Accuracy and Precision in Estimating Noise Power Spectrum in Radiography Imaging

In order to observe the noise property of the radiography image detector, the noise power spectrum (NPS) is usually measured. NPS curve can be measured from the average of the periodogram samples. Here, we can improve the measurement accuracy and precision by increasing the number of periodogram samples and spectral resolution. In this paper, we observe the accuracy and precision of the NPS measurement, which is based on the periodograms. For real digital X-ray images, which were acquired from an indirect CsI(Tl)-scintillator radiography detector, we observed the accuracy and precision of the NPS estimates for various resolutions and sample sizes. For a given image size, we could find an appropriate combination of the sample size and spectral resolution from minimizing the mean square error.