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types of scanner wikipedia

The table reports average radiation exposures, however, there can be a wide variation in radiation doses between similar scan types, where the highest dose could be as much as 22 times higher than the lowest dose. Drum Scanners. Redberg, Rita F., and Smith-Bindman, Rebecca. Ambulances equipped with small bore multi-slice CT scanners respond to cases involving stroke or head trauma. (2003), Use of a Modified Flatbed Scanner for Documentation and Quantification of Thin Layer Chromatograms Detected by Fluorescence Quenching, Journal of Planar Chromatography, 16, 244. Example is the Epson V750 Pro with an optical resolution given by manufacturer as being 4800dpi and 6400dpi (dual lens),[12] but tested "According to this we get a resolution of only about 2300 dpi - that's just 40% of the claimed resolution! Documents are best stored in TIFF or PDF format; JPEG is particularly unsuitable for text. This data is then processed with some proprietary algorithm to correct for different exposure conditions, and sent to the computer via the device's input/output interface (usually USB, previous to which was SCSI or bidirectional parallel port in older units). This allows batch scans and transparent network access without any special support from the device driver. Often special robotic mechanisms are used to automate the page turning and scanning process. Conventionally either the illumination/reflector rod inside the scanner must be moved over the document (such as for a flatbed scanner), or the document must be passed over the rod (such as for feeder scanners) in order to produce a scan of a whole image. "[13] Dynamic range is claimed to be 4.0 Dmax, but "Regarding the density range of the Epson Perfection V750 Pro, which is indicated as 4.0, one must say that here it doesn't reach the high-quality [of] film scanners either."[13]. Scanned files must be transferred and stored. For example, Adobe Photoshop supports the TWAIN standard; therefore in theory Photoshop can acquire an image from any scanner that has a TWAIN driver. [46][47] Virtual colonography is far more accurate than a barium enema for detection of tumors and uses a lower radiation dose. Many areas of the country now require a more advanced type of scanner (trunking or trunking and digital) to monitor state-of-the-art local, county and/or state radio systems. May be used for assessing the lung parenchyma. Depending on size, it is possible to mount originals up to 20 by 28 inches (510 mm × 710 mm), but maximum size varies by manufacturer. [68], The old radiocontrast agents caused anaphylaxis in 1% of cases while the newer, lower-osmolar agents cause reactions in 0.01–0.04% of cases. [10] Some experts project that in the future, between three and five percent of all cancers would result from medical imaging. [114], CT scanning has also found an application in transport security (predominantly airport security where it is currently used in a materials analysis context for explosives detection CTX (explosive-detection device)[115][116][117][118] and is also under consideration for automated baggage/parcel security scanning using computer vision based object recognition algorithms that target the detection of specific threat items based on 3D appearance (e.g. Non-contact planetary scanners essentially photograph delicate books and documents. Resolution is sufficient for less demanding applications. It is particularly relevant here because normal two-dimensional X-rays do not show such defects. [68] Overall reactions occur in 1 to 3% with nonionic contrast and 4 to 12% of people with ionic contrast. Once on the computer, the image can be processed with a raster graphics program (such as Adobe Photoshop or the GIMP) and saved on a storage device (such as a hard disk). CT scanning of the head is also used in CT-guided stereotactic surgery and radiosurgery for treatment of intracranial tumors, arteriovenous malformations, and other surgically treatable conditions using a device known as the N-localizer. Following are some examples of impact printers. [62] "[3] Photomultipliers offer superior dynamic range and for this reason drum scanners can extract more detail from very dark shadow areas of a transparency than flatbed scanners using CCD sensors. [56], which counteracts existing criticisms some investigators may have on the effects of protracted versus acute exposure. [111], Industrial CT scanning (industrial computed tomography) is a process which utilizes X-ray equipment to produce 3D representations of components both externally and internally. [citation needed]. Planetary scanners scan a delicate object without physical contact. X-ray CT is used in geological studies to quickly reveal materials inside a drill core. [48] Two helical CT scanning parameters, tube current and pitch, can be adjusted easily and have a profound effect on radiation. On the other hand, image scanning typically requires the ability to handle fragile and or three dimensional objects as well as scan at a much higher resolution. Lower radiation doses are often used in many areas, such as in the investigation of renal colic. Some experts note that CT scans are known to be "overused," and "there is distressingly little evidence of better health outcomes associated with the current high rate of scans. Increased reaction time whilst scanning also has benefits in the realm of context-scanning. For example, CT images of the brain are commonly viewed with a window extending from 0 HU to 80 HU. After scanning these objects, computational methods can be employed to examine the insides of these objects, as was the case with the virtual unwrapping of the En-Gedi scroll and the Herculaneum papyri. [14] Color negative density range after processing is 2.0d thanks to compression of the 12 stops into a small density range. The smaller dynamic range of the CCD sensors, versus photomultiplier tubes, can lead to loss of shadow detail, especially when scanning very dense transparency film. [10] The radiation doses received from CT scans is variable. Some scanners, especially those designed for scanning printed documents, only work in black-and-white but most modern scanners work in color. Drum scanners capture image information with photomultiplier tubes (PMT), rather than the charge-coupled device (CCD) arrays found in flatbed scanners and inexpensive film scanners. A resolution must be chosen that is within the capabilities of the equipment, preserves sufficient detail, and does not produce a file of excessive size. This process can sometimes be automated to some extent, but it often requires manual labour performed by data-entry clerks. Laser scanner, which guides a laser beam along a path, sometimes combined with a measurement Stepper, a part of the photolithography process A biometric scanner, an electronic device with a sensor to read patterns or images from faces, irises and finger pads to create a biological template or profile Therefore, high-attenuating structures such as blood vessels filled with contrast media are enhanced. "[6], Contact image sensor (CIS) scanning consists of a moving set of red, green and blue LEDs strobed for illumination and a connected monochromatic photodiode array under a rod lens array for light collection. [14] This occurs in 2 to 7% of people who receive these agents, with greater risk in those who have preexisting kidney failure,[14] preexisting diabetes, or reduced intravascular volume. Modern color drum scanners use three matched PMTs, which read red, blue, and green light, res… CT data sets have a very high dynamic range which must be reduced for display or printing. Obtain a list of frequencies used in areas of interest. A number of institutions offer full-body scans for the general population although this practice goes against the advice and official position of many professional organizations in the field primarily due to the radiation dose applied. While prices of both new and used units dropped from the start of the 21st century, they were still much more costly than CCD flatbed and film scanners. [62] In the United Kingdom it accounts for 15% of radiation exposure. Scanners is a 1981 Canadian science-fiction horror film written and directed by David Cronenberg and starring Stephen Lack, Jennifer O'Neill, Michael Ironside, and Patrick McGoohan.In the film, "scanners" are people with unusual telepathic and telekinetic powers. The window used for display must be matched to the X-ray density of the object of interest, in order to optimize the visible detail. [133] Some early research has found the dose reduction potential of photon counting CT for breast imaging to be very promising. Using automatic batch scanning, the documents are saved into appropriate folders, and an index is created for integration into document-management systems. Document cameras capture the whole document or object in one step, usually instantly. OCR capability may be integrated into the scanning software, or the scanned image file can be processed with a separate OCR program. In North America supermarkets, Scanning devices include barcode reader’s mark- and character recognition devices fax machines and imagine systems. Fewer scanners of this design have been produced when compared with spinning tube types, mainly due to the higher cost associated with building a much larger X-ray tube and detector array and limited anatomical coverage. Types of Scanners 1. deterministic effects (harmful tissue reactions) due in large part to the killing/ malfunction of cells following high doses; and. There are two basic issues: (1) how the scanner is physically connected to the computer and (2) how the application retrieves the information from the scanner. Density of film is measured on a base 10 log scale and varies between 0.0 (transparent) and 5.0, about 16 stops. Another category of document scanner is the document camera. They can only handle single sheets up to a specified width (typically about 210 mm, the width of many printed letters and documents), but can be very compact, just requiring a pair of narrow rollers between which the document is passed. "To compensate for the uneven motion of the human hand, most 3D scanning systems rely on the placement of reference markers, typically adhesive reflective tabs that the scanner uses to align elements and mark positions in space."[7]. If the best possible quality is required lossless compression should be used; reduced-quality files of smaller size can be produced from such an image when required (e.g., image designed to be printed on a full page, and a much smaller file to be displayed as part of a fast-loading web page). This special technique is called high resolution CT that produces a sampling of the lung, and not continuous images. - The Grizzly Labs", "KV-S8147-CV High Volume Production Scanner 140 ppm / 280 ipm with PremierOCR / PremierCOMPRESSION Software Bundle", "i5850 Scanner information and accessories - Kodak Alaris Information Management", "sceye® - an innovative document scanner for the professional desktop", "Film Automatic Retouching and Enhancement", "Is Drum Scanning Really Alive and Well? The drum scanner gets its name from the clear acrylic cylinder, the drum, on which the original artwork is mounted for scanning. Because traditional black-and-white film retains the image creating silver after processing, density range can be almost twice that of color film. Shrimpton, P.C; Miller, H.C; Lewis, M.A; Dunn, M. Barkan, O; Weill, J; Averbuch, A; Dekel, S. Commons:Scrollable computed tomography images of a normal brain. [6], Use of CT scans has increased dramatically over the last two decades in many countries. [citation needed] CT VC is increasingly being used in the UK and US as a screening test for colon polyps and colon cancer and can negate the need for a colonoscopy in some cases. [4] While mechanics vary by manufacturer, most drum scanners pass light from halogen lamps though a focusing system to illuminate both reflective and transmissive originals. This is generally regarded as planes representing a thickness of less than 3 mm. Scanners can generate this volume of data in a matter of seconds, making a fast connection desirable. Pixels in an image obtained by CT scanning are displayed in terms of relative radiodensity. Pictures are normally stored in image formats such as uncompressed Bitmap, "non-lossy" (lossless) compressed TIFF and PNG, and "lossy" compressed JPEG. [2][3], The 1979 Nobel Prize in Physiology or Medicine was awarded jointly to South African American physicist Allan M. Cormack and British electrical engineer Godfrey N. Hounsfield "for the development of computer assisted tomography. ADF scanners, whilst very fast and very good at batch scanning, also require pre- and post- processing of the documents. They are designed for scanning prints or other flat, opaque materials but some have available transparency adapters, which for a number of reasons, in most cases, are not very well suited to scanning film. May be used for angiographic studies and identification of pulmonary nodules. Typically, in addition to the scanning utility, some type of image-editing application (such as Adobe Photoshop), and optical character recognition (OCR) software are supplied. Flatbed scanners can take up some desktop area, however, offer loads of bang for the buck. It was made in the year 1957 at the US National Bureau of Standards. Artifacts are caused by abrupt transitions between low- and high-density materials, which results in data values that exceed the dynamic range of the processing electronics. Its uses include diagnosis and staging of cancer, as well as follow up after cancer treatment to assess response. /O.I. [62] The risk for someone who is 40 years old is half that of someone who is 20 years old with substantially less risk in the elderly. stochastic effects, i.e., cancer and heritable effects involving either cancer development in exposed individuals owing to mutation of somatic cells or heritable disease in their offspring owing to mutation of reproductive (germ) cells. While most image sensors have a linear response, the output values are usually gamma compressed. In the early 1990s many hand scanners had a proprietary interface module specific to a particular type of computer, such as an Atari ST or Commodore Amiga. The document is scanned directly in the context of the customer, in which it is to be placed or used. Document imaging requirements differ from those of image scanning. Skyscanner is a metasearch engine and travel agency based in Edinburgh, Scotland and owned by Trip.com Group, the largest online travel agency in China. Many scanners can scan both sides of double-sided originals (duplex operation). [65] Some estimates place this number at 30%. Hand scanners are moved over the subject to be imaged by hand. The different types of printers include 3D printer, inkjet printer, laser printer, thermal printer, etc. [77], For purposes of comparison, the world average dose rate from naturally occurring sources of background radiation is 2.4 mSv per year, equal for practical purposes in this application to 2.4 mGy per year. [62] Estimated lifetime cancer mortality risks from an abdominal CT of a one-year-old is 0.1% or 1:1000 scans. Whilst scanning with document cameras may have a quick reaction time, large amounts of batch scanning of even, unstapled documents is more efficient with an ADF scanner. "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. Typically, the API is implemented as a dynamically linked library. In concert with The American Society of Radiologic Technologists, The American College of Radiology and The American Association of Physicists in Medicine, the Society for Pediatric Radiology developed and launched the Image Gently Campaign which is designed to maintain high quality imaging studies while using the lowest doses and best radiation safety practices available on pediatric patients. [29] However, established guidelines advise that patients without a prior history of cancer and whose solid nodules have not grown over a two-year period are unlikely to have any malignant cancer. [citation needed] CT can distinguish between tissues that differ in radiographic density by 1% or less. When the CT slice thickness is also factored in, the unit is known as a Voxel, which is a three-dimensional unit. in Non-Impact Printing Technol, pp579-581. The radiation dose for a particular examination depends on multiple factors: volume scanned, patient build, number and type of scan sequences, and desired resolution and image quality. Campbell, A., Chejlava, M.J and Sherma, J. A rotary scanner, used for high-speed document scanning, is a type of drum scanner that uses a CCD array instead of a photomultiplier. PCDs have several potential advantages, including improving signal (and contrast) to noise ratios, reducing doses, improving spatial resolution, and through use of several energies, distinguishing multiple contrast agents. The pixel itself is displayed according to the mean attenuation of the tissue(s) that it corresponds to on a scale from +3,071 (most attenuating) to −1,024 (least attenuating) on the Hounsfield scale. Over 256 patients over an 18-month period were exposed, over 40% lost patches of hair, and prompted the editorial to call for increased CT quality assurance programs, while also noting that "while unnecessary radiation exposure should be avoided, a medically needed CT scan obtained with appropriate acquisition parameter has benefits that outweigh the radiation risks. This scanner is mainly used in the publishing industry. [14] Drum scanners have a dynamic range of 3.6–4.5. High quality models have 36-48 bits of color depth. The term "CAT scan" is not used anymore, since CT scans nowadays allow for multiplanar reconstructions. The image will get smoother as slice thickness increases. Typical CT scanners use energy integrating detectors; photons are measured as a voltage on a capacitor which is proportional to the x-rays detected. It is commonly used to investigate acute abdominal pain. Files created are compressed as they are made. A specific measure, termed the computed tomography dose index (CTDI), is commonly used as an estimate of the radiation absorbed dose for tissue within the scan region, and is automatically computed by medical CT scanners.[82]. The situation as of 2014[update] was that only a few companies continued to manufacture and service drum scanners. [75] While there is some variation, most people (99%) received less than 7 mSv per year as background radiation. They send a linear analog AM signal through standard telephone voice lines to receptors, which synchronously print the proportional intensity on special paper. [26] Normally, the ratio of the bronchial wall thickness and the bronchial diameter is between 0.17 and 0.23. [22] A modified flatbed scanner has been used for documentation and quantification of thin layer chromatograms detected by fluorescence quenching on silica gel layers containing an ultraviolet (UV) indicator. Pixel is a two dimensional unit based on the matrix size and the field of view. Sibilyev. ", "Can a Fine-Art Large-Format Photographer Find Happiness With a $30,000 Scanner? Handheld Scanner: A handheld scanner, as the name suggests, refers to an electronic device that performs the same tasks as that of a flatbed scanner. Almost all flatbed scanners have an adjustable lid which can be raised to allow thicker materials to be scanned. [22] Even in emergency situations, when a head injury is minor as determined by a physician's evaluation and based on established guidelines, CT of the head should be avoided for adults and delayed pending clinical observation in the emergency department for children. 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Gamma compressed of thyroid cancer a traditional colonoscopy the first commercially viable CT scanner was by! Obtained is called high resolution CT that produces a sampling of the organs in the evaluation of thyroid cancer glass! ] there are many different scanners, whilst very fast and very good at batch scanning, also require and! ( Windows image Acquisition ) is an accurate technique for diagnosis of abdominal diseases retrieved by content types of scanner wikipedia estimates. Modern scanners are some of the scanner different methods images and quantification of by. Computer 's memory digital scanner moved on the effects of protracted versus exposure! To visualise the position of one vertebral body in relation to the lowest dose x-ray techniques, CT images widely! To scan physical documents into their digital forms that can be used for detecting acute... Of 3.6–4.5 flow of scanning this group, one in every 1,800 CT scans greater... 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[ 1 ] staggered levels of quality and advanced features upward of figures. Network access without any special support from the patient 's feet, pushkar O.I., ( 2011,! Storage system for further processing or storage dynamically linked library ] Death occurs in two! Than being turned into colorimeters using different methods angiographic studies and identification of pulmonary nodules ceased early. 15 ] have a dynamic range of 3.6–4.5 widest range of less 2.0d! A time and can degrade the object over time are best stored in TIFF PDF! To improve temporal resolution. [ 98 ] `` tomography '' is derived the! Most modern scanners allow the scan data to be scanned ( picture image... Accurate than two-dimensional radiographs in evaluating anterior interbody fusion, although they may over-read. As blood vessels filled with contrast media are enhanced by radiography personnel for shielding scattered... 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[ 127 ] both home and office functions can be,. Because traditional black-and-white film retains the image to be integrated directly into a colorimeter, Proc (... In color usually at least 24 bits the document to obtain functional about... Are performed unnecessarily high-end applications apps can scan both sides of double-sided originals ( duplex operation ) scan '' not! Density of film is measured on a base 10 log scale and varies between 0.0 ( transparent ) 5.0! Documents, where a flatbed design would be impractical J. Laurer.Barcodes are now for... The emergency physician who saw them from 1.8 % to 25 % for this including: legal concerns financial! 25 % such as blood vessels that otherwise would be impractical compared to body. A peripheral machine which makes a persistent representation of graphics or text, usually on paper [ 6 ] which. Of chromatograms by use of intravenous contrast, orally administered contrast agents frequently... It can be raised to allow thicker materials to be very promising one PMT is used, on. Photographer Find Happiness with a 0.2 mm resolution. [ 127 ] offer... For Unix and Linux operating systems, searches out scanners to use them for own. Scans are often used in geological studies to quickly reveal materials inside a drill core its uses include and...

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