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Dimensional Metrology
Published in Richard Leach, Stuart T. Smith, Basics of Precision Engineering, 2017
Massimiliano Ferrucci, Han Haitjema, Richard Leach
Gauge blocks can be used as secondary standards and working standards. As secondary standards, gauge block lengths are typically calibrated by interferometry. These ‘master’ gauge blocks can then be used to calibrate the lengths of ‘working’ gauge blocks by comparison (see Section 5.3). Working gauge blocks are commonly used to calibrate length scales on measuring tools such as micrometers, calipers and dial indicators. Depending on the application, various gauge block grades are available. ISO specification standard 3650 (1998) defines the maximum (‘limit’) deviation of length from nominal and the tolerance for variation in length for four gauge block grades: K, 0, 1 and 2. The values of these limits for gauge blocks up to a nominal length of 100 mm are shown in Table 5.2.
Measurement Systems
Published in Robert B. Northrop, Introduction to Instrumentation and Measurements, 2018
Gauge blocks are used as secondary standards for length. These are generally platinum alloys or stainless steel cubes or blocks whose dimensions are established interferometrically to within a fraction of a wavelength of light and whose faces are polished to optical smoothness. Gauge blocks are used to calibrate micrometers and to set up precision mechanical and optical systems.
A static and fast calibration method for line scan camera based on cross-ratio invariance
Published in Journal of Modern Optics, 2022
Shuaipeng Yuan, Dexue Bi, Zexiao Li, Ning Yan, Xiaodong Zhang
The following points should be paid attention to in the process of calibration: (1) even if the height information of the gauge block is adjusted, it is not necessary for the calibration plate to be fully aligned with the gauge block, and the slight rotation or lateral movement of the calibration plate will not affect the calibration results. As shown in Figure 6, when the calibration plate rotates or translates slightly, it will affect the intersection of line L and the calibration plate; that is, the coordinate values of Pi and ui (i = 1, 3, 5, … , N−1), but the corresponding relationship between them will not change. (2) Herein, the calibration plate and gauge block are deliberately placed obliquely to avoid the phenomenon of no solution due to the parallel state between the calibration plate and the target surface of the linear array camera. When the linear array camera is calibrated, it is not necessary to know the specific angle of the calibration plate inclination. Still, when changing the height of the gauge block under the calibration plate every time, it is not necessary to know the specific angle of the calibration plate inclination. Still, when changing the height of the gauge block under the calibration plate every time, it is critical to ensure that the included angle between the calibration plate and the horizontal plane is consistent.
Detection of the fluff fabric surface quality based on machine vision
Published in The Journal of The Textile Institute, 2022
Qiangqiang Lin, Jinzhu Zhou, Qiurui Ma
In the experiment, the standard gauge block is used as the calibration object, the standard gauge block is placed on the conveyor belt, the same lighting conditions and object distance are adjusted, and the object surface resolution K = 0.358 mm/pixel is obtained after multiple measurements. In Table 7, the four categories of fabrics in Figure 1 are quantitatively evaluated and compared with the results of manual testing.