Added work around for a bug in the CIAO tool dmimgpick which caused inaccuracies in background scaling. Helpdesk ticket #7381 describes an apparent bug in dmimgpick. The effect of the bug is that in the /EXTRACT_BACKGROUNDS stage events falling near the edges of the background.emap image are excluded from the background spectrum, even if they fall on non-zero pixels in background.emap. In other words in AE versions prior to 3.56 the background.emap and background.evt files may not be consistent with each other, leading to an error in background scaling and subtraction.
The bug is that dmimgpick returns NaN values for positions on the image supplied but near the edge. The work around in AE is to use [opt full] when creating background.emap to keep the non-zero pixels far from the edge of the image.
