and Kinect, respectively. We can regard them as two-dimensional (2D) cross-sectional images along the depth direction. The generation of CGHs from the 2D cross-sectional images requires multiple diffraction calculations. If we use convolution-based diffraction such as the angular spectrum method, the diffraction calculation takes a long time and requires large memory usage because the convolution diffraction calculation requires the expansion of the 2D cross-sectional images to avoid the wraparound noise. In this paper, we first describe the acceleration of the diffraction calculation using “Band-limited double-step Fresnel diffraction,” which does not require the expansion. Next, we describe color CGH acceleration using color space conversion. In general, color CGHs are generated on RGB color space; however, we need to repeat the same calculation for each color component, so that the computational burden of the color CGH generation increases three-fold, compared with monochrome CGH generation. We can reduce the computational burden by using YCbCr color space because the 2D cross-sectional images on YCbCr color space can be down-sampled without the impairing of the image quality.

Ptychography is a promising phase retrieval technique for visible light, X-ray and electron beams. Conventional ptychography reconstructs the amplitude and phase of an object light from a set of the diffraction intensity patterns obtained by the X–Y moving of the probe light. The X–Y moving of the probe light requires two control parameters and accuracy of the locations. We propose ptychography by changing the area of the probe light using only one control parameter, instead of the X–Y moving of the probe light. The proposed method has faster convergence speed. In addition, we propose scaled ptychography using scaled diffraction calculation in order to magnify retrieved object lights clearly.

Computer-Generated Hologram (CGH) is well known to take an enormous computational time. We propose an efficient computational method for CGH suitable for hardware devices, which are fixed-point DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array) and ASIC (Application Specific Integrated Circuit). To be concrete, this method can compute a phase on a hologram by addition. When we operated this method on a personal computer, we could maximally compute CGH about 24 times faster than a traditional method. And also, when we adopted this method to FPGA chip, we could implement circuits about 5 times more than a traditional method.

We present a special-purpose computer named HORN (HOlographic ReconstructioN) for fast calculation of computer- generated holograms (CGHs). The HORN can realize parallel processing of the CGH calculation by using field- programmable gate arrays. The latest version of HORNs, HORN-7, can reconstruct holographic images more clearly than previous HORNs because HORN-7 can make CGHs as a phase-only hologram (kinoform). In addition, the HORN- 7 can directly output calculated CGHs on a spatial-light modulator via Digital Visual Interface. In this paper, we demonstrate real-time reconstruction of holographic motion pictures by the HORN-7. We calculated CGHs, which consist of 1,920 × 1,080 pixels, from the object data of ~6,000 points, and succeeded in reconstructing holographic motion pictures from the calculated CGHs at the rate of ~7 frames per second.

We have designed and built a special-purpose computer for holography, HORN-3 (HOlographic ReconstructioN) using PLD (Programmable Logic Device) technology. We could integrate a pipeline to calculate hologram into one PLD chip, so that we can readily parallelize the system. By mounting two of the PLD chips on a PCI (Peripheral Component Interconnect) universal board, HORN-3 calculates light intensity at high speed of about 1.2 G flops. The cost of HORN-3 board is 200,000 Japanese yen (1600 US dollar). We obtained 1024× 768 grids hologram from a virtual 3D-image composed of 2500 points in about 60 sec with the HORN-3 system.

Electroholography is one of the techniques for achieving 3-Dimensional (3-D) television. We connected a special-purpose computer for holography and to a display board with a high-definition reflective liquid crystal display, and then we constructed the integration system to make and to display the computer generated hologram. We succeeded in the reproducing 14 frames per second in a 3-D image composed of about 6,000 points using this system.

We demonstrate an in-line digital holographic microscopy using a consumer scanner. The consumer scanner can scan an image with 4,800 dpi. The pixel pitch is approximately 5.29 μm. The system using a consumer scanner has a simple structure, compared with synthetic aperture digital holography using a camera mounted on a two-dimensional moving stage. In this demonstration, we captured an in-line hologram with 23, 602 × 18, 023 pixels (≈0.43 gigapixels). The physical size of the scanned hologram is approximately 124 mm × 95 mm. In addition, to accelerate the reconstruction time of the gigapixel hologram and decrease the amount of memory for the reconstruction, we applied the band-limited double-step Fresnel diffraction to the reconstruction.

We present a fast computational system for high-speed parallel phase-shifting digital holography. The image reconstruction process of parallel phase-shifting digital holography consists of the following processes: decomposition of recorded phase-shifted hologram, interpolation of vacant pixels in decomposed holograms, phase-shifting interferometry, and light propagation. We accelerated phase-shifting interferometry and light propagation processes, whose computational load was much heavier than that of the others, by a graphics processing unit (GPU). We adopted Compute Unified Device Architecture (CUBA) as a software development environment. A GPU with CUDA can achieve 6.3× and 9.0× faster computational times in phase-shifting interferometry and light propagation processes than a CPU, respectively.

We have developed an algorithm for recording multiple gradated two-dimensional projection patterns in a single three-dimensional object. When a single pattern is observed, information from the other patterns can be treated as background noise. The proposed algorithm has two important features: the number of patterns that can be recorded is theoretically infinite and no meaningful information can be seen outside of the projection directions. We confirmed the effectiveness of the proposed algorithm by performing numerical simulations of two laser crystals: an octagonal prism that contained four patterns in four projection directions and a dodecahedron that contained six patterns in six directions. We also fabricated and demonstrated an actual prototype laser crystal from a glass cube engraved by a laser beam. This algorithm has applications in various fields, including media art, digital signage, and encryption technology.

Numerical simulation of Fresnel diffraction with fast Fourier transform (FFT) is widely used in optics, especially computer holography. Fresnel diffraction with FFT cannot set different sampling rates between source and destination planes, while shifted-Fresnel diffraction can set different rates. However, an aliasing error may be incurred in shifted-Fresnel diffraction in a short propagation distance, and the aliasing conditions have not been investigated. In this paper, we investigate the aliasing conditions of shifted-Fresnel diffraction and improve its properties based on the conditions.

We report fast computation of computer-generated holograms (CGHs) using Xeon Phi coprocessors, which have massively x86-based processors on one chip, recently released by Intel. CGHs can generate arbitrary light wavefronts, and therefore, are promising technology for many applications: for example, three-dimensional displays, diffractive optical elements, and the generation of arbitrary beams. CGHs incur enormous computational cost. In this paper, we describe the implementations of several CGH generating algorithms on the Xeon Phi, and the comparisons in terms of the performance and the ease of programming between the Xeon Phi, a CPU and graphics processing unit (GPU). Program Summary Program title: Xeon-Phi-CGH Catalogue identifier: AETM_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AETM_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 26 539 No. of bytes in distributed program, including test data, etc.: 6 144 291 Distribution format: tar.gz Programming language: C, C++. Computer: Intel Xeon Phi coprocessor. Operating system: Linux. Has the code been vectorised or parallelized?: Yes. CPU and many cores in Xeon Phi coprocessor. RAM: 256M bytes Classification: 6.1, 6.5, 18. External routines: Intel MKL Nature of problem: We describe how to program fast computation of computer-generated holograms (CGHs) and diffraction calculation using Xeon Phi coprocessors, released by Intel. We describe the implementations of several CGH generating algorithms on the Xeon Phi, and the comparisons in terms of the performance and the ease of programming between the Xeon Phi, a CPU and graphics processing unit (GPU). Solution method: FFT-based diffraction calculations, computer-generated-hologram by direct integration.

This paper summarizes a wavefront recording method, that is one of fast algorithms for computer generated hologram (CGH), and related works.

Computer holography addresses holographic nature on a computer by computing light propagation. In this paper, we present our acceleration techniques for computer holography using hardware (FPGAs, GPUs and Intel XeonPhi) and our algorithms.

Electro-holography is promising for one of three-dimensional (3-D) display technologies. A hologram displayed on an electronic device such as LCD can be created by simulating propagation of the light on a computer, which is referred to as computer-generated hologram (CGH). To generate a CGH, however, it is necessary to perform a huge computation. To solve the issue, parallel computing is one of effective ways.

For a three-dimensional display using computer-generated holograms (CGHs), fast CGH calculations are required. The multiple wavefront recording planes (WRPs) method can reduce the computational amount by placing WRPs near an object. In previous studies using this method, the numbers and intervals of the WRPs were fixed. Hence, the calculation time was heavily affected by calculation conditions, such as variation in the distribution of object points. This paper proposes a method that can automatically optimize the number and arrangement of WRPs to accelerate CGH generation.

Parallel calculations of large-pixel-count computer-generated holograms (CGHs) are suitable for multiple-graphics processing unit (multi-GPU) cluster systems. However, it is not easy for a multi-GPU cluster system to accomplish fast CGH calculations when CGH transfers between PCs are required. In these cases, the CGH transfer between the PCs becomes a bottleneck. Usually, this problem occurs only in multi-GPU cluster systems with a single spatial light modulator. To overcome this problem, we propose a simple method using the InfiniBand network. The computational speed of the proposed method using 13 GPUs (NVIDIA GeForce GTX TITAN X) was more than 3000 times faster than that of a CPU (Intel Core i7 4770) when the number of three-dimensional (3-D) object points exceeded 20,480. In practice, we achieved ∼40 tera floating point operations per second (TFLOPS) when the number of 3-D object points exceeded 40,960. Our proposed method was able to reconstruct a real-time movie of a 3-D object comprising 95,949 points.

In this paper, we show fast signal reconstruction for compressive holography using a graphics processing unit (GPU). We implemented a fast iterative shrinkage-thresholding algorithm on a GPU to solve the l1 and total variation (TV) regularized problems that are typically used in compressive holography. Since the algorithm is highly parallel, GPUs can compute it efficiently by data-parallel computing. For better performance, our implementation exploits the structure of the measurement matrix to compute the matrix multiplications. The results show that GPU-based implementation is about 20 times faster than CPU-based implementation.

3D-TV systems by holography technique have been studied in the world. In this paper, we report a color holographic reconstruction system by time division multiplexing method with reference lights of laser. The method can reconstruct a color holographic image by switching reference lights of red, green and blue colors at certain intervals. We can observe a color holographic image using red and green lasers as the reference lights, a high minute liquid crystal display (LCD) panel as a spatial light modulator (SLM) and electro-shutters as the shuttering device of the laser lights in the optical system. This approach has some advantages. Namely, the structure of the optical system can be simple and the number of LCD panels in the optical system can be decreased.

To overcome the computational complexity of a computer-generated hologram (CGH), we implement an optimized CGH computation in our multi-graphics processing unit cluster system. Our system can calculate a CGH of 6,400×3,072 pixels from a three-dimensional (3D) object composed of 2,048 points in 55 ms. Furthermore, in the case of a 3D object composed of 4096 points, our system is 553 times faster than a conventional central processing unit (using eight threads).

The angular spectrum method (ASM) calculates diffraction calculation in a high numerical aperture, unlike Fresnel diffraction. However, this method does not allow us to calculate at different sampling rates on source and destination planes. In this Letter, we propose a scaled ASM that calculates diffraction at different sampling rates on source and destination planes using the nonuniform fast Fourier transform.