Index: trunk/ppImage/src/ppImageLoop.c
===================================================================
--- trunk/ppImage/src/ppImageLoop.c	(revision 5976)
+++ trunk/ppImage/src/ppImageLoop.c	(revision 6079)
@@ -1,3 +1,35 @@
 # include "ppImage.h"
+
+// Read the entire FPA
+void readFPA(ppFile *file,              // File to read
+             ppConfig *config           // Configuration, containing the DB handle
+    )
+{
+    if (file->fpa && file->fits) {
+        if (! pmFPARead(file->fpa, file->fits, file->phu, config->database)) {
+            psErrorStackPrint(stderr, "Unable to populate camera from input FITS file\n");
+            exit(EXIT_FAILURE);
+        }
+    }
+}
+
+// Read a specified chip only
+void readChip(ppFile *file,             // File to read
+              ppConfig *config,         // Configuration
+              int chipNum               // Chip number to read
+    )
+{
+    pmFPASelectChip(file->fpa, chipNum);
+    readFPA(file, config);
+}
+
+
+void readCell(ppFile *file, ppConfig *config, int chipNum, int cellNum)
+{
+    pmChip *chip = file->fpa->chips->data[chipNum];
+    pmChipSelectCell(chip, cellNum);
+    readFPA(file, config);
+}
+
 
 bool ppImageLoop(ppData *data, ppOptions *options, ppConfig *config)
@@ -5,33 +37,38 @@
     ppDetrend detrend;
 
-    if (options->imageLoadDepth == PP_LOAD_FPA) {
+    int processChip = psMetadataLookupS32(NULL, config->arguments, "-chip"); // Chip number to process or -1
+
+    // Load at FPA level if requested
+    if (processChip < 0 && options->imageLoadDepth == PP_LOAD_FPA) {
         psTrace(__func__, 1, "Loading pixels for FPA...\n");
-        ppImageLoadPixels(data->input, config->database, -1, -1);
-        ppImageLoadPixels(data->bias,  config->database, -1, -1);
-        ppImageLoadPixels(data->dark,  config->database, -1, -1);
-        ppImageLoadPixels(data->mask,  config->database, -1, -1);
-        ppImageLoadPixels(data->flat,  config->database, -1, -1);
+        readFPA(data->input, config);
+        readFPA(data->bias,  config);
+        readFPA(data->dark,  config);
+        readFPA(data->mask,  config);
+        readFPA(data->flat,  config);
     }
 
-    for (int i = 0; i < data->input->fpa->chips->n; i++) {
-        pmChip *inputChip = data->input->fpa->chips->data[i]; // Chip of interest in input image
-        pmChip *biasChip  = data->bias->fpa->chips->data[i];  // Chip of interest in bias image
-        pmChip *darkChip  = data->dark->fpa->chips->data[i];  // Chip of interest in dark image
-        pmChip *maskChip  = data->mask->fpa->chips->data[i];  // Chip of interest in mask image
-        pmChip *flatChip  = data->flat->fpa->chips->data[i];  // Chip of interest in flat image
-
-        printf("Chip %d: %x %x\n", i, inputChip->exists, inputChip->process);
-        if (! inputChip->process) { continue; }
-
+    psArray *chips = data->input->fpa->chips; // Component chips
+    for (int i = 0; i < chips->n; i++) {
+        if (processChip >= 0 && i != processChip) {
+            continue;
+        }
         if (options->imageLoadDepth == PP_LOAD_CHIP) {
             psTrace(__func__, 1, "Loading pixels for chip %d...\n", i);
-            ppImageLoadPixels(data->input, config->database, i, -1);
-            ppImageLoadPixels(data->bias,  config->database, i, -1);
-            ppImageLoadPixels(data->dark,  config->database, i, -1);
-            ppImageLoadPixels(data->mask,  config->database, i, -1);
-            ppImageLoadPixels(data->flat,  config->database, i, -1);
+            readChip(data->input, config, i);
+            readChip(data->bias,  config, i);
+            readChip(data->dark,  config, i);
+            readChip(data->mask,  config, i);
+            readChip(data->flat,  config, i);
         }
 
-        for (int j = 0; j < inputChip->cells->n; j++) {
+        pmChip *inputChip = chips->data[i];
+        pmChip *biasChip  = data->bias->fpa->chips->data[i];
+        pmChip *darkChip  = data->dark->fpa->chips->data[i];
+        pmChip *maskChip  = data->mask->fpa->chips->data[i];
+        pmChip *flatChip  = data->flat->fpa->chips->data[i];
+
+        psArray *cells = inputChip->cells;
+        for (int j = 0; j < cells->n; j++) {
             detrend.input = inputChip->cells->data[j]; // Cell of interest in input image
             detrend.bias  = biasChip->cells->data[j];  // Cell of interest in bias image
@@ -40,17 +77,16 @@
             detrend.flat  = flatChip->cells->data[j];  // Cell of interest in flat image
 
-            printf ("\tCell %d: %x %x\n", j, detrend.input->exists, detrend.input->process);
             if (! detrend.input->process) { continue; }
 
             if (options->imageLoadDepth == PP_LOAD_CELL) {
                 psTrace(__func__, 1, "Loading pixels for chip %d, cell %d...\n", i, j);
-                ppImageLoadPixels(data->input, config->database, i, j);
-                ppImageLoadPixels(data->bias,  config->database, i, j);
-                ppImageLoadPixels(data->dark,  config->database, i, j);
-                ppImageLoadPixels(data->mask,  config->database, i, j);
-                ppImageLoadPixels(data->flat,  config->database, i, j);
+                readCell(data->input, config, i, j);
+                readCell(data->bias,  config, i, j);
+                readCell(data->dark,  config, i, j);
+                readCell(data->mask,  config, i, j);
+                readCell(data->flat,  config, i, j);
             }
 
-            ppDetrendCell (&detrend, options, config);
+            ppDetrendCell(&detrend, options, config);
         }
     }