Distance measure for optimization: The fourth option provides the possibility to choose between two different distance measures used to estimate the similarity between the images: normalised cross-correlation (NCC) and sum of square differences (SSD). For more information, please see background.
Apply intensity correction: Intensity correction means correcting the intensity values of pixels when the area has been stretched or compressed. This is performed by multiplying the corrected images with its derivatives.
Order of Gaussian: This parameter controls the smoothness of the opposite phase encoded files in the first cycle of the estimation of the voxel displacement map. This smoothing is only used during estimation and has no further effect on the original files. Default: 0. If during the estimation process values of 'NaN' (not a number) are reported, try value 1.
Save derivative of VDM: The second option is to save the derivative of the VDM. To view a map, open a corrected file (e.g., “example_undist.fmr”), go to Analysis > Overlay Volume Maps and load the corresponding map file (e.g. “example_undist_vdmderiv.map”).
Use fast, linear algorithm: The third option enables a fast estimation via a linear algorithm. This is only for testing purposes.
Latest update of this page: 20 July 2018