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21-1230: SVS may refer to: Technology [ edit ] Advanced Space Vision System , a computer vision system for the ISS OS/VS2 (SVS) , a precursor of MVS ScanScope Virtual Slide , a medical image file format (".svs" suffix) Software Virtualization Solution , by Symantec Supply Voltage Supervisor , an electronic protective device Surround-view system , assisted driving system with multiple cameras Synthetic vision system for aircraft Organizations and companies [ edit ] Second Viennese School Society for Vascular Surgery Sudbury Valley School State Veterinary Service , UK Saint Vladimir's Orthodox Theological Seminary , Crestwood, NY, US Svenska Vitterhetssamfundet , Swedish publisher Transport [ edit ] Seven Sisters station , London, England, National Rail station code Stevens Village Airport , IATA code Other uses [ edit ] Standard VIE Settings , of SubSpace video game Specific Area Message Encoding , US emergency weather event code S. V. Sahasranamam , Indian actor Schwartz Value Survey ,

42-454: A medium with one index of refraction into a second medium with a different index of refraction. Specular reflection from a body of water is calculated by the Fresnel equations . Fresnel reflection is directional and therefore does not contribute significantly to albedo which primarily diffuses reflection. A real water surface may be wavy. Reflectance, which assumes a flat surface as given by

63-407: A perfect machine if the material filled half of all space. Given that reflectance is a directional property, most surfaces can be divided into those that give specular reflection and those that give diffuse reflection . For specular surfaces, such as glass or polished metal, reflectance is nearly zero at all angles except at the appropriate reflected angle; that is the same angle with respect to

84-446: A personality test Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title SVS . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=SVS&oldid=1241702646 " Category : Disambiguation pages Hidden categories: Short description

105-558: A small commercial enterprise located in Kanata, a suburb of Ottawa . The system runs on Neptec's Advanced Vision Unit (AVU) processing platform, which handles video routing, algorithm processing, video overlays, and the system interface. The operating system is the Unix-like and POSIX compliant QNX Real-time operating system , running the Photon windowing interface. The Photon implementation

126-745: A surface, denoted R ν and R λ respectively, are defined as R ν = Φ e , ν r Φ e , ν i , {\displaystyle R_{\nu }={\frac {\Phi _{\mathrm {e} ,\nu }^{\mathrm {r} }}{\Phi _{\mathrm {e} ,\nu }^{\mathrm {i} }}},} R λ = Φ e , λ r Φ e , λ i , {\displaystyle R_{\lambda }={\frac {\Phi _{\mathrm {e} ,\lambda }^{\mathrm {r} }}{\Phi _{\mathrm {e} ,\lambda }^{\mathrm {i} }}},} where The directional reflectance of

147-439: A surface, denoted R Ω , is defined as R Ω = L e , Ω r L e , Ω i , {\displaystyle R_{\Omega }={\frac {L_{\mathrm {e} ,\Omega }^{\mathrm {r} }}{L_{\mathrm {e} ,\Omega }^{\mathrm {i} }}},} where This depends on both the reflected direction and the incoming direction. In other words, it has

168-513: A surface, denoted R , is defined as R = Φ e r Φ e i , {\displaystyle R={\frac {\Phi _{\mathrm {e} }^{\mathrm {r} }}{\Phi _{\mathrm {e} }^{\mathrm {i} }}},} where Φ e is the radiant flux reflected by that surface and Φ e is the radiant flux received by that surface. The spectral hemispherical reflectance in frequency and spectral hemispherical reflectance in wavelength of

189-421: A value for every combination of incoming and outgoing directions. It is related to the bidirectional reflectance distribution function and its upper limit is 1. Another measure of reflectance, depending only on the outgoing direction, is I / F , where I is the radiance reflected in a given direction and F is the incoming radiance averaged over all directions, in other words, the total flux of radiation hitting

210-409: A value of I / F (see above) for a given wavelength. For homogeneous and semi-infinite (see halfspace ) materials, reflectivity is the same as reflectance. Reflectivity is the square of the magnitude of the Fresnel reflection coefficient , which is the ratio of the reflected to incident electric field ; as such the reflection coefficient can be expressed as a complex number as determined by

231-468: Is a black color that appears even blacker than the flattest black paint. In photos the disks look like small black dots, and a minimum of three are needed, so they are quite unobtrusive on most payloads. The basic elements of the system were devised at the National Research Council of Canada in the 1970s, to study car collisions. In 1990, development was transferred to Neptec Design Group ,

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252-421: Is different from Wikidata All article disambiguation pages All disambiguation pages Advanced Space Vision System Because of the small number of viewing ports on the station and on the shuttle, most of the assembly and maintenance is done using cameras, which do not give stereoscopic vision, and thus do not allow a proper evaluation of depth. In addition the difficult conditions created by

273-460: Is involved. The Advanced Space Vision System images objects with cooperative targets and uses the known positions of the targets to triangulate their exact relative positions in real time. The targets are composed of thin films of silicon dioxide layered with inconel to form an inconel interference stack. A stack like this has nearly no reflectivity in the Electromagnetic spectrum . The result

294-491: Is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the response of the electronic structure of the material to the electromagnetic field of light, and is in general a function of the frequency, or wavelength , of the light, its polarization, and the angle of incidence . The dependence of reflectance on the wavelength is called a reflectance spectrum or spectral reflectance curve . The hemispherical reflectance of

315-407: Is the limit value of reflectance as the sample becomes thick; it is the intrinsic reflectance of the surface, hence irrespective of other parameters such as the reflectance of the rear surface. Another way to interpret this is that the reflectance is the fraction of electromagnetic power reflected from a specific sample, while reflectivity is a property of the material itself, which would be measured on

336-492: The Fresnel equations for a single layer, whereas the reflectance is always a positive real number . For layered and finite media, according to the CIE , reflectivity is distinguished from reflectance by the fact that reflectivity is a value that applies to thick reflecting objects. When reflection occurs from thin layers of material, internal reflection effects can cause the reflectance to vary with surface thickness. Reflectivity

357-465: The particular conditions of illumination and obscurity in space, make it much more difficult to distinguish objects, even when the assembly work can be viewed directly, without using a camera. For instance, the harsh glare of direct sunlight can blind human vision. Also, the contrasts between objects in black shadows and objects in the solar light are much greater than in Earth's atmosphere, even where no glare

378-489: The surface normal in the plane of incidence , but on the opposing side. When the radiation is incident normal to the surface, it is reflected back into the same direction. For diffuse surfaces, such as matte white paint, reflectance is uniform; radiation is reflected in all angles equally or near-equally. Such surfaces are said to be Lambertian . Most practical objects exhibit a combination of diffuse and specular reflective properties. Reflection occurs when light moves from

399-1189: The surface per unit area, divided by π. This can be greater than 1 for a glossy surface illuminated by a source such as the sun, with the reflectance measured in the direction of maximum radiance (see also Seeliger effect ). The spectral directional reflectance in frequency and spectral directional reflectance in wavelength of a surface, denoted R Ω, ν and R Ω, λ respectively, are defined as R Ω , ν = L e , Ω , ν r L e , Ω , ν i , {\displaystyle R_{\Omega ,\nu }={\frac {L_{\mathrm {e} ,\Omega ,\nu }^{\mathrm {r} }}{L_{\mathrm {e} ,\Omega ,\nu }^{\mathrm {i} }}},} R Ω , λ = L e , Ω , λ r L e , Ω , λ i , {\displaystyle R_{\Omega ,\lambda }={\frac {L_{\mathrm {e} ,\Omega ,\lambda }^{\mathrm {r} }}{L_{\mathrm {e} ,\Omega ,\lambda }^{\mathrm {i} }}},} where Again, one can also define

420-551: Was first tested in its early form on STS-52 in October 1992, and used in subsequent missions. The advanced version was first tested on STS-74 in November 1995. The system has been used with success on shuttle flights since then, and with equal success for the assembly and maintenance of the station since 1997. Reflectivity The reflectance of the surface of a material is its effectiveness in reflecting radiant energy . It

441-470: Was optimized to be the most worry free direct manipulation interface possible for the particular needs and work habits of the astronauts. The Canadian Space Agency was involved at several stages in the development and deployment of the space vision system. Training for the system takes place in the simulators located at the agency's headquarters at the John H. Chapman Space Centre near Montreal . The system

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