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Drum Scanner
Drum scanners are a type of image scanner that capture image information with photomultiplier, photomultiplier tubes (PMT), rather than the charge-coupled device (CCD) arrays found in flatbed scanners and inexpensive film scanners. "Reflective and transmissive originals are mounted on an acrylic cylinder, the scanner drum, which rotates at high speed while it passes the object being scanned in front of precision optics that deliver image information to the PMTs. Modern color drum scanners use three matched PMTs, which read red, blue, and green light, respectively. Light from the original artwork is split into separate red, blue, and green beams in the optical bench of the scanner with dichroic filters."Pushkar O.I., (2011), Information systems and technologies. Summary of lectures. /O.I. Pushkar, K.S. Sibilyev. – Kharkiv: Publishing House of KhNUE, p.38 Photomultipliers offer superior dynamic range and for this reason, drum scanners can extract more detail from very dark shadow a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lathe
A lathe () is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, threading and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis. Lathes are used in woodturning, metalworking, metal spinning, thermal spraying, reclamation, and glass-working. Lathes can be used to shape pottery, the best-known design being the Potter's wheel. Most suitably equipped metalworking lathes can also be used to produce most solids of revolution, plane surfaces and screw threads or helices. Ornamental lathes can produce three-dimensional solids of incredible complexity. The workpiece is usually held in place by either one or two ''centers'', at least one of which can typically be moved horizontally to accommodate varying workpiece lengths. Other work-holding methods include clamping the work about the axis of rotation using a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Document Camera
A document camera, also known as a visual presenter, visualizer, digital overhead, docu-cam, or simply a doc-cam, is a Image resolution, high-resolution image capture device used to display objects in real-time to a large audience, such as in a classroom or lecture hall. It can also function as an alternative to a traditional image scanner for digitizing documents for archival or digital storage. The camera is typically mounted on an adjustable arm, allowing it to be positioned over a document or object. It connects to a projector or similar video display system, enabling the presenter to display text, images, or an object to the audience. Larger objects can be placed in front of the camera, which can then be rotated as needed. Use cases Document cameras are used in various settings, including: * Lecture halls and classrooms. * Presentations in Conference, conferences, Meeting, meetings, and training sessions. * Videoconferencing and telepresence. * Presentation of evidence in Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pixel Density
Pixels per inch (ppi) and pixels per centimetre (ppcm or pixels/cm) are measurements of the pixel density of an electronic image device, such as a computer monitor or television display, or image digitizing device such as a camera or image scanner. Horizontal and vertical density are usually the same, as most devices have square pixels, but differ on devices that have non-square pixels. Pixel density is not the same as where the former describes the amount of detail on a physical surface or device, the latter describes the amount of pixel information regardless of its scale. Considered in another way, a pixel has no inherent size or unit (a pixel is actually a sample), but when it is printed, displayed, or scanned, then the pixel has both a physical size (dimension) and a pixel density (ppi). Basic principles Since most digital hardware devices use dots or pixels, the size of the media (in inches) and the number of pixels (or dots) are directly related by the 'pixels per inch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mainframe Computer
A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise resource planning, and large-scale transaction processing. A mainframe computer is large but not as large as a supercomputer and has more processing power than some other classes of computers, such as minicomputers, server (computing), servers, workstations, and personal computers. Most large-scale computer-system architectures were established in the 1960s, but they continue to evolve. Mainframe computers are often used as servers. The term ''mainframe'' was derived from the large cabinet, called a ''main frame'', that housed the central processing unit and main computer memory, memory of early computers. Later, the term ''mainframe'' was used to distinguish high-end commercial computers from less powerful machines. Design Modern mainfr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SEAC (computer)
SEAC (''Standards Eastern Automatic Computer'' or ''Standards Electronic Automatic Computer'') was a first-generation electronic computer, built in 1950 by the U.S. National Bureau of Standards (NBS) and was initially called the ''National Bureau of Standards Interim Computer'', because it was a small-scale computer designed to be built quickly and put into operation while the NBS waited for more powerful computers to be completed (the DYSEAC). The team that developed SEAC was led by Samuel N. Alexander and Ralph J. Slutz. SEAC was demonstrated in April 1950 and was dedicated in June 1950; it is claimed to be the first fully operational stored-program electronic computer in the US. Description Based on EDVAC, SEAC used only 747 vacuum tubes (a small number for the time) eventually expanded to 1,500 tubes. It had 10,500 germanium diodes which performed all of the logic functions (see the article diode–transistor logic for the working principles of diode logic), later expa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russell Kirsch
Russell A. Kirsch (June 20, 1929 – August 11, 2020) was an American engineer at the National Bureau of Standards (now known as the National Institute of Standards and Technology). He was recognized as the developer of the first digital image scanner, and subsequently scanned the world's first digital photograph – an image of his infant son. Early life Kirsch was born in Manhattan on June 20, 1929. His parents were Jewish emigrants from Russia and Hungary. He attended the Bronx High School of Science, graduating in 1946. He continued his education at New York University in 1950, Harvard University in 1952, and later the Massachusetts Institute of Technology. Career In 1951 Kirsch joined the National Bureau of Standards as part of the team that ran SEAC (Standards Eastern Automatic Computer). SEAC was the U.S.'s first stored-program computer to become operational, having entered service in 1950. In 1957, Kirsch's group developed a digital image scanner, to "trace variations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Institute Of Standards And Technology
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into Outline of physical science, physical science laboratory programs that include Nanotechnology, nanoscale science and technology, engineering, information technology, neutron research, material measurement, and physical measurement. From 1901 to 1988, the agency was named the National Bureau of Standards. History Background The Articles of Confederation, ratified by the colonies in 1781, provided: The United States in Congress assembled shall also have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of the respective states—fixing the standards of weights and measures throughout the United States. Article 1, section 8, of the Constitution of the United States, ratified i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photo Etching
Photochemical machining (PCM), also known as photochemical milling or photo etching, is a chemical milling process used to fabricate sheet metal components using a photoresist and etchants to corrosively machine away selected areas. This process emerged in the 1960s as an offshoot of the printed circuit board industry. Photo etching can produce highly complex parts with very fine detail accurately and economically. This process can offer economical alternatives to stamping, punching, laser or water jet cutting, or wire electrical discharge machining (EDM) for thin gauge precision parts. The tooling is inexpensive and quickly produced. This makes the process useful for prototyping and allows for easy changes in mass production. It maintains dimensional tolerances and does not create burrs or sharp edges. It can make a part in hours after receiving the drawing. PCM can be used on virtually any commercially available metal or alloy, of any hardness. It is limited to materials wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMYK Color Model
The CMYK color model (also known as process color, or four color) is a subtractive color model, based on the CMY color model, used in color printing, and is also used to describe the printing process itself. The abbreviation ''CMYK'' refers to the four ink plates used: cyan, magenta, yellow, and key (most often black). The CMYK model works by partially or entirely masking colors on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected. Such a model is called ''subtractive'', as inks ''subtract'' some colors from white light; in the CMY model, white light minus red leaves cyan, white light minus green leaves magenta, and white light minus blue leaves yellow. In additive color models, such as RGB, white is the ''additive'' combination of all primary colored lights, and black is the absence of light. In the CMYK model, it is the opposite: white is the natural color of the paper or other background, and black results from a full ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Correction
Color correction is a process used in stage lighting, photography, television, cinematography, and other disciplines, which uses color gels, or filters, to alter the overall color of the light. Typically the light color is measured on a scale known as color temperature, as well as along a green–magenta axis orthogonal to the color temperature axis. Without color-correction gels, a scene may have a mix of various colors. Applying color-correction gels in front of light sources can alter the color of the various light sources to match. Mixed lighting can produce an undesirable aesthetic when displayed on a television or in a theatre. Conversely, gels may also be used to make a scene ''appear'' more natural by simulating the mix of color temperatures that occur naturally. This application is useful, especially where ''motivated lighting'' (lending the impression that it is diegetic) is the goal. Color gels may also be used to tint lights for artistic effect. Correlated color ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photomultiplier Tube
Photomultiplier tubes (photomultipliers or PMTs for short) are extremely sensitive detectors of light in the ultraviolet, visible light, visible, and near-infrared ranges of the electromagnetic spectrum. They are members of the class of vacuum tubes, more specifically vacuum phototubes. These detectors multiply the current produced by incident light by as much as 100 million times or 108 (i.e., 160 decibel, dB),Decibels are power ratios. Power is proportional to I2 (current squared). Thus a current gain of 108 produces a power gain of 1016, or 160 decibel, dB in multiple dynode stages, enabling (for example) individual photons to be detected when the incident flux of light is low. The combination of high Gain (electronics), gain, low Noise (electronics), noise, high frequency response or, equivalently, ultra-fast response, and large area of collection has maintained photomultipliers an essential place in Spectroscopy, low light level spectroscopy, confocal microscopy, Raman spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
