Changeset 4115 for trunk/psphot/src/image_stats.c

Timestamp:

Jun 4, 2005, 5:22:13 PM (21 years ago)

Author:

eugene

Message:

running sources in brightness order, using a mask

File:

• trunk/psphot/src/image_stats.c (modified) (1 diff)

trunk/psphot/src/image_stats.c

@@ -13 +13 @@
     // pass on the stats
     { 
-        bool   status    = false;
+        bool     status  = false;
+        int      Npixels = image->numRows*image->numCols;
+        int      Nsubset = PS_MIN (Npixels, psMetadataLookupF32 (&status, config, "NSUBSET"));
+        psVector *subset = psVectorAlloc (Nsubset, PS_TYPE_F32);
         psRandom *rnd    = psRandomAlloc (PS_RANDOM_TAUS, 0);
-        int    Nsubset   = psMetadataLookupF32 (&status, config, "NSUBSET");
-        double fSubset   = (double) Nsubset / (image->numRows*image->numCols);
-        psVector *subset = psVectorAlloc (Nsubset, PS_TYPE_F32);
 
-        subset->n = 0;
-        for (int i = 0; i < image->numRows; i++) {
-            for (int j = 0; j < image->numCols; j++) {
-                double frnd = psRandomUniform (rnd);
-                if ((fSubset < 1.0) && (fSubset < frnd)) continue;
-                subset->data.F32[subset->n] = image->data.F32[j][i];
-                subset->n ++;
-                if (subset->n == Nsubset) goto got_subset;
-            }
+        // choose Nsubset points between 0 and Nx*Ny, convert to coords
+        Npixels = image->numRows*image->numCols;
+        for (int i = 0; i < Nsubset; i++) {
+          double frnd = psRandomUniform (rnd);
+          int pixel = Npixels * frnd;
+          int ix = pixel / image->numCols;
+          int iy = pixel % image->numCols;
+          subset->data.F32[i] = image->data.F32[iy][ix];
         }
 
-    got_subset:
         // this should use ROBUST not SAMPLE median
         // robust median is broken in pslib (0.5)