Dictionary:

raster

  (răs'tər)

A scanning pattern of parallel lines that form the display of an image projected on a cathode-ray tube of a television set or display screen.

[German, from Latin rāstrum, rake (from the resemblance of the parallel lines to a rake's path).]

The horizontal lines (scan lines) displayed on a TV or computer monitor. This is the origin of the term "raster graphics," which is the major category that all bitmapped images and video frames fall into (GIF, JPEG, MPEG, etc.). See raster scan, raster display, analog video and bitmapped graphics.

In Geographic Information Systems, a grid square. Raster data are spatial data expressed as a matrix of cells, with spatial order indicated in the ordering of the cells. A raster map is a map stored as a regular array of cells; a raster scanner records an image by breaking it into pixels. Raster to vector conversion consists of changing an image made up of cells (rasters) into one made up of lines and polygons.

Raster may refer to:

• Raster graphics, graphical techniques using arrays of pixel values
• Raster scan, the pattern of image readout, transmission, storage, and reconstruction in television and computer images
• Rasterisation, or rasterization, conversion of a vector image to a raster image
• Raster image processor, or RIP, a component of a printing system that performs rasterisation
• Raster to vector, an image conversion process
• Raster bar, an effect used in computer demos
• Raster-Noton, a record label
• Rastrum, a device used in medieval music manuscripts to draw staff lines

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