scholarly journals Holographic Pepper’s Ghost: Upright Virtual-Image Screen Realized by Holographic Mirror

2019 ◽  
Author(s):  
Tomoya Nakamura ◽  
Shinji Kimura ◽  
Kazuhiko Takahashi ◽  
Yuji Aburakawa ◽  
Shunsuke Takahashi ◽  
...  
Keyword(s):  
Virtual Image ◽  
Image Screen

Resolution in photoelectron microscopy

1991 ◽  
Vol 49 ◽  
pp. 458-459
Author(s):  
G. F. Rempfer
Keyword(s):  
Electron Microscopy ◽  
Electric Field ◽  
Ultraviolet Light ◽  
Uniform Field ◽  
Virtual Image ◽  
Lens System ◽  
Photoemission Electron Microscopy ◽  
Planar Electrode ◽  
Electron Lens ◽  
Photoemission Electron

In photoelectron microscopy (PEM), also called photoemission electron microscopy (PEEM), the image is formed by electrons which have been liberated from the specimen by ultraviolet light. The electrons are accelerated by an electric field before being imaged by an electron lens system. The specimen is supported on a planar electrode (or the electrode itself may be the specimen), and the accelerating field is applied between the specimen, which serves as the cathode, and an anode. The accelerating field is essentially uniform except for microfields near the surface of the specimen and a diverging field near the anode aperture. The uniform field forms a virtual image of the specimen (virtual specimen) at unit lateral magnification, approximately twice as far from the anode as is the specimen. The diverging field at the anode aperture in turn forms a virtual image of the virtual specimen at magnification 2/3, at a distance from the anode of 4/3 the specimen distance. This demagnified virtual image is the object for the objective stage of the lens system.

scholarly journals Metalens Eyepiece for 3D Holographic Near-Eye Display

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1920
Author(s):  
Chang Wang ◽  
Zeqing Yu ◽  
Qiangbo Zhang ◽  
Yan Sun ◽  
Chenning Tao ◽  
...  
Keyword(s):  
Light Field ◽  
Three Dimensional ◽  
Fresnel Diffraction ◽  
Virtual Image ◽  
Display Devices ◽  
Computer Generated Holography ◽  
Wavefront Shaping ◽  
3D Scene ◽  
Optimum Solution ◽  
532 Nm

Near-eye display (NED) systems for virtual reality (VR) and augmented reality (AR) have been rapidly developing; however, the widespread use of VR/AR devices is hindered by the bulky refractive and diffractive elements in the complicated optical system as well as the visual discomfort caused by excessive binocular parallax and accommodation-convergence conflict. To address these problems, an NED system combining a 5 mm diameter metalens eyepiece and a three-dimensional (3D), computer-generated holography (CGH) based on Fresnel diffraction is proposed in this paper. Metalenses have been extensively studied for their extraordinary capabilities at wavefront shaping at a subwavelength scale, their ultrathin compactness, and their significant advantages over conventional lenses. Thus, the introduction of the metalens eyepiece is likely to reduce the issue of bulkiness in NED systems. Furthermore, CGH has typically been regarded as the optimum solution for 3D displays to overcome limitations of binocular systems, since it can restore the whole light field of the target 3D scene. Experiments are carried out for this design, where a 5 mm diameter metalens eyepiece composed of silicon nitride anisotropic nanofins is fabricated with diffraction efficiency and field of view for a 532 nm incidence of 15.7% and 31°, respectively. Furthermore, a novel partitioned Fresnel diffraction and resample method is applied to simulate the wave propagations needed to produce the hologram, with the metalens capable of transforming the reconstructed 3D image into a virtual image for the NED. Our work combining metalens and CGH may pave the way for portable optical display devices in the future.

Micromirror based virtual image automotive head-up display

2016 ◽  
Vol 23 (6) ◽  
pp. 1671-1676 ◽  
Author(s):  
Chao Fan ◽  
Siyuan He
Keyword(s):  
Virtual Image

scholarly journals Body Self-Esteem, Virtual Image in Social Networks And Sexuality in Adolescent

2013 ◽  
Vol 3 (2) ◽  
pp. 171-180
Author(s):  
Montserrat Peris ◽  
Carmen Maganto ◽  
Lorea Kortabarria
Keyword(s):  
Social Networks ◽  
Positive Emotions ◽  
Basque Country ◽  
Self Esteem ◽  
Assessment Instruments ◽  
Virtual Image ◽  
Sexual Advance ◽  
Virtual Images ◽  
Body Self ◽  
Verbal Strategies

Adolescence is characterized by concerns about body self-esteem, as well as sexual arousal. Social Networks (SN) have become the way to express the sex interests in adolescents and the place where they publish more virtual photographs. Objectives: a) Analyze the sex and age differences in body self-esteem, virtual images and sexual advance strategies; b) Carry out correlations among variables studied. Participants: 200 adolescents from 14 to 17 years, 98 boys (49%), selected randomly from the Basque country. Assessment instruments: Body Self-Esteem Scale (Maganto & Kortabarria, 2011), Questionnaire of Virtual Image on Social Network (Maganto & Peris, 2011), Sexual Advance Strategies (Roman, 2009). Results: Statistically significant differences in sex and age were obtained. The boys obtained higher scores than girls in body self-esteem, erotic publications and coercive sexual strategies. Youth of 16-17 years have more strategies of sexual advances and positive emotions to sexuality than adolescents of 14-15 years. Social and erotic body self-esteem correlates positively with aesthetic, erotic publications and physical and verbal sexual advance strategies. Conclusions: Adolescents with higher body self esteem, both aesthetic and erotic, more virtual images on social networks publish, and they are those who carry out more strategies of sexual advance, specifically physical and verbal strategies.

Quantitative measurement of vertigo frequency: Preliminary results

2003 ◽  
Vol 13 (1) ◽  
pp. 53-56
Author(s):  
Robert Aureo Zalewski-Zaragoza ◽  
Erik Scott Viirre
Keyword(s):  
Quantitative Measurement ◽  
Average Frequency ◽  
Repeated Measurements ◽  
Virtual Image ◽  
Subjective Ratings ◽  
Image System ◽  
Head Mounted Display ◽  
Tinnitus Treatment ◽  
Specific Frequency ◽  
Rehabilitation Exercises

Persons who experience vertigo often describe their symptoms as a sensation of oscillations. Based on such a description, a pilot study was performed to determine if the frequency of the vertigo sensation could be quantified in a manner analogous to tone matching in tinnitus treatment. Fifteen subjects were tested using a virtual image system that consisted of a head mounted display showing a scene that oscillated horizontally or vertically at an adjustable frequency. Subjects were asked to adjust the direction and frequency to match their typical vertigo sensation. Results show that most persons with chronic vertigo had symptoms that could be realistically simulated by vection induced by the oscillating scene and that matched to a consistent specific frequency. They reported an average frequency of 1.09 Hz (range 0.27 to 3.3 Hz, SD 0.25). The large majority (13 out of 15) matched to a horizontal stimulus. Subjects that gave particularly high subjective ratings of the similarity of the motion sensation (7–8 out of 10) from the vection to their vertigo had lower frequency matches (average 0.61 +/- 0.25). Repeated measurements in 4 subjects 8 to 27 days later showed consistent results. This vertigo measurement technique may be used in the future to assess the ability of vestibular rehabilitation to reduce chronic vertigo. Identification of a specific frequency of chronic vertigo may be important in the specification of rehabilitation exercises.

scholarly journals Shape determination of unidimensional objects: the virtual image correlation method

2010 ◽  
Vol 6 ◽  
pp. 10004
Author(s):  
M. Francois ◽  
B. Semin ◽  
H. Auradou ◽  
J. Vatteville
Keyword(s):  
Correlation Method ◽  
Image Correlation ◽  
Virtual Image ◽  
Shape Determination

An Optical Imaging Simulation Method for Inverted Microscope and its Application in Automatic Cell Manipulation

2012 ◽  
Vol 490-495 ◽  
pp. 1981-1985
Author(s):  
Qi Liang Du ◽  
Xue Song Lan ◽  
Ling Yuan ◽  
Rui Liang
Keyword(s):  
Optical Imaging ◽  
Forward Direction ◽  
Simulation Method ◽  
Considerable Effect ◽  
Cell Manipulation ◽  
Egg Cell ◽  
Virtual Image ◽  
Sensing Element ◽  
Inverted Microscope ◽  
Imaging Simulation

For a further understanding of the features of objects in the microscopic image during automatic cell manipulation, an optical imaging simulation method for inverted microscope was studied, with an assumption of parallel rays of light. The proposed method calculated the forward direction of every ray starting from the source until it reached the lens or disappeared from the effective range. A virtual image could be generated by an imitation of a CCD sensing element. Emulations in cases of a micro glass bar, a micro pipette and an egg cell which were commonly encountered in cell manipulation were carried out, whose gray-level virtual images were contrasted to real ones for verification. Results showed a considerable effect of the proposed simulation method

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