QC3 background ROI included in the low contrast ROIs

[brjdenis]

This is more of a comment, not really an issue. The background ROI of the QC3 phantom is included in the low contrast ROI list. This has an effect on the graph display (starting value 0), and also lowers the median contrast and cnr values. I think it would perhaps be best to consider the background ROI as seperate from the low contrast ROIs.

[jrkerns]

This happens because I don't have a good reference for the background ROI, so I simply use the first ROI as a reference. Unfortunately, the side effect is that the contrast is 0 for the first ROI. I'll think about it some more. If you have any better suggestions let me know.