DETERMINATION OF INFORMATIVE PARAMETERS AND JUSTIFICATION OF THE RULE FOR THE THRESHOLD IDENTIFICATION OF DEFECTS IN THERMAL NON-DESTRUCTIVE CONTROL
DOI:
https://doi.org/10.31471/1993-9981-2023-2(51)-5-15Keywords:
тепловізійна термографія, інформативні параметри, несуцільність, порогова ідентифікація дефектів, димова труба.Abstract
The analysis of modern foreign and domestic research and publications related to the application of the rule of threshold identification of defects in the methods of non-destructive testing of various products and industrial objects was carried out. It is shown that the rule for different control methods can be based on its own threshold value of the informative signal from discontinuities, which divides the measured values of the signals obtained from them into correspondence with defect-free and defective zones of the product or object of control. The methods of defect identification in active and passive methods of non-destructive control of products and control objects are analyzed, in particular, with the application of the rule of threshold identification of defects in active thermal control of industrial objects. By comparing the characteristics of the methods of active and passive thermal imaging thermography, the main informative parameters used in the mentioned methods of non-destructive thermal control when detecting discontinuities in products and control objects based on the histograms of anomalies of the temperature field on their external surfaces by the thermal imaging method were determined. It is shown that the determination of product defects during active thermography requires the fixation of two additional informative parameters related to the time of optimal observation of the temperature drop during thermography of the surface of the product and the selection of the frequency of recording histograms to accumulate the necessary number of them before reaching the optimal time. The rule for the threshold identification of defects in industrial chimneys is substantiated, which is based on a defined set of received signal amplitudes from the histograms of anomalies of the temperature field on the selected section of the chimney and determination of the threshold value of the signal by dividing them into two classes.
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