 |
 |
Hi John, Thanks for the quick reply. Because the template encompasses the whole head, while the functional runs only have a small slab of recorded voxels, new voxels are added, so the file sizes increases drastically. How can I find out the size of my bounding box? I think I would like to reduce it but don't know what the 2x3 matrix represents. Can I click on different parts of the image and select the boundary points that contain all of the image? Regards, Glad On 10/18/2016 11:30 AM, John Ashburner wrote: > It depends on the image dimensions and datatype. 16 bit images require > two bytes per voxel. Floating point images and 32 bit images require > four bytes per voxel (you can see the data types via the Display > button). Multiply the number of bytes per voxel by the number of voxels > (by multiplying the image dimensions together). The .nii files also > have a tiny header of 352 bytes to account for. > > If you want smaller spatially normalised images, you could change the > bounding box (and hence the image dimensions) for them. You could also > increase the size of the voxels so that fewer of them cover the same > field of view. > > Best regards, > -John > > > > > On 18 October 2016 at 10:10, Paul Glad Mihai <[log in to unmask] > <mailto:[log in to unmask]>> wrote: > > Dear subscribers, > > I was wondering why is there such a huge jump in the file size after I > normalize my functional data (1.1 mm isovoxel) using a created template > and corresponding flow field. The jump is from 246 MB to 3.2 GB -- a > 13-fold increase! Is this normal? > > Regards, > Glad > -- > Paul Glad Mihai, PhD > > Independent Research Group "Neural Mechanisms of Human Communication" > Max Planck Institute for Human Cognitive and Brain Sciences > Stephanstraße 1A, 04103 Leipzig, Germany > > Phone: +49 (0) 341-9940-2478 <tel:%2B49%20%280%29%20341-9940-2478> > E-mail: [log in to unmask] <mailto:[log in to unmask]> > > -- Paul Glad Mihai, PhD Independent Research Group "Neural Mechanisms of Human Communication" Max Planck Institute for Human Cognitive and Brain Sciences Stephanstraße 1A, 04103 Leipzig, Germany Phone: +49 (0) 341-9940-2478 E-mail: [log in to unmask]