Initially the position of an event is given as raw detector pixel numbers, 0-255, where value (0,0) lies outside the active detector area. RAWX and RAWY are integers. During COR processing level, these detector values are corrected for known errors in the position determination across the detector area (with the the help of JEMXi-CORX-MOD and JEMXi-CORY-MOD). The position correction models provide detector coordinates of each pixel in millimeters from the center of the detector (columns DETX and DETY).
The center-most intersection of the collimator defines the detector center. Each shadowgram pixel is 1mm, and the origin of the detector coordinates is at [127.5, 127.5] expressed as corrected pixels.