X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=core%2Fsrc%2Fcom%2Fgoogle%2Fzxing%2Fqrcode%2Fdetector%2FFinderPatternFinder.java;h=199b895a854257d4f2b941a5f470551c249c8353;hb=abe15d5bb8bd23019ca9c4ab48f9385c6a92bd0e;hp=9d3855809a04c1f2423bbc1346e3fea0c5861c29;hpb=88e5e1bed654d322da10c394d7f6ce6944528189;p=zxing.git

diff --git a/core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java b/core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java
index 9d385580..199b895a 100755
--- a/core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java
+++ b/core/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java
@@ -463,7 +463,7 @@ public class FinderPatternFinder {
     // OK, we have at least 3 confirmed centers, but, it's possible that one is a "false positive"
     // and that we need to keep looking. We detect this by asking if the estimated module sizes
     // vary too much. We arbitrarily say that when the total deviation from average exceeds
-    // 15% of the total module size estimates, it's too much.
+    // 5% of the total module size estimates, it's too much.
     float average = totalModuleSize / (float) max;
     float totalDeviation = 0.0f;
     for (int i = 0; i < max; i++) {
@@ -480,33 +480,34 @@ public class FinderPatternFinder {
    * @throws ReaderException if 3 such finder patterns do not exist
    */
   private FinderPattern[] selectBestPatterns() throws ReaderException {
-    Collections.insertionSort(possibleCenters, new CenterComparator());
-    int size = 0;
-    int max = possibleCenters.size();
-    while (size < max) {
-      if (((FinderPattern) possibleCenters.elementAt(size)).getCount() < CENTER_QUORUM) {
-        break;
-      }
-      size++;
-    }
 
-    if (size < 3) {
+    int startSize = possibleCenters.size();
+    if (startSize < 3) {
       // Couldn't find enough finder patterns
       throw ReaderException.getInstance();
     }
 
-    if (size > 3) {
-      // Throw away all but those first size candidate points we found.
-      possibleCenters.setSize(size);
-      //  We need to pick the best three. Find the most
-      // popular ones whose module size is nearest the average
-      float averageModuleSize = 0.0f;
-      for (int i = 0; i < size; i++) {
-        averageModuleSize += ((FinderPattern) possibleCenters.elementAt(i)).getEstimatedModuleSize();
+    // Filter outlier possibilities whose module size is too different
+    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;
+      for (int i = 0; i < startSize; i++) {
+        totalModuleSize += ((FinderPattern) possibleCenters.get(i)).getEstimatedModuleSize();
       }
-      averageModuleSize /= (float) size;
-      // We don't have java.util.Collections in J2ME
-      Collections.insertionSort(possibleCenters, new ClosestToAverageComparator(averageModuleSize));
+      float average = totalModuleSize / (float) startSize;
+      for (int i = 0; i < possibleCenters.size() && possibleCenters.size() > 3; i++) {
+        FinderPattern pattern = (FinderPattern) possibleCenters.get(i);
+        if (Math.abs(pattern.getEstimatedModuleSize() - average) > 0.2f * average) {
+          possibleCenters.remove(i);
+          i--;
+        }
+      }
+    }
+
+    if (possibleCenters.size() > 3) {
+      // Throw away all but those first size candidate points we found.
+      Collections.insertionSort(possibleCenters, new CenterComparator());      
+      possibleCenters.setSize(3);
     }
 
     return new FinderPattern[]{
@@ -525,22 +526,4 @@ public class FinderPatternFinder {
     }
   }
 
-  /**
-   * <p>Orders by variance from average module size, ascending.</p>
-   */
-  private static class ClosestToAverageComparator implements Comparator {
-    private final float averageModuleSize;
-
-    private ClosestToAverageComparator(float averageModuleSize) {
-      this.averageModuleSize = averageModuleSize;
-    }
-
-    public int compare(Object center1, Object center2) {
-      return Math.abs(((FinderPattern) center1).getEstimatedModuleSize() - averageModuleSize) <
-          Math.abs(((FinderPattern) center2).getEstimatedModuleSize() - averageModuleSize) ?
-          -1 :
-          1;
-    }
-  }
-
 }