Image Math is a tool to calculate the average and the median of all the diffractograms.

It was written by Gavin Vaughan at ESRF and is available on the old fable website: https://sourceforge.net/p/fable/code/HEAD/tree/ImageTools/trunk/Image/code/image_math.c. You have to install the whole image package to get it working.

In fact there is a small issue with it. S. Merkel did find it a fix some years ago but does not remember what he did. He has a binary called image_math_petra that works. This should be fixed at some point…

From the command line in the folder with the .edf files type image_math_petra [stem name] [first file] [last file] [operation]

Example:

image_math_petra fcc_1_ 0 111 median

The program will create three new files, which are named the same as your previous .edf images, just with an 'm' in the middle.

• fcc_1_m10000.edf (average image)
• fcc_1_m20000.edf (median image)
• fcc_1_m30000.edf (trimean image)

We proceed with the “normal” median (file no. 2). In Fabian go to Image, then to Correction, then to Background Correction and load the median file (in this example fcc_1_m20000.edf)