High-contrast, speckle-free, true 3D holography via binary CGH optimization

Abstract

Holography is a promising approach to implement the three-dimensional (3D) projection beyond the present two-dimensional technology. True 3D holography requires abilities of arbitrary 3D volume projection with high-axial resolution and independent control of all 3D voxels. However, it has been challenging to implement the true 3D holography with high-reconstruction quality due to the speckle. Here, we propose the practical solution to realize speckle-free, high-contrast, true 3D holography by combining random-phase, temporal multiplexing, binary holography, and binary optimization. We adopt the random phase for the true 3D implementation to achieve the maximum axial resolution with fully independent control of the 3D voxels. We develop the high-performance binary hologram optimization framework to minimize the binary quantization noise, which provides accurate and high-contrast reconstructions for 2D as well as 3D cases. Utilizing the fast operation of binary modulation, the full-color high-framerate holographic video projection is realized while the speckle noise of random phase is overcome by temporal multiplexing. Our high-quality true 3D holography is experimentally verified by projecting multiple arbitrary dense images simultaneously. The proposed method can be adopted in various applications of holography, where we show additional demonstration that realistic true 3D hologram in VR and AR near-eye displays. The realization will open a new path towards the next generation of holography.

Perceptually motivated loss functions for computer generated holographic displays

“…Current IQMs are not well specifically benchmarked for those real-world and CGH distortions. For partial coherent light illumination in the holographic optical system that could bring more blurry effect and contrast reduction in the replay field 57 , 64 , modern IQMs may take advantage in inferring blurry and contrast-reduced information. Therefore, the use of IQMs may potentially have better performance in partial coherent holographic displays.…”

“…All reconstructed images are averaged out across three captured images which are captured in sRGB, the camera’s native color space. We further applied the image linearization process that converts the captured image from sRGB intensity into monochromatic linear space amplitude 13 , 57 .…”

End-to-end learning of 3D phase-only holograms for holographic display

“…Using an incoherent rendering model to generate the target focal stack while matching it under the constraint of the coherent propagation model may offer a more realistic 3D perception without breaking holography’s principle of operation. This can be further combined with temporal time-multiplexing to improve the image quality 47 .…”

Effect of Bit-depth in Stochastic Gradient Descent Performance for Phase-only Computer-generated Holography Displays

“…We develop our own algorithm, Quantised Stochastic Gradient Descent (Q-SGD), which extends the SGD algorithm such that it can to executed on an arbitrary bit-depth display device. Q-SGD iterates on previously developed SGD [31] (continuous phase) and B-SGD [40] (binary-amplitude) algorithms for high-fidelity holographic display images. 3.…”

“…Hence it is not possible to use standard techniques for transforming continuous-phase to quantised-phase holograms. Peng et al used continuous-phase holograms for the SGD algorithm [31] whilst Lee et al [40] developed B-SGD in order to provide binary-amplitude quantisation by using a HardTanh function to provide binary quantisation whilst maintaining mathematical continuity in the output. Our work here is a more general extension to B-SGD.…”