HSV
'''HSV''' is a three-letter abbreviation with multiple meanings, including:
For other uses, see [[HSV (disambiguation)]].
Computing
HSV Color Space
The HSV (Hue, Saturation, Value) color space is a cylindrical-coordinate representation of points in the RGB color model, designed to align more closely with human perception of color than the standard additive RGB model from which it is derived.[1] It reorganizes the RGB gamut into three intuitive components: hue, which specifies the dominant color type; saturation, which indicates the purity or intensity of that color; and value, which represents the brightness level. This model facilitates easier manipulation of colors in digital environments, particularly for tasks involving artistic selection and adjustment.[1]
Hue (H) is an angular measure denoting the type of color, ranging from 0° to 360°, where 0° corresponds to red, 120° to green, and 240° to blue, with the spectrum wrapping around continuously.[2] Saturation (S) quantifies the purity of the hue, expressed as a percentage from 0% (fully desaturated, appearing gray) to 100% (fully saturated, the purest form of the color). Value (V) measures brightness, also from 0% (black) to 100% (maximum brightness for that saturation level). These components collectively enable a more perceptual mapping of colors, separating chromatic information from luminance in a way that RGB does not.[1][3]
Developed in the mid-1970s by computer graphics researcher Alvy Ray Smith, the HSV model emerged from efforts to create intuitive color tools for early digital painting systems. Smith introduced it formally in his 1978 paper, where it was applied successfully in frame buffer painting programs at Xerox PARC and the New York Institute of Technology, allowing users to select and mix colors as artists would with physical pigments.[1] The model's perceptual advantages over RGB stem from its emphasis on human visual intuition: hue isolates color identity, saturation captures vibrancy independent of brightness, and value handles lightness separately, making adjustments like desaturating to grayscale or brightening without altering hue straightforward. This separation of chroma from intensity proves particularly useful in computer graphics for tasks such as color picking and image editing, where uniform perceptual changes are desired.[1][2]
In practice, HSV is widely implemented in design software for its user-friendly interface. For instance, Adobe Photoshop employs the equivalent HSB (Hue, Saturation, Brightness) model in its color picker, enabling designers to intuitively cycle through hues via a wheel while adjusting saturation and brightness sliders for precise control.[4] Representative examples illustrate its utility: pure red is represented as H=0°, S=100%, V=100%, yielding a vivid crimson; reducing saturation to S=0% produces grayscale tones where V determines the shade from black (V=0%) to white (V=100%), regardless of hue. These features make HSV ideal for applications requiring perceptual uniformity in color manipulation, such as digital art and graphic design.[2][3]
Visually, the HSV model is conceptualized as a color cylinder (or hexcone), with hue forming the angular coordinate around the central axis, saturation as the radial distance from the axis (0% at the center, 100% at the periphery), and value as the height along the vertical axis (0% at the bottom black point, 100% at the top). This structure provides a natural 3D representation where cross-sections at constant value are hexagonal disks of color, tapering to a point at black, offering an intuitive way to navigate the color spectrum.[1][5]
The HSV color space operates on normalized RGB values in the range [0, 1], typically obtained by dividing integer RGB components (0–255) by 255.[1] Let r, g, b denote these normalized red, green, and blue values. The forward conversion to HSV begins by computing the value V = \max(r, g, b), which represents the brightness as the maximum component.[1] The chroma C = V - \min(r, g, b) measures the color purity range.[6]
The saturation S is then S = \frac{C}{V} if V > 0, otherwise S = 0 to handle achromatic cases where all components are equal.[1] The hue H, expressed in degrees from 0° to 360°, depends on which component is maximum:
- If r = V, then H = 60^\circ \times ( (g - b)/C \mod 6 )
- If g = V, then H = 60^\circ \times ( (b - r)/C + 2 )
- If b = V, then H = 60^\circ \times ( (r - g)/C + 4 )
This case-based calculation positions the hue angle around the color wheel, with modulo 6 ensuring continuity.[1]
For the inverse conversion from HSV to RGB, start with normalized inputs H (0°–360°), S (0–1), and V (0–1). Compute C = V \times S and the hue sector H' = H / 60^\circ. An intermediate value is X = C \times (1 - |(H' \mod 2) - 1|), which interpolates between primary colors.[6] Define temporary values R', G', B' based on the sector floor i = \lfloor H' \rfloor \mod 6:
\begin{align*}
&i=0: (R', G', B') = (C, X, 0) \\
&i=1: (R', G', B') = (X, C, 0) \\
&i=2: (R', G', B') = (0, C, X) \\
&i=3: (R', G', B') = (0, X, C) \\
&i=4: (R', G', B') = (X, 0, C) \\
&i=5: (R', G', B') = (C, 0, X)
\end{align*}
Add the offset m = V - C to each: (r, g, b) = (R' + m, G' + m, B' + m). For achromatic cases where S = 0, set r = g = b = V.[1]
HSV differs from the related HSL color space in its definitions of saturation and the third component. In HSV, value V is simply the maximum RGB component, whereas HSL lightness L = \frac{\max(r,g,b) + \min(r,g,b)}{2} averages the extremes for a more perceptually uniform brightness.[6] HSL saturation is S = \frac{C}{2L} if L \leq 0.5, or S = \frac{C}{2 - 2L} otherwise, contrasting HSV's S = \frac{C}{V} by scaling relative to lightness rather than maximum.[6]
These formulations are implemented in standard libraries; for example, Python's colorsys module provides functions like rgb_to_hsv(r, g, b) and hsv_to_rgb(h, s, v), where hue is in [0, 1] (multiply by 360 for degrees).[6] A pseudocode adaptation follows:
def rgb_to_hsv(r, g, b):
r, g, b = r/255.0, g/255.0, b/255.0 # Normalize
v = max(r, g, b)
c = v - min(r, g, b)
if c == 0:
return 0, 0, v * 255 # Achromatic
s = c / v
h_prime = 0
if r == v:
h_prime = (g - b) / c
elif g == v:
h_prime = 2 + (b - r) / c
elif b == v:
h_prime = 4 + (r - g) / c
h = (h_prime % 6) * 60 # Degrees
return h, s * 100, v * 255 # Often scaled to 0-360, 0-100, 0-255
def rgb_to_hsv(r, g, b):
r, g, b = r/255.0, g/255.0, b/255.0 # Normalize
v = max(r, g, b)
c = v - min(r, g, b)
if c == 0:
return 0, 0, v * 255 # Achromatic
s = c / v
h_prime = 0
if r == v:
h_prime = (g - b) / c
elif g == v:
h_prime = 2 + (b - r) / c
elif b == v:
h_prime = 4 + (r - g) / c
h = (h_prime % 6) * 60 # Degrees
return h, s * 100, v * 255 # Often scaled to 0-360, 0-100, 0-255
Similar logic applies to the inverse, with sector-based assignment as above.[6]
Virology
Herpes Simplex Virus Overview
The Herpes Simplex Virus (HSV) is a member of the genus Simplexvirus within the subfamily Alphaherpesvirinae of the family Herpesviridae, order Herpesvirales.[7] It is an enveloped, double-stranded DNA virus with two primary species that infect humans: HSV-1 (Human alphaherpesvirus 1, or HHV-1) and HSV-2 (Human alphaherpesvirus 2, or HHV-2).[7] These viruses are neurotropic and establish lifelong infections in their hosts.[8]
The virion structure of HSV features a large, linear double-stranded DNA genome enclosed within an icosahedral capsid measuring approximately 125 nm in diameter, composed of 162 capsomeres.[9] Surrounding the capsid is a proteinaceous tegument layer containing approximately 24 viral proteins that facilitate early stages of infection and replication.[10] The outer lipid envelope, derived from host cell membranes, is embedded with multiple glycoproteins, including gB (essential for viral penetration and cell-to-cell spread) and gD (critical for receptor binding and entry).[11]
HSV's lifecycle alternates between lytic replication and latency. In the lytic phase, the virus infects mucosal epithelial cells, uncoats its genome, and utilizes host machinery for DNA replication, capsid assembly, and virion maturation, ultimately lysing the cell to release progeny viruses.[12] Following primary infection, HSV establishes latency in sensory neurons—primarily trigeminal ganglia for HSV-1 and sacral ganglia for HSV-2—where the viral genome persists as an episome without producing infectious particles.[12] Reactivation from latency, triggered by stressors such as UV light exposure, hormonal changes, or immune suppression, leads to recurrent lytic replication and viral shedding.[13]
Epidemiologically, HSV is one of the most prevalent human viruses worldwide. According to World Health Organization estimates for 2020 updated in 2025, HSV-1 infects approximately 3.8 billion people under age 50 (64% prevalence), primarily causing oral infections, while HSV-2 affects 520 million individuals aged 15-49 (13% prevalence), mainly associated with genital disease.[14] Transmission occurs via direct contact with infected secretions or lesions from active lesions or asymptomatic shedding, which for genital HSV-2 occurs on approximately 15-30% of days (higher in the first year post-infection), and less frequently for HSV-1.[15]
Types and Clinical Aspects
Herpes simplex virus type 1 (HSV-1) primarily causes oral herpes, manifesting as recurrent cold sores or fever blisters on or around the mouth, though it is increasingly responsible for genital infections, accounting for up to 50% of new genital herpes cases in some regions.[16] In addition to mucocutaneous lesions, HSV-1 is associated with ocular complications such as herpetic keratitis, a leading cause of corneal blindness in developed countries, and severe neurological conditions like herpes simplex encephalitis, which has a mortality rate exceeding 70% if untreated.[17][18] In contrast, herpes simplex virus type 2 (HSV-2) predominantly causes genital herpes, with higher rates of asymptomatic viral shedding—estimated at 15-30% of days in infected individuals—facilitating transmission without visible symptoms.[19] HSV-2 infection also triples the risk of HIV acquisition due to genital ulceration and inflammation that compromise mucosal barriers.[20]
Clinical symptoms for both types typically include vesicular lesions on erythematous bases that evolve into painful ulcers, often preceded by a prodromal phase of tingling, itching, or burning at the site. Recurrences are more frequent and severe with HSV-2, occurring 4-6 times per year on average compared to 1-2 times for genital HSV-1 infections.[21] A rare but serious complication is neonatal herpes, primarily from HSV-2 transmission during delivery, with an estimated incidence of 15.7 per 100,000 births (approximately 1 in 6,400) in the United States based on 2019 data analyzed in 2025, leading to high morbidity including disseminated disease and neurological damage.[22]
Diagnosis relies on laboratory confirmation, with polymerase chain reaction (PCR) serving as the gold standard due to its sensitivity exceeding 95% for detecting HSV DNA in lesion swabs or cerebrospinal fluid.[23] Viral culture offers specificity but lower sensitivity (around 50-70%), while type-specific serologic tests for IgM and IgG antibodies (e.g., targeting glycoprotein G) distinguish between HSV-1 and HSV-2, though IgM results can be unreliable early in infection.[23][24]
There is no cure for HSV infections, but antiviral therapy manages symptoms and reduces transmission. For initial episodes, acyclovir at 400 mg orally three times daily for 7-10 days is standard, with alternatives like valacyclovir (1 g twice daily) showing comparable efficacy in shortening outbreak duration.[23] Suppressive therapy with valacyclovir (500 mg daily) decreases recurrence frequency by 70-80% and asymptomatic shedding, thereby lowering transmission risk by about 50% in discordant couples. As of 2025, several HSV vaccine candidates are in clinical trials, but none are approved.[23][25] Prevention strategies include consistent condom use, which reduces HSV-2 acquisition risk by approximately 30%, and antiviral prophylaxis in infected partners to further mitigate transmission in serodiscordant relationships.[26][23]
Transportation
Huntsville International Airport
Huntsville International Airport (HSV), officially known as Carl T. Jones Field, is a public airport located approximately 12 miles southwest of downtown Huntsville in Madison County, Alabama, United States. It serves the Huntsville metropolitan area, which has a population of around 500,000 residents, providing essential air connectivity for the region's residents, businesses, and visitors. The airport opened on October 29, 1967, as the Huntsville-Madison County Jetport, replacing the city's older municipal airport to accommodate growing commercial and military aviation needs tied to the area's burgeoning aerospace industry. It was renamed Huntsville International Airport – Carl T. Jones Field in 1996 to honor Carl T. Jones, a prominent local businessman and civic leader who advocated for its development.[27][28]
The airport features two parallel asphalt runways: Runway 18R/36L, measuring 12,600 feet in length, and Runway 18L/36R, at 10,001 feet, supporting a mix of commercial, cargo, and general aviation operations.[29] Its single terminal building includes 12 gates and handles both passenger and substantial cargo traffic, with a focus on freight due to its role as a hub for FedEx Express and other carriers. In 2024, HSV recorded a record 1,591,139 passengers, marking an 11.1% increase from 2023's 1,473,629, while year-to-date figures through September 2025 show 1,293,703 passengers, up 6.9% from the same period in 2024. The airport set all-time monthly passenger records in June (160,455) and July (168,281) 2025. Cargo operations are prominent, processing 78.9 million pounds in 2024, facilitated by the adjacent International Intermodal Center.[30][31][32][33]
Major airlines operating at HSV include American Airlines, Delta Air Lines, United Airlines, Allegiant Air, and Breeze Airways, offering nonstop service to key destinations such as Atlanta, Dallas/Fort Worth, Chicago, Charlotte, Denver, and New York City. Recent expansions include new routes to Florida cities like Fort Lauderdale (starting November 2025), Orlando/Sanford (February 2026), and Tampa/St. Petersburg (March 2026) via Allegiant Air, reflecting growing demand from tourism and business travel. The airport's proximity to NASA's Marshall Space Flight Center enhances its ties to the space industry, supporting travel for engineers, researchers, and executives in aerospace.[34][35][36]
Economically, HSV plays a vital role in sustaining Huntsville's aerospace and defense sectors, which include major employers like Boeing and Lockheed Martin, by facilitating the transport of personnel and high-tech components. The broader Port of Huntsville, which manages the airport, generates an estimated $1.8 billion in annual regional economic impact through aviation, cargo, and related activities. Passenger growth is projected at around 5-7% for 2025, driven by tech innovation, tourism, and space-related developments, underscoring the airport's contribution to the area's status as a key U.S. aerospace hub.[37][38]
Unique amenities at HSV include complimentary high-speed Wi-Fi throughout the terminal, a collection of public art installations under the "Art in the Airport" program featuring local and regional artists, and an on-site Four Points by Sheraton hotel for convenience. While it primarily handles domestic passenger flights, the airport maintains U.S. Customs Service facilities for international cargo operations, enabling efficient global freight handling without passenger international service.[39][40]
HSV-2 Swift
The HSV-2 Swift is a wave-piercing catamaran high-speed vessel originally developed as a proof-of-concept platform for the U.S. military's Joint High Speed Vessel (JHSV) program.[41] Built by Incat Tasmania Pty Ltd in Hobart, Australia, and delivered in August 2003, the vessel measures 97.22 meters in length overall and 26.6 meters in beam, with a shallow draft of 3.43 meters when loaded, enabling access to littoral and austere ports.[42] Its hybrid aluminum hull design incorporates active ride control systems, including trim tabs and a T-foil, to maintain stability at high speeds, achieving a maximum of 42 knots when lightly loaded and 38 knots at 627 tonnes deadweight.[42]
The vessel's propulsion system consists of four MTU 20V 8000 diesel engines powering waterjet propulsors, providing a range of 1,100 nautical miles at 35 knots or 4,000 nautical miles at 20 knots.[42] It features a flexible vehicle deck totaling 2,114 square meters, capable of accommodating up to 627 tonnes of cargo, including vehicles and equipment, alongside berthing for up to 353 personnel.[42] A helicopter deck, certified for operations with MH-60S and CH-46 aircraft, supports vertical replenishment and includes night-landing lighting, enhancing its role in expeditionary logistics.[42] These specifications made the HSV-2 Swift a versatile asset for rapid intra-theater transport, influencing the design of the subsequent Expeditionary Fast Transport (EPF) class ships under the JHSV initiative.[41]
Initially operated commercially as the Westpac Express before being chartered by the U.S. Military Sealift Command in 2003, the HSV-2 Swift supported a range of U.S. Navy operations through 2013, including humanitarian relief for Hurricane Katrina in 2005, the Indian Ocean tsunami in 2005, and the Haiti earthquake in 2010.[42] It participated in military exercises such as the Southern Partnership Station, Africa Partnership Station, and Global Fleet Station, demonstrating capabilities in theater security cooperation, mine warfare support, and sea basing concepts.[42] Following the end of its U.S. lease in 2013, the vessel was transferred to private operation and subsequently leased to the United Arab Emirates Navy.[43]
On October 1, 2016, while conducting a logistics mission off the coast of Yemen, the HSV-2 Swift was struck by an anti-ship cruise missile launched by Houthi rebels, causing severe structural damage including a large fire and hull breach.[44] The attack rendered the vessel inoperable, and it was towed to port for assessment but was not repaired, leading to its decommissioning.[43] As of 2025, the HSV-2 Swift remains out of service and is no longer an active U.S. Navy or allied asset, serving as a case study in the vulnerabilities of high-speed logistics vessels to asymmetric threats.[45]
Sports
Hamburger SV
Hamburger SV, officially known as Hamburger Sport-Verein e.V., is a multi-sport club founded on September 29, 1887, in Hamburg, Germany, making it one of the country's oldest sports organizations.[46] With over 135,000 members as of 2025, it stands as one of Germany's largest clubs, encompassing a wide array of athletic disciplines while maintaining a strong emphasis on community engagement.[47]
The club's football section is its most prominent, competing in the Bundesliga following promotion from the 2. Bundesliga after a decisive 6-1 victory over SSV Ulm on May 10, 2025.[48] Matches are held at the Volksparkstadion, a 57,000-capacity venue that has served as the home ground since 1953.[49] The team's traditional colors are blue, white, and black, though home kits often feature white jerseys paired with red shorts, reflecting Hamburg's city emblem.[50]
As a multi-sport entity, Hamburger SV includes sections for handball, volleyball, athletics, and other disciplines like badminton and basketball, but football remains dominant, having secured six German national championships, including three Bundesliga titles—the last in 1983—and the 1983 European Cup.[51] The professional football operations are managed by HSV Fußball AG & Co. KGaA, a subsidiary structure that oversees commercial and competitive aspects, including a renowned youth academy that developed talents such as Son Heung-min, who joined at age 16 in 2008.[52][53]
Hamburger SV boasts a passionate fan culture, characterized by large ultras groups that create vibrant atmospheres at matches, particularly in the heated Hamburg derby against rivals FC St. Pauli.[54] This rivalry underscores the club's deep roots in local identity, with supporters known for their loyalty and elaborate choreographies.
Club History and Recent Developments
Hamburger SV claimed their first German national championship in 1923 by defeating Union Oberschöneweide 3-0 in the final.[55] The club amassed six German titles overall, including three Bundesliga championships during their golden era in the late 1970s and early 1980s: 1978–79, 1981–82, and 1982–83.[51] Their most prestigious European success came in 1983, when they won the European Cup with a 1–0 victory over Juventus in the final at Athens' Olympic Stadium, courtesy of a goal by Felix Magath.[56] This triumph marked HSV as the only German club to win the competition during the 1980s and solidified their status as a European powerhouse.[57]
HSV's uninterrupted presence in the Bundesliga ended dramatically in 2018, following a 2–1 defeat to VfL Wolfsburg on the final matchday, marking the first relegation in the club's 55-year top-flight history as a founding member of the league.[58] From 2018 to 2025, the club competed in the 2. Bundesliga, enduring several intense promotion battles, including a narrow loss in the 2022 promotion/relegation playoff to Hertha BSC after a 1–1 aggregate draw decided by away goals. Recovery efforts intensified under various managers, with consistent top-four finishes, culminating in direct promotion on May 10, 2025, via a commanding 6–1 home win over SSV Ulm 1846 that secured second place in the 2. Bundesliga.[59]
Post-2000 achievements included a DFB-Ligapokal victory in 2003, defeating Borussia Dortmund 4–2 in the final to end a 16-year trophy drought.[60] HSV also reached the semi-finals of the UEFA Europa League in both 2008–09 (eliminated by Manchester City) and 2009–10 (knocked out by Fulham), showcasing competitive European form during that decade.[61]
In the 2025–26 Bundesliga season, HSV have navigated early challenges, highlighted by a resilient 1–1 home draw against Borussia Dortmund on November 8, 2025, where Carney Chukwuemeka scored in the 64th minute for the visitors, only for HSV's Ransford Königsdörffer to equalize in the 90+7th minute.[62] Off the pitch, the club has pursued squad strengthening; although interest was expressed in loaning young defender Tim Oermann from Bayer Leverkusen, he ultimately joined Sturm Graz on loan. Under head coach Merlin Polzin, appointed permanently in December 2024 after guiding the promotion push, HSV employs a high-intensity pressing system that emphasizes quick transitions and youth involvement, with academy products like Ludovit Reis featuring prominently.[63] As of November 18, 2025, following 10 matchdays, the team occupies 13th place in the Bundesliga table with 9 points from two wins, three draws, and five losses, positioning them as mid-table contenders focused on integrating emerging talents to build long-term stability.[64]
Other Uses
Holden Special Vehicles
Holden Special Vehicles (HSV) was established in 1987 as the performance vehicle division of Holden, a subsidiary of General Motors, through a joint venture with British motorsport firm Tom Walkinshaw Racing (TWR). Based in Clayton, Victoria, HSV opened its doors to the public in February 1988, following the unveiling of its inaugural model, the Walkinshaw, at the 1987 Sydney Motor Show. The company specialized in enhancing Holden platforms with high-performance modifications, particularly V8-powered sedans, utes, and wagons tailored for Australian driving conditions and enthusiast preferences.[65]
HSV's model lineup prominently featured Commodore-based vehicles, including the GTS sedan equipped with a supercharged 6.2-liter LSA V8 engine producing 430 kW of power and 740 Nm of torque. The Maloo ute, derived from the Commodore platform, utilized a naturally aspirated 6.2-liter LS3 V8 delivering 317 kW in its later models until production ended in 2017.[66][67] Additionally, HSV imported and localized the Chevrolet Camaro ZL1, reaching a milestone with the assembly of its 1,000th unit in 2019, featuring a supercharged 6.2-liter LT4 V8. Over its history, HSV produced more than 85,000 vehicles, with production peaking in the 1990s and 2000s, including a record of over 4,000 units delivered in 2007 alone.[68][69][70]
Following the closure of Holden's Australian manufacturing operations in 2020, HSV adapted by shifting focus to importing and converting U.S.-built General Motors products under the ownership of Walkinshaw Automotive Group. This transition aligned with the formation of General Motors Specialty Vehicles (GMSV), enabling HSV to continue operations independently. Walkinshaw Performance offers a 375 kW upgrade kit for LS3 V8-equipped HSV models, but HSV now prioritizes right-hand-drive conversions of the Chevrolet Silverado HD pickup, which offers up to 9 tonnes of towing capacity in its LTZ configuration. HSV's legacy endures as a cornerstone of Australian muscle car culture, symbolizing local innovation in high-performance vehicles, though it faces challenges from global electrification trends and the end of domestic V8 production.[71][72][73][74]
Additional Acronyms
In the realm of imaging and cinematography, HSV stands for High-Speed Video, a technology that captures motion at frame rates typically exceeding 1000 frames per second to enable detailed slow-motion playback and analysis. This is widely applied in sports biomechanics, engineering crash tests, and medical procedures such as laryngeal examinations, with examples including specialized cameras like the NAC HSV series that record full-color footage at up to 200 fields per second for precise motion dissection.[75][76]
Within electrical engineering, particularly in power system design, HSV refers to Highest System Voltage, defined as the maximum root-mean-square line-to-line voltage that electrical equipment must endure continuously under normal conditions. This parameter is critical for insulation ratings and appears in international standards, such as those from the International Electrotechnical Commission (IEC), where it guides the selection of transformers and circuit breakers—for instance, a nominal 220 kV system might have an HSV of 245 kV.[77][78]
HSV also denotes the Hue-Saturation-Value color model in computer graphics and digital design, a cylindrical representation of colors that facilitates intuitive adjustments in software tools, differing from the RGB model by emphasizing perceptual attributes. Although not a native syntax in CSS (which favors HSL), it is supported in various programming libraries and image processing applications for color manipulation.
In naval architecture, HSV signified High Speed Vessel in the U.S. military's experimental program during the early 2000s, focusing on wave-piercing catamarans for fast intra-theater transport, though the initiative was phased out after prototyping vessels beyond the HSV-2 Swift.
The interpretation of HSV remains highly context-specific across these domains, exhibiting no significant overlaps with dominant usages like the automotive Holden Special Vehicles marque. As of 2025, high-speed video (HSV) applications are gaining traction in AI-driven video processing for automated feature detection in healthcare and manufacturing, such as stiffness mapping in vocal diagnostics.[79]