A computer-generated hologram (CGH) allows synthetizing view of 3D scene of real or virtual objects. Additionally, CGH with wide-angle view offers the possibility of having a 3D experience for large objects. An important feature to consider in the calculation of CGHs is occlusion between surfaces because it provides correct perception of encoded 3D scenes. Although there is a vast family of occlusion culling algorithms, none of these, at the best of our knowledge, consider occlusion when calculating CGHs with wide-angle view. For that reason, in this work we propose an occlusion culling algorithm for wide-angle CGHs that uses the Fourier-type phase added stereogram (PAS). It is shown that segmentation properties of the PAS can be used for setting efficient conditions for occlusion culling of hidden areas. The method is efficient because it enables processing of dense cloud of points. The investigated case has 24 million of point sources. Moreover, quality of the occluded wide-angle CGHs is tested by two propagation methods. The first propagation technique quantifies quality of point reproduction of calculated CGH, while the second method enables the quality assessment of the occlusion culling operation over an object of complex shape. Finally, the applicability of proposed occlusion PAS algorithm is tested by synthetizing wide-angle CGHs that are numerically and optically reconstructed.

Small eyebox in wide-angle holographic near-eye display is a severe limitation for 3D visual immersion of the device. In this paper, an opto-numerical solution for extending the eyebox size in these types of devices is presented. The hardware part of our solution expands the eyebox by inserting a grating of frequency f_g within a non-pupil forming display configuration. The grating multiplies eyebox, increasing the possible eye motion. The numerical part of our solution is an algorithm that enables proper coding of wide-angle holographic information for projecting correct object reconstruction at arbitrary eye position within the extended eyebox. The algorithm is developed through the employment of the phase-space representation, which facilitates the analysis of the holographic information and the impact of the diffraction grating in the wide-angle display system. It is shown that accurate encoding of the wavefront information components for the eyebox replicas is possible. In this way, the problem of missing or incorrect views in wide angle near-eye display with multiplied eyeboxes is efficiently solved. Moreover, this study investigates the space-frequency relation between the object and the eyebox and how the hologram information is shared between eyebox replicas. The functionality of our solution is tested experimentally in an augmented reality holographic near-eye display that has maximum field of view of 25.89°. Obtained optical reconstructions demonstrate that correct object view is obtained for arbitrary eye position within extended eyebox.

High-quality wide-angle holographic content is at the heart of the success of near-eye display technology. This work proposes the first digital holographic (DH) system enabling recording wide-angle scenes assembled from objects larger than the setup field of view (FOV), which can be directly replayed without 3D deformation in the near-eye display. The hologram formation in the DH system comprises free space propagation and Fourier transform (FT), which are connected by a rectangular aperture. First, the object wave propagates in free space to the rectangular aperture. Then, the band-limited wavefield is propagated through the single lens toward the camera plane. The rectangular aperture can take two sizes, depending on which DH operates in off-axis or phase-shifting recording mode. An integral part of the DH solution is a numerical reconstruction algorithm consisting of two elements: fringe processing for object wave recovery and wide-angle propagation to the object plane. The second element simulates propagation through both parts of the experimental system. The free space part is a space-limited angular spectrum compact space algorithm, while for propagation through the lens, the piecewise FT algorithm with Petzval curvature compensation is proposed. In the experimental part of the paper, we present the wide-angle DH system with FOV 25°×19°, which allows high-quality recording and reconstruction of large complex scenes.

Near-eye holographic displays are the holy grail of wear-on 3D display devices because they are intended to project realistic wide-angle virtual scenes with parameters matching human vision. One of the key features of a realistic perspective is the ability to move freely around the virtual scene. This can be achieved by addressing the display with wide-angle computer-generated holograms (CGHs) that enable continuous viewpoint change. However, to the best of our knowledge there is no technique able to generate these types of content. Thus, in this work we propose an accurate and non-paraxial hologram update method for wide-angle CGHs that supports continuous viewpoint change around the scene. This method is based on the assumption that with a small change in perspective, two consecutive holograms share overlapping data. This enables reusing the corresponding part of the information from the previous view, eliminating the need to generate an entirely new hologram. Holographic information for the next viewpoint is calculated in two steps: first, a tool approximating the Angular Spectrum Propagation is proposed to generate the hologram data from previous viewpoint; and second, the efficient Phase Added Stereogram algorithm is utilized for generating the missing hologram content. This methodology offers fast and accurate calculations at the same time. Numerical and optical experiments are carried out to support the results of the proposed method.

Wide-angle capability is essential for holographic near-eye displays. Most of these employ phase-only spatial light modulators, so CGH must be encoded as phase-only holograms (PoHs). Thus, this paper investigates three known encoding methods: double phase hologram (DPH), direct phase only hologram (D-PoH), and complex amplitude modulation (CAM). To determine the most optimal phased-encoding method, we evaluate them by field of view, image quality, and diffraction efficiency. It was found that CAM gives very low brightness and quality; thus, improvement of the CAM is proposed. Also, we conclude that D-PoH is the optimal method for the wide-angle case. Full Text: PDF References T. Zhan, K. Yin, J. Xiong, Z. He, S.T. Wu, "ugmented Reality and Virtual Reality Displays: Perspectives and Challenges", iScience 23(8), 101397 (2020). CrossRef T. Gu, C. Han, H. Qin, K. Sun, "Phase-only hologram optimization with adaptive constraint strategy for high-quality optical reconstruction", Opt. Express 32(25), 379 (2024). CrossRef S.J. Liu, L.F. Feng, S.J. Ji, H.N. Yan, K. Yang, P.P. Li, D. Wang, "Speckle noise suppression method in holographic display using optimized pixel processing", Opt. Laser Technol. 181, 111644 (2025). CrossRef J. Wu, K. Liu, X. Sui, L. Cao, "High-speed computer-generated holography using an autoencoder-based deep neural network", Opt. Lett. 46(12), 2908 (2021). CrossRef O. Mendoza-Yero, G. Mínguez-Vega, J. Lancis, "Encoding complex fields by using a phase-only optical element", Opt. Lett. 39(7), 1740 (2014). CrossRef Y. Qi, C. Chang, J. Xia, "Speckleless holographic display by complex modulation based on double-phase method", Opt. Express 24(26), 30368 (2016). CrossRef J. Martinez-Carranza, T. Kozacki, "High diffraction efficiency complex amplitude modulation technique by using antiwave functions", Opt. Lett. 49(18), 5115 (2024). CrossRef T. Kozacki, J. Martinez-Carranza, I. Gerej, R. Kukolowicz, M. Chlipala, M. Sajeev Idicula, "Frequency domain method for wide angle computer generated hologram", Opt. Laser Technol. 181, 111610 (2025). CrossRef T. Kozacki, J. Martinez-Carranza, M. Chlipala, R. Kukolowicz, M. Sajeev Idicula, Arxiv (i), 1-18 (2024). CrossRef