2022 Volume 39 Issue 2 Pages 30-37
The median filter processing is applied to some flat panel detector systems used for defect pixel compensation. The aim of our study was to examine the effect of median filter processing for the presampled MTF measurement to determine whether the presampled MTF measurement could be performed using the edge method. First, we simulated the edge image, and evaluated the effect of the inclination angle of the edge, the kernel size, noise. Then, we applied median filter processing to a reference edge image and examined the effect of the presampled MTF.
The effect of median filtering did not generate moire patterns in the simulated edge images and reference median filtering image. Although the MTF could be measured, the effect of the median filter was different because of the noise level. For the presampled MTF measurement of a reference edge image with a median filter, the relative error with respect to the true value decreased in the MTF by approximately 3.4% at the maximum. Although the effect of median filtering was shown, the presampled MTF measurements using the edge method can be calculated in the same clinical settings. However, the median filter should be eliminated wherever measurement accuracy is required.