Testing a Display Device Invention for Digital Mammography Workstations

In this day when everybody is talking about solid state devices, it appears that there is one vacuum tube component which is not likely to be replaced for some time. This is the cathode ray tube. It is the prime transducer of information from the intangible electrical medium to human beings and is also widely used for film scanning and recording. The cathode ray tube today is fast, versatile, accurate, and is capable of demonstrating a resolving ability which challenges optical lenses.The purpose of this paper is to discuss the category of cathode ray tubes which are capable of resolving detail which is beyond that which the human eye can appreciate. This is the class of tubes used primarily for scanning of film or recording on photo sensitive materials.High resolution gun designs will not be discussed. The major purpose here will be to give the designer who is interested in high‐resolution cathode‐ray tube systems a guide for use in intelligent selection and practical operation of these tubes.

An experimental high resolution cathode ray tube (CRT) printer was developed to produce high quality 3. 5in. x 5 in. and 4 in. x 6 in. photographic prints. A monochrome CRT utilizing red green and blue filtration was used to sequenlially expose continuous-tone color images directly onto conventional photographic paper. A summary of the design and implementation of the printer at the systems level will be presented. The design approach taken to meet the system quality requirements is described from the electrical mechanical and optical points of view. In addition the presentation will emphasize the design challenges of implementing a CRT imager and the solutions to the unique problems it presents. Other concerns discussed in detail include spatial resolution and bit resolution image size and magnification colorimetry and paper response matching. Sample prints of test patterns and scanned images will be shown. 1.

An automated white uniformity inspection system for high-resolution color CRTs (cathode ray tubes) was developed. White uniformity is the general evaluation of whiteness on CRT screens and is especially important for CRTs used in computer display terminals. A color television camera was used to obtain color data on a CRT screen at high speed. Perceptual color differences on chrominance signal color space are discussed. An algorithm for white uniformity inspection is presented using the chrominance signals. Color contrast between a defect region and the background, hue, area, and edge strength of the defect was used for the evaluation. The validity of the algorithm has been verified by experimental results. >

In order to reduce trailing phenomenon for moving image in FPD (Flat Panel Display), grayscale control algorithm is proposed that simulates CRT (Cathode Ray Tube) grayscale rendition process. First, after the reason of trailing phenomenon for moving image is introduced, work processes of human eyes are illuminated and grayscale rendition of a pixel is obtained, when seeing moving image on CRT and FPD; Then, based on algorithm derivation, algorithm realization steps and compared experiment results of traditional and proposed FPD grayscale control algorithm are discussed; Finally, implemented main program with VHDL (Very-High-Speed Integrated Circuit Hardware Description Language) is presented and specific rendition process is described. Experimental results indicate image quality is evidently improved and proposed algorithm reduces trailing phenomenon nearly 90%, when FPD displays moving image, according with eyes reflection mechanism and programs can correctly implement on circuit board.

A random access fixed store is described, which has a capacity of more than 3 million bits and an access time of the order of 5 μs. The storage medium is a photographic emulsion, accessed by a high resolution cathode-ray tube as light source and 10 stage photomultipliers as detectors. Addressing is under the control of an optoelectronic, closed loop cathode-ray tube beam positioning system, and parallel readout of 50 bits is achieved by optical multiplexing, by means of a square cross section mirror tunnel.

ObjectiveTo compare observer performance using liquid-crystal display (LCD) and cathode-ray tube (CRT) monitors in the interpretation of soft-copy chest radiographs for the detection of small solitary pulmonary nodules.Materials and MethodsBy reviewing our Medical Center's radiologic information system, the eight radiologists participating in this study (three board-certified and five resident) retrospectively collected 40 chest radiographs showing a solitary noncalcified pulmonary nodule approximately 1 cm in diameter, and 40 normal chest radiographs. All were obtained using a storage-phosphor system, and CT scans of the same patients served as the gold standard for the presence of a pulmonary nodule. Digital images were displayed on both high-resolution LCD and CRT monitors. The readers were requested to rank each image using a five-point scale (1 = definitely negative, 3 = equivocal or indeterminate, 5 = definitely positive), and the data were interpreted using receiver operating characteristic (ROC) analysis.ResultsThe mean area under the ROC curve was 0.8901±0.0259 for the LCD session, and 0.8716±0.0266 for the CRT session (p > 0.05). The reading time for the LCD session was not significantly different from that for the CRT session (37.12 and 41.46 minutes, respectively; p = 0.889).ConclusionFor detecting small solitary pulmonary nodules, an LCD monitor and a CRT monitor are comparable.

The aim of this study was to evaluate feasibility of reporting brain CT examinations on liquid crystal display (LCD) flat-screen monitors vs state-of-the-art cathode-ray-tube (CRT) monitors. Ninety-five brain CT examinations of 95 patients were displayed on Picture archiving and communications system (PACS) workstations equipped either with a dedicated medical imaging LCD colour monitor or on a high-resolution CRT which is used for routine reporting of CT, MRI and digital radiography images in our institution. Fifty cases were negative and 45 cases were positive for early brain infarction (EBI), the latter being defined by a combination of one or more signs: dense artery; hypodensity of brain parenchyma; and local brain swelling verified by control scans. Ten radiologists had to rate presence or absence of EBI on a five-point scale. Ratings were evaluated by CORROC2 ROC software and areas under the ROC curve (A(z)) were computed. Significance of differences between the two viewing conditions were evaluated with Wilcoxon test. Mean A(z) of the ten observers was 0.7901 with LCD vs 0.7695 with CRT which did not show statistical significance (p=0.2030). In the setting investigated, reporting of CT studies from high-performance LCD monitors seems feasible without significant detriment to diagnostic performance.

Flat-panel displays (FPDs) will soon become ubiquitous products in our homes, workplaces, and a number of places in between. Familiar display applications pioneered by the venerable cathode-ray tube (CRT) will progressively utilize a number of different FPDs. Flat-panel displays will also initiate and pioneer new applications, as was the case with notebook computers and personal digital assistants.The future proliferation of FPDs can no longer be doubted for two simple reasons. First, such devices help us cope with this already information-saturated society. Second, the technological momentum and financial commitment needed for FPDs to take hold are already irreversibly set in place. It is the insatiable current and near-future demand that are pulling the field, and that are fueling a flurry of research and development activities. The display market has grown in size from tens of millions of dollars only a decade ago to a nearly ten-billion-dollar industry. This market growth is expected to continue at a brisk pace during the next decade.This of course is in no way bad news for materials scientists and engineers. We nearly always benefit from development of new and complex products. It is in regard to these rather incipient but advanced manufacturing technologies where we often encounter challenging, relevant, and interesting materials problems. The better we address these obstacles during these early and therefore critical times, the more successful the FPD technology will be in fulfilling the potential opportunities that lie ahead.

Today, in a multimedia age, electronic displays are the essential key devices involved in the relation between multimedia equipment and human beings. Flat panel displays are overcoming the restrictions of traditional CRTs (Cathode Ray Tubes) regarding portability and large screen capability, and they are ready to expand their multimedia application fields. TFT-LCDs (Thin Film Transistor-Liquid Crystal Displays) in particular have advantages such as light weight, low profile, low power consumption, and motion picture display, and importantly contribute the development of multimedia. The color PDP (Plasma Display Panel) features emissive display, a large screen, and a low profile, and mass production aimed at implementing space-saving, and wall-hung HDTV (High Definition Television) is about to be started. Since further development of multimedia is expected in the twenty-first century, the scale of this market is immeasurable. At the same time, the flat panel display market will also expand. Wide variety of flat panel displays will gain wider use as they secure their respective markets through their particular advantages.KeywordsMultimediaDevice technologyElectronic displayFlat panel displayLCDTFT-LCDColor PDP

Although there are remarkable differences in maximum luminance in cathode ray tube (CRT) and liquid crystal display (LCD) monitors and film/viewer systems, these differences cannot be recognized in our perception of them. To clarify the reason for this conflict, we analyzed the psychophysical gradient (delta), which is based on the minimum perceptible luminance difference (DeltaL(min)) and can express contrast visually recognized by observers. In this study, we first confirmed the compatibility of the psychophysical analysis to the CRT and the LCD monitors by using their threshold contrasts (C(t)s). Second, we calculated and compared the delta's of the above output devices. The C(t)s values of each device were in good agreement. Moreover, the Moon & Spencer model, which expressed the perceptibility of luminance change, was well suited to the measured C(t)s over the whole luminance range. The psychophysical analysis is therefore available not only for the film/viewer system, but also for the CRT and LCD systems. The difference of physical gradient G of the luminance characteristics curve among the output devices was larger than 20 times, whereas that of d was within 3 times. The display devices listed in the order of decreasing delta were film/viewer>LCD>CRT. These results corresponded to the visual contrast sensation and our clinical experience, which cannot recognize remarkable differences in perception. By using the psychophysical analysis, we clarified the reason for the conflict between the results of physical evaluation and the contrast visually recognized by observers.

Digital mammography is gradually replacing screen-film analog mammography, a transition driven by a desire to improve the efficiency and possibly the quality of the interpretation of mammograms. Digital mammography involves the use of electronic display devices to display the mammograms. Currently, two electronic technologies are used to display digital mammograms: the cathode-ray tube (CRT) and liquid crystal display (LCD). CRT and LCD devices have imaging characteristics markedly different from those of transilluminated film, which has conventionally been used to display analog mammograms. Consequently, the transition to digital mammography necessitates consideration of a number of psychophysical factors pertaining to effective display of mammograms. Some of these factors are related to specific performance characteristics of the display devices, whereas others are related to inherent characteristics of the human visual system. The main psychophysical factors that affect the interpretation of medical images are contrast, resolution, and noise. Optimal display of mammograms is achieved by taking these factors into consideration and by using time-efficient, intuitive, and reader-specific user interfaces. Because display devices are susceptible to variations in hardware and calibration and to degradation over time, acceptance testing and quality control testing are necessary to maintain an adequate level of display quality.

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In the era of vigorous development of optoelectronic technology, the high-performance lithium niobate optical beam splitter, as a core component for optical signal processing and transmission, provides an excellent material basis for optical signal modulation with its outstanding electro-optical properties. At present, it has been found in research and application that three-dimensional ridge-shaped strip waveguides can enhance the interaction between light and electric fields. Multimode interferometric couplers (MMI) have the advantages of compact structure, simple fabrication and stable mode conversion. The combination of the two can achieve efficient optical beam splitting and precise modulation, effectively improving the modulation efficiency. Through theoretical analysis and numerical simulation, the light field distribution, mode characteristics and modulation performance parameters of this structure were deeply studied. The results show that compared with the traditional structure, this design significantly improves the modulation efficiency, and can effectively reduce mode crosstalk at the same time, achieving stable optical signal beam splitting and modulation. This research provides a new approach for the application of lithium niobate beam splitters in high-speed optical communication, optical signal processing and other fields, which is conducive to promoting the development of optoelectronic integrated devices.

Chapter 1 - Liquid crystals for electro-optic applications

Flat panel displays (FPDs) have simulated a tremendous amount of research interest in the past two decades as replacements for cathode ray tube (CRT) displays in applications where weight, volume, and power consumption are important.