The Advanced Space Vision System (also known as the Space Vision System or SVS) is a

computer vision Computer vision is an Interdisciplinarity, interdisciplinary scientific field that deals with how computers can gain high-level understanding from digital images or videos. From the perspective of engineering, it seeks to understand and automate t ...

system designed primarily for

International Space Station The International Space Station (ISS) is the largest Modular design, modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos ( ...

(ISS) assembly. The system uses regular 2D cameras in the

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program na ...

bay, on the

Canadarm Canadarm or Canadarm1 (officially Shuttle Remote Manipulator System or SRMS, also SSRMS) is a series of robotic arms that were used on the Space Shuttle orbiters to deploy, manoeuvre, and capture payloads. After the Space Shuttle ''Columbia'' ...

, or on the ISS along with cooperative targets to calculate the 3D position of an object. 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 Stereoscopy (also called stereoscopics, or stereo imaging) is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. The word ''stereoscopy'' derives . Any stereoscopic image is ...

vision, and thus do not allow a proper evaluation of depth. In addition the difficult conditions created by 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 is involved.

Background

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 The reflectance of the surface of a material is its effectiveness in reflecting radiant energy. It is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the response of the electroni ...

in the

Electromagnetic spectrum The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from ...

. The result 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.

Development

The basic elements of the system were devised at the

National Research Council of Canada The National Research Council Canada (NRC; french: Conseil national de recherches Canada) is the primary national agency of the Government of Canada dedicated to science and technology research & development. It is the largest federal research ...

in the 1970s, to study car collisions. In 1990, development was transferred to

Neptec Design Group Neptec Design Group is an Ottawa-based Canadian vision systems company that provides machine vision solutions for space, industrial, and military applications. Privately owned and founded in 1990, Neptec supplies operational systems to NASA's ...

, a small commercial enterprise located in Kanata, a suburb of

Ottawa Ottawa (, ; Canadian French: ) is the capital city of Canada. It is located at the confluence of the Ottawa River and the Rideau River in the southern portion of the province of Ontario. Ottawa borders Gatineau, Quebec, and forms the core ...

. 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 A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

and

POSIX The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system- and user-level application programming inte ...

compliant

QNX QNX ( or ) is a commercial Unix-like real-time operating system, aimed primarily at the embedded systems market. QNX was one of the first commercially successful microkernel operating systems. The product was originally developed in the early 19 ...

Real-time operating system A real-time operating system (RTOS) is an operating system (OS) for real-time applications that processes data and events that have critically defined time constraints. An RTOS is distinct from a time-sharing operating system, such as Unix, which ...

, running the Photon windowing interface. The Photon implementation was optimized to be the most worry free

direct manipulation interface In computer science, human–computer interaction, and interaction design, direct manipulation is an approach to interfaces which involves continuous representation of objects of interest together with rapid, reversible, and incremental actions ...

possible for the particular needs and work habits of the astronauts. The

Canadian Space Agency The Canadian Space Agency (CSA; french: Agence spatiale canadienne, ASC) is the national space agency of Canada, established in 1990 by the ''Canadian Space Agency Act''. The president is Lisa Campbell, who took the position on September 3, 20 ...

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 Montreal ( ; officially Montréal, ) is the second-most populous city in Canada and most populous city in the Canadian province of Quebec. Founded in 1642 as '' Ville-Marie'', or "City of Mary", it is named after Mount Royal, the triple- ...

Implementation

The system was first tested in its early form on

STS-52 STS-52 was a ''Space Transportation System'' ( NASA Space Shuttle) mission using Space Shuttle ''Columbia'', and was launched on October 22, 1992. Crew Backup crew Mission highlights Primary mission objectives were deployment of t ...

in October 1992, and used in subsequent missions. The advanced version was first tested on

STS-74 STS-74 was the fourth mission of the US/Russian Shuttle-Mir Program, and the second docking of the Space Shuttle with ''Mir''. Space Shuttle ''Atlantis'' lifted off from Kennedy Space Center launch pad 39A on 12 November 1995. The mission end ...

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.

References

{{reflist International Space Station Spacecraft components