5.5 CROSS-CORR Output

The VD data output by CROSS-CORR are an essential component for NEWSIPS processing. The information it carries is used as input to the photometric correction scheme to align properly the raw science image to the raw-space ITF image ( Chapter 6) and by the geometric correction scheme as one of the vector components to the geometric resampling stage (Chapter 7). These specific data, however, are not retained directly in an IUE Final Archive output data product. As is discussed in Chapter 7 , the VD FITS file (VDLO/VDHI) produced during the geometric correction procedure contains the summation of all the geometric corrections implemented to perform the single image resampling. The raw cross-correlation information can be retrieved indirectly from the binary table extension to the VDLO/VDHI. CROSS-CORR does not generate any $\nu$ flag values.

The CROSS-CORR module writes the following information to the HISTORY portion of the image label:

• window size,
• template size,
• ITF identification,
• percent successful correlations,
• median cross-correlation coefficient,
• standard deviation of the cross-correlation coefficient,
• mean computed displacement in pixels,
• maximum computed displacement in pixels, and
• number of isolated or semi-isolated displacements filtered.