Changes between Version 9 and Version 10 of Stack_Rejection_Discussion

Timestamp:

Aug 29, 2012, 5:00:22 PM (14 years ago)

Author:

watersc1

Comment:

--

Stack_Rejection_Discussion

@@ -31 +31 @@
 
 2. Improve stack pixel rejection.  The fact that the brightest portions of these trails are removed suggests that the current stack rejection is correctly identifying these outliers and rejecting them.  However, as the trails become faint (and therefore more consistent with the sky level), they are less likely to be removed from the pixel array.  The large variance values clearly let larger outliers remain that is desirable, but without further algorithm tests, it's unclear how to fix this.
+
+=== August 29, 2012: Example pixel ===
+
+Here is the input pixel data for the region marker in set #X above:
+
+||exp_name    || Input pixel|| Input Mask|| Input Variance || sqrt(V + (0.1 * D)^2) || sqrt(V + sKMM^2) || D - median(D) || D - KMMmean(D) || Z_KMM     || Z_sys || 
+||o5745g0469  ||  -23.9121  ||  128      || 100.885        || 10.3249               || 10.802           ||  -26.5705     || -25.0804       || -2.42912  ||  -2.45978 ||
+||o5746g0483  ||  -11.189   ||  8192     || 56.7516        || 7.61601               || 8.51761          ||  -13.8474     || -12.3573       || -1.62254  ||  -1.62574 ||
+||o5748g0414  ||  -5.42352  ||  0        || 70.1953        || 8.3958                || 9.27326          ||  -8.08191     ||  -6.59186      || -0.785138 ||  -0.871528 ||
+||o5746g0462  ||  -3.30118  ||  0        || 50.6332        || 7.12335               || 8.15054          ||  -5.95957     ||  -4.46952      || -0.627446 ||  -0.731187 ||
+||o5745g0471  ||  -1.07381  ||  0        || 60.485         || 7.77795               || 8.73402          ||  -3.7322      ||  -2.24215      || -0.28827  ||  -0.427318 ||
+||o5746g0474  ||  1.12729   ||  8192     || 73.2749        || 8.56082               || 9.43785          ||  -1.5311      ||  -0.04105      || -0.0047951||  -0.16223 ||
+||o5746g0472  ||  2.15857   ||  0        || 65.3082        || 8.08423               || 9.0059           ||  -0.49982     ||   0.99023      ||  0.122489 ||  -0.0554992 ||
+||o5745g0461  ||  2.65839   ||  0        || 66.9029        || 8.18374               || 9.09401          ||  0            ||   1.49005      ||  0.182074 ||  0 || 
+||o5745g0479  ||  3.1499    ||  128      || 136.597        || 11.6917               || 12.3448          ||  0.49151      ||   1.98156      ||  0.169484 ||  0.0398151 ||
+||o5745g0481  ||  5.66383   ||  0        || 66.293         || 8.16173               || 9.06041          ||  3.00544      ||   4.49549      ||  0.550801 ||  0.331711  ||
+||o5745g0449  ||  7.05781   ||  0        || 67.3096        || 8.23454               || 9.11634          ||  4.39942      ||   5.88947      ||  0.715215 ||  0.482586  ||
+||o5748g0394  ||  40.3914   ||  128      || 71.9988        || 9.39752               || 9.37             ||  37.733       ||  39.2231       ||  4.17377  ||  4.027     ||
+||o5748g0405  ||  56.0568   ||  128      || 110.147        || 11.8983               || 11.2225          ||  53.3984      ||  54.8885       ||  4.61314  ||  4.75816   ||
+
+The first column contains the input exposure name, followed by the image/mask/variance values for that pixel.  Next we have two calculations of the value of sigma for that input. The first adds a "systematic error" component equal to 0.1 * image value.  The second uses the KMM mixture model calculation to determine the scatter of the main component, and uses this as the systematic component.  The next two columns have the deviation from some "mean" values.  The first is the default method, which simply calculates the median value (2.65839) and subtracts this off the image data.  The second again uses the KMM calculation, and removes the mean value of the main component (1.16834).  Finally, I've made two versions of Z = (D - m)/s, using the systematic/median form and the KMM calculated forms.
+
+Based on the rejection threshold of 3.5 (from the config file), both of the burn inputs should have been rejected from the final stack.  I do not understand why this hasn't happened, and suggests that ppStack has some issue that is incorrectly doing the rejection.
+
+This example pixel also shows that excluding all pixels with an input value of 128 (SUSPECT) is not necessarily a bad thing.  Only one non-extreme input has this bit set.
 == July 31, 2012 ==