Digital RadiographyⅥ: A Discussion on the Equivalence of the Defect Detectivity of Digital Radiography with Radiography

The concept on equivalence on the basic theory of imaging process was given. The discussion on the index and class of equivalence was carried out. The approach and method for discussion on the scope of equivalence was established. The process of discussion on the thick scope of equivalence was described with the sample in which the spread function of imaging system was similar to square pulse function.