Wall thickness measurement using using Computed Radiography

Nerazorne metode ispitivanja vrlo su cijenjene u industriji zbog neoštećivanja materijala prilikom mjerenja. Računalna radiografija, koja je ujedno i tema ovoga rada, je jedna od najstarijih, najvažnijih i najsvestranijih metoda nerazornih ispitivanja koja se često koristi za određivanje debljine stijenke. Tehnika snimanja se odvija pomoću rendgenskih zraka kojima se dobiju kvalitetniji radiogrami ili gama zrakama koje imaju veću prodornost pa se koriste za prozračivanje debljih uzoraka. Proces nastajanja slike se od klasične radiografije razlikuje samo u pohrani latentne slike u fosfornom sloju osjetljivom na zračenje, koji se pomoću laserske simulacije mijenja u svjetlost te se zapis pretvara u digitalnu snimku. U ovom radu bit će prikazane mogućnosti i ograničenja primjene računalne radiografije za određivanje debljine planparalelne geometrije stijenke ispitivane komponente temeljem kontrasta, tj. temeljem intenziteta piksela digitalnog radiograma. Na dva uzorka stepenica provedeno je radiografsko snimanje te je procijenjena debljina stijenke obradom i analizom dobivenih slikovnih zapisa.Non – destructive testing methods are highly valued in the industry for non – damaging materials during measurements. Computed radiography, which is also the topic of this paper, is one of the oldest, most important and most versatile methods of non – destructive testing often used to determine wall thickness. Scanning technique is using X - rays to obtain radiograms with better quality or γ - rays that have higher penetration and are used for thicker samples ventilation. The process of image formation differs from classical radiography only in the storage of the latent image in a phosphor layer sensitive to radiation, which is converted into light by laser simulation and the record is converted into a digital image. In this work the possibilities and limitations of the application of computed radiography will be presented to determine the plane – parallel wall geometry of the examined component based on the contrast, ie. based on the pixel intensity of the digital radiogram. Radiographic imaging was performed on two samples of stairs and the wall thickness was estimated by processing and analyzing the obtained image records