Analysing subtracted planar images using StandardImagingQ3

[Andrea Fischer]

Hi Everyone,

I am using StandardImagingQ3 to analyse some EPID images of the phantom. To determine the noise, I would like to take 2 images one after the other, subtract them and then look at the standard deviations for circular ROIs positioned in the usual positions for the low contrast ROIs on the subtracted image. I can successfully analyse each of the images individually and create a dicom file containing the subtracted pixel data, but when I feed the subtracted dicom file into StandardImagingQ3, not surprisingly it doesn’t recognise the phantom. For a given ROI, I can access the pixel data in that ROI for each of the two normal images using circle_mask() and was hoping I could just subtract this data. This works for some image pairs, but for others the circle_masks() arrays are slightly different in size, so there is no obvious way to see which pixels correspond to which.

Any suggested workarounds would be much appreciated.

Kind regards,

Andrea