XMM-Newton Science Analysis System


omqualitymap (omqualitymap-1.5) [xmmsas_20230412_1735-21.0.0]

Setting of bit 9 (Isolated exceptionally bright pixels)

The algorithm works as follows

1. Loop through each column of the image and for each column number i
2. Loop through each row of the image and for each row number j
   1. Examine the 8 (less if near an edge) neighbouring image pixels around the pixel i, j and count how many have a value at least 1/20th of the central pixel.
   2. If the number is less than 2 then assume the pixel i, j is abnormal- set bit 9 of the quality pixels within a box of width and height 41 unbinned pixels.