Computer-generated holography (CGH), which is a process of generating digital holograms, is computationally expensive. Recently, several methods/systems of parallelizing the process using graphic processing units (GPUs) have been proposed. Indeed, use of multiple GPUs or a personal computer (PC) cluster (each PC with GPUs) enabled great improvements in the process speed. However, extant literature has less often explored systems involving rapid generation of multiple digital holograms and specialized systems for rapid generation of a digital video hologram. This study proposes a system that uses a PC cluster and is able to more efficiently generate a video hologram. The proposed system is designed to simultaneously generate multiple frames and accelerate the generation by parallelizing the CGH computations across a number of frames, as opposed to separately generating each individual frame while parallelizing the CGH computations within each frame. The proposed system also enables the subprocesses for generating each frame to execute in parallel through multithreading. With these two schemes, the proposed system significantly reduced the data communication time for generating a digital hologram when compared with that of the state-of-the-art system.
We describe and evaluate a practical approach for implementing computer-generated-holography (CGH) using multiple graphic processing units (GPUs). The proposed method can generate high-definition (HD) resolution (1920×1080) digital holograms in real-time. In order to demonstrate the plausibility of our method, some experimental results will be given. First, we discuss the advantage of GPUs for CGH against central processing units (CPUs) by comparing the performance of both. Our results show that use of GPUs can shorten CGH computation time by 2791 times. Then, we discuss the potential of multiple GPUs for generating HD resolution digital holograms in real-time by measuring and analyzing the CGH computational time in accordance with the number of GPUs. Our result shows that the CGH computational time decreases nonlinearly, with a logarithmic-like curve, as the number of GPU increases. Therefore, we can determine the number of GPUs to maximize the efficiency. Consequently, our implementation can generate HD resolution digital holograms at a rate of more than 66 hps (holograms-per-second) using two NVIDIA GTX 590 cards.