Figure 14.

Pixel variance comparison between detector modes. The pixel noise variance after logarithmic preprocessing is shown with different detector modes. The air kerma level was 1.06 μGy for a 156 mm polyethylene cylinder. The discrete data points were calculated from experimentally measured data using Eq. 4. The solid lines (closely overlapped with the discrete data points) were calculated from empirical prediction using Eq. 5b, with measured fitting coefficients and additive noise measured from offset images. The pixel noise variance with the dynamic gain mode is only about 50% of that with the fixed low gain mode.