1990 年 46 巻 4 号 p. 634-639
Number of noise-equivalent quanta (NEQ (u)) has provided a useful means for evaluating image quality. In this paper, we simulated the effects of various evaluated imaging factors (modulation transfer function (MTF), gamma and absorption efficiency) on NEQ (u). Regarding the simulations, the ideal values of evaluated imaging factors were substituted to Rossmann's equation. As a result, it was found that NEQ (u) at high frequencies is reduced by the lower MTF and NEQ (u) at low frequencies was reduced by the lower absorption efficiency and structure mottle. Gamma also changes completely throughout NEQ (u). We concluded that these results are useful to and in understanding the concept of NEQ (u).