Three-dimensional rendering of computer-generated holograms acquired from point-clouds on light field displays

Abstract

Holograms, either optically acquired or simulated numerically from 3D datasets, such as point clouds, have special rendering requirements for display. Evaluating the quality of hologram generation techniques is not straightforward, since high-quality holographic display technologies are still immature, In this paper we present a framework for three-dimensional rendering of colour computer-generated holograms (CGHs) acquired from point-clouds, on high-end light field displays. This allows for the rendering of holographic content with horizontal parallax and wide viewing angle. We deploy prior work, namely a fast CGH method that inherently handles occlusion problems to acquire high quality colour holograms from point clouds. Our experiments showed that rendering holograms with the proposed framework provides 3D effect with depth disparity and horizontal-only with wide viewing angle. Therefore, it allows for the evaluation of CGH techniques regarding functional properties such as depth cues and efficient occlusion handling.

JPEG Pleno: Providing representation interoperability for holographic applications and devices

“…Nonetheless, other information such as color space definitions, and (calibration) metadata will be signaled by generic boxes valid for the different modalities. Because the various imaging modalities may be converted between each other—imagine for instance an imaging chain where a point cloud is converted to a hologram, which is subsequently rendered on a light field display —the overall JPEG Pleno file format container will be utilized to contain successively, or at the end of the chain simultaneously, the different modality representations of the processed content. In summary, the JPEG Pleno file format can be considered as a Lego box that allows for a (semi)flexible combination of its composing elements.…”

Recent Advances in the Processing and Rendering Algorithms for Computer-Generated Holography

“…The reconstruction distance and the three angles for aperture position and size definition are declared by the user before launching the tool. The synthetic aperture can be apodized with a bidimensional Hanning window as proposed in [26] to reduce strong diffraction effects at the aperture's borders that may occurs in the reconstruction process. The synthetic aperture setting and its apodization are optional steps that the user can decide whether or not to perform.…”

“…Subsequently, the Absolute (ABS) block extracts the complex magnitude of the reconstructed wavefield. At this stage, the reconstructed image can be enhanced with a linear histogram stretching after a percentile clip to remove extreme values, as suggested in [26]. This optional process is performed on the Clipping & Stretch.…”

“…Holographic displays have been improved, focusing on the image quality [23] and on the compactness and portability [24], nevertheless they are not actually ready for consumer production. Due to the lack of high-performance holographic displays, other types of displays are used in these experiments, such as autostereoscopic [25], and light field [26]. Moreover, conventional 2D displays are often adopted for experimenting image reproduction schemes for analyzing the scene from different perspectives and reconstruction distances [27][28][29].…”

A Roadmap Towards Holographic Television From a Signal Processing Perspective

“…Utilizing the holographic test data that was generated by our CGH algorithms, we subjectively assessed, deploying a double stimulus method on high-end 4K displays [5]. In a subsequent step, our holograms were converted into light fields and rendered on a Holografika HoloVizio 722RC display, with a field of view of 70 • with 1 view per degree [6].…”