Changes between Version 8 and Version 9 of DetectorLinearity

Timestamp:

Aug 13, 2010, 5:04:03 PM (16 years ago)

Author:

watersc1

Comment:

--

DetectorLinearity

@@ -1 +1 @@
 == Detector Linearity ==
 
-These plots show the maximum fractional deviation of the flux in a given cell or row from the model:
+I've regenerated all the linearity data, refit it all, and tested some correction code that seems to repair some of the issues.  This reprocessing was needed to fix two errors I made the first time:
+ 1. The original data had been dark corrected, confusing the reason why things weren't linear.  This analysis now uses the raw images.
+ 1. I mislabeled rows and columns because I read my own code wrong.  All row/column data in this analysis is labeled xXXX or yYYY to denote the single x or y value that was held constant while the median was taken over that row or column.
+
+As before, the deviation is measured by creating a model for the expected flux for the region under consideration as a function of exposure time.
 
 model_flux = b_fit + m_fit * exptime
 
-The model is calibrated by fitting the flux between 7000 and 30000 counts, and then measuring the deviation between 1000 and 4000 counts (the region in which sagging counts have been observed).
+The model is calibrated by fitting the observed data between taken with exposure times between 12 and 50 seconds.  The correction code samples this model once for each exposure times input, and calculates the ratio of the model to the observed fluxes.  The set of (observed flux,ratio) samples from the reference data (chosen as the 2010-07-02 "linearity" data) are then linearly interpolated based on the observed flux values in the test data.
 
-Note: the plots sent around before for the "original configuration" had a bug where cells with bad data were set to zero instead of NaN.  This bug is fixed in these figures.
+John pointed out that the edges that seem to have significant issues do not correlate with what I observed in January ([wiki:EdgeRolloff]).  I do not currently know if this is a labeling issue or due to some camera change.
 
-Only row 1 is plotted, as it shows the largest deviations from linearity, as noted before [wiki:EdgeRolloff].  This previous data also showed that the bottom and left side edges are not corrected by applying the dark and flat.
-
-|| Configuration || Cell Statistics vs. !ExpTime || Row 1 Stats vs. !ExpTime||
-|| Original Configuration 2010-07-21|| [[Image(ipp_cell_fit_reftime.metric.2.png, 400px)]] || [[Image(ipp_row_fit_time.row_metric.2.png, 400px)]] ||
-|| Same Configuration 2010-07-27 || [[Image(ipp2_cell_fit_reftime.metric.2.png, 400px)]] || [[Image(ipp2_row_fit_reftime.row_metric.2.png, 400px)]] ||
-|| utest1 Configuration 2010-07-27 || [[Image(ipp2_utest1_cell_fit_reftime.metric.2.png, 400px)]] || [[Image(ipp2_utest1_row_fit_reftime.row_metric.2.png, 400px)]] ||
-|| utest1a Configuration 2010-07-27 || [[Image(ipp2_utest1a_cell_fit_reftime.metric.2.png, 400px)]] || [[Image(ipp2_utest1a_row_fit_reftime.row_metric.2.png, 400px)]] ||
-
-Subtractions relative to original configuration
-
-|| Configuration || Cell Statistics vs. !ExpTime || Row 1 Stats vs. !ExpTime||
-|| Original Configuration 2010-07-21|| [[Image(ipp_cell_fit_time_sub.metric.png, 400px)]] || [[Image(ipp_row_fit_time_sub.metric.png, 400px)]] ||
-|| Same Configuration 2010-07-27 || [[Image(ipp2_cell_fit_time_sub.metric.png, 400px)]] || [[Image(ipp2_row_fit_time_sub.metric.png, 400px)]] ||
-|| utest1 Configuration 2010-07-27 || [[Image(ipp2_utest1_cell_fit_time_sub.metric.png, 400px)]] || [[Image(ipp2_utest1_row_fit_time_sub.metric.png, 400px)]] ||
-|| utest1a Configuration 2010-07-27 || [[Image(ipp2_utest1a_cell_fit_time_sub.metric.png, 400px)]] || [[Image(ipp2_utest1a_row_fit_time_sub.metric.png, 400px)]] ||
+= Cell Level =
+|| Configuration     || Date     || Cell linearity deviations                         || Corrected deviations ||
+|| linearity         ||2010-07-02|| [[Image(data_linearity.cell.small.png)]]          || [[Image(corrected_linearity.cell.small.png)]]          ||
+|| linearity2        ||2010-07-21|| [[Image(data_linearity2.cell.small.png)]]         || [[Image(corrected_linearity2.cell.small.png)]]         ||
+|| linearity_std     ||2010-07-28|| [[Image(data_linearity_std.cell.small.png)]]      || [[Image(corrected_linearity_std.cell.small.png)]]      ||
+|| linearity_utest1  ||2010-07-28|| [[Image(data_linearity_utest1.cell.small.png)]]   || [[Image(corrected_linearity_utest1.cell.small.png)]]   ||
+|| linearity_utest1a ||2010-07-28|| [[Image(data_linearity_utest1a.cell.small.png)]]  || [[Image(corrected_linearity_utest1a.cell.small.png)]]  ||
+|| linearity3_std    ||2010-08-02|| [[Image(data_linearity3_std.cell.small.png)]]     || [[Image(corrected_linearity3_std.cell.small.png)]]     ||
+|| linearity3_utest1 ||2010-08-02|| [[Image(data_linearity3_utest1.cell.small.png)]]  || [[Image(corrected_linearity3_utest1.cell.small.png)]]  ||
+|| linearity3_utest1a||2010-08-02|| [[Image(data_linearity3_utest1a.cell.small.png)]] || [[Image(corrected_linearity3_utest1a.cell.small.png)]] ||