Comprehensive optimization for full-color holographic stereogram printing system based on single-shot depth estimation and time-controlled exposure

• Published in: Optics and laser technology 2025-02, Vol.181, p.111966, Article 111966
• Main Authors: Khuderchuluun, Anar, Erdenebat, Munkh-Uchral, Dashdavaa, Erkhembaatar, Kwon, Ki-Chul, Jeon, Seok-Hee, Kang, Hoonjong, Kim, Nam
• Format: Article
• Language: English
• Subjects: Computer-generated hologram (CGH); Computer-generated integral imaging (CGII); Convolutional neural network (CNN); Depth estimation; Holographic printer; Holographic printing; Holographic stereogram
• ISSN: 0030-3992
• DOI: 10.1016/j.optlastec.2024.111966

•Comprehensive optimization method of full-color holographic stereogram printing.•Single-shot depth estimation for proper 3D visualization of real objects.•Full-color hogel via integral imaging and unique non-iterative phase modulation.•Time-controlled exposure of full-color hogel using a single spatial light modulator.•Automated holographic printing with a custom-designed user interface. A comprehensive optimization method for a full-color holographic stereogram (HS) printing system based on single-shot depth estimation for real-world objects and time-controlled exposure is proposed. Both processing steps, including digital content generation and optical printing, are optimized to ensure possible high-quality three-dimensional (3D) holographic image printing, rapid computation, and proper full-color visualization. In the digital content generation, first a high-resolution two-dimensional (2D) image of the real object is captured, and its depth map is then estimated via a pre-trained convolutional neural network (CNN) model, ensuring an identical resolution with a given 2D image. As a post-processing, the unnecessary scenes and background are removed from the captured color image, without losing the main information of a primary object. Then, a hogel array (HA) is obtained by utilizing the estimated depth map and a post-processed color image through a fast inverse-directed propagation (IDP) method. Each hogel undergoes unique non-iterative phase modulation in a quite short time without the degradation of image quality while the chromatic dispersion errors are minimized. Finally, the hogels are sequentially printed onto holographic material using a time-controlled exposure, to provide the color-balanced full-color reconstruction using a single spatial light modulator (SLM). The overall procedure is seamlessly performed automatically via custom-designed graphical user interface. This study experimentally confirmed a simple and effective optimization for HS printing systems in both digital content generation and optical printing unit.