Description:
This recipe
processes FTS-2 ZPD calibration data to estimate the location of the ZPD (zero path difference) point.
The input data are split into separate scans, baseline-subtracted and labeled with an approximate
moving mirror position coordinate system frame. The position of the peak fringe, corresponding to
the ZPD position, is estimated for each scan and then averaged for each subarray. Finally, to ensure a
smooth ZPD map without gaps, a surface is fitted to the average ZPD positions.
Notes:
The FTS
shutter status is normally read from the FTS_SH8D and FTS_SH8C FITS headers. If these
are not defined (i.e. in older data) then an attempt is made to read this information from
the OCS configuration XML (which of course indicates the requested configuration).
Available Recipe Parameters :
FTS_STAGE_CENTER
Center position of moving mirror
travel, usually read from the FTS_CNTR FITS header.
FTS_SCANDIR_ZPD
Indicates
whether to derive scan direction-specific ZPD measurements.
FTS_ZPD_ESTIMATE
Initial estimate of ZPD position.
FTS_ZPD_TOLERANCE
Tolerance in ZPD position.
FTS_ZPD_BASE_OFFSET
Distance to ZPD baselining region.
FTS_ZPD_BASE_WIDTH
Width of
ZPD baselining region.
FTS_ZPD_PEAK_HEIGHT
Initial estimate of ZPD peak height.
FTS_ZPD_PEAK_WIDTH
Initial estimate of ZPD peak width.
Display
kapview window 1 region
1 Initial ZPD position estimate mosaicked image. kapview window 1 region 3 Initial ZPD
position estimate histogram. kapview window 1 region 2 Final ZPD position measurement
mosaicked image. kapview window 1 region 4 Final ZPD position measurement histogram.
Copyright © 2014 University ofBritish Columbia and the Science & Technology Facilities Council