STUDY OF VIDEO CAMERA-BASED METROLOGY WILL DETERMINE NATURE OF MEASUREMENT ERRORS.
NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. researchers are carrying out a study of video camera geometry geometry [Gr.,=earth measuring], branch of mathematics concerned with the properties of and relationships between points, lines, planes, and figures and with generalizations of these concepts. effects that limit the accuracy of video-based dimensional measurements. These effects are investigated by scanning a small, 5 [micro]m diameter spot of light across the camera chip in a controlled pattern. The camera is mounted on a coordinate Belonging to a system of indexing by two or more terms. For example, points on a plane, cells in a spreadsheet and bits in dynamic RAM chips are identified by a pair of coordinates. Points in space are identified by sets of three coordinates. measuring machine, which can be positioned reliably with an uncertainty of 0.05 [micro]m. The camera is moved in a square raster 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.). pattern across the light spot, and data are taken at points forming a square matrix, with a point spacing of 2 [micro]m. This study is aimed at understanding the accuracy of video-based dimensional measurements, particularly the properties of sub-pixel edge operators.
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