Changes between Version 5 and Version 6 of GPC1_M31_OTA_Offset_Study

Timestamp:

Feb 26, 2013, 2:44:23 PM (13 years ago)

Author:

watersc1

Comment:

--

GPC1_M31_OTA_Offset_Study

@@ -1 +1 @@
 = 2013-02-26 =
+
+The following table of images shows an M31 frame with standard science processing (top left), with the background restored using the camera stage adjusted background models (top right), background restored again but with the PATTERN.CONTINUITIY correction disabled (bottom left), and the background unsubtracted reduction Bill did previously (bottom right).  The two background restored images did not have the mask data applied, but have effectively the same masks as those seen on the automated JPEGs.  
 
 || [[Image(o5511g0093o.253986.cm.750306.b1.jpg,400px)]] || [[Image(o5511g0093o.bgc.b1.jpg,400px)]] ||
 || [[Image(o5511g0093o.bgc2.b1.jpg,400px)]] || [[Image(o5511g0093o.253986.cm.729023.b1.jpg,400px)]] ||
 
+This profile plot is the same region as those done previously, showing Bill's reduction and the background restored without CONTINUITY (top), and the profile of the background restored/CONTINUITY=T (bottom).
+
 [[Image(science_processing.png,800px)]]
+
+The important points:
+
+ 1. Background restoration appears to generate largely the same solution as not subtracting the background at all.  This is good, as we expect that we should be able to subtract a model and then readd that same model to return to the initial case.
+ 2. OTA-to-OTA offsets still exist in the background restored images.  Again, this is likely an error in the dark model, and as noted above, we add back what we've previously subtracted.  The camera stage background adjustment seems to have not completely fixed this, most likely because this dark error occurs on one edge of the OTA, and the adjustment solution is a function of the offsets on all edges.
+ 3. PATTERN.CONTINUITY introduces a constant offset on all OTAs, as there is an open degree of freedom.  The added adjustments to each cell allows for the OTA-to-OTA offsets to be minimized as well.  However, sharp gradients in the image are broken by this correction.
+
 
 = 2013-02-22 =