The radiographic grid is an array of high atomic number blades interleaved with relatively transparent ones. The radiograph of a grid is a grating having a square wave transmittance function. If two such radiographs are superposed in a convenient way and looked at on a film viewer, moire fringes appear. From visual inspection of the fringes several structural defects in the grid show up. Some pictures explain how to enhance line defects, frequency, and pulse width modulation defects, all of them being related to uneven thickness of the blades which form the grid. Other manufacturing defects, which do not affect the periodical structure and must therefore be detected by other test methods, are also discussed.

Crosta, G. (1981). Incoherent Optical Quality Control of Radiographic Grids. OPTICAL ENGINEERING, 20(4), 562-567 [10.1117/12.7972762].

Incoherent Optical Quality Control of Radiographic Grids

CROSTA, GIOVANNI FRANCO FILIPPO
1981

Abstract

The radiographic grid is an array of high atomic number blades interleaved with relatively transparent ones. The radiograph of a grid is a grating having a square wave transmittance function. If two such radiographs are superposed in a convenient way and looked at on a film viewer, moire fringes appear. From visual inspection of the fringes several structural defects in the grid show up. Some pictures explain how to enhance line defects, frequency, and pulse width modulation defects, all of them being related to uneven thickness of the blades which form the grid. Other manufacturing defects, which do not affect the periodical structure and must therefore be detected by other test methods, are also discussed.
Articolo in rivista - Articolo scientifico
X-ray scattering; Compton scattering; amplitude modulation; phase modulation; manufacturing; moire patterns; optical inspection; transmittance; radiographic grids; radiography; x-ray apparatus; moire fringes; incoherent optical processing; image processing
English
562
567
6
results made possible with technical help by Mr. David Tortorich, Metaire, LA and Dr. Eng. Giovanni Sommaruga, Milan, IT
Crosta, G. (1981). Incoherent Optical Quality Control of Radiographic Grids. OPTICAL ENGINEERING, 20(4), 562-567 [10.1117/12.7972762].
Crosta, G
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/48346
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