Dear SPM users,
I need some explanation about how a relative threshold mask is built.
I found the following explanation in the SPM8 manual : "Images are thresholded at a given value and only voxels at which all images exceed the threshold
are included. This option allows you to specify the value of the threshold as a proportion of the global value."
1. What exactly is the global value: the mean of all the voxels of all the images ? One mean by image ?
2. I guess the image background is ignored : how ? With a brain mask ? With an estimated threshold ?
3. Once the images thresholded, how the mask is created : the intersection of all the image masks (this is what I understand from the manual) ?
Thanks in advance for your help !
Best,
JB Martini
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