What determines the FOV and voxel size in FLIRT?
The reference image in FLIRT determines the Field of View (FOV) and voxel size of the output image. This works in either registration mode (where it is finding the transformation that aligns the input and reference images) and also in applyxfm mode (where it is applying a saved transformation to the input image). Note that only in registration mode does it use the intensity information from the reference image. To apply saved transformations, the GUI ApplyXFM can also be used which provides the option of specifying the number of voxels and voxel size directly. • What cost function and/or degrees of freedom (DOF) should I use in FLIRT? There are two main types of cost function: intra-modal (least squares and normalised correlation) and inter-modal (correlation ratio and mutual information-based options). If you are registering two images of different modality then you must use an inter-modal cost function, whereas for images of the same modality either can be used, although the intra-mo
