Holographic display stands as a prominent approach for achieving lifelike three-dimensional (3D) reproductions with continuous depth sensation. However, the generation of a computer-generated hologram (CGH) always relies on the repetitive computation of diffraction propagation from point-cloud or multiple depth-sliced planar images, which inevitably leads to an increase in computational complexity, making real-time CGH generation impractical. Here, we report a new CGH generation algorithm capable of rapidly synthesizing a 3D hologram in only one-step backward propagation calculation in a novel split Lohmann lens-based diffraction model. By introducing an extra predesigned virtual digital phase modulation of multifocal split Lohmann lens in such a diffraction model, the generated CGH appears to reconstruct 3D scenes with accurate accommodation abilities across the display contents. Compared with the conventional layer-based method, the computation speed of the proposed method is independent of the quantized layer numbers, and therefore can achieve real-time computation speed with a very dense of depth sampling. Both simulation and experimental results validate the proposed method.

The bidirectional error diffusion (BERD) algorithm is free from random phase modulation that introduces speckle noise on the reconstructed images, compared with other computer-generated phase-only hologram (POH) approaches. During the POH generation process, the amplitudes of all pixels are traditionally set to one for diffusing the errors to their neighborhood of unprocessed pixels. In this paper, we reveal that the reconstruction quality depends on the uniform amplitude value for different object pattern. The pattern-adaptive BERD (PA-BERD) algorithm is proposed for high-quality holographic reconstruction. The optimized amplitude value can be acquired for each object pattern and each propagation distance. The PA-BERD-based POHs have shown higher reconstruction quality than traditional BERD-based POHs in simulations as well as optical experiments.

Past research has demonstrated that a sampled phase-only hologram (SPOH) is capable of representing an image without the magnitude component of the hologram. At present, an SPOH can only record and reconstruct a single source image. In this Letter, we propose, for the first time, to the best of our knowledge, a method for representing multiple images with a single integrated SPOH (ISPOH). Subsequently, each image can be retrieved from the ISPOH with a unique key parameter and displayed as a visible image on a phase-only spatial light modulator.

Computer-generated holography (CGH) is a technique for converting a three-dimensional (3D) object scene into a two-dimensional (2D), complex-valued hologram. One of the major bottlenecks of CGH is the intensive computation that is involved in the hologram generation process. To overcome this problem, numerous research works have been conducted with the aim of reducing arithmetic operations involved in CGH. In this paper, we shall review a number of fast CGH methods that have been developed in the past decade. These methods, which are commonly referred to as point-based CGH, are applied to compute digital Fresnel holograms for an object space that is represented in a point cloud model. While each method has its own strength and weakness, trading off conflicting issues, such as computation efficiency and memory requirement, they also exhibit potential grounds of synergy. We hope that this paper will bring out the essence of each method and provide some insight on how different methods may crossover into better ones.

We propose a method for color electroholography using a simple red–green–blue (RGB) gradation representation method without controlling the respective brightness of the reference RGB-colored lights. The proposed method uses RGB multiple bit planes comprising RGB binary-weighted computer-generated holograms with various light transmittances. The object points of a given three-dimensional (3D) object are assigned to RGB multiple bit planes according to their RGB gradation levels. The RGB multiple bit planes are sequentially displayed in a time-division-multiplexed manner. Consequently, the proposed method yields a color gradation representation of a reconstructed 3D object.

A method is proposed to realize accurate spatial complex modulation based on the spatial cross-modulation method (SCMM) via a phase-only spatial light modulator. The conventional SCMM cannot achieve high quality reconstruction, especially when the diffusion ratio is small. We propose an iterative algorithm in the calculation of a computer-generated hologram to implement accurate complex modulation. It enables us to generate a high quality reconstruction under a small diffusion ratio. The feasibility of the method is verified by both a numerical simulation and an optical experiment.

We propose a simple gradation representation method using a binary-weighted computer-generated hologram (CGH) to be displayed on a high-speed spatial light modulator that can be controlled by the pulse-width modulation technique. The proposed method uses multiple bit planes comprising binary-weighted CGHs with various pulse widths. The object points of a three-dimensional (3D) object are assigned to multiple bit planes according to their gray levels. The bit planes are sequentially displayed in a time-division-multiplexed manner. Consequently, the proposed method realizes a gradation representation of a reconstructed 3D object.

A computer generated holographic stereogram based on the wavefront recording plane (WRP) is presented. A WRP closed to the parallax image plane is introduced to record the complex amplitude in a small region for each point in the parallax image. By using three times of fast Fourier transform (FFT) to execute the Fresnel diffraction calculation between the WRP and the holographic stereogram plane, the object wave contributing to the hologram pattern can be achieved. The computation complexity of the proposed approach is dramatically reduced. The results show that the calculation time can be decreased by more than one order of magnitude.