Speckle suppression in holographic displays using temporal averaging effect combined with rotating symmetric diffuser

2015 ◽  
Author(s):  
Zhenxiang Zeng ◽  
Huadong Zheng ◽  
Yingjie Yu ◽  
Hongyue Gao
Keyword(s):  
Temporal Averaging ◽  
Holographic Displays ◽  
Speckle Suppression

scholarly journals Gaze-Contingent Retinal Speckle Suppression for Perceptually-Matched Foveated Holographic Displays

2021 ◽  
pp. 1-1
Author(s):  
Praneeth Chakravarthula ◽  
Zhan Zhang ◽  
Okan Tursun ◽  
Piotr Didyk ◽  
Qi Sun ◽  
...  
Keyword(s):  
Holographic Displays ◽  
Speckle Suppression

scholarly journals Computer-Generated Hologram Based on Reference Light Multiplexing for Holographic Display

2021 ◽  
Vol 11 (16) ◽  
pp. 7199
Author(s):  
Dapu Pi ◽  
Juan Liu
Keyword(s):  
Image Quality ◽  
Numerical Simulations ◽  
Light Wave ◽  
Information Capacity ◽  
Improve Image Quality ◽  
Multiple Images ◽  
Holographic Display ◽  
Light Waves ◽  
Computer Generated Holograms ◽  
Holographic Displays

In this article, we propose a reference light wave multiplexing scheme to increase the information capacity of computer-generated holograms. The holograms were generated by different reference light waves and superimposed together as a multiplexed hologram. A modified Gerchberg–Saxton algorithm was used to improve image quality, and different images could be reconstructed when the multiplexed hologram was illuminated by corresponding reference light waves. We performed both numerical simulations and optical experiments to demonstrate the feasibility of the proposed scheme. Numerical simulations showed that the proposed method could reconstruct multiple images successfully by a single multiplexed hologram and optical experiments are consistently good with numerical simulations. It is expected that the proposed method has great potential to be widely applied in holographic displays in the future.

scholarly journals Dynamic Speckle Illumination Digital Holographic Microscopy by Doubly Scattered System

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 276
Author(s):  
Yun Liu ◽  
Peihua Bu ◽  
Mingxing Jiao ◽  
Junhong Xing ◽  
Ke Kou ◽  
...  
Keyword(s):  
Time Correlation ◽  
Digital Holographic Microscopy ◽  
Laser Source ◽  
Speckle Reduction ◽  
Single Shot ◽  
Coherent Noise ◽  
Real Time Measurement ◽  
Dynamic Speckle ◽  
Holographic Microscopy ◽  
Speckle Suppression

The coherent noise always exists in digital holographic microscopy due to the laser source, degrading the image quality. A method of speckle suppression using the dynamic speckle illumination, produced by double-moving diffusers, is presented in digital holographic microscopy. The space–time correlation functions are theoretically analyzed from the statistics distribution in the doubly and singly scattered system, respectively. The configuration of double-moving diffusers is demonstrated to have better performance in speckle suppression compared with the single diffuser and moving-static double diffusers cases. The experiment results verify the feasibility of the approach. The presented approach only requires a single shot interferogram to realize the speckle reduction, accordingly it has the potential application in real-time measurement.

scholarly journals Suppressing meta-holographic artifacts by laser coherence tuning

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yaniv Eliezer ◽  
Geyang Qu ◽  
Wenhong Yang ◽  
Yujie Wang ◽  
Hasan Yılmaz ◽  
...  
Keyword(s):  
Spatial Coherence ◽  
Fine Tuning ◽  
Total Power ◽  
Image Sharpness ◽  
Continuous Tuning ◽  
Fine Spatial Resolution ◽  
Compact Size ◽  
Wide Range ◽  
Fabrication Defects ◽  
Holographic Displays

AbstractA metasurface hologram combines fine spatial resolution and large viewing angles with a planar form factor and compact size. However, it suffers coherent artifacts originating from electromagnetic cross-talk between closely packed meta-atoms and fabrication defects of nanoscale features. Here, we introduce an efficient method to suppress all artifacts by fine-tuning the spatial coherence of illumination. Our method is implemented with a degenerate cavity laser, which allows a precise and continuous tuning of the spatial coherence over a wide range, with little variation in the emission spectrum and total power. We find the optimal degree of spatial coherence to suppress the coherent artifacts of a meta-hologram while maintaining the image sharpness. This work paves the way to compact and dynamical holographic displays free of coherent defects.

RGB imaging volumes alignment method for color holographic displays

2016 ◽  
Author(s):  
Weronika Zaperty ◽  
Tomasz Kozacki ◽  
Radosław Gierwiało ◽  
Małgorzata Kujawińska
Keyword(s):  
Alignment Method ◽  
Holographic Displays

scholarly journals Averaging-Related Biases in Monthly Latent Heat Fluxes

2012 ◽  
Vol 29 (7) ◽  
pp. 974-986 ◽  
Author(s):  
Paul J. Hughes ◽  
Mark A. Bourassa ◽  
Jeremy J. Rolph ◽  
Shawn R. Smith
Keyword(s):  
Latent Heat ◽  
Classical Method ◽  
Surface Flux ◽  
Heat Fluxes ◽  
Western Boundary ◽  
State University ◽  
Boundary Current ◽  
Surface Energy Fluxes ◽  
Temporal Averaging ◽  
The Impact

Abstract Seasonal-to-multidecadal applications that require ocean surface energy fluxes often require accuracies of surface turbulent fluxes to be 5 W m−2 or better. While there is little doubt that uncertainties in the flux algorithms and input data can cause considerable errors, the impact of temporal averaging has been more controversial. The biases resulting from using monthly averaged winds, temperatures, and humidities in the bulk aerodynamic formula (i.e., the so-called classical method) to estimate the monthly mean latent heat fluxes are shown to be substantial and spatially varying in a manner that is consistent with most prior work. These averaging-related biases are linked to nonnegligible submonthly covariances between the wind, temperature, and humidity. To provide additional insight into the averaging-related bias, the methodology behind the third-generation Florida State University monthly mean surface flux product (FSU3) is detailed to highlight additional sources of errors in gridded datasets. The FSU3 latent heat fluxes suffer from this averaging-related bias, which can be as large as 90 W m−2 in western boundary current regions during winter and can exceed 40 W m−2 in synoptically active portions of the tropics. The regional impacts of these biases on the mixed layer temperature tendency are shown to demonstrate that the error resulting from applying the classical method is physically substantial.

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