No, that's not the implementation that we use.
All the best,
On 31 Jan 2012, at 22:56, Yiou Li wrote:
> Hi Mark,
> Thanks for the prompt feedback! As I understand, the rmsdiff measure
> is invariant to the order of transform matrices just as |X1 - X2|^2 is
> symmetric to both variables?
> On Tue, Jan 31, 2012 at 2:44 PM, Mark Jenkinson <[log in to unmask]> wrote:
>> Dear Leo,
>> There is no right answer.
>> The two different ways just average over a slightly different
>> spherical ROIs. However, the difference will be pretty minor
>> and I can't think of an example where these small differences
>> would matter.
>> All the best,
>> On 31 Jan 2012, at 22:08, Yiou Li wrote:
>>> Hi Mark,
>>> I want to use rmsdiff to measure the difference between image X1 and
>>> X2 in terms of affine linear transformation, to do that, I ran flirt
>>> to register X1 to X2, taking X2 as reference image and get the
>>> transformation xmat_1_to_2, now I got two slightly different number by
>>> 1. rmsdiff xmat_identity xmat_1_to_2 X2
>>> 2. rmsdiff xmat_1_to_2 xmat_identity X2
>>> Can you please advise which one is the correct order in this case?
>>> Thanks in advance!