# Transforming Monochromatic Images into 3D Holographic Stereograms Through Depth-Map Extraction
## 1 Introduction  
As public interest in three-dimensional (3D) images grows, there is a rising demand for solutions to address the issues associated with stereoscopic or multiview 3D imaging, such as discomfort and dizziness. Several 3D imaging and display methods have been developed [1, 2], leading to an increased research interest in holography, which enables highly accurate 3D imaging [3, 4, 5]. However, the generation of holograms is highly expensive, which remains a significant challenge [6, 7] despite their potential. Holography is a technique used to record and reconstruct the intensity and phase information of a signal wavefront using a reference wave. It was invented by [PERSON] in 1948, marking the beginning of a revolutionary imaging approach. The invention of coherent laser sources in the 1960s paved the way for substantial advancements in the field of holography. Notable milestones include [PERSON]'s single-beam reflection holography and [PERSON]'s off-axis transmission holography, which laid thegroundwork for modern holographic display. These techniques not only simplify the recording process but also broaden the scope of holography, enabling its application in various fields, from art to scientific visualization [8; 9; 10]. In a typical hologram-recording setup, whether in reflection or transmission mode, a physical object is required to record a hologram, and the holographic image is usually captured at a 1:1 scale. These limitations can be addressed by adopting holographic printing techniques that use suitable datasets. There are two primary approaches to digital holographic printing [2; 11]: the numerical computation of interference fringes and optical multiplexing of digital perspective images. Numerical computation involves the algorithmic calculation of interference patterns and the encoding of the resulting data into a medium suitable for holographic displays. Although computationally intensive, this approach provides precise control over phase and intensity information, enhancing the quality of the holographic representation. By contrast, optical multiplexing integrates a series of digital perspective images into a holographic medium. This method is particularly advantageous for creating scaled holographic images and supporting dynamic features such as slight movements, animations, layering effects, and multiple encoding channels, thereby broadening the scope of holographic visualization applications [12; 13]. Perspective image datasets can be derived from digital videos or photographs, or generated using 3D computer graphics software. This method allows the integration of natural scenes or real-world images with computer-generated 3D graphics within the same holographic print, thereby offering enhanced flexibility and creativity in hologram production. This capability opens up new possibilities for holography, making it accessible for applications ranging from entertainment and education to industrial and scientific visualization. Memory preservation through holography has seen significant advancements with the advent of digital technology. Existing methods for generating digital holograms predominantly rely on stereo camera setups, photogrammetry, or high-resolution 3D models [14; 15]. However, these approaches are often inadequate when only a single black-and-white photograph is available. Our approach addresses the limitations of current hologram generation techniques by facilitating the creation of digital stereoscopic holograms from a single black-and-white photograph. In the proposed approach, digital holograms are generated from minimal input data by combining colorization techniques with depth mapping using video editing software. Our approach leverages recent advancements in image colorization and depth-mapping algorithms to transform a single monochromatic image into rich datasets suitable for holographic reconstruction.