rheaders -- Compute registration parameters using FITS coordinates.
rheaders reffile secfile outtable
This task lets you compute the parameters needed to register a "Secondary" file to the pixel coordinate scale of a "Reference" file using the FITS coordinate parameters (CRVAL, CRPIX, etc.) contained in the group parameter block. The coordinate types (CTYPE) in the reference and secondary files must be the same.
The output table from this task may be used in the resamp task to resample the secondary file to the same scale and orientation as the reference file. Input files can be images or vectors.
In the case of vectors, the output columns to the table are the coefficients c1 and c2 in the equation
X = c1 + c2*x
X is the position of a pixel in the reference vector and x is the position of the pixel in the secondary vector. Also, for informational purposes, there are two columns in the table that show the offset in X (DELTAX) and a magnification in X (XMAG).
In the case of images, the output columns to the table are the coefficients c1 - c6 in the equations
X = c1 + c2*x + c3*y Y = c4 + c5*x + c6*y
(X,Y) are the pixel coordinates of a feature in the reference image and (x,y) are the pixel coordinates of the feature in the secondary image. Also, for informational purposes, the offset in X (DELTAX) the offset in Y (DELTAX), the rotation angle (THETA), the magnification in X (XMAG) and the magnification in Y (YMAG),
- reffile [file name]
- Name of the reference file.
- secfile [file name]
- Name of the secondary file.
- outtable [file name]
- Name of the output registration table.
1. Derive the registration table reg.tab to resample the image image2.hhh to the same scale and orientation as the image image1.hhh.
pl> rheaders reffile=image1.hh secfile=image2.hhh outtable=reg.tab
Type "help registration option=sys" for a higher-level description of the registration package.