Index: /trunk/psastro/src/Makefile.am
===================================================================
--- /trunk/psastro/src/Makefile.am	(revision 16078)
+++ /trunk/psastro/src/Makefile.am	(revision 16079)
@@ -52,4 +52,7 @@
 	psastroChipAstrom.c         \
 	psastroOneChip.c	    \
+	psastroOneChipGrid.c	    \
+	psastroOneChipFit.c	    \
+	psastroRemoveClumps.c	    \
 	psastroUtils.c	       	    \
 	psastroTestFuncs.c          \
@@ -57,4 +60,5 @@
 	psastroRefstarSubset.c      \
 	psastroFixChips.c           \
+	psastroFixChipsTest.c       \
 	psastroUseModel.c           \
 	psastroMosaicAstrom.c       \
Index: /trunk/psastro/src/psastro.h
===================================================================
--- /trunk/psastro/src/psastro.h	(revision 16078)
+++ /trunk/psastro/src/psastro.h	(revision 16079)
@@ -41,7 +41,10 @@
 bool              psastroChipAstrom (pmConfig *config);
 bool              psastroOneChip (pmFPA *fpa, pmChip *chip, psArray *refset, psArray *rawset, psMetadata *recipe, psMetadata *updates);
+bool              psastroOneChipGrid (pmFPA *fpa, pmChip *chip, psArray *refset, psArray *rawset, psMetadata *recipe, psMetadata *updates);
+bool              psastroOneChipFit (pmFPA *fpa, pmChip *chip, psArray *refset, psArray *rawset, psMetadata *recipe, psMetadata *updates);
 bool              psastroChooseRefstars (pmConfig *config, psArray *refs);
 bool              psastroRefstarSubset (pmReadout *readout);
 pmLumFunc        *psastroLuminosityFunction (psArray *stars);
+psArray          *psastroRemoveClumps (psArray *input, int scale);
 
 // utility functions:
@@ -81,5 +84,8 @@
 
 bool              psastroFixChips (pmConfig *config, psMetadata *recipe);
+bool              psastroFixChipsTest (pmConfig *config, psMetadata *recipe);
 bool              psastroUseModel (pmConfig *config, psMetadata *recipe);
+bool              psastroDumpCorners (char *filename, pmFPA *fpa);
+
 
 psArray          *psastroReadGetstarCatalog (psFits *fits);
Index: /trunk/psastro/src/psastroRemoveClumps.c
===================================================================
--- /trunk/psastro/src/psastroRemoveClumps.c	(revision 16079)
+++ /trunk/psastro/src/psastroRemoveClumps.c	(revision 16079)
@@ -0,0 +1,95 @@
+# include "psastroInternal.h"
+
+// look for and exclude objects in clumps in the input list
+psArray *psastroRemoveClumps (psArray *input, int scale) {
+
+    // determine data range
+    pmAstromObj *obj = input->data[0];
+    float Xmin = obj->FP->x;
+    float Xmax = obj->FP->x;
+    float Ymin = obj->FP->y;
+    float Ymax = obj->FP->y;
+    for (int i = 0; i < input->n; i++) {
+	obj = (pmAstromObj *)input->data[i];
+	if (!isfinite(obj->FP->x)) continue;
+	if (!isfinite(obj->FP->y)) continue;
+	Xmin = PS_MIN (Xmin, obj->FP->x);
+	Xmax = PS_MAX (Xmax, obj->FP->x);
+	Ymin = PS_MIN (Ymin, obj->FP->y);
+	Ymax = PS_MAX (Ymax, obj->FP->y);
+    }
+
+    int nX = (Xmax - Xmin) / scale + 10;
+    int nY = (Ymax - Ymin) / scale + 10;
+    psImage *count = psImageAlloc (nX, nY, PS_TYPE_U32);
+
+    // accumulate 2D histogram in image
+    for (int i = 0; i < input->n; i++) {
+	obj = (pmAstromObj *)input->data[i];
+	if (!isfinite(obj->FP->x)) continue;
+	if (!isfinite(obj->FP->y)) continue;
+	int Xi = PS_MIN (PS_MAX((obj->FP->x - Xmin) / scale + 5, 0), count->numCols);
+	int Yi = PS_MIN (PS_MAX((obj->FP->y - Ymin) / scale + 5, 0), count->numRows);
+	count->data.U32[Yi][Xi] ++;
+    }
+
+    // determine image statistics
+    psStats *stats = psStatsAlloc (PS_STAT_MAX | PS_STAT_MAX | PS_STAT_SAMPLE_MEDIAN | PS_STAT_SAMPLE_STDEV);
+    if (!psImageStats(stats, count, NULL, 0)) {
+	psError(PS_ERR_UNKNOWN, false, "Unable to get image statistics.\n");
+	psFree(stats);
+	psFree(count);
+	return NULL;
+    }
+
+    if (stats->max < 1) {
+	psError(PS_ERR_UNKNOWN, false, "no valid sources in image\n");
+	psFree(stats);
+	psFree(count);
+	return NULL;
+    }
+
+    // XXX make this a user option
+    float limit = 5.0*stats->sampleStdev;
+
+    // find and exclude objects in bad pixels
+    psArray *output = psArrayAllocEmpty (input->n);
+    for (int i = 0; i < input->n; i++) {
+	obj = (pmAstromObj *)input->data[i];
+	if (!isfinite(obj->FP->x)) continue;
+	if (!isfinite(obj->FP->y)) continue;
+	int Xi = PS_MIN (PS_MAX((obj->FP->x - Xmin) / scale + 5, 0), count->numCols);
+	int Yi = PS_MIN (PS_MAX((obj->FP->y - Ymin) / scale + 5, 0), count->numRows);
+	if (count->data.U32[Yi][Xi] > limit) continue;
+	psArrayAdd (output, 16, obj);
+    }
+
+    psFree(stats);
+    psFree(count);
+    return output;
+}
+
+# if (0)
+// make a list of the outlier pixels
+psArray *badpix = psArrayAllocEmpty (16);
+for (int iy = 0; iy < count->numRows; iy++) {
+    for (int ix = 0; ix < count->numCols; ix++) {
+	if (count->data.U32[iy][ix] > limit) {
+	    psPlane *pixel = psPlaneAlloc();
+	    pixel->x = ix;
+	    pixel->y = iy;
+	    psArrayAdd (badpix, 16, pixel);
+	    psFree (pixel);
+	}
+    }
+}
+
+if (badpix->n == 0) {
+    psArray *output = psMemIncrRefCounter (input);
+    psFree (stats);
+    psFree (count);
+    psFree (badpix);
+    return output;
+}
+# endif
+