OR R - ORientation Search - 2D, rotation, uses polar coords. ||

PURPOSE

Determines rotational orientation between two images using cross correlation following remapping into polar coordinates. This is eqivalent to: 'AP REF' or 'AP SH' without the translational search but this operation processes a single pair of images. Optionally multiple correlation peaks corresponding to different rotations can be found and stored in a document file.
(See align_overview.html for comparison of 'AP' and 'OR' operations.)
NOTE: This operation was altered in Jan 2013 to give results using same conventions as other SPIDER 'AP' and 'OR' operations and to fix a angular bug.   Example.

SEE ALSO

OR SH	[Orientation Search - 2D, rotation & shift, uses polar coords. ||]
OR MAP	[ORientation MAP - 2D, rotational cross correlation plot ||]

USAGE

.OPERATION: OR R [ang],[peak]

<or>
OR R [peaks]

[The optional output parameters: [ang],[peak] specify register variables to receive the rotation angle and the value of the angles correlation peak. If multiple peaks are requested the optional output parameter: [peaks] specifies a register variable to receive the actual number of peaks found and the angles and peaks are stored in a doc. file.]

.EXPERIMENTAL IMAGE: UUU001
[Enter name of the image file.]

.REFERENCE IMAGE: GGG002
[Enter the name of the file containing the reference image. Dimensions must correspond to those of the experimental image.]

.FIRST, LAST RING, & RING STEP: 5, 30, 1
[Only polar coordinate rings with the radii in the range 5-15 (in pixel units) will be used for the alignment. If skip=0 or 1 then each radial ring between 5 and 30 will be taken; for skip=2 every second, and so on.]

.FULL OR HALF CIRCLE (F/H): F
[F - full ring (360 degrees) will be used; H - half ring (180 degrees) will be used. Option 'H' is appropriate for rotational search using images which contain autocorrelation functions.]

.NUMBER OF PEAKS: 10
[Maximum number of peaks to be found.]

If the number of peaks requested is greater than one then the actual number of peaks found is returned in the optional register and the following question appears:

.OUTPUT ANGLE DOCUMENT FILE: peaks001
[Enter the name of the document file. First register column contains rotation angles found, second column contains corresponding peak values. The entries are sorted according to the peak value in a descending order.]

NOTES

1. Implemented by: Paul Penczek

2. Previously this operation was called 'OR 2' or 'OR 2M'.

SUBROUTINES

ORMD, ORMD_P, SETNUMRINGS, RINGWE, APRINGS, NORMAS, FRNGS, APPLYWS, CROSRNG, PRB1D, ANG_N

CALLER

UTIL3