Index: trunk/psModules/src/imcombine/pmStackReject.c
===================================================================
--- trunk/psModules/src/imcombine/pmStackReject.c	(revision 25468)
+++ trunk/psModules/src/imcombine/pmStackReject.c	(revision 26893)
@@ -35,6 +35,8 @@
 {
     int size = kernels->size;           // Half-size of convolution kernel
-    psImage *polyValues = p_pmSubtractionPolynomialFromCoords(NULL, kernels, numCols, numRows,
-                                                              xMin + size + 1, yMin + size + 1); // Polynomial
+    int x = PS_MIN(xMin + size + 1, kernels->xMax); // x coordinate of interest
+    int y = PS_MIN(yMin + size + 1, kernels->yMax); // y coordinate of interest
+
+    psImage *polyValues = p_pmSubtractionPolynomialFromCoords(NULL, kernels, x, y); // Polynomial
     int box = p_pmSubtractionBadRadius(NULL, kernels, polyValues, false, poorFrac); // Radius of bad box
     psTrace("psModules.imcombine", 10, "Growing by %d", box);
@@ -150,8 +152,9 @@
     pmReadout *inRO = pmReadoutAlloc(NULL); // Readout with input image
     inRO->image = image;
+    convRO->image = psImageAlloc(image->numCols, image->numRows, PS_TYPE_F32);
     for (int i = 0; i < numRegions; i++) {
         psRegion *region = subRegions->data[i]; // Region of interest
         pmSubtractionKernels *kernels = subKernels->data[i]; // Kernel of interest
-        if (!pmSubtractionConvolve(NULL, convRO, NULL, inRO, NULL, stride, 0, 0, 1.0, 0.0,
+        if (!pmSubtractionConvolve(NULL, convRO, NULL, inRO, NULL, stride, 0, 0, 1.0, 0.0, 0.0,
                                    region, kernels, false, true)) {
             psError(PS_ERR_UNKNOWN, false, "Unable to convolve mask image in region %d.", i);
@@ -165,9 +168,5 @@
 
         // Image of the kernel at the centre of the region
-        float xNorm = (region->x0 + 0.5 * (region->x1 - region->x0) - kernels->numCols/2.0) /
-            (float)kernels->numCols;
-        float yNorm = (region->y0 + 0.5 * (region->y1 - region->y0) - kernels->numRows/2.0) /
-            (float)kernels->numRows;
-        psImage *kernel = pmSubtractionKernelImage(kernels, xNorm, yNorm, false);
+        psImage *kernel = pmSubtractionKernelImage(kernels, 0.5, 0.5, false);
         if (!kernel) {
             psError(PS_ERR_UNKNOWN, false, "Unable to generate kernel image.");