;center.ori
; center untilted particles with an external reference
; which consists of a rotationally averaged 2D average.
; authors:m.radermacher, D.bubeck 7/2/97 and Montserrat Samso 8/98

fr
?image names? <1>
rr x10
?first image number? <2>
rr x11
?last image number? <3>
rr x50
?mask radius? <4>
fr
?output files? <5>
fr
?external reference? <6>
fr
?interm shift docfile? <7>
fr
?final shift docfile? <8>

;look for first existing file in order to find out dimensions
fi
<1>x10
x30=x1
x31=x2
x32=x30/2+1
x33=x31/2+1

cp
<6>
_9
do lb3 x27=x10,x11
ma
<1>x27
_3
x50
g
a
x32,x33
(3.5)
cc 
_3
_9
_4
x51=(x30/2-x50)+2 
;(distance for edge exclusion)
;                          find peak of the cross-correlation
pk c x40,x41           
_4
(3,0)
(10.,10.)
y
(2.)
x51
;                          shift the image
sh f
<1>x27
_5
-x40,-x41
;                          save the shift parameter
sd x0,x40,x41
<7>
ma
_5 
_3
x50
g
a
x32,x33
(3.5)
cc 
_3
_9
_6
x51=(x30/2-x50)+2 
;(distance for edge exclusion)            
;                          find peak of the cross-correlation
pk c x60,x61           
_6
(3,0)
(10.,10.)
y
(2.)
x51
;                          shift the image
x72=x40+x60
x73=x41+x61
x70=int(x72)
x71=int(x73)
sh f
<1>x27
<5>x27
-x70,-x71
;                          save the shift parameter
sd x0,x70,x71,x40,x41
<8>
lb3
re