Index: /trunk/psModules/src/extras/pmCensor.c
===================================================================
--- /trunk/psModules/src/extras/pmCensor.c	(revision 29389)
+++ /trunk/psModules/src/extras/pmCensor.c	(revision 29389)
@@ -0,0 +1,109 @@
+#include <pslib.h>
+#include <pmCensor.h>
+
+bool
+pmCensorGetMask(pmConfig *config, psU32 *pMaskMask)
+{
+    bool status;
+    psMetadata *masks = psMetadataLookupMetadata(&status, config->recipes, "MASKS");
+    if (!status) {
+        psError(PS_ERR_UNKNOWN, false, "failed to lookup MASKS in recipes.\n");
+        return false;
+    }
+
+    // first look for the value in the recipes
+    psU32 maskMask = psMetadataLookupU32(&status, config->camera, "MASK.NO.CENSOR");
+    if (status) {
+        // All done
+        *pMaskMask = ~maskMask;
+        return true;
+    }
+    // Not defined. Now we must compute it.
+
+    // Older sets of mask values had SPIKE and STARCORE with the same value as STREAK
+    // handle this case by making sure the streak bit is set
+    psU32 streak = psMetadataLookupU32(&status, masks, "STREAK");
+    if (!status) {
+        psError(PS_ERR_UNKNOWN, false, "failed to lookup mask value for STREAK in recipes.\n");
+        return false;
+    }
+
+    // preserve pixels that are only CONV.POOR
+    // check old name first
+    psU32 convPoor = psMetadataLookupU32(&status, masks, "POOR.WARP");
+    if (!status) {
+        convPoor = psMetadataLookupU32(&status, masks, "CONV.POOR");
+        if (!status) {
+            psError(PS_ERR_UNKNOWN, false, "failed to lookup either CONV.POOR and POOR.WARP in mask recipe.\n");
+            return false;
+        }
+    }
+    // preserve pixels that are only suspect
+    psU32 suspect = psMetadataLookupU32(&status, masks, "SUSPECT");
+    if (!status) {
+        psWarning("failed to lookup SUSPECT in mask recipe.\n");
+        suspect = 0;
+    }
+    // preserve pixels that are in a diffraction spike
+    psU32 spike = psMetadataLookupU32(&status, masks, "SPIKE");
+    if (!status) {
+        psWarning("failed to lookup SPIKE in mask recipe.\n");
+        spike = 0;
+    }
+    // preserve pixels that are in core of a bright star
+    psU32 starcore = psMetadataLookupU32(&status, masks, "STARCORE");
+    if (!status) {
+        psWarning("failed to lookup STARCORE in mask recipe.\n");
+        starcore = 0;
+    }
+
+    // The value we return is the set of bits to censor. 
+    // Including STREAK handles the case where any of these other bits have the same value as STREAK.
+    // That was true in older 8 bit mask configurations.
+
+    *pMaskMask = ~(convPoor | suspect | starcore | spike) | streak;
+
+    return true;
+}
+
+bool pmCensorMasked(pmConfig *config, psImage *image, psImage *mask, psImage *variance, long *pNumCensored)
+{
+    *pNumCensored = 0;
+
+    psU32 maskMask;
+    if (!pmCensorGetMask(config, &maskMask)) {
+        psError(PS_ERR_UNKNOWN, false, "failed to lookup set of mask bits to censor.\n");
+        return false;
+    }
+
+    if (~maskMask == 0) {
+        // censoring masked pixels is not required
+        return true;
+    }
+
+    double exciseValue;
+    if (image->type.type == PS_TYPE_U16) {
+        exciseValue = 0xffff;
+    } else if (image->type.type == PS_TYPE_F32) {
+        exciseValue = NAN;
+    } else {
+        // XXX: sooner or later we'll get passed another image type
+        psError(PS_ERR_PROGRAMMING, true, "unexpected image type: %d\n", image->type.type);
+        return false;
+    }
+
+    for (int y=0; y<image->numRows; y++) {
+        for (int x=0; x<image->numCols; x++) {
+            psU16 maskVal = psImageGet(mask, x, y);
+            if (maskVal & maskMask) {
+                (*pNumCensored)++;
+                psImageSet(image, x, y, exciseValue);
+                if (variance) {
+                    psImageSet(variance, x, y, exciseValue);
+                }
+            }
+        }
+    }
+
+    return true;
+}
Index: /trunk/psModules/src/extras/pmCensor.h
===================================================================
--- /trunk/psModules/src/extras/pmCensor.h	(revision 29389)
+++ /trunk/psModules/src/extras/pmCensor.h	(revision 29389)
@@ -0,0 +1,9 @@
+#ifndef _PM_CENSOR_H
+#define _PM_CENSOR_H
+
+#include <pmConfig.h>
+
+bool pmCensorGetMask(pmConfig *config, psU32 *pMaskMask);
+bool pmCensorMasked(pmConfig *config, psImage *image, psImage *mask, psImage *variance, long *pNumCensored);
+
+#endif // _PM_CENSOR_H