Scan
'''Scan''' may refer to: For specific contexts, see the relevant sections below.Science and Technology
Computing and Electronics
In computing and electronics, an image scanner is a device that optically captures and converts visual data from physical objects, such as documents or photographs, into digital formats for storage, processing, or transmission.[1] The first image scanner was developed in 1957 by Russell A. Kirsch and his team at the U.S. National Bureau of Standards (now NIST), using a rotating drum mechanism to create the world's first digital photograph—a 176x176 pixel black-and-white image of Kirsch's son—marking the beginning of digital imaging technology.[2] Over time, scanner technology evolved from these early prototypes to more accessible forms, driven by advancements in charge-coupled device (CCD) sensors and light sources. Common types of image scanners include flatbed scanners, which feature a flat glass platen for placing objects and use a moving light source and CCD array to capture images line by line, making them versatile for books, photos, and irregular objects.[1] Drum scanners, like the 1957 model, wrap originals around a rotating cylinder illuminated by a photomultiplier tube for high-resolution capture, though they are now largely obsolete due to their complexity and size.[2] Handheld scanners offer portability, allowing users to manually sweep a light-emitting diode (LED) or contact image sensor (CIS) over documents, though they may sacrifice resolution for mobility.[1] Software scanning processes in computing involve systematic examination of data for specific patterns or anomalies. In antivirus programs, scanning detects malware by comparing files and memory against databases of known virus signatures or using heuristic analysis to identify suspicious behaviors, enabling real-time protection or on-demand full-system checks.[3] Port scanning, a key network security technique, probes target hosts for open transmission control protocol (TCP) or user datagram protocol (UDP) ports to map vulnerabilities; the open-source Nmap tool, for instance, employs methods like SYN scans to efficiently discover services without completing full connections.[4] Document digitization workflows typically begin with physical scanning to create image files, followed by optical character recognition (OCR) for text extraction, indexing for searchability, and quality assurance to ensure accuracy, transforming paper records into editable digital assets.[5] Electronic scanning appears in input devices that read encoded data without direct contact. Barcode scanners operate on optical recognition principles, where a laser or LED emits light onto the barcode's alternating black and white bars; a photodetector measures the reflected intensity differences—higher from white spaces, lower from black bars—which are then decoded into alphanumeric data via standardized symbologies like UPC or Code 128.[6] RFID readers, in contrast, use radio frequency waves to wirelessly interrogate tags; the reader transmits an electromagnetic signal that powers passive tags (via inductive coupling) or communicates with active ones, exchanging data through protocols such as ISO 18000 for anti-collision and modulation schemes like amplitude shift keying (ASK).[7] Raster scanning is a fundamental technique in display and printing systems, where an image is rendered by sequentially addressing pixels in a grid pattern, line by line from top to bottom and left to right. In computer displays, such as cathode-ray tube (CRT) monitors, an electron beam sweeps across the phosphor-coated screen to illuminate pixels, controlled by horizontal and vertical deflection circuits to form frames at rates like 60 Hz; modern liquid crystal displays (LCDs) simulate this by refreshing pixel states in raster order.[8] Printers apply raster scanning similarly, with raster image processors (RIPs) converting digital images into bitmaps that drive print heads—inkjet models eject droplets line by line, while laser printers use electrophotographic processes to transfer toner in raster fashion onto drums. Resolution is measured in dots per inch (DPI), where higher values (e.g., 300 DPI for print) yield sharper output by increasing pixel density, though displays typically operate at 72-96 DPI for screen viewing.[9] Color reproduction in raster systems uses additive RGB models for displays, combining red, green, and blue light intensities per pixel, whereas printers employ subtractive CMYK models, layering cyan, magenta, yellow, and black inks to absorb light and simulate colors on paper.[10]Medical Imaging
Medical scans encompass a range of non-invasive imaging techniques that utilize various forms of energy—such as X-rays, magnetic fields, sound waves, and radioactive tracers—to visualize internal body structures and functions for diagnostic purposes. These methods allow clinicians to assess anatomy, detect abnormalities, and evaluate physiological processes without surgical intervention, thereby minimizing patient risk and recovery time. Common modalities include computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, positron emission tomography (PET), and dual-energy X-ray absorptiometry (DEXA), each leveraging distinct physical principles to generate cross-sectional or three-dimensional images.[11][12][13] Computed tomography (CT) scans employ a rotating X-ray source and detector array that encircle the patient, acquiring multiple projections of X-ray attenuation through the body at various angles. These projections are processed using mathematical algorithms, such as filtered back-projection or iterative reconstruction, to compute and reconstruct detailed cross-sectional images based on tissue density differences. The technique originated with the first clinical head CT scan performed in 1971 by Godfrey Hounsfield at Atkinson Morley Hospital in London, marking a pivotal advancement in medical imaging by enabling precise visualization of soft tissues and bones.[11][14][11] Magnetic resonance imaging (MRI) relies on a strong static magnetic field, typically generated by superconducting coils, to align the spin axes of hydrogen protons (primarily in water and fat molecules) within the body along the field's direction. A radiofrequency (RF) pulse is then applied to perturb this alignment, causing protons to absorb energy and precess; upon relaxation, they emit detectable RF signals that vary by tissue type, which are spatially encoded using gradient coils and processed via Fourier transform algorithms to produce high-contrast images of soft tissues. This method excels in delineating brain, spinal cord, and musculoskeletal structures without ionizing radiation.[12][15] Ultrasound scans utilize a handheld piezoelectric transducer that converts electrical energy into high-frequency sound waves (typically 2-18 MHz), which propagate through tissues and reflect at interfaces between structures of differing acoustic impedance. The returning echoes are detected by the same transducer, converted back to electrical signals, and used to form real-time images based on echo time-of-flight and amplitude; the Doppler effect further enables visualization of blood flow by measuring frequency shifts in reflected waves from moving red blood cells, aiding in vascular assessments. This modality is particularly valued for its portability, lack of radiation, and utility in obstetrics, cardiology, and abdominal imaging.[13][16][17] Positron emission tomography (PET) scans involve injecting a radiotracer, such as fluorodeoxyglucose (FDG) labeled with fluorine-18, which accumulates in tissues proportional to their metabolic activity, particularly glucose uptake in cancer cells or inflamed regions. As the tracer decays, it emits positrons that annihilate with electrons to produce pairs of gamma rays detected by a ring of scintillation crystals, allowing tomographic reconstruction of metabolic maps through coincidence detection algorithms. PET exposes patients to ionizing radiation, with an effective dose of approximately 7 mSv per scan, necessitating precautions like hydration and voiding post-procedure to minimize bladder exposure; preparation typically includes fasting for 6 hours to enhance tracer uptake accuracy.[18][19][20] Dual-energy X-ray absorptiometry (DEXA) measures bone mineral density by directing two low-energy X-ray beams (around 30-140 kV) through the body, differentiating bone from soft tissue based on differential absorption; a detector calculates areal density (g/cm²) using the ratio of attenuations from each beam, providing T-scores for osteoporosis diagnosis. This scan involves minimal radiation (about 0.001-0.01 mSv, comparable to a day's background exposure) and requires simple preparation, such as avoiding calcium supplements for 24 hours and removing metal objects to prevent artifacts.[21][21][22] Over time, medical scanning has evolved from standalone systems to hybrid modalities like PET-CT, introduced in the early 2000s, which fuse metabolic PET data with anatomical CT images in a single session for improved diagnostic precision in oncology and neurology, though this increases cumulative radiation exposure to 5-18 mSv. Such integrations reduce the need for multiple scans and enhance lesion localization, reflecting ongoing advancements since Hounsfield's breakthrough.[23][24][25]Physics and Engineering Applications
In physics and engineering, scanning techniques leverage wave interactions with matter to probe and map structures at various scales, from macroscopic environments to atomic lattices. Radar scanning exemplifies this by systematically sweeping radio waves to detect objects, operating on the principle of transmitting short electromagnetic pulses and receiving their echoes from targets. The range to an object is calculated using the time-of-flight method, where distance d = \frac{c \times t}{2}, with c as the speed of light and t the round-trip time, enabling applications in air traffic control and weather monitoring.[26][27] Sonar scanning adapts similar principles for underwater engineering, employing acoustic waves instead of radio frequencies to navigate opaque water environments. Pulses are transmitted, and echoes are analyzed to determine object distances and shapes, with frequency ranges typically from 10 kHz to 1 MHz influencing resolution and penetration depth—lower frequencies for deeper bathymetry surveys up to several kilometers, and higher ones for detailed seafloor mapping. This technique supports marine engineering tasks like submarine detection and ocean floor charting, where sound speed variations due to salinity and temperature are accounted for in range computations.[28][29][30] Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) extend scanning to nanoscale material analysis, rastering a focused electron beam over a sample to generate high-resolution images. In SEM, secondary electrons emitted from the surface reveal topography, requiring a high-vacuum environment (typically 10^{-5} to 10^{-7} Pa) to prevent beam scattering by air molecules, with magnifications up to 1,000,000x for surface details down to 1 nm. TEM, by contrast, transmits electrons through ultrathin samples to map internal structures, achieving resolutions below 0.1 nm but limited by sample thickness and vacuum constraints. These methods are pivotal in materials engineering for defect inspection and composition mapping.[31][32][33][34] Laser scanning, particularly through LiDAR (Light Detection and Ranging), facilitates precise 3D mapping in engineering by emitting laser pulses and measuring their return times to generate point clouds—dense sets of 3D coordinates representing surfaces. Each point's position derives from distance d = \frac{c \times t}{2} (using light speed c) combined with angular scanning from mirrors or rotating units, yielding resolutions from centimeters to millimeters over ranges up to kilometers. In surveying, this supports topographic modeling; advancements in the 2020s, such as frequency-modulated continuous-wave (FMCW) LiDAR, enhance velocity sensing for autonomous vehicles, enabling real-time environmental perception at speeds over 100 km/h.[35][36] In material science, X-ray diffraction scanning analyzes crystal structures by directing X-rays at samples and detecting diffracted beams to infer atomic arrangements. The technique relies on Bragg's law, n\lambda = 2d \sin\theta, where n is an integer, \lambda the X-ray wavelength, d the interplanar lattice spacing, and \theta the incidence angle; this arises from the path difference $2d \sin\theta between waves reflected from adjacent crystal planes, leading to constructive interference when equal to an integer multiple of \lambda. By rotating the sample or detector to vary \theta, diffraction patterns reveal lattice parameters, phase compositions, and defects, with applications in alloy development and semiconductor quality control.[37][38][39]Businesses and Organizations
Technology and Logistics Companies
Scan Global Logistics, a Danish freight forwarding and logistics company, traces its origins to 1989 when ScanAm Transport was established as part of its core operations in Denmark, later merging with Mahé Freight (founded 1975) in 2007 to form the current entity under ownership by private equity firms including CVC Capital Partners since 2023.[40] The firm specializes in parcel and express services, offering real-time tracking through its SGL Express Courier platform, which supports international shipments with customizable transit times and rates.[41] It integrates seamlessly with e-commerce platforms such as Shopify via dedicated apps that automate shipping label generation, order fulfillment, and customs documentation, catering to the growing demands of online retailers.[42] As of 2025, Scan Global Logistics operates over 200 offices across more than 60 countries worldwide, including more than 10 European nations through openings in France, Türkiye, and Ireland, alongside global entries into markets like India, Tanzania, Egypt, and Canada.[43][44][45][46] Scan Computers International Ltd., founded in 1987 in Bolton, United Kingdom, operates as a prominent retailer of PC components, peripherals, and high-performance computing hardware, serving both individual consumers and businesses through its online store and physical showroom.[47] The company provides custom PC build services via its 3XS Systems division, which assembles tailored gaming rigs, workstations, and servers using components from leading manufacturers, with build times as short as five working days and options for upgrades in areas like AI processing and 4K graphics.[48][49] As an NVIDIA Elite Partner, Scan Computers integrates advanced GPUs such as the RTX series into its custom solutions for gaming, AI, and professional applications, while also stocking and supporting AMD processors like Ryzen Threadripper for content creation and computing workloads.[48][50] In the realm of document management software, Scan123 offers cloud-based solutions for enterprise digitization, enabling users to scan, convert, and organize paper documents, PDFs, and digital media into a searchable, permissions-controlled system with OCR technology for efficient data extraction.[51] The platform supports remote access from any internet-connected device and includes API integrations for embedding scanning workflows into third-party enterprise applications, facilitating automated document processing.[51] Scan123 maintains compliance with SOC 2 standards for security and availability, ensuring robust data protection for business operations, though specific GDPR adherence is implied through its international user base without explicit certification details.[51] Among emerging technology firms, Scaniverse, launched in 2022 by Niantic as a mobile AR/VR application, specializes in 3D scanning for capturing real-world environments and objects using smartphone LiDAR and photogrammetry, producing shareable models for AR experiences and virtual exploration.[52] The app has incorporated post-2023 AI enhancements, including Gaussian Splatting for faster, higher-fidelity 3D reconstructions, allowing users to generate immersive scenes without specialized hardware and supporting a growing community-driven library of scanned content.[52] By 2025, Scaniverse had attracted millions of users worldwide, emphasizing accessibility for creators in fields like architecture and entertainment through free downloads on iOS and Android.[52]Healthcare and Service Providers
SCAN Health Plan is a nonprofit organization based in the United States, founded in 1977 by senior activists in Long Beach, California, to provide Medicare Advantage health plans tailored for seniors aged 65 and older.[53] The organization focuses on comprehensive coverage including medical, dental, vision, and prescription drug benefits, with a strong emphasis on preventive care to help members maintain independence and health.[54] As of 2025, SCAN Health Plan serves more than 310,000 members across 22 counties in five states, including California, Arizona, Nevada, New Mexico, and Texas, making it one of the larger Medicare Advantage providers in the nation.[55][56] It integrates telehealth services, such as virtual visits through platforms like Doctor On Demand, to facilitate remote consultations for non-emergency conditions and chronic disease management, enhancing accessibility for homebound or mobility-limited seniors.[57] Scan.com, established in 2017 in London, United Kingdom, operates as an online marketplace connecting patients directly to private diagnostic imaging services, including MRI and CT scans, without requiring a physician referral.[58] The platform emphasizes pricing transparency by displaying comparable costs from partnered clinics, starting from £180 for basic scans, which helps users select affordable options and reduces out-of-pocket expenses in the private healthcare sector.[59] Scan.com collaborates with over 200 scanning centers across the UK, enabling nationwide access and quick booking via its app or website.[60] Post-Brexit, the company expanded into European Union markets, notably Germany in 2022, to broaden its diagnostics-as-a-service model while adapting to regional regulations like GDPR for data protection.[61] These healthcare providers utilize scanning technologies to enhance affordability and access, particularly for underserved populations. SCAN Health Plan, for instance, leverages Medicare Advantage frameworks to offer low- or no-cost preventive screenings and telehealth integrations, while ensuring compliance with HIPAA standards through robust privacy practices that safeguard protected health information during virtual and in-person scans.[62] Similarly, Scan.com's model democratizes access to advanced imaging by bypassing traditional referral barriers and providing educational resources on scan types, thereby reducing wait times and costs in private systems.[63] Overall, such services prioritize patient-centric approaches, integrating digital tools to support early detection and chronic care management without compromising regulatory adherence.Arts, Media, and Publishing
Literature and Publishing
In the publishing industry, book scanning plays a pivotal role in the digitization of printed materials, transforming physical volumes into accessible digital formats. This process typically employs overhead scanners, which capture pages non-destructively by photographing open books from above, minimizing damage to bindings and rare artifacts compared to flatbed methods.[64][65] Projects like Google Books, launched in 2004, exemplify large-scale efforts, having digitized more than 40 million volumes as of 2023 through partnerships with libraries worldwide, enabling searchability and preservation of out-of-print works.[66][67][68] However, challenges persist, particularly with optical character recognition (OCR) accuracy for rare texts featuring archaic fonts, faded ink, or non-standard layouts, often requiring manual corrections to achieve reliable digital text extraction.[69][70] Scanning is integral to the evolution of digital publishing, especially in e-book creation, where it facilitates the conversion of legacy print editions into formats like EPUB. During production, scans undergo OCR to generate editable text, followed by metadata extraction—such as author names, titles, and keywords from title pages or tables of contents—to enhance discoverability in online catalogs.[71][72] Copyright issues frequently arise, as seen in lawsuits against mass-digitization initiatives for potentially infringing on reproduction rights without permission, though fair use defenses have been invoked for non-commercial archival purposes.[73] The EPUB 3.3 standard, released in May 2023 by the W3C, supports improved handling of scanned content through enhanced metadata schemas and accessibility features, ensuring better integration of digitized materials while addressing interoperability in e-book workflows.[74] In literary analysis, scansion refers to the metrical examination of poetry, identifying rhythmic patterns through stressed and unstressed syllables to reveal structure and emphasis. Common feet include the iamb (unstressed-stressed, as in "to BÉAT") and trochee (stressed-unstressed, as in "TÝger"), with scansion marking these to uncover a poem's meter, such as iambic pentameter in English verse.[75] This technique aids in interpreting tone and meaning; for instance, in Shakespeare's Hamlet, the soliloquy opens with the line "To be, or not to be: that is the question," scanned as iambic pentameter with a trochaic substitution and weak ending:This pattern (five iambs, with the initial "To" as an extra unstressed syllable) underscores Hamlet's contemplative rhythm, highlighting existential hesitation through subtle metrical variations.[76] Seminal works on scansion, such as those analyzing Elizabethan drama, emphasize its role in performance and textual criticism, prioritizing stress identification over rigid syllable counts to capture natural speech inflections.[77]× / × / × / / × × / to BE, or NOT to BE: that IS the QUES-tion× / × / × / / × × / to BE, or NOT to BE: that IS the QUES-tion