Changeset 43068 for branches/eam_branches/ipp-pstamp-20260421/ppSim/src/ppSimMakeBias.c

Timestamp:

Jul 3, 2026, 3:08:04 PM (4 weeks ago)

Author:

eugene

Message:

add -mjd-obs; add chip & cell names to output test file; more trace verbosity; fix chebyshev scales for bias variations

File:

• branches/eam_branches/ipp-pstamp-20260421/ppSim/src/ppSimMakeBias.c (modified) (3 diffs)

branches/eam_branches/ipp-pstamp-20260421/ppSim/src/ppSimMakeBias.c

@@ -16 +16 @@
     float biasLevel = psMetadataLookupF32(NULL, recipe, "BIAS.LEVEL"); // Bias level
     float biasRange = psMetadataLookupF32(NULL, recipe, "BIAS.RANGE"); // Bias range
-    int biasOrder   = psMetadataLookupS32(NULL, recipe, "BIAS.ORDER"); // Bias order
+    int   biasOrder = psMetadataLookupS32(NULL, recipe, "BIAS.ORDER"); // Bias order
 
     float readnoise = psMetadataLookupF32(NULL, cell->concepts, "CELL.READNOISE");// CCD read noise, e
@@ -40 +40 @@
         biasPoly->coeff[j] = biasRange * psRandomGaussian(rng);
     }
+    // polynomial is evaluated for the range 0 - numRows
+    biasPoly->scale[0] = +2.0 / numRows;
+    biasPoly->zero[0]  = -1.0;
+    // 0 -> -1, numRows -> 1.0
 
     psVector *biasRows = psVectorAlloc(numRows, PS_TYPE_F32); // Bias value, per row
-    int biasOffset = 0.5 * numRows * psRandomUniform(rng); // Offset to prevent common pattern
+
+    // ??? int biasOffset = 0.5 * numRows * psRandomUniform(rng); // Offset to prevent common pattern
 
     for (int y = 0; y < numRows; y++) {
         // Adjust bias level for this row
-        biasRows->data.F32[y] = psPolynomial1DEval(biasPoly, (float)(y + biasOffset) /
-                                                  (float)numRows - 0.5) + biasLevel;
+        biasRows->data.F32[y] = psPolynomial1DEval(biasPoly, y) + biasLevel;
+
+        // old version:
+        // biasRows->data.F32[y] = psPolynomial1DEval(biasPoly, (float)(y + biasOffset) / (float)numRows - 0.5) + biasLevel;
 
         for (int x = 0; x < numCols; x++) {
@@ -62 +69 @@
 }
 
+/* This function introduces a polynomial variation in the bias signal as 
+   a function of the row number.  
+
+   BIAS.LEVEL : pedestal value for the bias
+   BIAS.RANGE : max amplitude of the bias variation
+   BIAS.ORDER : order of the Chebyshev polynomial in the y-dir
+
+*/
+