Issue 520

git-svn-id: https://zxing.googlecode.com/svn/trunk@1540 59b500cc-1b3d-0410-9834-0bbf25fbcc57

core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java

@@ -132,11 +132,13 @@ public class FinderPatternFinder {
                     }
                   }
                 } else {
-                  // Advance to next black pixel
+                  stateCount[0] = stateCount[2];
-                  do {
+                  stateCount[1] = stateCount[3];
-                    j++;
+                  stateCount[2] = stateCount[4];
-                  } while (j < maxJ && !image.get(j, i));
+                  stateCount[3] = 1;
-                  j--; // back up to that last white pixel
+                  stateCount[4] = 0;
+                  currentState = 3;
+                  continue;
                 }
                 // Clear state to start looking again
                 currentState = 0;
@@ -502,13 +504,22 @@ public class FinderPatternFinder {
     if (startSize > 3) {
       // But we can only afford to do so if we have at least 4 possibilities to choose from
       float totalModuleSize = 0.0f;
+      float square = 0.0f;
       for (int i = 0; i < startSize; i++) {
-        totalModuleSize += ((FinderPattern) possibleCenters.elementAt(i)).getEstimatedModuleSize();
+        float size = ((FinderPattern) possibleCenters.elementAt(i)).getEstimatedModuleSize();
+        totalModuleSize += size;
+        square += size * size;
       }
       float average = totalModuleSize / (float) startSize;
+      float stdDev = (float) Math.sqrt(square / startSize - average * average);
+
+      Collections.insertionSort(possibleCenters, new FurthestFromAverageComparator(average));
+
+      float limit = Math.max(0.2f * average, stdDev);
+
       for (int i = 0; i < possibleCenters.size() && possibleCenters.size() > 3; i++) {
         FinderPattern pattern = (FinderPattern) possibleCenters.elementAt(i);
-        if (Math.abs(pattern.getEstimatedModuleSize() - average) > 0.2f * average) {
+        if (Math.abs(pattern.getEstimatedModuleSize() - average) > limit) {
           possibleCenters.removeElementAt(i);
           i--;
         }
@@ -517,7 +528,16 @@ public class FinderPatternFinder {
 
     if (possibleCenters.size() > 3) {
       // Throw away all but those first size candidate points we found.
-      Collections.insertionSort(possibleCenters, new CenterComparator());      
+
+      float totalModuleSize = 0.0f;
+      for (int i = 0; i < possibleCenters.size(); i++) {
+        totalModuleSize += ((FinderPattern) possibleCenters.elementAt(i)).getEstimatedModuleSize();
+      }
+
+      float average = totalModuleSize / (float) possibleCenters.size();
+
+      Collections.insertionSort(possibleCenters, new CenterComparator(average));
+
       possibleCenters.setSize(3);
     }
 
@@ -528,12 +548,37 @@ public class FinderPatternFinder {
     };
   }
 
+  /**
+   * <p>Orders by furthest from average</p>
+   */
+  private static class FurthestFromAverageComparator implements Comparator {
+    private final float average;
+    public FurthestFromAverageComparator(float f) {
+      average = f;
+    }
+    public int compare(Object center1, Object center2) {
+      float dA = Math.abs(((FinderPattern) center2).getEstimatedModuleSize() - average);
+      float dB = Math.abs(((FinderPattern) center1).getEstimatedModuleSize() - average);
+      return dA < dB ? -1 : (dA == dB ? 0 : 1);
+    }
+  }
+
   /**
    * <p>Orders by {@link FinderPattern#getCount()}, descending.</p>
    */
   private static class CenterComparator implements Comparator {
+    private final float average;
+    public CenterComparator(float f) {
+      average = f;
+    }
     public int compare(Object center1, Object center2) {
+      if (((FinderPattern) center2).getCount() != ((FinderPattern) center1).getCount()) {
         return ((FinderPattern) center2).getCount() - ((FinderPattern) center1).getCount();
+      } else {
+        float dA = Math.abs(((FinderPattern) center2).getEstimatedModuleSize() - average);
+        float dB = Math.abs(((FinderPattern) center1).getEstimatedModuleSize() - average);
+        return dA < dB ? 1 : (dA == dB ? 0 : -1);
+      }
     }
   }
 

core/test/src/com/google/zxing/qrcode/QRCodeBlackBox2TestCase.java

@@ -28,8 +28,8 @@ public final class QRCodeBlackBox2TestCase extends AbstractBlackBoxTestCase {
   public QRCodeBlackBox2TestCase() {
     super("test/data/blackbox/qrcode-2", new MultiFormatReader(), BarcodeFormat.QR_CODE);
     addTest(26, 26, 0.0f);
-    addTest(25, 25, 90.0f);
+    addTest(26, 26, 90.0f);
-    addTest(24, 24, 180.0f);
+    addTest(26, 26, 180.0f);
     addTest(25, 25, 270.0f);
   }
 

core/test/src/com/google/zxing/qrcode/QRCodeBlackBox3TestCase.java

@@ -27,10 +27,10 @@ public final class QRCodeBlackBox3TestCase extends AbstractBlackBoxTestCase {
 
   public QRCodeBlackBox3TestCase() {
     super("test/data/blackbox/qrcode-3", new MultiFormatReader(), BarcodeFormat.QR_CODE);
-    addTest(36, 36, 0.0f);
+    addTest(38, 38, 0.0f);
     addTest(38, 38, 90.0f);
     addTest(36, 36, 180.0f);
-    addTest(37, 37, 270.0f);
+    addTest(38, 38, 270.0f);
   }
 
 }

core/test/src/com/google/zxing/qrcode/QRCodeBlackBox5TestCase.java

@@ -31,10 +31,10 @@ public final class QRCodeBlackBox5TestCase extends AbstractBlackBoxTestCase {
 
   public QRCodeBlackBox5TestCase() {
     super("test/data/blackbox/qrcode-5", new MultiFormatReader(), BarcodeFormat.QR_CODE);
-    addTest(19, 19, 0.0f);
+    addTest(18, 18, 0.0f);
     addTest(19, 19, 90.0f);
-    addTest(18, 18, 180.0f);
+    addTest(19, 19, 180.0f);
-    addTest(18, 18, 270.0f);
+    addTest(19, 19, 270.0f);
   }
 
 }