Projection mapping glossary
74 terms used in projection mapping, projector specifications, show control and light art — each with a short definition and a fuller explanation.
- 3D mapping
- Mapping content that exploits a surface's depth to create illusions of movement, collapse or extrusion.
- 3D model (of the surface)
- A digital model of the building or object, used to render content and calibrate projectors.
- 3LCD
- An imaging technology using three LCD panels for red, green and blue.
- 4K UHD
- 3840×2160 pixels; true native 4K chips are rarer and pricier than pixel-shifted ‘4K’.
- Ambient light
- Light from other sources (streetlights, shop windows, the sky) that washes out the projection.
- Anamorphic illusion
- An image that looks correct (often 3D) only from one viewing position.
- ANSI lumens
- A standardised measurement of projector brightness averaged over nine points of the image.
- Art-Net
- A protocol for sending DMX data over Ethernet networks.
- Aspect ratio
- The ratio of image width to height — e.g. 16:9, 16:10, 4:3.
- Black level
- How dark ‘black’ really is — projectors always leak some light.
- Blend zone
- The overlapping strip between two edge-blended projectors.
- Camera-based calibration
- Using cameras and test patterns to align and blend projectors automatically.
- Colour brightness (CLO)
- Brightness measured on colour images, not just white.
- Contrast ratio
- The ratio between the brightest white and the darkest black a projector or scene can show.
- Corner pin
- The simplest warp: moving the four corners of the image to match a flat quadrilateral surface.
- Depth camera
- A camera that measures distance for each pixel (e.g. Kinect, Orbbec, Intel RealSense).
- DLP
- Digital Light Processing — an imaging technology using millions of tiny mirrors (DMD chips).
- DMX512
- The standard control protocol for stage lighting fixtures.
- Dome projection (fulldome)
- Projection onto a hemispherical dome, as in planetariums and immersive domes.
- Edge blending
- Overlapping several projectors and fading their edges so they form one seamless image.
- Facade mapping
- Projection mapping onto the front of a building, the classic large-scale format of light festivals.
- Generative art
- Art created with rules, code or algorithms that produce evolving results.
- Genlock
- Synchronising the frame timing of multiple video outputs or devices.
- HAP codec
- A GPU-accelerated video codec designed for smooth playback of very high resolutions.
- Haze
- A fine airborne mist that makes light beams visible.
- Holographic gauze (scrim)
- A fine mesh fabric that catches projection while staying semi-transparent.
- Immersive room
- A space whose walls and floor are covered with projection to surround visitors.
- Interactive mapping
- Mapped projection that reacts to people, sound or data through sensors.
- IP rating
- Ingress Protection code describing resistance to dust (first digit) and water (second digit).
- Keystone correction
- Correcting the trapezoid shape caused by projecting at an angle.
- Lamp-based projector
- Projectors using mercury or xenon lamps that need replacing every few thousand hours.
- Laser phosphor
- A light source that uses blue lasers exciting a phosphor wheel to create white light.
- LCoS
- Liquid Crystal on Silicon — a reflective imaging technology (Sony SXRD, JVC D-ILA).
- LED wall
- A video display made of LED modules; an alternative to projection that works in daylight.
- Lens shift
- Moving the image up/down or left/right optically without tilting the projector.
- LiDAR
- Laser scanning that measures distances to build accurate point clouds, also used as an interaction sensor.
- Light art
- Art in which light itself is the main medium — sculpture, installation, projection or environment.
- Long-throw lens
- A telephoto lens (throw ratio of roughly 3:1 or more) for projecting from far away.
- Lumens (ANSI / ISO)
- The total light output of a projector; ANSI and ISO 21118 are standard measurement methods.
- Lux
- Illuminance: lumens per square metre falling on a surface.
- Mapping template
- An accurate 2D image of the surface as seen from the projector, used to create content.
- Masking
- Hiding parts of the projected image so light falls only on the intended surfaces.
- Media server
- A computer and software system that plays back and maps high-resolution video to many outputs in sync.
- Mesh warp
- Warping with a grid of control points to fit curved or complex surfaces.
- MIDI
- A long-established protocol for musical instruments and controllers.
- Native resolution
- The real number of pixels on the projector's imaging chip.
- NDI
- Network Device Interface — a protocol for sending video between computers over a LAN.
- Nits (cd/m²)
- Luminance — how bright a surface appears; used for LED walls and screens.
- Object mapping
- Projection mapping onto objects such as cars, sculptures, products or stage sets.
- OSC
- Open Sound Control — a flexible network protocol for sending control messages between apps and devices.
- Pepper's ghost
- An illusion that reflects an image on angled glass or foil so it appears to float in space.
- Photogrammetry
- Building a 3D model from many overlapping photographs.
- Pixel mapping
- Treating individual LEDs or lighting fixtures as pixels of a video image.
- Pixel pitch
- Distance between the centres of adjacent LED pixels, in millimetres.
- Pixel shift
- A technique that moves a lower-resolution image by a fraction of a pixel very fast to simulate higher resolution.
- Projection mapping
- Projecting video onto irregular 3D surfaces — buildings, objects, stages — so the image fits their shape.
- Projection tower
- A scaffolded structure that holds projectors at the right height and distance.
- Projector stacking
- Aligning two or more projectors on the same area to multiply brightness.
- Real-time rendering
- Generating images live (game-engine style) instead of playing pre-rendered video.
- RGB laser
- A light source with separate red, green and blue lasers for a very wide colour gamut.
- sACN (E1.31)
- Streaming ACN — a standard way to send DMX universes over IP networks.
- Short-throw lens
- A lens with a throw ratio below about 1:1, for large images from short distances.
- SMPTE timecode
- A time reference (hours:minutes:seconds:frames) that keeps video, audio, lighting and lasers in sync.
- Spout / Syphon
- Ways to share video frames between applications on the same computer (Spout on Windows, Syphon on macOS).
- Structured light
- Projected patterns (stripes, grids) observed by a camera to measure geometry or calibrate projectors.
- Throw distance
- The distance between the projector lens and the projection surface.
- Throw ratio
- Distance from the lens to the image divided by the image width.
- Ultra-short-throw (UST)
- Projectors or lenses with throw ratios below about 0.4:1, placed right next to the surface.
- Video mapping
- Another name for projection mapping, common in Europe and in festival programmes.
- VJ (video jockey)
- A performer who mixes visuals live, often to music.
- Warping
- Distorting the output image so it lands correctly on the target surface.
- Weatherproof housing
- An enclosure that protects a projector from rain, dust and temperature.
- WUXGA
- A 1920×1200 resolution with a 16:10 aspect ratio, the standard for installation projectors.
- Zoom lens
- A lens with an adjustable throw ratio range.