Index: trunk/psModules/src/detrend/Makefile.am
===================================================================
--- trunk/psModules/src/detrend/Makefile.am	(revision 24888)
+++ trunk/psModules/src/detrend/Makefile.am	(revision 24891)
@@ -16,5 +16,6 @@
 	pmShifts.c \
 	pmDark.c \
-	pmRemnance.c
+	pmRemnance.c \
+	pmPattern.c
 
 #	pmSkySubtract.c
@@ -33,5 +34,6 @@
 	pmShifts.h \
 	pmDark.h \
-	pmRemnance.h
+	pmRemnance.h \
+	pmPattern.h
 
 #	pmSkySubtract.h
Index: trunk/psModules/src/detrend/pmPattern.c
===================================================================
--- trunk/psModules/src/detrend/pmPattern.c	(revision 24891)
+++ trunk/psModules/src/detrend/pmPattern.c	(revision 24891)
@@ -0,0 +1,84 @@
+#include <stdio.h>
+#include <pslib.h>
+
+#include "pmFPA.h"
+
+#include "pmPattern.h"
+
+
+bool pmPatternRow(pmReadout *ro, int order, int iter, float rej,
+                  psStatsOptions clipMean, psStatsOptions clipStdev)
+{
+    PM_ASSERT_READOUT_NON_NULL(ro, false);
+    PM_ASSERT_READOUT_IMAGE(ro, false);
+    PS_ASSERT_INT_NONNEGATIVE(order, false);
+    PS_ASSERT_INT_NONNEGATIVE(iter, false);
+    PS_ASSERT_FLOAT_LARGER_THAN(rej, 0.0, false);
+
+    psImage *image = ro->image;         // Image to correct
+    int numCols = image->numCols, numRows = image->numRows; // Size of image
+
+    // Indices are distributed [-1:1)
+    psVector *indices = psVectorAlloc(numCols, PS_TYPE_F32); // Indices for fitting
+    float norm = 2.0 / (float)numCols;  // Normalisation for indices
+    for (int x = 0; x < numCols; x++) {
+        indices->data.F32[x] = x * norm - 1.0;
+    }
+
+    psStats *clip = psStatsAlloc(clipMean | clipStdev); // Clipping statistics
+    clip->clipIter = iter;
+    clip->clipSigma = rej;
+    psVector *mask = psVectorAlloc(numCols, PS_TYPE_VECTOR_MASK); // Mask for fitting
+    psPolynomial1D *poly = psPolynomial1DAlloc(PS_POLYNOMIAL_ORD, order); // Polynomial to fit
+    psVector *data = psVectorAlloc(numCols, PS_TYPE_F32); // Data to fit
+
+    for (int y = 0; y < numRows; y++) {
+        psVectorInit(mask, 0);
+        data = psImageRow(data, image, y);
+        int num = 0;                    // Number of good pixels
+        for (int x = 0; x < numCols; x++) {
+            if (ro->mask->data.PS_TYPE_IMAGE_MASK_DATA[y][x] > 0) {
+                mask->data.PS_TYPE_VECTOR_MASK_DATA[x] = 0xFF;
+            } else {
+                mask->data.PS_TYPE_VECTOR_MASK_DATA[x] = 0;
+                num++;
+            }
+        }
+        if (num < order + 1) {
+            // Not enough points to fit
+            continue;
+        }
+        if (!psVectorClipFitPolynomial1D(poly, clip, mask, 0xFF, data, NULL, indices)) {
+            psError(PS_ERR_UNKNOWN, false, "Unable to fit polynomial to row %d", y);
+            psFree(indices);
+            psFree(clip);
+            psFree(mask);
+            psFree(poly);
+            psFree(data);
+            return false;
+        }
+        psVector *solution = psPolynomial1DEvalVector(poly, indices); // Solution vector
+        if (!solution) {
+            psError(PS_ERR_UNKNOWN, false, "Unable to evaluate polynomial for row %d", y);
+            psFree(indices);
+            psFree(clip);
+            psFree(mask);
+            psFree(poly);
+            psFree(data);
+            return false;
+        }
+
+        for (int x = 0; x < numCols; x++) {
+            image->data.F32[y][x] -= solution->data.F32[x];
+        }
+        psFree(solution);
+    }
+
+    psFree(indices);
+    psFree(clip);
+    psFree(mask);
+    psFree(poly);
+    psFree(data);
+
+    return true;
+}
Index: trunk/psModules/src/detrend/pmPattern.h
===================================================================
--- trunk/psModules/src/detrend/pmPattern.h	(revision 24891)
+++ trunk/psModules/src/detrend/pmPattern.h	(revision 24891)
@@ -0,0 +1,34 @@
+/* @file pmPattern.h
+ * @brief Fit and remove pattern noise
+ *
+ * @author Paul Price, IfA
+ *
+ * @version $Revision: 1.16 $
+ * @date $Date: 2009-02-12 19:25:52 $
+ * Copyright 2004-2009 Institute for Astronomy, University of Hawaii
+ */
+
+#ifndef PM_PATTERN_H
+#define PM_PATTERN_H
+
+#include <pslib.h>
+#include <pmFPA.h>
+
+/// @addtogroup detrend Detrend Creation and Application
+/// @{
+
+/// Fit and remove pattern noise over rows
+bool pmPatternRow(
+    pmReadout *ro,                      ///< Readout to correct
+    int order,                          ///< Polynomial order
+    int iter,                           ///< Number of clipping iterations
+    float rej,                          ///< Rejection threshold for clipping
+    psStatsOptions clipMean,             ///< Statistic to use for mean
+    psStatsOptions clipStdev             ///< Statistic to use for standard deviation
+    );
+
+/// @}
+#endif
+
+
+
Index: trunk/psModules/src/psmodules.h
===================================================================
--- trunk/psModules/src/psmodules.h	(revision 24888)
+++ trunk/psModules/src/psmodules.h	(revision 24891)
@@ -77,4 +77,5 @@
 #include <pmDark.h>
 #include <pmRemnance.h>
+#include <pmPattern.h>
 
 // the following headers are from psModule:astrom