Index: branches/eam_branches/ipp-dev-20210817/psModules/src/detrend/pmPattern.c
===================================================================
--- branches/eam_branches/ipp-dev-20210817/psModules/src/detrend/pmPattern.c	(revision 41857)
+++ branches/eam_branches/ipp-dev-20210817/psModules/src/detrend/pmPattern.c	(revision 41859)
@@ -642,4 +642,6 @@
 	    for (int j = 0; j < NPIX; j++) {
 		int pix = sample  * NPIX + j; // real pixel elements in x-dir
+		psAssert (pix >= 0, "invalid pix value");
+		psAssert (pix < numCols, "invalid pix value");
 		if ((mask && mask->data.PS_TYPE_IMAGE_MASK_DATA[y][pix] & maskVal)) continue;
 		if (data->data.F32[pix] < lower || data->data.F32[pix] > upper) continue;
@@ -665,4 +667,8 @@
 
 	    int midPt = 0.5 * seq;
+	    if (seq % 2 == 1) { psAssert (midPt >= 0, "invalid midPt"); }
+	    if (seq % 2 == 0) { psAssert (midPt >= 1, "invalid midPt"); }
+	    psAssert (midPt < NPIX, "invalid midPt");
+
 	    float medValue = (seq % 2) ? sampleArray[midPt] : 0.5*(sampleArray[midPt] + sampleArray[midPt-1]);
 	    yFit->data.F32[sample] = medValue;