Mix-and-match holography

Abstract

Fig. 1. Overview of mix-and-match holography. We computationally design pairs of diffractive optical elements that encode multiple holograms or target images under different geometric alignments or DOE pairings (top left: encoding scheme, bottom left: fabricated DOEs). By changing the geometric alignment or pairing different DOEs, the individual encoded holograms can be de-multiplexed. Illumination with a pre-determined lighting condition produces the corresponding target image, that can be generalized in a wide range of scenarios (selected results presented on the right: through offset layer pairing (a), combinational pairing (b), multiview images' encoding (c), and animated images through linear translation (d)). The design process makes use of a combination of iterative phase retrieval methods and complex matrix factorization.Computational caustics and light steering displays offer a wide range of interesting applications, ranging from art works and architectural installations to energy efficient HDR projection. In this work we expand on this concept by encoding several target images into pairs of front and rear phasedistorting surfaces. Different target holograms can be decoded by mixing and matching different front and rear surfaces under specific geometric alignments. Our approach, which we call mix-and-match holography, is made possible by moving from a refractive caustic image formation process to a diffractive, holographic one. This provides the extra bandwidth that is required to multiplex several images into pairing surfaces.We derive a detailed image formation model for the setting of holographic projection displays, as well as a multiplexing method based on a combination of phase retrieval methods and complex matrix factorization. We demonstrate several application scenarios in both simulation and physical prototypes.

Quantitative Phase and Intensity Microscopy Using Snapshot White Light Wavefront Sensing

“…All data required to determine the phase shift are gathered in a single snapshot utilizing a coded wavefront sensor 34 , so there is no need for scanning, which however is one potential future research direction to obtain scattering images 44,57,58 . Specific grating (mask) designs or multi-layer designs 59,60 are potential directions. Fast simultaneous amplitude and phase acquiring advances current tomography techniques 61–63 beyond X-ray.…”

P‐81: Full‐Color Computer‐Generated Holograms Based on Offset Algorithm and Tilted Mechanism

“…To effectively solve the effect of zero-order light, a tilted lightguide mechanism and the offset of algorithm location multiplex are used for the image reconstruction design to effectively separate zero-order item and non-image light and largely enhance the image quality as shown in Figure 3. Related diffraction efficiency (RDE), root mean square error (RMSE), signal to noise ratio (SNR), speckle contrast (SC), and structure similarity index (SSIM index) are utilized in this study for evaluating the image reconstruction [3][4][5]. The experimental result is captured by Nikon D90 with 85mm/F1.8-16 zoom lens equipped on the tripod to simulate the viewer's eyes, and the recorded images are further analyzed with RDE, RMSE, SNR, SC, and SSIM, Table 1.…”

Design and fabrication of freeform holographic optical elements

“…The design of optical elements to create specific caustics is an interesting extension of conventional freeform illumination design that has been investigated in the computer graphics community [Damberg and Heidrich 2015;Mérigot et al 2017;Schwartzburg et al 2014;Yue et al 2014]. Some computergenerated holograms can also create images by simulating wave propagation directly to fabricate the proper phase masks [Peng et al 2017]. However our caustic HOEs are distinct from computergenerated holograms since ours are based on smooth optical power variations rather than complicated diffraction phase patterns.…”