Brain Imaging & Analysis Center

usage: -expr censor [timeref] [flag [filloption]] CENSOR replaces flagged with new values, or it can completely remove images. Which images to censor is controlled by a reference time series. By default, the reference time series is the data set's “ACTIVE” reference timeline (0/1 value for each image). Alternatively, a reference time series can be specified explicitly by name as the first argument (TIMEREF). Usually the reference series should have at least as many values as their are images, in which case the images to be censored are those for which the corresponding reference value is less than or equal to zero (any positive reference value means keep that image). Alternatively, if the FLAG argument includes the 16 option, then the reference series is assumed to be an explicit list of which image numbers to censor. Image numbering always starts with 0 for the first image of the first volume, then the 2nd image of the first volume, etc. For example, if a data set has 20 image slices per volume and TIMEREF has values [ 0, 4, 107 ] then the only images to be censored would be: slice 0 volume 0, slice 4 volume 0, and slice 7 volume 4. Such a TIMEREF must contain only unique values sorted in ascending order; the list can be any length up to the total number of images. What happens to censored images depends on the values of the FLAG and FILLOPTION arguments. FILLOPTION can be a number, indicating wwhich image volume to use as fill images, or the name of a 3D image data set (same XYZ dims as the data being censored) FLAG - censoring operation:
* 0 - (default) if FILLIMAGES replace with linear interpolation of surrounding time points

• 1 - replace with spline interpolation of surrounding time points
• 2 - replace with zeros
• 3 - excise the value (result is fewer time points)

Other FLAG values can be combined with the above byb addition:

• 4 - adjust values after 0 reference values to have similar means to earlier values (matches means of 3 values before and after)
• 8 - The TIMEREF is a list of time point indices to censor (default is TIMEREF is 0/1 flag for every timepoint)
• adjust values after censored values to have similar means to earlier values (matches means of 3 values before and after)

			/* val:  0 - (default) replace with linear interpolation; or
			             same as VAL=8 if VAL2 is non-zero
					 1 - replace with spline interpolation
					 2 - replace with 0's
					 3 - excise
					 4 - match post-mean to pre-mean
					 8 - replace with value at 1st censored timept at or after timept VAL2
					 9 - replace with value at 1st uncensored timept at or after VAL2
					10 - replace with value at timept VAL2
					16 - active is t-index; otherwise is 0/1 flag

See Also:
fScan Home, fScan Manual, CmdLineOptions, Expression Command, Manual Help