Changes between Version 3 and Version 4 of IPP_Progress_Report_20100104

Timestamp:

Jan 12, 2010, 8:36:11 AM (17 years ago)

Author:

eugene

Comment:

--

IPP_Progress_Report_20100104

@@ -5 +5 @@
 
 === Eugene Magnier ===
+
+I have been continuing the study the choice and scaling of the difference image kernels, driven by the level of residual seen in the differences for simulated images with roughly Moffat PSFs.  I have implemented a few variations on the standard ISIS kernels to examine this question, and have found that a kernel set that seems to work fairly well: a standard ISIS Gaussians modified by low-order polynomials, supplemented with higher-order radial Hermitians.  This kernel set addresses the different fall-offs between Moffats with different scales.  For best results, the size range of the kernels needs to be chosen based on the difference of the PSF FWHMs, and it seems to be necessary to avoid integer multiples for the kernel sizes.  I have added some statistics to ppSub to track the amplitude of the residuals.  I am putting together a write-up of the analysis of the kernels, and will provide a suite of sample images that we can also test against 'Hotpants' or other difference image code.
 
 === Heather Flewelling === 
@@ -40 +42 @@
 === Bill Sweeney ===
 
+Bill has been working on getting the 'update' (re)-processing to work.  This subsystem is required to provide data products to the users after the bulk of the result products have been 'cleaned' (deleted).  The basic code has been in place for a while, but it has not been tested; Bill has found a number of bugs and logical issues that he has been sorting out.  He has succeeded in getting the 'chip' and 'warp' stage to update, but needs to ensure the updated 'warps' work with the stacking and differencing stages.
+
 === Chris Waters ===
+
+Chris has finished making tweaks to the cosmic ray masking code, but there is an under-lying bug that is now in Gene's court (footprints that are apparently defined, but do not have valid pointers -- these do seem to be real sources, but a mis-interpretation of the flags).  He spent part of last week looking into the roll-off effect at the edge of the cells (http://svn.pan-starrs.ifa.hawaii.edu/trac/ipp/wiki/EdgeRolloff).  The main conclusions are that (a) the first/last column(s) of the cells seem to correct well, but the first/last row(s) do not; and (b) this effect has been present since at least run 3, but was previously not a magic trigger because of the 'PATTERN' correction.  At most, we need to mask an additional 2-3 rows per cell, but it may not be all cells.  Chris still needs to determine what fraction of cells need to be masked.