Camera Tube Research Articles

A new sediment trap system

A new sedment trap system intended for use in lakes and marine coastal and shelf areas is presented. The system is designed to (1) keep the sediment collection tubes in a steady vertical position, (2) avoid contamination of the samples by material detached from overhead rigging, (3) fachtate quick exchange of collection tubes at sea, and (4) provide duplicate samples. In situ experimental s tudes , SCUBA v T: trap retaining line; G : ground line; S: surface line. Line T is always taut whereas G and S are usually slack. ICT: inset collection tube; BB: buoyant body; F: frame; AS: attachment swivel. Dimensions of hollow frame: outer length 110 cm, outer width 30 cm, outer diameter of the tubes 5 cm, wall thickness 0.4 cm and marine coastal and shelf areas. Similar mooring arrangements are used to deploy current sensors (cf. Duxbury 1971). Study location and field test. The new sediment trap was tested in the Baltic Sea, near the Ask6 Laboratory about 65 km south of Stockholm, Sweden, in an archipelago area with negligible tide. The main test was carried out at 1.5 m depth in a narrow, 3.5 m deep sound, with relatively turbulent currents of up to 40 cm S-' . The degree of vertical stability of the collection tubes was recorded in situ by time-lapse filming. An 8 mm film camera was enclosed in a waterproof housing and mounted at the bottom of one of the collection tubes; the other tube was counterbalanced with gravel. The inner diameter of the tubes had to be 150 mm, to allow space for the camera. The entire trap was therefore scaled up according to the difference between the tubes in this test trap and the regular trap described above. At the top of the camera tube, 2 independent protractors were mounted, and readings recorded on film every 30 S. One protractor acted as a pendulum, recorhng the deviation from the vefical of the tube, the other was connected to an outside arm in order to give a relative reading of the current velocity. To relate the relative readings to actual current velocities a current meter was deployed close to the trap, integrating current velocities over 10 S. Readings were taken at intervals of 1 to 5 min. These current measurements were correlated to the corresponding protractor readings recorded on the film, using non-linear regression by SAS software (Allen Rey 1982). The regression equation (protractor reading = 0.203 current vel o ~ i t ~ ' . ~ ~ ~ , n = 26) was then used to estimate water currents every 30 S. Results. Despite highly variable water currents (5 to 40 cm S-') the collection tube of the new sediment trap Fig. 2. Predicted ambient water current velocities (above) and simultaneous recording, by time-lapse filming in situ. of the inclination from vertical of the collection tube of the EXPOSURE TIME (min) sediment trap (below) Larsson et al.: New sediment trap system 207 never deviated more than + 2.5 from a true vertical position (Fig. 2). Observations by water glass confirmed that the trap does not wobble and invariably maintains an alignment perpendicular to the current direction. In situ inspections of the regular trap by SCUBA diving at water depths down to 12 m in a coastal area support these observations. Not even when the diver rocked the trap frame did the collection tubes deviate noticeably from the vertical. Concluding remarks. The new sediment trap rnaintains satisfactory stabdity of the collection tubes and an alignment perpendicular to the current direction at highly variable current velocities (up to at least 40cm S-'). The buoyancy of the trap permits a noninterfering mooring arrangement. The new trap has functioned reliably for more than 4 yr in a coastal area of the Baltic Sea. Acknowledgements. Ragnar Elmgren and Jiirg Bloesch commented on the manuscript, Sture Hansson assisted in the divmg, Leif Lundgren drew the figures and Maureen Moir typed and corrected the language. This work was supported by the National Swedish Environment Protection Board and the Swedish Natural Science Research Council.

Surface-roughness measurement by digital processing of Nomarski phase-contrast images

Surface roughnesses down to 0.1 nm rms were measured on low-reflectance polished glass and silica substrates by quantitative analysis of Nomarski differential phase-contrast images with a fast digital image processor. A measure of roughness was obtained from the standard deviation of intensities in the Nomarski image observed by a vidicon tube with linear response and digitized in real time.

The holographic film scanning machine “Chimaera”

The design and construction of a computer controlled machine for scanning and measuring in-line holograms. The equipment was designed for holograms produced in the bubble chamber HOBC used in the experiment NA25 at CERN. The choice of optical system and video camera tubes is discussed. The control system is described briefly. The problems of scanning and measuring charmed particle decays recorded on holographic film are discussed, and the errors in the measured spatial coordinates are considered.

An improved Senarmont retardation analysis method

SUMMARYThe phase difference between two plane polarized light rays whose electric field vectors (planes of polarization) are at right angles is often determined by Senarmont analysis. In this analysis, a quarter‐wave plate whose vibration axes lie at an azimuth of ±45° to the planes of polarization of the two rays is inserted. The rotation of the analyser that leads to extinction is then determined by manual adjustment. This classical method has been significantly improved by, instead, measuring light intensities at thirty‐two evenly spaced analyser angles which span 180° of analyser rotation. An unbiased estimate of the phase difference may then be extracted with high accuracy by analysis as a designed experiment.Of the several numerical analysis methods investigated, harmonic analysis is particularly attractive for routine use—especially with small computers. Iterative non‐linear least‐squares analysis on a mainframe computer was taken as the standard of numerical accuracy, against which direct algebraic solutions on a personal computer were evaluated. An ‘accuracy’ statistic (which measures the goodness‐of‐fit to the theoretical cosine function) has proven invaluable in assessing the validity of actual data.Data of exceptional quality are produced by the Leitz Jamin–Lebedeff optical system using intensities measured with a photodiode detector placed in the camera tube of the microscope. These data will support analysis to better than 0.0001° of analyser position, or <6×10−7 periods. Since alignment of the optics with comparable accuracy is impossible, a method for accurately quantitating the contribution to the observed retardation that originates from within the optics, by performing the analysis on an air sample, has been devised.

Amorphous Silicon Resistive Sea for Silicon Vidicon Targets

In this experiment, GD a-Si film was studied as a bakeout-proof resistive sea for a silicon-diode-array camera-tube target. It was found that the resistivity of an a-Si film deposited at temperatures between 400 and 600°C lay in the range 10-7–10-9 Ωcm, and that the film was suitable for used as a resistive sea when baked out in a vacuum at a temperature below 350°C. An Si target with an a-Si resistive sea from 40 nm to 1 µm thick, deposited at about 400–500°C, was baked in a vacuum at 350°C for two hours and then mounted in a camera tube, giving improved bakeout-proof and X-ray protection characteristics, and low lag.

Earth-to-geosynchronous satellite laser beam transmission

Some experimental results for detection of a ground-based laser beacon by a geosynchronous satellite are reported. A 50-cm diam telescope and silicon intensifier tube camera were used for optical observation of the satellite. The transmitted argon laser beam was detected by the visible channel of a radiometer on board the Japanese Geostationary Meteorological Satellite. Two activities, (1) orbit prediction correction using optical observation and (2) detection of the earth laser beacon by the radiometer, are described.

Development of a Novel Electrostatic Focus Electrostatic Deflection Camera Tube

An electrostatic focus and deflection camera tube has the following advantages: no bulky yoke is required as all the electron optics are inside the tube, power consumption is very low, and the scanning rate can be varied. Several all-electrostatic camera tubes have been reported [1] [2] [3], but none of these tubes is currently in general use.

Fluid Particle Sizing Using A Fully Automated Optical Imaging System

This paper describes the development of a fully automated instrument that measures critical spray characteristics of liquid atomizers via an optical, direct-imaging method. The system uses a gas laser as the illumination source to backlight a liquid spray and a lens system to project an image of silhouetted droplets on a vidicon tube. A microcomputer performs all system control and data analysis as well as diagnostic functions. A data acquisition front-end supplies droplet data to the computer in real time. Pertinent system design issues are discussed, and the resulting design choices are described. When fully operational, the cycle time for sample hardware testing, data analysis, and report preparation is expected to be under 30 min. The optical portion of the system has already been used successfully to visualize and videotape numerous sprays.

2-11 撮像管集束磁界中の静電レンズの働きについて

2-11 撮像管集束磁界中の静電レンズの働きについて

Lag and Resolution Related with Current Distribution of Electron Beam in Camera Tubes

The effect of the current distribution across the electron beam on beam discharge lag and resolution capability of camera tubes are investigated analytically and experimentally. It is found that the resolution capability and beam discharge lag are dominated by both the current density distribution, especially at the leading edge, and by the equivalent temperature of the scanning electron beam. Experimental results show that a rectangular beam, cross section with 100 µm (horizontal size)× 40 µm (vertical size) on the target, can resolve more than 800 TV lines in standard scanning format fat a 1 inch diameter tube (1/2'' wide×3/8'' high) and also reduce beam discharge lag, for example to about 30% compared with that for a narrow beam at the same beam temperature.

The design of the shifting section of an intensifier silicon target pick-up tube

The principle for designing the shifting image section of an intensifier silicon target pick-up tube is given. An electrostatic electron-optical system with a photocathode having an effective diameter of 40mm and a system magnification of 0.65 has been designed. Experiments show that when the electron image of the photocathode is transferred to the silicon target, the geometric distortion is 2%, and the field curvature is 2mm. The astigmatism is less than 0.32 mm at 80 percent of the viewing field and the resolution is over 50 Ip/mm. It shows that the design of the electron-optical system is good and reasonable.

Modern Trends in Color Broadcasting Camera Systems

Recent developments in broadcast camera tube design have led to improvements in camera performance. This article compares two new camera tube systems that have recently become available for professional television cameras. The first is the 13mm 80XQ Plumbicon™, which is a complementary field (CF) system based on electrostatic focusing with an accelerating lens followed by magnetic deflection. An 18mm version of the CF Plumbicon is also discussed. The second system is the 87XQ MS Plumbicon, which is based on a combination of magnetic focusing and electrostatic deflection by means of a deflectron.

A cooling device for the SIT camera tube of a TV image recording system for conventional transmission electron microscopy

Describes a simple device to cool the target of a SIT camera tube. The simplicity rests on the use of cold nitrogen gas. Since cooling of detectors, multipliers and camera tubes is a common problem, the authors provide a detailed description of the design and performance so that it may be duplicated and modified in any regularly equipped physics laboratory.

Rapidly sequenced pair of two-dimensional images of OH laser-induced fluorescence in a flame

A Nd:YAG laser was Q switched twice during one flashlamp pulse and pumped a dye laser, whose frequency-doubled output, tuned to an OH absorption line, illuminated a planar region through a flame. The OH laser-induced fluorescence was focused onto an oscillating mirror, which directed the successive two-dimensional images onto different halves of a vidicon tube. Usable pair separation times of 40 to 180 microsec were obtained. The method has promise for studying changes in small-scale structure in turbulent reactive flows and for instantaneous measurement of the spatial distribution of two observables.

X-ray small angle camera with block-collimation system an instrument of colloid research

1. For X-ray small angle research usually a primary beam of line shaped crosssection is applied. The longest known is the three-slit-camera with two parallel diaphragms defining the primary beam and the third one limiting the parasitic scattering caused by the second one. 2. The difficulty of the correct mutual adjustment of the three diaphragms is circumvented by the block collimation system, where the primary beam is guided by three bodies (2 blocks and 1 edge). The essential principle is the exact coincidence of the extremely smooth upper surface of the first block (middle block) with the also perfectly plane bottom surface of the second block (bridge) in their mutual extension. The third diaphragm, the edge, controls the widths of the ribbon-shaped primary beam and is situated as entrance slit in front of the two blocks, this being closest to the X-ray tube. 3. The basic concept from 1954 has been maintained, however, the entire apparatus of the small angle camera has been modified. Only the earliest professional type, the building block camera, has been described in a comprehensive communication (1958); the more recently developed types are only known from short communications and from prospects of the manufacturer, A. Paar KG. The main topic of the present work is the description of the most important recent type, the compact camera. Whereas the individual parts of the building block camera are mounted on some kind of optical rail in a mutually adjustable way, all parts of the compact camera except the detector slit and the detector are accomodated in an evacuated compact rigid housing without foils or air paths to be penetrated like for the building block camera. An important feature is the support of the front end of the camera on top of the X-ray tube avoiding those minor movements between camera and X-ray tube caused by thermal and mechanical influences. As shown by experiment, practically perfect stability of the scattering intensity at medium and high resolution (above 1000 A) is obtained by these means. Moreover, the independent motion of detector slit and detector shall be mentioned, as well as the improved coincidence of surfaces of the beam — guiding blocks, operation of the vacuum surrounded entrance slit from outside etc. 4. An attempt of an optimization is made with view to obtain maximum primary intensity at a given resolution, measured by the smallest angle from which on a scattering measurement is possible. This optimization was tried to be achieved by variation of two experimental parameters: Variation of the pick-up angle of the radiation from the focus and the position of the middle-block of the collimation system which is in between the entrance slit and the bridge. The primary energy entering the collimation system in dependence of the two variables has been calculated

A camera-tube diode-gun with very small beam divergence

A diode-gun having a special beam-defining aperture is proposed. The measured beam-divergence angles were 0.3-0.65° in the range of 10-25 V of G1 voltage, and the current-density profiles showed a steep edge. A camera tube using this diode-gun gave high-resolution characteristics with amplitude responses of 58 percent at the center and 47 percent at the corner, at 600 TV lines in the normal scanning area of the 1-in tube.

Fluoroscopic imaging: quantitation of image lag or smearing.

Image lag (smearing or persistence of the image) is a characteristic of video imaging systems that is exhibited when rapidly moving objects are blurred due to motion. Video pick-up tubes can exhibit differing amounts of image lag depending on the age of the tube, the amount of light reaching the tube, the set-up parameters used (e.g., beam current and target voltages, etc.), and the tube type. We describe a new quantitative method for measuring image lag that requires only a storage oscilloscope and an inexpensive shutter. Examples of lag measurements on different systems under varying clinical conditions are given. Suggested limits for clinically acceptable amounts of image lag range from 10% to 50% depending on the particular application.

Detection and three-dimensional localization by stereoscopic visual sensor and its application to a robot for picking asparagus

This paper describes a three-dimensional localization process used on an agricultural robot designed to pick white asparagus. The system uses two cameras (CCD and Newvicon). Thanks to diascopic lighting, the images can easily be binarized. The threshold of digitalization is determined automatically by the system. A statistical study of the different shapes of asparagus tips allowed us to determine certain discriminating parameters to detect the tips as they appear on the silhouette of the mound of earth. The localization is done stereometrically with two cameras. As the robot carrying the system moves, the images are altered and decision criteria modified. A study of the images from mobile objects produced by both tube and CCD cameras was carried out. A simulation of this phenomenon has been done to determine the modifications concerning object shapes, thresholding levels and decision parameters as a function of robot speed.

Formations‐elliptical scanning electron‐beam cross section for removing unscanned area in high resolution camera tubes

AbstractIt is proposed that electric charge stored in unscanned areas on the field of a high resolution camera tube can be removed by an electron beam with an elliptic cross section which is formed by a beam‐limiting aperture, or by applying vertical rf electric field on the beam, which is called wobbling. These effects have been discussed analytically. the beam‐limiting aperture is applicable to a magnetic focusing and deflecting tube in which, however, the beam spot direction differs slightly from point to point on the picture area; it is applicable also to an electrostatic focusing, magnetic deflecting tube which has rather poor resolution but in which the spot direction is independent of the position on the picture area. On the other hand, wobbling is applicable to a magnetic focusing, electrostatic deflecting tube.

Fluorescence microscopy on monomolecular films at an air/water interface

An experimental set-up is described which can be used to study microscopically the fluorescence of monolayers at the air/water interface. The apparatus consists of a film balance placed on the objective stage of a microscope. Light emitted from fluorescent probes is detected via a senstive camera tube. In a first application the phase diagram of L-α-dipalmitoylphosphatidylcholine (DPPC) is re-examined. Textures peculiar to different regions in the pressure versus area diagram are observed. The measurements show that (a) in the so-called LE/LC region two different states coexist and (b) another transition appearing at a pressure below 0.5 mN m −1 can be localized by using this method.