We investigate how the splicing mode of a holographic element(hogel)affects the reconstruction of a 3 D scene to improve the reconstruction resolution of a holographic stereogram fabricated using the effective perspec...We investigate how the splicing mode of a holographic element(hogel)affects the reconstruction of a 3 D scene to improve the reconstruction resolution of a holographic stereogram fabricated using the effective perspective image segmentation and mosaicking method(EPISM).First,the effect of hogel spatial multiplexing on holographic recording and reconstruction is studied based on the mechanism of recording interference fringes in the holographic recording medium.Second,combined with the influence of multiple exposures on the hologram's diffraction efficiency,the diffraction efficiency of the holographic stereogram is analyzed in the spatial multiplexing mode.The holographic stereogram is then regarded as a special optical imaging system.The theory of spatial bandwidth product is adopted to describe the comprehensive resolution of the holographic stereogram,which explains why hogel spatial multiplexing can significantly improve the reconstruction resolution of a holographic stereogram.Compared with the traditional printing method under the same parameters in optical experiments,hogel spatial multiplexing has a lower diffraction efficiency but a higher quality of reconstructed image,consistent with the theoretical analysis.展开更多
A simple and effective approach is proposed to minimize the effect of unmodulated light and uneven intensity caused by the pixelated structure of the spatial light modulator in a holographic display. A more uniform im...A simple and effective approach is proposed to minimize the effect of unmodulated light and uneven intensity caused by the pixelated structure of the spatial light modulator in a holographic display. A more uniform image is produced by purposely shifting the holographic images of multiple reconstructed lights with different incident angles from the zero-diffraction-order and overlapping those selected different orders. The simulation and optical experimental results show that the influence of the zero-diffraction-order can be reduced, while keeping the good uniformity of the target images by this new approach.展开更多
The recently proposed random-phase-free method enables holographic reconstructions with very low noise,which allows fine projections without time integration of sub-holograms. Here, we describe the additional advantag...The recently proposed random-phase-free method enables holographic reconstructions with very low noise,which allows fine projections without time integration of sub-holograms. Here, we describe the additional advantage of this method, namely, the extended depth of sharp imaging. It can be attributed to a lower effective aperture of the hologram section forming a given image point at the projection screen. We experimentally compare the depth of focus and imaging resolution for various defocusing parameters in the cases of the random-phase method and the random-phase-free method. Moreover, we discuss the influence of the effective aperture in the presence of local obstacles in the hologram＇s plane.展开更多
This Letter proposes a scanned holographic display system that takes the advantage of a high-speed resonant scanner to augment a galvanometer and hence improves the opto-mechanical information distribution capabilitie...This Letter proposes a scanned holographic display system that takes the advantage of a high-speed resonant scanner to augment a galvanometer and hence improves the opto-mechanical information distribution capabilities,thereby potentially achieving an increased image size and enlarged viewing angles.展开更多
Undersampling and pixelation affect a number of imaging systems, limiting the resolution of the acquired images, whichbecomes particularly significant for wide-field microscopy applications. Various super-resolution t...Undersampling and pixelation affect a number of imaging systems, limiting the resolution of the acquired images, whichbecomes particularly significant for wide-field microscopy applications. Various super-resolution techniques have been implemented to mitigate this resolution loss by utilizing sub-pixel displacements in the imaging system, achieved, for example, byshifting the illumination source, the sensor array and/or the sample, followed by digital synthesis of a smaller effective pixel bymerging these sub-pixel-shifted low-resolution images. Herein, we introduce a new pixel super-resolution method that is basedon wavelength scanning and demonstrate that as an alternative to physical shifting/displacements, wavelength diversity can beused to boost the resolution of a wide-field imaging system and significantly increase its space-bandwidth product. We confirmedthe effectiveness of this new technique by improving the resolution of lens-free as well as lens-based microscopy systems anddeveloped an iterative algorithm to generate high-resolution reconstructions of a specimen using undersampled diffraction patterns recorded at a few wavelengths covering a narrow spectrum (10–30 nm). When combined with a synthetic-aperture-baseddiffraction imaging technique, this wavelength-scanning super-resolution approach can achieve a half-pitch resolution of250 nm, corresponding to a numerical aperture of ~ 1.0, across a large field of view (420 mm^(2)). We also demonstrated theeffectiveness of this approach by imaging various biological samples, including blood and Papanicolaou smears. Compared withdisplacement-based super-resolution techniques, wavelength scanning brings uniform resolution improvement in all directionsacross a sensor array and requires significantly fewer measurements. This technique would broadly benefit wide-field imagingapplications that demand larger space-bandwidth products.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2017YFB1104500)the National Natural Science Foundation of China(Grant No.61775240)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201432)。
文摘We investigate how the splicing mode of a holographic element(hogel)affects the reconstruction of a 3 D scene to improve the reconstruction resolution of a holographic stereogram fabricated using the effective perspective image segmentation and mosaicking method(EPISM).First,the effect of hogel spatial multiplexing on holographic recording and reconstruction is studied based on the mechanism of recording interference fringes in the holographic recording medium.Second,combined with the influence of multiple exposures on the hologram's diffraction efficiency,the diffraction efficiency of the holographic stereogram is analyzed in the spatial multiplexing mode.The holographic stereogram is then regarded as a special optical imaging system.The theory of spatial bandwidth product is adopted to describe the comprehensive resolution of the holographic stereogram,which explains why hogel spatial multiplexing can significantly improve the reconstruction resolution of a holographic stereogram.Compared with the traditional printing method under the same parameters in optical experiments,hogel spatial multiplexing has a lower diffraction efficiency but a higher quality of reconstructed image,consistent with the theoretical analysis.
基金supported by the UK Engineering and Physical Sciences Research Council(EPSRC) for the support through the EPSRC Centre for Innovative Manufacturing in Ultra Precision(EP/I033491/1)
文摘A simple and effective approach is proposed to minimize the effect of unmodulated light and uneven intensity caused by the pixelated structure of the spatial light modulator in a holographic display. A more uniform image is produced by purposely shifting the holographic images of multiple reconstructed lights with different incident angles from the zero-diffraction-order and overlapping those selected different orders. The simulation and optical experimental results show that the influence of the zero-diffraction-order can be reduced, while keeping the good uniformity of the target images by this new approach.
基金funded by the Polish National Centre for Research and Development(No.LIDER/013/469/L-4/12/NCBR/2013)the Polish National Science Centre(No.2015/17/B/ST7/03754)
文摘The recently proposed random-phase-free method enables holographic reconstructions with very low noise,which allows fine projections without time integration of sub-holograms. Here, we describe the additional advantage of this method, namely, the extended depth of sharp imaging. It can be attributed to a lower effective aperture of the hologram section forming a given image point at the projection screen. We experimentally compare the depth of focus and imaging resolution for various defocusing parameters in the cases of the random-phase method and the random-phase-free method. Moreover, we discuss the influence of the effective aperture in the presence of local obstacles in the hologram＇s plane.
基金part of the COIN-3DⅡproject as a collaboration between the University of Cambridge and Disney Research under the CAPE consortium
文摘This Letter proposes a scanned holographic display system that takes the advantage of a high-speed resonant scanner to augment a galvanometer and hence improves the opto-mechanical information distribution capabilities,thereby potentially achieving an increased image size and enlarged viewing angles.
基金The Ozcan Research Group at UCLA gratefully acknowledges the support of the Presidential Early Career Award for Scientists and Engineers(PECASE),the Army Research Office(ARO,W911NF-13-1-0419 and W911NF-13-1-0197)the ARO Life Sciences Division,the ARO Young Investigator Award,the National Science Foundation(NSF)CAREER Award,the NSF CBET Division Biophotonics Program,the NSF Emerging Frontiers in Research and Innovation(EFRI)Award,the NSF EAGER Award,NSF INSPIRE Award,NSF PFI(Partnerships for Innovation)Award,the Office of Naval Research(ONR)+1 种基金and the Howard Hughes Medical Institute(HHMI)This work is based on research performed in a laboratory renovated by the National Science Foundation under Grant No.0963183,which is an award funded under the American Recovery and Reinvestment Act of 2009(ARRA).
文摘Undersampling and pixelation affect a number of imaging systems, limiting the resolution of the acquired images, whichbecomes particularly significant for wide-field microscopy applications. Various super-resolution techniques have been implemented to mitigate this resolution loss by utilizing sub-pixel displacements in the imaging system, achieved, for example, byshifting the illumination source, the sensor array and/or the sample, followed by digital synthesis of a smaller effective pixel bymerging these sub-pixel-shifted low-resolution images. Herein, we introduce a new pixel super-resolution method that is basedon wavelength scanning and demonstrate that as an alternative to physical shifting/displacements, wavelength diversity can beused to boost the resolution of a wide-field imaging system and significantly increase its space-bandwidth product. We confirmedthe effectiveness of this new technique by improving the resolution of lens-free as well as lens-based microscopy systems anddeveloped an iterative algorithm to generate high-resolution reconstructions of a specimen using undersampled diffraction patterns recorded at a few wavelengths covering a narrow spectrum (10–30 nm). When combined with a synthetic-aperture-baseddiffraction imaging technique, this wavelength-scanning super-resolution approach can achieve a half-pitch resolution of250 nm, corresponding to a numerical aperture of ~ 1.0, across a large field of view (420 mm^(2)). We also demonstrated theeffectiveness of this approach by imaging various biological samples, including blood and Papanicolaou smears. Compared withdisplacement-based super-resolution techniques, wavelength scanning brings uniform resolution improvement in all directionsacross a sensor array and requires significantly fewer measurements. This technique would broadly benefit wide-field imagingapplications that demand larger space-bandwidth products.
