These posts describe several topics, including:
- SFRplus Quadrant analysis (it includes the center region as well),
- Saturation analysis, which attempts to estimate the severity of saturation in slanted-edge regions (ROIs), and a few other recent additions (November 2012). Saturation is important because saturated light or dark regions will result in artificially high MTF readings.
- How to select regions at a fixed distance from center to corner (typically in the range of 65-85%)