Differences between revisions 4 and 5

Name

Transform Class

Usage

Here are some examples of creating a Transform3D object. Much more will be added later.

All angles are in degrees

Creating just rotations:

RA=Transform3D(0,0,25); # Default is the ZXZ convention
RA=Transform3D(EULER_SPIDER,0,0,25); # This is the typical ZYZ convention
RA=Transform3D(m11,m12,m13,m21,m22,m23,m31,m32,m33) # create the transformation by entering
components

Creating more complicated transformations using set :

RA = Transform3D(); # this creates the 3D identity matrix
RA.set_rotation(0,0,25); # creates a matrix that will rotate 2D images by 25 degrees
RA.set_posttrans(Vec3f(1,0,0)); # the matrix will now also shift 1 pixel in the x-direction
RA.set_scale(1); # Occaisionally one will wish to rescale.

Notes:

a) We could have used EMAN, IMAGIC, SPIN, QUATERNION, SGIROT, MRC, XYZ, MATRIX instead of the SPIDER of EULER_SPIDER above.
b) There is also a set_rotation via a dictionary object, which we will explain at length soon.
c) The first two lines of the second block of commands, could have been written as the second line of the first block of commands. This command sets RA to a rotation that rotates a 2D image by 25 degrees around the Z-axis.
d) There are corresponding "get" calls to extract the information from the transformation matrices. SPARX has some of its own, that are wrappers for these get calls. More later.

Purpose: to apply rotation/shift/scaling operations for 2D or 3D images via a variety of methods.

P. R. Baldwin

P. R. Baldwin

libEM

Infancy

-  ⇤ ← Revision 4 as of 2006-08-21 21:58:09 → 
  Size: 1777
  Editor: Philip Baldwin
  Comment:
+   ← Revision 5 as of 2006-08-21 22:06:39 → ⇥
  Size: 1869
  Editor: Philip Baldwin
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 27:
- . c) The first two lines of the second block of commands, could have been written as the second line of the first block of commands.
+ . c) The first two lines of the second block of commands, could have been written as the second line of the first block of commands. This command sets RA to a rotation that rotates a 2D image by 25 degrees around the Z-axis.