Pupil replication with crossed gratings in an AR display is modelled and characterised. It is found that, compared to linear gratings, crossed gratings in a hexagonal lattice offer an additional degree of freedom to control the angular spread of pupils and can potentially improve the uniformity of the pupil map. In terms of characterisation, the model explains well the trend observed in experiments. Good quantitative agreement of the relative pupil intensity is obtained for a number of the measured waveguides.
The digital holography and holographic display constitute the best framework of 3D imaging as they aim to recreate the complete optical field emitted by a recorded scene. In this paper, we present two techniques of Fourier holographic imaging of real world objects. The first solution is an end-to-end full color Fourier holographic imaging approach, which involves standard RGB holographic recording an LED-driven viewing window display. It gives possibility of almost undistorted orthoscopic reconstruction of large real objects. Second architecture uses the same digital holographic content and horizontal parallax rainbow holographic display, which has reduced space bandwidth product requirements.
Proc. SPIE. 9970, Optics and Photonics for Information Processing X
KEYWORDS: Holograms, Holography, 3D image reconstruction, Digital holography, Sensors, Image processing, Image registration, Spatial light modulators, 3D image processing, RGB color model, RGB color model
In this work we present a high pixel count color holographic registration system that is designed to provide 3D
holographic content of real-world large objects. Captured data is dedicated for holographic displays with a wide-viewing
angle. The registration in color is realized by means of sequential recording with the use of three RGB laser light
sources. The applied Fourier configuration of capture system gives large viewing angle and an optimal coverage of the
detector resolution. Moreover, it enables to filter out zero order and twin image. In this work the captured Fourier
holograms are transformed to general Fresnel type that is more suitable for 3D holographic displays. High resolution and
large pixel count of holographic data and its spatial continuity is achieved through synthetic aperture concept with
camera scanning and subpixel correlation based stitching. This grants an access to many tools of numerical hologram
processing e.g. continuous viewing angle adjustment, and control of 3D image position and size. In this paper the
properties of 1D synthetic aperture (60000 x 2500 pixels) are investigated. Each of the RGB 1D SA holograms is
composed of 71 frames, which after stitching result in approx. 150 Megapixel hologram pixel count and 12° angular field
of view. In experimental part high quality numerical reconstructions for each type of the hologram are shown. Moreover,
the captured holograms are used for generation of hybrid hologram that is assembled from a set of RGB holograms of
different color statues of height below 20 cm. In the final experiment this hybrid hologram as well as RGB hologram of a
single object are reconstructed in the color holographic display.