A structured light pattern designed for surface inspection
An Seamtracker arc welding">Automatix Seamtracker arc welding robot equipped with a camera and structured laser light source, enabling the robot to follow a welding seam automatically
Structured light is the process of projecting a known pattern (often grids or horizontal bars) on to a scene. The way that these deform when striking surfaces allows vision systems to calculate the depth and surface information of the objects in the scene, as used in
structured light 3D scanners.
''Invisible'' (or ''imperceptible'') structured light uses structured light without interfering with other computer vision tasks for which the projected pattern will be confusing. Example methods include the use of infrared light or of extremely high frame rates alternating between two exact opposite patterns.
Structured light is used by a number of police forces for the purpose of photographing fingerprints in a 3D scene. Where previously they would use tape to extract the fingerprint and flatten it out, they can now use cameras and flatten the fingerprint digitally, which allows the process of identification to begin before the officer has even left the scene.
See also
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Structured Illumination Microscopy (SIM)
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Stereoscopy
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 ...
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3D scanner#Structured light
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Structured-light 3D scanner
A structured-light 3D scanner is a 3D scanning device for measuring the three-dimensional shape of an object using projected light patterns and a camera system.
Principle
Projecting a narrow band of light onto a three-dimensionally shaped sur ...
s often employed in a
multiple-camera setup
The multiple-camera setup, multiple-camera mode of production, multi-camera or simply multicam is a method of filmmaking and video production. Several cameras—either film or professional video cameras—are employed on the set and simultaneous ...
in conjunction with structured light to capture the geometry of the target
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Dual photography
Dual photography is a photographic technique that uses Helmholtz reciprocity to capture the light field of all light paths from a structured illumination source to a camera. Image processing software can then be used to reconstruct the scene as it ...
* More advanced
light stage
A light stage or light cage is equipment used for shape, texture, reflectance and motion capture often with structured light and a multi-camera setup.
Reflectance capture
The reflectance field over a human face was first captured in 1999 by ...
s make use of structured light to capture geometry of the target. The primary use of a light stage is an instrumentation setup for
reflectance capture
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 electronic ...
.
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Depth map
In 3D computer graphics and computer vision, a depth map is an image or image channel that contains information relating to the distance of the surfaces of scene objects from a viewpoint. The term is related (and may be analogous) to ''depth ...
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Laser Dynamic Range Imager The Laser Dynamic Range Imager (LDRI) is a LIDAR range imaging device developed by Sandia National Laboratories for the US Space Shuttle program. The sensor was developed as part of NASA's "Return to Flight" effort following the Space Shuttle Colu ...
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Lidar
Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...
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Range imaging
Range imaging is the name for a collection of techniques that are used to produce a 2D image showing the distance to points in a scene from a specific point, normally associated with some type of sensor device.
The resulting range image has pix ...
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Kinect
Kinect is a line of motion sensing input devices produced by Microsoft and first released in 2010. The devices generally contain RGB cameras, and infrared projectors and detectors that map depth through either structured light or time of flig ...
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Time-of-flight camera
A time-of-flight camera (ToF camera), also known as time-of-flight sensor (ToF sensor), is a range imaging camera system for measuring distances between the camera and the subject for each point of the image based on time-of-flight, the round tr ...
External links
Projector-Camera Calibration ToolboxStructured light using pseudorandom codesHigh-accuracy stereo depth maps using structured lightA comparative survey on invisible structured lightDual-frequency Pattern Scheme for High-speed 3-D Shape MeasurementHigh-Contrast Color-Stripe Pattern for Rapid Structured-Light Range Imaging
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Image sensor technology in computer vision
Machine vision