We analyzed the relationship between the noise components and detectability of the various Imaging Plates to find the essential factors for improving Imaging Plate.
CR system noise is classified into quantum noise and fixed noise. The dominant component of fixed noise is the structural noise of IP. The contribution of the structural noise was relatively high at higher exposure and at higher spatial frequency. For example the ratio of structural noise of early type of IP is 55% in case of 2 mR (5.16 × 10-7 C/kg) exposure at 2 cycles/mm spatial frequency. On the other hand, the ratio of the latest type is about 20%. This
improvement leads to 2.3 times NEQ combined with improvement of quantum noise. Threshold depth of the 0.5 mm diameter hole of CD diagram was improved from 1.4 mm to 0.8 mm according to the improvement of NEQ from 50,000 to 100,000 /mm2 at the related spatial frequencies. Amount of improvement of threshold contrast was influenced especially by the NEQ at relatively high spatial frequencies. So improvement of the structural noise, which
is dominant at higher frequency, is important as well as quantum noise.