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.TH xf2rotmagstr 1 4.6.34 IMOD
.SH NAME
xf2rotmagstr - Convert transforms to rotation, magnification, stretch
.SH SYNOPSIS
xf2rotmagstr input_file
.SH DESCRIPTION
xf2rotmagstr takes a file with a set of linear transformations expressed as
2x2 matrices plus a shift in X and Y, and converts each 2x2 matrix to a
rotation, magnification, and stretch along an axis. The output appears as:
.P
1: rot= 11.80, mag= 1.0001, str= 0.9916 on -4.9 axis, Mean mag= 0.9959
.P
where rot is rotation angle in degrees, mag is magnification factor, str is
a stretch factor, the axis of the stretch is given in degrees of rotation
from the X axis (counterclockwise positive). Mean mag is the average size
change with the stretch taken into account. Rot, mag, and str match the
values that would be shown if the transformations were read into midas(1).
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The program will also accept a warping file as produced by Midas(1) or
Tiltxcorr(1). In that case, it extracts the linear transformation for each
section and uses it to produce the same report.
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The format of each line of a simple linear transformation file is
a11 a12 a21 a22 dx dy
.br
where the coordinate transformation is
x' = a11 * (x - xci) + a12 * (y - yci) + dx + xco
y' = a21 * (x - xci) + a22 * (y - yci) + dy + yco
.br
and x, y is the original position, x', y' is the position in the transformed
image, xci, yci is the center of input images, and xco, yco is the center of
transformed images.
.SH HISTORY
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Written by David Mastronarde, added to IMOD 10/5/06
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.SH BUGS
Email bug reports to mast@colorado.edu.