TV Display Research Articles

Subjective Evaluation of Apparent Reduction of Chromatic Blur Depending on Luminance Signals

Chromatic blur seen along the contours of a figure on a color TV display is not so annoying if the contour luminance signal is sharp. This is due to the human visual property that chromatic blur is masked by the luminance by spatial luminance changes. This paper describes the subjective evaluation of the visual masking effect of chromatic blur depending on luminance signals. From the experiments, the chromatic blur becomes less perceptible with the increase in level of superposed luminance signals and the blur is more annoying in red than in blue or yellow. Highly saturated red figures cause poor picture quality.

Gray scale performance of displays for dynamic ultrasound imaging

Methods used to convert the output of diagnostic ultrasound dynamic imaging systems to television format are reviewed. The gray scale characteristics of a large-screen direct display are compared with the transfer through a display monitor-television camera-television monitor chain. Available direct display devices have distinct performance limitations in this application and the transfer linearity and dynamic range of the television converter described are objectively superior. This confirmed a subjective preference of system users to view the TV display.

Lamp phosphors and color gamut in positive-column gas-discharge cells for TV displays

Phosphors suitable for a full-color TV display in recently reported new high-luminance (360-fL green) high-efficiency (3.4-lm/W) gas-discharge cells have been determined: blue Sr <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> Cl(PO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> ) <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Eu <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+2</sup> , green Zn <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> :Mn <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+2</sup> , and red Y <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Eu <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+3</sup> . A decrease in color gamut with increasing current density has been measured and related to gas-discharge effects rather than phosphor saturation, using experimental results and a simplified model calculation. Aging of the green phosphor was measured and its causes are discussed.

Visual field size necessary for length comparison

Influence of visual field size upon acuity for comparing lengths of two lines was investigated. The visual field was effectively narrowed to any desired size by use of a TV display system. The TV screen presented a portion of the test stimulus, the position of which was controlled by the subject’s eye movement so that his fixation point always coincided with the center of the portion. The test stimulus was composed of two lines arranged horizontally, one of which had a length of 81 mm and the other a slightly different value. Sizes of the narrowed visual field were 20, 40, 70, 100, 150, and 340 mm wide. The comparison acuity dropped rapidly as the visual field was narrowed to and below 70 mm which was about the same extent as one of the two lines. The implication is that our excellent ability for length comparison is only possible when we can observe the whole line at one time.

PLZT electrooptic shutters: applications

This paper describes advances in the development of several electrooptic shutter devices utilizing the quadratic electrooptic effect of lead lanthanum zirconate titanate (PLZT) ceramic wafers. Aperture sizes utilized in these PLZT devices ranged from 25 microm to 0.25 m. Practical applications of the shutters discussed in this paper include eye protection in military and industrial applications, a goggle-type device with dual synchronously operated PLZT shutters for use in a stereoscopic three-dimensional TV display, an electrically controlled variable density filter for use with vidicon tubes, a large-aperture photographic shutter for image motion compensation cameras, and a page composer for use in a holographic memory system.

Fiber-optic laser illumination

Multiple-wavelength light from an ion laser was transmitted through a 85-µm optical fiber to provide illumination for viewing and color photography. Also adequate black-and-white TV display and photography were obtained using red light from an He-Ne laser transmitted through the same optical fiber.

Case history: Store and forward: Here, in one system, are interfaces for communications, a floppy disk, and a TV display

Discusses interfaces for communications, a floppy disk, and a TV display in a microprocessor-based store-and-forward system for international leased line communications.

A technique for the growth of thick films of zinc sulphide

Single crystal cubic zinc sulphide exhibits a longitudinal electro-optic effect in the (100) direction. Its large electro-optic constant renders the material suitable for light modulation and has applications in image storage devices and projection TV display. These devices require films of high-quality strain-free ZnS, about 100 mu m thick and with areas typically 6 cm2. The authors describe the techniques used in the growth of homo-epitaxial deposits from the vapour phase.

Identification of Cartographic Symbols from TV Displays

An experiment was conducted to investigate the resolution capability of TV displays in distinguishing details from line-maps and picto-maps, and to establish the relative merits of color and black-and-white TV display systems. The experimental variables included two display types, three map types, four symbol types, and three image-resolution levels. The results showed that a color display offered some advantage over a black-and-white display of equivalent effective resolution. However, a black-and-white system could provide the same performance at the expense of a slightly higher effective resolution. At an image-resolution level of nine TV-lines/mm, alphanumeric symbols were identified almost 100% correctly for all map types and display types. Area and line symbols achieved their maximum level of performance at five and seven TV-lines/mm, respectively. United States Geological Survey (USGS) 1:24,000 maps were significantly better than TOPOCOM line-maps and picto-maps.

DC EL materials and techniques for flat-panel TV display

The preparation and properties of direct current electroluminescent (dc EL) materials using manganese-activated ZnS powders for a flat-panel TV display are described. The firing process, the copper coating process, and the ferming process have been investigated. Suitable powder phosphors for the display panel contain 0.1-0.5 wt % manganese and 0.25-0.35 wt % copper coated on the ZnS powder surface. Although the powder-type dc EL still has low luminous efficiency, the light output can be increased to a useful level by exciting the panel with voltage pulses of high peak power. The crosstalk effect in the display panel can also be suppressed, since the brightness is very nonlinear with respect to the applied voltage. The sealing of the panel with silicone oil is effective in lengthening the life of the panel. An experimental dc EL panel with a 13-in diagonal and 50 176 picture elements has been fabricated, capable of reproducing broadcast TV images. These images have a highlight brightness of 10 fL, a contrast ratio of 20:1, a limiting resolution of about 150 TV lines in both horizontal and vertical directions, and a gray-scale capability of 16 steps.

Closed Circuit TV Microscopy

We recently installed a fiber optics TV display system made by N. V. Philips Gloeilampenfabrieken, Eindhoven, Holland, on our EM-300. The TV chain consists of a highly efficient transmission fluorescent screen deposited onto a fiber optics disc. In direct contact with this disc is a fiber optics window on a special Plumblcon tube in the TV camera. The camera signal is viewed on a 12-inch monitor having an EIA scanning system, 525 lines/sec, 30 frames/sec, 2:1 interlace. Horizontal resolution is 135 lines with a band width of 5 MHz.The camera and fiber optic adaption piece is fitted at the bottom of the microscope column in place of the 70 mm camera. Normal use of the 35 mm and plate cameras remains possible. If desired, the TV system and the 70 mm camera can be interchanged in less than 30 minutes. Cables connect the camera to a control unit and control box.

Continuous patient monitoring with a small digital computer

This monitoring system, which is centered on a small computer with a 12 bit word size and 8 K of core memory, is controlled by core resident programming which carries out continuous monitoring of several analog signals from 4 patients while a variety of programs are paged into core from disk or tape when needed. The continuous programs monitor the electrocardiograph for arrhythmias, the respiratory rate, temperature, indirect blood pressure and intra-arterial pressure with a cardiac output estimation. Paged programs provide respiratory mechanics, intermittent cardiac output and an analysis of blood gases in addition to service functions such as those which control the TV display and those which type graphs for the medical record. Peripheral instrumentation has been developed from commercially available equipment with some modifications and additions. The system is designed for growth. Expansion from continuous monitoring of 4–8 patients could be provided by adding 4 K of memory to core. The paging system will permit the additon of many new programs to handle intermittent functions.

Detection of TV Imagery by Humans vs Machines

The probability of detection of moving small and point targets embedded in random, white noise on a TV display has been measured for the human observer and compared to the observer's performance for detection of larger images; the improvement in detection performance by the insertion of cues onto the TV display is shown; and the probability of detection by machine-processed pattern recognition techniques is compared to the performance of the human observer.

Television Display of Topographic Maps

Television is ideally suited as a cockpit display device in air navigation and as a real time communication link in a topographic data bank. Resolution and geometric fidelity are the two critical factors that must be considered in the design of a TV system for displaying topographic information. Experimental studies showed that a display scale of 8 TV-lines per mm on the map sample would be needed to distinguish the fine details in the TV display. Although the geometric distortions in a conventional TV system may amount to 7.4 TV-lines at one sigma level, an accurate distortion map of the display can be obtained by a photogrammetric calibration procedure.

Liquid crystal matrix displays

Liquid crystal cells possess many properties that make their use in flat-panel displays very attractive. Most important, liquid crystal cells do not generate light but rather modify incident light, and they consume only a small amount of electrical energy while activated. The various electrical and optical properties of liquid crystal cells which make them useful for displays are reviewed in some detail. Several methods for speeding up the dynamic response of the cells are presented. The description of a variety of addressing schemes for activating liquid crystal cells in two-dimensional matrix displays is given. A number of these schemes have been tested in conjunction with a 2 × 18 element display matrix where the electrical environment of a full-size TV display has been faithfully simulated. The merits of both ac and dc excitation of cells in liquid crystal displays are discussed from the standpoint of complexity of addressing circuitry and operating life, as well as power consumption of the displays.

SLAC Control Room Consolidation Using Linked Computers

Consolidation of two large accelerator control rooms using digital computers connected by a data link is described. Several consolidation plans are discussed and the adopted solution is described. The key elements are touch panels operating with a TV display system.

Evaluation of Several TV Display System Configurations for Visual Simulation of the Landing Approach

A study has been conducted to determine the effects of several variations of two types of visual display systems on subjective pilot evaluations and objective measures of performance in the landing approach. Two types of flight approaches were made with either a projector or collimatmoed nitor visual display: 1) the instrument approach, and 2) the visual approach without the nonmal cockpit instrumentation assistance. The variables examined were color, differences between displays due to collimation, and reduced resolution. The use of color had two main effects on pilot performance in the landing approach. The touchdown distance and standard deviations increased more for the monitor displays, and the touchdown rates of descent were slightly lower. With collimation, the standard deviations of touchdown distance increased, and the rate-of-descent standard deviations decreased in a direction more favorable with the actual flight data. The time outside the glide-slope error limits was less with the monitor display, and the lateral localizer error was smaller for the projector display, because the pilots intercepted the runway center line at a greater distance from the threshold. With reduced resolution, there was a slight change in the touchdown distance and the standard deviation; for the flights made without color, the landings were predominantly to the right of the runway center line with twice the standard deviation. The pilots were more critical of the black and white variation for either display, and favored more use of a color system.

Immediate hospital-wide access to x-ray film images.

The system to be described permits examination of stored televised film images by referring physicians on various hospital floors and clinics from which the patient was referred. The images are available immediately after the films are made. Films would never leave the file room. The system can also be used for viewing films at conferences. Figure 1 shows the general arrangement. Apparatus Required for the TV Display of Images of Films In the X-Ray Department (Fig. 2) A. View box with variable brightness and variable size masks B. TV camera (I) with remotely controlled zoom lens and iris control for film recording C. TV camera (II) for viewing identifying data D. Special effects generator E. Local TV monitor F. Videodisc recorder G. Switches and cables to connect 1. TV camera to x-ray department monitor 2. TV camera to remote Videodisc recorder 3. Remote Videodisc recorders to x-ray department monitor In the Remote Stations A. Videodisc recorder B. TV monitor Operation of the System As the films of a patient leave the automatic processor, the radiologist examines them for adequacy of technic and completion of the examination. He may report the case immediately or let it proceed through its normal course for later reporting. He circles with a wax pencil any area of the film which is to be transmitted as an enlarged image. He may write a diagnosis on one of the films or on a separate piece of clear film. The films, requisition, and an identification card are given to the TV x-ray technician. He notes the location of the patient, that is, the floor of the hospital or clinic from which the patient originated. He connects the video output of the TV cameras to his local monitor and Videodisc and to the Videodisc recorder in the area from which the patient came. By remote control the radiologist moves the recording head on the remote disc to the first available space beyond the last recorded image for recording the new images. He places the films on the light box and adjusts the light, lens, mask, and camera for the best image on the local monitor. Under the second TV camera, he places the film-identifying information. He then records the films with their identifying data one after the other. The enlarged detailed images of any parts marked on the film and pertinent previous films are similarly recorded. A single disc will accept up to 1,600 images if both sides are used. The physician on the ward operates his local disc recorder. Its images are seen on his local monitor. Since no ward or clinic in our hospital sends more than 10 to 20 patients per day, the viewer has to review no more than a few patients on any given date before coming to the images of the films he wants, even without an index. Consideration was given to making all the retrieval mechanisms automatic, but this becomes very expensive and rather complicated.

The near, medium I.R. Earth albedo; Its use for cloud height determination

A method to determine cloud-top altitudes from satellite infra-red observations is presented here. A theoretical treatment of the spectral radiance of a cloudless and cloudy atmosphere is considered. These results are compared with experimental data obtained from sounding rockets etc., and extrapolated to satellite altitudes. On the basis of the latter correlation, it is shown that the parameters which affect the observed spectral radiance have the necessary content to yield cloud tops. Information obtained with a TIROS-like TV display can enhance the confidence level of the determination.

A Slow-Scan TV System Using the Permachon for Scan Conversion

To satisfy a requirement of the U. S. Weather Bureau to view weather radar images many miles from the radar site, a system was developed which uses a slow-scan vidicon to convert an optical image of the radar display to a narrow-band television signal suitable for transmission over conventional telephone circuits. Scan-conversion equipment utilizing the Permachon storage vidicon converts the received slow-scan TV image to a bright 625-line TV display. The equipment cost is comparable to the cost of one possible alternative; a single hop microwave link and low brightness radar indicator. It is considerably less expensive than a microwave link plus bright display scan-conversion system. The slow-scan system has the further advantage that it can be used with a telephone circuit of any length, whereas a single microwave link is limited to about 30 miles.