A Co-catalyzed reductive cyclization
of acrylate-containing
1,6-enynes
is reported, providing an approach to construct five-membered carbocyclic
and heterocyclic scaffolds containing enol ethers and all-carbon quaternary
carbons. This novel process enables an E/Z mixture of 1,6-enynes to react with good functional group
tolerance and good isolated yields, in an operationally simple manner.
We previously proposed to recombine subpixels across elemental images to triple the spatial resolution of integral imaging light field displays; however, the sampling errors of subpixels force us to waive a portion of subpixels, resulting in a reduced angular resolution. In this study, the sampling errors of all subpixels are demonstrated to be zero under a specific system configuration; thus, no angular resolution is lost with a tripled spatial resolution.
Vision-correcting near-eye displays are necessary concerning the large population with refractive errors. However, varifocal optics cannot effectively address astigmatism (AST) and high-order aberration (HOAs); freeform optics has little prescription flexibility. Thus, a computational solution is desired to correct AST and HOA with high prescription flexibility and no increase in volume and hardware complexity. In addition, the computational complexity should support real-time rendering. We propose that the light field display can achieve such computational vision correction by manipulating sampling rays so that rays forming a voxel are re-focused on the retina. The ray manipulation merely requires updating the elemental image array (EIA), being a fully computational solution. The correction is first calculated based on an eye’s wavefront map and then refined by a simulator performing iterative optimization with a schematic eye model. Using examples of HOA and AST, we demonstrate that corrected EIAs make sampling rays distributed within ±1 arcmin on the retina. Correspondingly, the synthesized image is recovered to nearly as clear as normal vision. We also propose a new voxel-based EIA generation method considering the computational complexity. All voxel positions and the mapping between voxels and their homogeneous pixels are acquired in advance and stored as a lookup table, bringing about an ultra-fast rendering speed of 10 ms per frame with no cost in computing hardware and rendering accuracy. Finally, experimental verification is carried out by introducing the HOA and AST with customized lenses in front of a camera. As a result, significantly recovered images are reported.
Integral imaging light field displays (InIm-LFDs) can provide realistic 3D images by showing an elemental image array (EIA) under a lens array. However, it is always challenging to computationally generate an EIA in real-time with entry-level computing hardware because the current practice that projects many viewpoints to the EIA induces heavy computations. This study discards the viewpoint-based strategy and revisits the early point retracing rendering method, and then proposes that InIm-LFDs and regular 2D displays share two similar signal processing phases: sampling and reconstructing. An InIm-LFD is demonstrated to create a finite number of static voxels for signal sampling. And each voxel is invariantly formed by homogeneous pixels for signal reconstructing. We obtain the static voxel-pixel mapping through arbitrarily accurate raytracing in advance and store it as a lookup table (LUT). Our EIA rendering method first resamples input 3D data with the pre-defined voxels and then assigns every voxel’s value to its homogeneous pixels through the LUT. As s result, the proposed method reduces the computational complexity by several orders of magnitude. The experimental rendering speed is as fast as 7 ms for a full-HD EIA frame on an entry-level laptop. Finally, considering a voxel may not be perfectly integrated by its homogeneous pixels, called the sampling error, the proposed and conventional viewpoint-based methods are analyzed in the Fourier domain. We prove that even with severe sampling errors, the two methods negligibly differ in the output signal’s frequency spectrum. The proposed method breaks the long-standing tradeoff among rendering speed, accuracy, and system complexity for computer-generated integral imaging (CGII), expected to remove the hinder for real-time CGII.
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