Wirtinger holography for near-eye displays

Abstract

Near-eye displays using holographic projection are emerging as an exciting display approach for virtual and augmented reality at high-resolution without complex optical setups --- shifting optical complexity to computation. While precise phase modulation hardware is becoming available, phase retrieval algorithms are still in their infancy, and holographic display approaches resort to heuristic encoding methods or iterative methods relying on various relaxations. In this work, we depart from such existing approximations and solve the phase retrieval problem for a hologram of a scene at a single depth at a given time by revisiting complex Wirtinger derivatives, also extending our framework to render 3D volumetric scenes. Using Wirtinger derivatives allows us to pose the phase retrieval problem as a quadratic problem which can be minimized with first-order optimization methods. The proposed Wirtinger Holography is flexible and facilitates the use of different loss functions, including learned perceptual losses parametrized by deep neural networks, as well as stochastic optimization methods. We validate this framework by demonstrating holographic reconstructions with an order of magnitude lower error, both in simulation and on an experimental hardware prototype.

Light source optimization for partially coherent holographic displays with consideration of speckle contrast, resolution, and depth of field

“…Note that the normal LED’s aperture is adjusted to 200 μm from 600 μm because 600 μm aperture carries too much resolution reduction that hinders accurate analysis. ( b ) Phase holograms generated by Wirtinger method 46 reconstruct the resolution chart for resolution analysis. Using the experimental results, we estimate the speckle contrast as well as ( c ) the relative contrast function.…”

“…6 , where the holograms reconstruct volumetric scenes. Second, we optimize phase-only holograms following the method called Wirtinger holography 46 . We apply 100 iterations for the hologram optimization.…”

Imaging with Local Speckle Intensity Correlations: Theory and Practice

“…In all of the previous figures, the reconstructions for the fullframe approach are achieved using an ADAM optimization procedure [Kingma and Ba 2014] with non-negativity constraints. This is analogous to Wirtinger flow optimization for phase retrieval [Candes et al 2014;Chakravarthula et al 2019]. We found that this approach works better than the classical optimization algorithm by Fienup [1982].…”

Time-division Color Holographic Projection in Large Size Using a Digital Micromirror Device

“…However, this method works well for amplitude holograms but needs improvements for phase-only and binary holograms [12,13]. Optimization of CGH using the Gerchberg-Saxton algorithm [14,15] and the gradient descent method [16] obtains a reconstructed image with good image quality, however, it is computationally expensive due to iterative calculations.…”