Linear Light Source Research Articles

Concentration and collimation of diffuse linear light sources

We present an approach for concentration and collimation of a diffuse linear light source to achieve extremely high concentration in the long direction at the expense of the short direction. The approach is based on free-space optics and involves either arrays of prisms or holographic optical elements that couple between the two spatial directions. The results for a specific arrangement that concentrates a 40 mm by 0.4 mm source, with diffusive angle of about 0.1 rad, into a 1 mm by 1 mm isotropic spot are presented.

Extensions of the linear and area lighting models

Techniques that aid the realistic rendering of lighting effects achieved from linear (1-D) and area (2-D) light sources are presented. They are based on a radiosity model that can be inserted into any traditional ray tracer. The approach is applied to both a 1-D light, analogous to a fluorescent tube, and to a 2-D light, analogous to a light set into the ceiling. >

Shading and shadowing with linear light sources

In virtually all rendering systems, linear light sources are modeled with a series of point light sources that require considerable computing resources to produce realistic looking results. A general solution for shading surfaces illuminated by a linear light source is proposed. A formulation allowing for faster computation of the diffuse component of light reflection is derived. By assuming Phong's specular component, simple, inexpensive and convincing results are produced with the use of a Chebyshev approximation. A shadowing algorithm is also presented. As shadowing from linear light sources is expensive, two acceleration schemes, extended from ray tracing, are evaluated.

Development of a compact X-ray linear light source and FEL at UCLA

There is a need for a new type of light source that provides subpicosecond, extremely intense X-ray burst for biological and chemical studies. The development of a system that uses a very bright electron source, bunch rotation, a high-gradient accelerating structure and an advanced undulator to produce this light source (LLS) is described. The possibility of operating the LLS in an FEL mode and present calculations on the required performance of each component in the LLS for this purpose is illustrated. The construction of the components at UCLA is outlined. This article concludes with a discussion of the high-gradient accelerator structure and undulator system being developed jointly with Pulse Sciences Incorporated and Rocketdyne and the prospects for future compact X-ray FEL light sources using this technique.

An automated stream-centres dielectrophoretic system

Dielectrophoresis has been shown to be potentially useful as a technique for identifying dielectric properties of particles and separating them on that basis. Particles range from simple polystyrene microspheres to the more complex biological cells. An automated system which allows the characterization and potential separation of particles/biological cells on a continuous basis is described. Here, a narrow sample stream suspended within a large sheath is injected between a pair of isomotive electrodes. Upon application of an AC field the sample particles undergo a positive or negative displacement, depending on their polarization characteristics relative to the medium. This deflection is detected using a linear 1024-element photodiode array and laser light source, to provide a measure of the response over a range of frequencies (110 Hz-50 MHz) under computer control. This enables the dielectrophoretic spectra to be obtained with very little human intervention. Details of the design and preliminary test results, based on inert and biological test particles, are presented and potential applications discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

水平直線光源下に置いた遮光球による影の特性

水平直線光源下に置いた遮光球による影の特性

Shading models for point and linear sources

The degree of realism of the shaded image of a tree-dimensional scene depends on the successful simulation of shading effects. The shading model has two main ingredients, properties of the surface and properties of the illumination falling on it. Most previous work has concentrated on the former rather than the latter. This paper presents an improved version for generating scenes illuminated by point and linear light sources. The procedure can include intensity distributions for point light sources and output both umbrae and penumbrae for linear light sources, assuming thr environment is composed of convex polyhedra. This paper generalizes Crow's procedure for computing shadow volumes caused by the end points of the linear source results in an easy determination of the reions of penumbrae and umbrae on the face prior to shading calculation. This paper also discusses a method for displaying illuminance distribution on a shaded image aby using colored isolux contours.

直線光源による影の面積計算

直線光源による影の面積計算

A Comprehensive Light-Source Description for Computer Graphics

For realistic simulation, light source descriptions require definitions of the geometry, the spectral distribution, and the spatial distribution of the luminous intensity. A procedure is described in which these light source characteristics are defined, and the resultant intensity computations are integrated into a testbed ray-tracing system. Point, linear, and area light sources are considered. Results are shown which account for the spectral distribution and illustrate the directional dependence of the intensity calculations. The procedures are applicable to environments of unlimited complexity. Light sources can be arbitrarily placed within the environment and contained within the simulated image.

直線光源による影の面積について

直線光源による影の面積について

Some Characteristics of the Shadow Produced by a Horizontal Disk Setting under a Vertical Linear Light Source

The previous paper described some characteristics of the shadow on the working plane due to ahorizontal disk under a horizontal linear light source. The present paper purports to make elaborate discussion on some results of using a vertical linear light source.First, the shadow-factor on the working plane for varied positions of the disk and a fixed positionof the light source is calculated.Next, the shadow-factor on the working plane directly under a fixed position of the disk under amoving light source is found.From these results, method of predicting the zone produced by the shadow, and the suitable position of the light source in order to produce as little shadow as possible can be obtained.Furthermore, the paper compares and discusses the characteristics of the shadows under the horizontal and vertical linear light sources.

Characteristics of the Shadow Produced by a Horizontal Disk Setting under a Horizontal Linear Light Source

The method of calculating the direct illuminance and the shadow factor in the shadow which is produced on the illuminated plane by a horizontal disk under the condition that a diffused linear light source is kept in a horizontal or vertical position was discussed in our previous report.In this paper we describe and discuss the results of some calculations on the shadow factor when the diffused linear light source is kept in a horizontal position.First, with the light source fixed, the shadow factor on the illuminated plane under various positions of a disk is calculated.Then, with the disk fixed, variations of the shadow factor at the illuminated point which is directly under a disk when the light source is moved are calculated.From these results, the methods of predicting the shadow zone and the suitable position of a light source to make the shadow as little as possible can be obtained.

A minicomputer-automated array spectrometer for liquid-chromatographic detection of metabolites.

A third-generation multiwavelength array spectrometer was developed as a detector for the high-resolution liquid-chromatographic characterization of metabolites. Components include a PDP-8/e minicomputer, matched pair of linear photodiode arrays, holographically-ruled gratings, fiber optics, flow cells, and high intensity xenon light source. The wavelength range is 256 nm differential with 1-nm resolution and can be adjusted from 200 to 800 nm. The system is capable of storing 20 spectra per second (200-456 nm) in a dual-beam mode. Special features include minicomputer-driven signal enhancement via integration as a function of signal strength. The display output includes presentation of the total absorption chromatogram vs. elution time in both real and post-run time as well as selectable single absorption band vs. elution time (post-run time). Application of this dedicated system is illustrated by the separation and charcterization of the metabolites of a carcinogen, 4-ethylsulfonyl-1 napthalenesulfonamide.

A Note on the Characteristics of Some High Voltage Linear Spark Light Sources

AbstractFlash durations havc been measured for two designs of spark light source operating with electrode, constructed of slainless steel and a lung ten-copper inlermetallic compound. It is found that the flash characteristics are controlled by the cathode and that non-confined dischargcs are of shorler duration With the laller malerial.

精密旋削面の虹むら

The iridescent unevenness of a precisely turned surface is investigated by a ray-tracing procedure with reference to the pitch unevenness of turned grooves. The surface is illuminated at an oblique angle with a linear light source which is crossed at right angles to the cylindrical axis of the surface, and the image of the light source focussed by the surface is observed in the direction of diffraction. The image is smooth parabolic when no pitch unevenness is present on the surface. The image calculated on the assumption of sinusoidal pitch unevenness arises disturbance of the image corresponding to the change of pitch. When the surface is illuminated with a white light source, this disturbance turns into iridescent unevenness. A surface having sinusoidal unevenness of pitch is worked by a lathe provided with a periodically variable feed device connected to the tool slide, and the theoretical result is confirmed. The pitch unevenness tolerable in the existence of iridescent unevenness differs depending to the intensity of iridescence on the surface.

Illuminance in the Shadow Formed by a Horizontal Disk

The shadow is a phenomenon which reduces the illuminance on an illuminated plane, because the light is obscured by an object interposed between a light source and an illuminated plane. Therefore, when viewing the light source from the illuminated point in the shadow, all or a part of light source is obscured by the object.For, calculating the illuminance values in the shadow, it is necessity to consider only the part of light source which can be viewed practically from an illuminated point.This paper describes the method of calculating the illuminance in the shadow, and the results of the experiments under the condition that the diffused linear light source is kept in a horizontal or vertical position and the horizontal disk is used as an object by which the shadow is formed.And the calculated values was confirmed experimentally.

Opportunities for use of a linear light source in spectral analysis

Opportunities for use of a linear light source in spectral analysis

Surface topography by multisource moiré patterns

Moire patterns produced by interference of a series of periodically arranged linear light sources with a line-specimen grating of similar pitch are located at a plane parallel to the sources and the specimen grating and at some distance away from these planes. A transparent or reflecting specimen located at a distance from the specimen grating distorts the image of the multisource projected on the specimen grating due to its surface irregularities and forms a moire pattern. This pattern yields the partial-slope contours of the topography of the specimen along a direction normal to the lines of the grating. Two such contour patterns taken at mutually perpendicular directions are sufficient to yield the complete topographic picture of the surface.

Electroluminescent Panel as a Modulatable Light Source

The electroluminescent panel can be used as a linear modulatable light source at audio frequencies. (Brightness vs voltage linearity is extremely good for modulation as high as 60%.) Linear operation is accomplished by operating the panels at three times the normal voltage with a carrier frequency of 10 kHz. The rapid aging and resultant light loss which normally accompanies operation under these conditions is eliminated through the use of an efficient heat sink.

Approximate Ellipsoidal Closed Surface for Luminous Flux Integrator

It was suggested to measure the total luminous flux of linear light source as a fluorescent lamp, using an approximate ellipsoidal closed surface, with both ends of the cylinder being rounded off.We found that this closed surface had been used by some manufactories; we examined, therefore, the fundamental character of the flux integrator, using “Coefficient of Relative Sensitivity” and “Coefficient of the Final Illumination of Interreflection” given by N. Muroi, one of the authors. A lso we discussed some errors due to the substitution method that compares an unknown linear light source with a standard incandescent lamp or with a known light source whose distribution is similar to the linear light distribution.As the major axis was equal to the minor axis x (1.5, 2.0, 2.5, 3.0, & 3.5), we estimated the flux integrator's errors.For instance, if the major axis was equal to 2.5 times the minor axis, the substitution of a standard incandescent lamp for an unknown linear light source resulted in less than about 4% errors.Also, the substitution of an unknown linear light source for a known light source whose distribution is similar to the linear light distribution, their light lengths being equal, resulted in far less errors.