Fourier horizontal parallax only computer and digital holography of large size

Abstract

Registration and reconstruction of high-quality digital holograms with a large view angle are intensive computer tasks since they require the space-bandwidth product (SBP) of the order of tens of gigapixels or more. This massive use of SBP severely affects the storing and manipulation of digital holograms. In order to reduce the computer burden, this work focuses on the generation and reconstruction of very large horizontal parallax only digital holograms (HPO-DHs). It is shown that these types of holograms can preserve high quality and large view angle in x direction while keeping a low use of SBP. This work first proposes a numerical technique that allows calculating very large HPO-DHs with large pixel size by merging the Fourier holography and phase added stereogram algorithm. The generated Fourier HPO-DHs enable accurate storing of holographic data from 3D objects. To decode the information contained in these Fourier HPO-DHs (FHPO-DHs), a novel angular spectrum (AS) technique that provides an efficient use of the SBP for reconstruction is proposed. Our reconstruction technique, which is called compact space bandwidth AS (CSW-AS), makes use of cylindrical parabolic waves that solve sampling issues of FHPO-DHs and AS. Moreover, the CSW-AS allows for implementing zero-padding for accurate wavefield reconstructions. Hence, suppression of aliased components and high spatial resolution is possible. Notably, the imaging chain of Fourier HPO-DH enables efficient calculation, reconstruction and storing of HPO holograms of large size. Finally, the accuracy and utility of the developed technique is proved by both numerical and optical reconstructions.

Advances in Digital Holographic Interferometry

“…Reconstruction and filtering of high-resolution holograms are resource-intensive tasks that require high information throughput of computer channels for transmitting digital holograms with a resolution of the order of tens of gigapixels. To reduce the load on the computer, it is proposed to create and reconstruct horizontal parallax digital holograms [ 74 ].…”

Automotive Holographic Head‐Up Displays

“…This method was achieved by the rotation or translation of a scene in 2D with parallax effect in the rendering process. [175,176] Original images could also be recreated through the binocular disparity (stereopsis), which defined a visual process for both eyes when a scene is viewed from slightly different angles. [174,177] This process recreated close to real-life holographic projections due to the meshing process of 2D scenes in one coherent depth-perceived visual response.…”

Fast 3D Content Update for Wide-Angle Holographic Near-Eye Display

“…Thus, the PAS algorithm was employed for filling the blank part of the hologram. Moreover, PAS enables easy calculation of hologram information directly from the frequency domain, which further improves execution time [21,36,38].…”

“…are the discrete local directional frequencies [21] where ∆f s = 1/N s ∆ is the frequency sampling, • is the rounding operation, and the angles θ pxnm , θ pynm are the incident angles of object beams on x and y directions according to the center position of the segment, respectively. Notably, Equation (2) allows representing the three-dimensional point source information as a set of two-dimensional Dirac deltas [36,38]. The position of each delta into Õ mn is given by the discrete frequencies shown in Equations ( 3) and ( 4).…”

“…On the other hand, when the segment size is larger to reduce the amount of discretization error, the reconstruction noise will be increased because of the condition from sampling [36]. Thus, the proper size of a segment is a kind of compromise for PAS [38]. The accuracy problem in PAS is improved by using accurate PAS (A-PAS) [36].…”