نتایج جستجو برای: hologram

تعداد نتایج: 1597  

Journal: :Optics letters 2009
P Ferraro M Paturzo P Memmolo A Finizio

We show here that through an adaptive deformation of digital holograms it is possible to manage the depth of focus in 3D imaging reconstruction. Deformation is applied to the original hologram with the aim to put simultaneously in focus, and in one reconstructed image plane, different objects lying at different distances from the hologram plane (i.e., CCD sensor). In the same way, by adapting t...

Journal: :Optics letters 2006
Lingfeng Yu Myung K Kim

A new method for resolution control in numerical reconstruction of digital holography is proposed. The wave field on a tilted or vertical plane can be reconstructed without being subject to the minimum object-to-hologram distance requirement, and the pixel resolution can be easily controlled by adjusting the position of a transitional plane. The proposed method solves the problem of pixel resol...

2016
Wenyu Zhao Huan Jiang Bingyi Liu Jie Song Yongyuan Jiang Chengchun Tang Junjie Li

Conventional metasurface holograms relying on metal antennas for phase manipulation suffer from strong Ohmic loss and incomplete polarization conversion. The efficiency is limited to rather small values when operating in transmission mode. Here, we implement a high-efficiency transmissive metasurface hologram by leveraging the recently developed Huygens' metasurface to construct an electric and...

Journal: :Optics letters 1993
J Rosen M Segev A Yariv J Barhen

We suggest a method for coding high-resolution computer-generated volume holograms. It involves splitting the computer-generated hologram into multiple holograms, their individual recording as volume holograms by use of the maximal resolution available from the spatial light modulator, and subsequent simultaneous reconstruction. We demonstrate the recording and the reconstruction of a computer-...

Journal: :Optics letters 1986
J Hong D Psaltis

The storage capacity of holographic associative memories is estimated. An argument based on the available degrees of freedom shows that the number of patterns that can be stored is limited by the space-bandwidth product of the hologram divided by the number of pixels in each pattern. A statistical calculation shows that if we attempt to store associations by multiply exposing the hologram, the ...

Journal: :Applied optics 2012
Hong Di Kangfeng Zheng Xin Zhang Edmund Y Lam Taegeun Kim You Seok Kim Ting-Chung Poon Changhe Zhou

We present multiple-image encryption (MIE) based on compressive holography. In the encryption, a holographic technique is employed to record multiple images simultaneously to form a hologram. The two-dimensional Fourier data of the hologram are then compressed by nonuniform sampling, which gives rise to compressive encryption. Decryption of individual images is cast into a minimization problem....

Journal: :Applied optics 2002
Cristian Neipp Inmaculada Pascual Augusto Beléndez

The mechanism of hologram formation in fixation-free rehalogenating bleaching processes have been treated by different authors. The experiments carried out on Agfa 8E75 HD plates led to the conclusion that material transfer from the exposed to the unexposed zones is the main mechanism under theprocess. We present a simple model that explains the mechanism of hologram formation inside the emulsi...

Journal: :Applied optics 2008
Mark L Tachiki Masahide Itoh Toyohiko Yatagai

Focus analysis techniques from computer vision are applied to digital holography to determine the depth (range) of multiple objects and their surfaces from a single hologram capture. With this method the depths of objects can be determined from a single hologram capture without the need for manual focusing and without prior information on object location. Variance and the Laplacian of Gaussian ...

Journal: :Optics express 2014
Tiffany Harte Graham D Bruce Jonathan Keeling Donatella Cassettari

Direct minimisation of a cost function can in principle provide a versatile and highly controllable route to computational hologram generation. Here we show that the careful design of cost functions, combined with numerically efficient conjugate gradient minimisation, establishes a practical method for the generation of holograms for a wide range of target light distributions. This results in a...

Journal: :Optics express 2009
M Paturzo P Memmolo A Tulino A Finizio P Ferraro

We investigated a method for the angular multiplexing and de-multiplexing of digital holograms recorded in microscope off-axis configuration. The multiplexing has been performed rotating numerically one hologram at different angles and adding all the rotated holograms to obtain a single synthetic digital hologram. Then the digital holograms were de-multiplexed thanks to the unique property of t...

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