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There are some factors that play a crucial role in deciding the image quality during the optical as well as the micrographic association with the technique of the shadow casting in which contrast of the image has influenced with obliquely depositing of a thin layer of the metal during the process of the microscopic preparations. Further castingadvantages of the using shadow technique are to be observed during the process if shadow casting itself. Shadow casting posses’ number of the advantages over the other casting methods. The most prominent advantage is that if the height and thickness of an object is not completely flat that can be easily notice by the shadow of that object. The lengths of the shadow of the uneven part are so differentiate from other part that can be easily determined. Shadow casting uses the scattering power or even the optical efficiency to bring out the specimens contours and will easily get notice in order to check the flatness of the surfaces.

The developed and tested methods of dynamic control of micro-objects (MOs) of nuclear fuel, based on the reconstruction of spatial geometric characteristics of MOs along the contours of two-dimensional shadow projections, are considered. To describe the dimensions of the MOs, the overall dimensions and the average projected diameter are chosen, and their shape is described using the nonsphericity coefficient, which is defined as the ratio of the maximum overall size of the object to its minimum overall size. Metrological characteristics of control methods are given.

Variation in electrical performance measurement of industrial crystalline Si (c-Si) solar cells is commonly observed. The probable reasons include non-uniform illumination, spectral mismatch, shadow due to dissimilar probing bars and probing schemes incompatible to cell front metal contact design. In the present work, we have studied the impact of shadow of probing bars on the I-V measurement of Al-BSF c-Si test solar cell. The shadow created due to fixed width of probe bars (PB) reduce the current generation along the contact bus bars (BB). A correction factor is devised for shadow loss in short circuit current of the test cell and applied in the I-V measurements. Additionally, we observed the variation in correction factor due to the difference in BB and PB width resulted in the difference in power loss even contacting using the same bus bars. In conclusion, we have successfully applied shadow correction in our I-V testing facility (B) and reduced the magnitude of variation from 2.75% to 0.25% in solar cell performance when compared with other testing facility (A).

—An informative and very clear experimental method for studying the processes that accompany the propagation of shock waves in transparent materials under powerful pulsed exposure is proposed. The method is based on analysis of the shadow streak image formed by probe laser radiation that passes through a sample. The sensitivity of the method is estimated. The method was tested on samples of polymethyl methacrylate (PMMA) and K-8 optical glass at electron beam currents of up to 45 kA and electron energies of up to 300 keV. The effectiveness of the proposed method is demonstrated.

This paper proposes a novel method to achieve pose measurement in 3-D space using a microscopic camera. For an object with flange on its surface, there is a shadow region around the flange in the image if the camera is equipped with a ring light source. The flange’s shadow distribution caused by the ring light source is deduced based on imaging principle. An optimal model used to estimate object’s pose is designed based on the flange’s shadow distribution. Take the objects with circle flange, which are commonly used in precision assembly as an example, the shadow-forming model and the relation between the rotation angle and the shadow width deviation are presented. The rotation axis is determined on the basis of two particular rays on the shadow. Then the object’s orientation is computed based on the rotation axis and the rotation angle. A series of simulations and experiments are conducted to verify the high precision of the proposed pose measurement method. The root-mean-square (rms) errors of position and orientation measurement are 6.26 $\mu \text{m}$ and 0.19°, respectively.

We present a method for geometric point light source calibration. Unlike prior works that use Lambertian spheres, mirror spheres, or mirror planes, we use a calibration target consisting of a plane and small shadow casters at unknown positions above the plane. We show that shadow observations from a moving calibration target under a fixed light follow the principles of pinhole camera geometry and epipolar geometry, allowing joint recovery of the light position and 3D shadow caster positions, equivalent to how conventional structure from motion jointly recovers camera parameters and 3D feature positions from observed 2D features. Moreover, we devised a unified light model that works with nearby point lights as well as distant light in one common framework. Our evaluation shows that our method yields light estimates that are stable and more accurate than existing techniques while having a much simpler setup and requiring less manual labor.

Shadow on the absorber plate of a flat-plate solar collector or a solar cooker box can reduce absorbed energy. The main goal of this research is to investigate the effective factors on the shadow formation inside a solar collector. In addition, the energy gain reduction due to shadow was calculated. The length, width (0.5–2.5) and height (0.01–0.2 m) of a solar collector, tilt angle (0.01–80°) and latitude (0.01–65°) were considered as the effective variables on the shadow formation. The sum of shadow ratio and the percentage of energy gain reduction per year were chosen as the dependent variables, and the effect of each factor was discussed. Results showed that the effective variables (strong to weak) were height, width, tilt angle, latitude and length for the sum of shadow ratio per year, and height, tilt angle, width, latitude and length for the energy gain reduction per year. The minimum and maximum energy gain reduction per year due to shadow for a solar collector with length = width = 1 and height = 0.04 m were obtained 5.23 and 21.64%, respectively. If a solar collector has a rectangular plate, the larger width is more suitable than the larger length for the shadow reduction.

A system is presented for registering shadow images obtained from dense pulsed plasma with a high background illumination level, wherein an LGI-21 molecular nitrogen laser is used as an illuminator (laser pulse power 12 µW, duration 20 ns), and a modified Canon EOS 1000D camera is used as a registering unit. A micropinch discharge such as a high-current low-inductance vacuum spark (HCLIVS) has been used as the plasma object under investigation.

A novel approach to obtaining hypersonic flows is proposed and the results of experimental study of hypersonic flows around cones with semivertex angles τ1 = 3° and τ2 = 12° and inflow Mach numbers M = 18 (τ1 = 3°) and 14.4 (τ2 = 12°) are presented. The use of a light-gas gun where a de Laval nozzle is mounted instead of an acceleration channel allows obtaining a hypersonic flow with a high value of optical density of the outflowing gas sufficient for visualization and diagnostics of the flow by optical methods. The flow pattern is visualized by the shadow method. Shadow images are registered using a high-speed Photron Fastcam camera with an exposure time of 1 μs and frame rate of 300 000 fps. The inflow Mach number is computed using the shadow images based on the angle of shock wave inclination.

A general strategy for generating various Janus particles (JPs) based on shadow sphere lithography (SSL) by varying incident and azimuthal angles, as well as deposition numbers is introduced, forming well-identified flower-like patches on microsphere monolayers. An in-house simulation program is worked out to predict the patch morphology with complicated fabrication parameters. The predicted patch morphology matches quite well that of experimentally produced JPs. The relationships between patch shape/area/size/and incident angle/deposition numbers are quantitatively determined by calculating morphology and transmission spectrum correlations, which facilitated further implementation of SSL in fabricating more varieties of JPs. Such an SSL strategy can be used to create JPs with anticipated patch morphology and uniformity that may be used for self-assembly, drug delivery, or plasmonic sensors as well as exploring some fundamental principles relating to the properties of nanostructures.

Three-dimensional (3D) shape measurement with fringe projection technique and vertical scanning setup can alleviate the problem of shadow and occlusion. However, the shape-from-defocus based method suffers from limited sensitivity and low signal-to-noise ratio (SNR), whereas the projection-triangulation based is sensitive to the zero-phase detection. In this paper, we propose paraxial 3D shape measurement using parallel single-pixel imaging (PSI). The depth is encoded in the radial distance to the projector optical center, which is determined by the projection of light transport coefficients (LTCs). The third-order polynomial fitting is used for depth mapping and calibration. Experiments on 5 objects with different materials and textures are conducted, and standards are measured to test the accuracy. The results verified that the proposed method can achieve robust, dense reconstruction with depth accuracy at 20 μm while the root-mean-square error (RMSE) of plane fitting up to 43 μm.

We propose a synthesis model for fiber Bragg gratings (FBGs) to monitor temperature measurement errors due to aging behavior. This approach might be called a Digital Shadow since we are able to monitor all essential parameters of the grating to perform error prediction and consequently compensation. The model is tested during accelerated aging experiments, which furthermore reveal the shift of the center wavelength because of thermal decay.

Particles can be manipulated along boundary-free channels in a noncontact way by designing acoustic structures in the shadow., Acoustic tweezers use ultrasound for contact-free, bio-compatible, and precise manipulation of particles from millimeter to submicrometer scale. In microfluidics, acoustic tweezers typically use an array of sources to create standing wave patterns that can trap and move objects in ways constrained by the limited complexity of the acoustic wave field. Here, we demonstrate spatially complex particle trapping and manipulation inside a boundary-free chamber using a single pair of sources and an engineered structure outside the chamber that we call a shadow waveguide. The shadow waveguide creates a tightly confined, spatially complex acoustic field inside the chamber without requiring any interior structure that would interfere with net flow or transport. Altering the input signals to the two sources creates trapped particle motion along an arbitrary path defined by the shadow waveguide. Particle trapping, particle manipulation and transport, and Thouless pumping are experimentally demonstrated.

The Moon acts as a shield against the cosmic rays, preventing them from reaching the earth, which gives rise to a deficit in the flux along the direction of the Moon. The observed deficit can be used for obtaining the absolute calibration of the angular resolution and to verify the pointing accuracy of the array. GRAPES-3 is an extensive air shower experiment located at Ooty, India consisting of a dense array of scintillator detectors. It records $\sim$$10^9$ showers per year with a median energy of 10 TeV. With the precise determination of the arrival time of shower particles and an accurate correction for the shower front curvature, a major improvement in the angular resolution of the array has been achieved. This was done by the array division methods including the left-right and even-odd methods. Here, we present a verification of the angular resolution estimates and the pointing accuracy by observing shadow of the Moon in the cosmic ray flux.

Mnookin and Kornhauser’s Bargaining in the Shadow of the Law is a critically important work for the alternative dispute resolution (ADR) field because it legitimized the study of negotiation within the legal academy. It did so by tethering bargaining to jurisprudence. Without Mnookin and Kornhauser’s insight that bargaining is a function of legal rules, the law remains confined to its portrayal in a standard first-year curriculum....

As part of our ongoing research on lensless imaging with a Fresnel zone aperture (FZA), we propose a method for optimizing the configuration of the FZA, which reflects the influence of the diffraction of its shadow, and the sensitivity characteristics of an image sensor.

The attenuation of solar direct radiation passing through stratospheric balloon has great impacts on solar array output performance and thermal characteristic. The thermal characteristic of solar array with balloon shadows taken into account is rare. In this study, we established a theoretical model which consists of solar radiation model, shadow model, thermal model and energy output power model to evaluate their power performance and thermal characteristic under shaded conditions. Based on the theoretical model, a MATLAB simulation program was developed. For model validation, solar array performances are simulated and compared with literature results. Comparing the results of calculation whether balloon shadow is considered or not, the balloon shadow greatly affects the output power and temperature of solar array. Effects of the date, latitude, rope length on the output performance and thermal characteristic of solar array were investigated in detail. The results show that the balloon shadow covering the solar array effectively reduces the direct solar radiation received by the solar array, which has contributed to the decline of the output power and average temperature of the solar array. In addition, it is found that choosing the appropriate rope length can effectively reduce the detrimental effects of the balloon shadow.

Based on the the third-order aberration theory of plane-symmetric optical systems, this paper studies the effect on aberrations of the second-order accuracy of aperture-ray coordinates and the extrinsic aberrations of this kind of optical system; their calculation expressions are derived. The resultant aberration expressions are then applied to calculate the aberrations of two design examples of soft X-ray and vacuum ultraviolet (XUV) optical systems; images are compared with ray-tracing results using SHADOW software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory.

An algorithm is proposed that makes it possible to calculate the coefficients of power polynomials approximating the illuminated and shadow surfaces of bifocal lens antennas. The algorithm is based on providing equality of electrical lengths of rays passing from the focus points through lens body and its edge and on the assumption that the phase front is flat and is inclined at a determined angle relative to the main optical axis of the lens on the aperture of the lens antenna. For each of the rays an expression was written that determines its electrical length. The electrical length of the rays depends on the points coordinates of the illuminated and shadow surface of the lens, in which they are refracted. The analytical solution of the obtained equation is difficult. Therefore, it is proposed to determine the exact coordinate values by numerical methods. The proposed algorithm determines in series the three points lying on the illuminated and shadow surfaces. The coordinates of the points are used to form systems of equations whose solutions are the coefficients of power polynomials approximating the illuminated and shadow surfaces of the lens antenna. The algorithm does not impose restrictions on the relative dielectric constant of the material from which the lens antenna is made.

The meniscus surrounding a hydrophobic circular plate floating on a transparent liquid surface could refract light to form a shadow with a bright edge at the bottom of the vessel. This paper demonstrated the feasibility of a simple method to visually measure the force applied on the top surface of this circular plate by using its shadow image. The shadow area represented the floating force according to the updated Archimedes’ principle. The viscous damping of liquid could reduce the high-frequency noises from the environmental vibration, which improved the stability and sensitivity of the measuring system. The water depth, initial weight of the plate, and the size of the circular plate effects on the shadows and the edge quality have been evaluated. With an ordinary camera to monitor the shadow, a simple circular plate device could realize a force resolution of up to 10 nN. The force measuring range and sensitivity can be easily extended by changing the radius of the circular plate. The shadow method could be developed into a novel nano scale precision force measurement apparatus.

This paper aims to determine the effect of the smartphone warm color temperature function that relieves display's HEVL (high-energy visible light and short wavelength series blue light), which is known to cause suppression of melatonin secretion on actual image reproduction quality. For this study, the author of this paper measured the display based on the color difference in 26 sampling colors. It was found that for correlated color temperature (CCT) of 4000 K or less, the color difference rose sharply, centering around red and green. In hardware or software, a low CCT was realized by reducing the output centered on blue and green, but in actual color quality, a problem arose in the red and green channels. As far as tone gradation is concerned, ΔE increased for CCT of 4500 K or less while the accuracy of the shadow detail was reduced. With regard to color gamut reproduction, for the coverage of sRGB color space, the color gamut became narrow for CCT of 5500 K or less, and for volume, the color gamut became narrow sharply for CCT of 4000 K. It was found that the maximum CCT changes to prevent a decline in melatonin secretion at a level of minimizing the degradation of image quality is 4000-4500 K.

In Swing Time, her newest novel to date, Zadie Smith makes use of a first-person narrator for the first time in her career as a writer, and this change in narrative perspective is crucial to our understanding of the novel. Her narrator is slightly odd and we come to question the veracity of her account. Thus, she is ‘unreliable’ in traditional terms, but this article argues that we can equally call her inauthentic because she obviously represses feelings that are vital to the story. She does not fully expose herself, for she tries to hide the fact that she does not know who she is. Trapped between the intersectionality of race, class, and gender, oppressed by an overbearing mother and a racist society, the narrator has confined herself to an existence as a shadow. By way of Charles Taylor’s politics of recognition and Frantz Fanon’s image in the third person, this article tries to show that Swing Time’s narrator exists only as a shadow because she finds no external affirmation of herself as a black woman.

A shadow projection approach for near-field microwave imaging is developed to distinguish the size and shape of objects embedded in layered media. An ordinary microwave image may only present a small portion of the front surface of an object due to the lensing effect of refraction at the boundary between two adjacent layers with a high dielectric contrast. Therefore, instead of looking at the primary image, the projection onto the interface behind the object is investigated to better discern the object’s true size and shape. A diffraction tomographic algorithm is modified to accentuate the shadow image. The efficacy of this shadow projection method is demonstrated by 3-D numerical simulations of air voids in a dense dielectric slab.

We proposed a single-shot diagnostic for spatiotemporal laser-plasma evolution by the multi-dimensional encoding (MuDE) holography. It can achieves high and adjustable temporal resolution measurement of three-dimensional plasma distribution without delay scanning. Experimentally, we verified the feasibility of this technique, and the retrieved results of laser-plasma evolution agreed well with the direct shadow measurement. This technique is expected to provide a helpful tool for the complex spatiotemporal evolution of plasma in ICF and high energy density physics.

To solve the problem of shadow area in wireless network, a metasurface is expected to anomalously reflect the wave from base station to user in non-line-of-sight (NLOS) area. However, the sensitivity between an incident and reflection angles makes more inflexibility for reflector installation. Therefore, the technique to maintain the reflection angle of reflector, as the incident angle changed, is studied by separating supercell of metasurface. From both of simulation and experimental results, the designed 28 GHz metasurface can maintain a constant reflection angle at 45° while the incident angle is varied up to 0° - 10° without re-designing process.

The magic lantern had to wait almost two centuries before it was able to project for large audiences on big screens, which was, for the most part, dependent on improvements in illumination technology. Candles, animal fat, or oil was bright enough for projection on small screens, and in the seventeenth and part of the eighteenth centuries, that was all that was available. One solution was the use of multiple lamps to increase brightness so that painted slides might be seen with vivid colors rather than as monochromatic shadow images. In 1695, the priest M. I. L. de Vallemont mounted a parabolic reflector and its holder, located behind the lantern’s oil lamp, on grooves to permit backward and forward translation for focusing the lamp’s light on the condenser lens to increase brightness. In 1710 Johann Michael Conradi chose to keep the mirror fixed but move the oil lamp, which was mounted to two fixed tracks, to achieve the same concentration of light as had de Vallemont (Rossell 2008, p. 52).

Using ray tracing for shadows is a great method to get accurate direct illumination: precise hard shadows throughout the scene at all scales, and beautiful penumbras from soft box light sources. However, there is a long-standing and well-known issue: the terminator problem.

When a leaky rectangular waveguide is used to realize the coverage of radio wave in the small confined spaces, there will be a shadow region, which influences the coverage performance. In this paper, the traditional leaky rectangular waveguide is improved according to the principle of the equivalent circuit, by cutting interdigital slots in the upper wall and adding uniserial metal vias between the upper and lower walls of the rectangular waveguide. Thus, the right/left-handed transmission line property is introduced to the periodic leaky-waveguide (LWG), realizing the broadside radiation with relatively high gain (15.7 dBi), good cross polarization (−50 dB), and narrow half-power beamwidth (10.9°) at 6.97 GHz and providing a method for a uniform coverage of the radio wave in rooms without a shadow region.

The phenomenon of colored shadows were first published by Goethe in 1810. These colored shadows can be displayed stereoscopically through a pair of colored glasses. Furthermore, the stereoscopic shadow images can also be used to perform optical measurements. We present the principles of the measurements, particularly for measuring the threedimensional position of an object. The limits of the measurement method, in terms of its sensitivity, resolution, and sources of errors, are described. When the size of the measured object becomes comparable with the light wavelength, and when the light intensity becomes smaller and the photon nature of the light needs to be taken into account, the geometrical analysis of the measurement method needs to be replaced first with the wave analysis and then with the photon analysis. Our measurement of position can be extended into measurements of displacement, velocity, acceleration, shape, and orientation.

The results of experimental studies of multiple-beam Ku-band klystron with a pyrolytic graphite shadow grid and klystron of the same type with a hafnium shadow grid are presented. The high antiemissive properties of pyrolytic graphite give a decrease in the thermionic current from 15–30 mA to zero compared to the hafnium grid. This allowed for stable operation of the klystron at lower values of the off-duty ratio compared to the klystron with a hafnium shadow grid.

In a typical digital fringe projection (DFP) system, the shadows in the fringe images cause errors in the phase map. We propose a novel discriminative repair approach to remove the shadow-induced error in the phase map. The proposed approach first classifies the shadow area in the phase map obtained by the DFP into two categories: valid shadow area and invalid shadow area. Then the valid shadow area is repaired by a proposed neighboring information fusion phase estimation (NIFPE) method, which fuses the phase gradient into the result of kernel density estimation (KDE) through the Kalman filter (KF) algorithm. The invalid shadow area is repaired by a proposed background phase matching (BPM) method. The experimental results demonstrate that the shadow-induced error in the phase map can be removed, which verifies the effectiveness of the proposed approach.

International audience; Is there a bright spot in the shadow of an opaque disk? Nearly 200 years ago, Augustin Fresnel and François Arago’s remarkable answer to this question validated the wave theory of light and inaugurated the modern theories of diffraction. Today, their renowned experiment can be easily reproduced using lasers and cameras. Far beyond its historical interest, the experiment is a versatile platform to illustrate the main concepts of optical physics, including diffraction, interference, speckle, and Fourier optics.