[This operation takes a variable number of optional register variables.
On completion of the operation, the variable(s) receive the
values in header locations specified by their SPIDER header variable
.INPUT FILE: PIC002
[SPIDER or MRC file name.]
If register variables are present on the operation line SPIDER asks:
.HEADER VARIABLE(S): NX, PHI
[Enter names of standard variables stored in header of SPIDER format
value of NX (SPIDER file header location: 12) (also called: NSAM) will
be placed in register variable: [cols] and
value of PHI (SPIDER file header location: 15) will
be placed in register variable: [ang] ]
If FMIN, FMAX, AV, or SIG values are requested and they are not yet
available in header then they are calculated here. This is different
behaviour from operation 'FI'.