Applied patch provided by Sergiy Korobov in Ticket #3 "Cannot detect QR code".

source/zxing/zxing/qrcode/detector/FinderPatternFinder.h

@@ -47,6 +47,7 @@ protected:
   bool hasSkipped_;
 
   Ref<ResultPointCallback> callback_;
+  mutable int crossCheckStateCount[5];
 
   /** stateCount must be int[5] */
   static float centerFromEnd(int* stateCount, int end);
@@ -65,6 +66,9 @@ protected:
   Ref<BitMatrix> getImage();
   std::vector<Ref<FinderPattern> >& getPossibleCenters();
 
+  bool crossCheckDiagonal(int startI, int centerJ, int maxCount, int originalStateCountTotal) const;
+  int *getCrossCheckStateCount() const;
+
 public:
   static float distance(Ref<ResultPoint> p1, Ref<ResultPoint> p2);
   FinderPatternFinder(Ref<BitMatrix> image, Ref<ResultPointCallback>const&);

source/zxing/zxing/qrcode/detector/QRFinderPatternFinder.cpp

@@ -23,6 +23,7 @@
 #include <zxing/qrcode/detector/FinderPatternFinder.h>
 #include <zxing/ReaderException.h>
 #include <zxing/DecodeHints.h>
+#include <cstring>
 
 using std::sort;
 using std::max;
@@ -106,9 +107,9 @@ bool FinderPatternFinder::foundPatternCross(int* stateCount) {
 float FinderPatternFinder::crossCheckVertical(size_t startI, size_t centerJ, int maxCount, int originalStateCountTotal) {
 
   int maxI = image_->getHeight();
-  int stateCount[5];
-  for (int i = 0; i < 5; i++)
-    stateCount[i] = 0;
+  int stateCount[5] = {0};
+//  for (int i = 0; i < 5; i++)
+//    stateCount[i] = 0;
 
 
   // Start counting up from center
@@ -174,9 +175,9 @@ float FinderPatternFinder::crossCheckHorizontal(size_t startJ, size_t centerI, i
     int originalStateCountTotal) {
 
   int maxJ = image_->getWidth();
-  int stateCount[5];
-  for (int i = 0; i < 5; i++)
-    stateCount[i] = 0;
+  int stateCount[5] = {0};
+//  for (int i = 0; i < 5; i++)
+//    stateCount[i] = 0;
 
   int j = startJ;
   while (j >= 0 && image_->get(j, centerI)) {
@@ -241,7 +242,7 @@ bool FinderPatternFinder::handlePossibleCenter(int* stateCount, size_t i, size_t
   if (!isnan_z(centerI)) {
     // Re-cross check
     centerJ = crossCheckHorizontal((size_t)centerJ, (size_t)centerI, stateCount[2], stateCountTotal);
-    if (!isnan_z(centerJ)) {
+    if (!isnan_z(centerJ) && crossCheckDiagonal((int)centerI, (int)centerJ, stateCount[2], stateCountTotal)) {
       float estimatedModuleSize = (float)stateCountTotal / 7.0f;
       bool found = false;
       size_t max = possibleCenters_.size();
@@ -459,11 +460,7 @@ Ref<FinderPatternInfo> FinderPatternFinder::find(DecodeHints const& hints) {
   for (size_t i = iSkip - 1; i < maxI && !done; i += iSkip) {
     // Get a row of black/white values
 
-    stateCount[0] = 0;
-    stateCount[1] = 0;
-    stateCount[2] = 0;
-    stateCount[3] = 0;
-    stateCount[4] = 0;
+    memset(stateCount, 0, sizeof(stateCount));
     int currentState = 0;
     for (size_t j = 0; j < maxJ; j++) {
       if (matrix.get(j, i)) {
@@ -510,11 +507,7 @@ Ref<FinderPatternInfo> FinderPatternFinder::find(DecodeHints const& hints) {
               }
               // Clear state to start looking again
               currentState = 0;
-              stateCount[0] = 0;
-              stateCount[1] = 0;
-              stateCount[2] = 0;
-              stateCount[3] = 0;
-              stateCount[4] = 0;
+              memset(stateCount, 0, sizeof(stateCount));
             } else { // No, shift counts back by two
               stateCount[0] = stateCount[2];
               stateCount[1] = stateCount[3];
@@ -555,5 +548,91 @@ Ref<BitMatrix> FinderPatternFinder::getImage() {
 }
 
 vector<Ref<FinderPattern> >& FinderPatternFinder::getPossibleCenters() {
-  return possibleCenters_;
+    return possibleCenters_;
+}
+
+bool FinderPatternFinder::crossCheckDiagonal(int startI, int centerJ, int maxCount, int originalStateCountTotal) const
+{
+  int *stateCount = getCrossCheckStateCount();
+
+  // Start counting up, left from center finding black center mass
+  int i = 0;
+  while (startI >= i && centerJ >= i && image_->get(centerJ - i, startI - i)) {
+    stateCount[2]++;
+    i++;
+  }
+
+  if (startI < i || centerJ < i) {
+    return false;
+  }
+
+  // Continue up, left finding white space
+  while (startI >= i && centerJ >= i && !image_->get(centerJ - i, startI - i) &&
+         stateCount[1] <= maxCount) {
+    stateCount[1]++;
+    i++;
+  }
+
+  // If already too many modules in this state or ran off the edge:
+  if (startI < i || centerJ < i || stateCount[1] > maxCount) {
+    return false;
+  }
+
+  // Continue up, left finding black border
+  while (startI >= i && centerJ >= i && image_->get(centerJ - i, startI - i) &&
+         stateCount[0] <= maxCount) {
+    stateCount[0]++;
+    i++;
+  }
+  if (stateCount[0] > maxCount) {
+     return false;
+  }
+
+  int maxI = image_->getHeight();
+  int maxJ = image_->getWidth();
+
+  // Now also count down, right from center
+  i = 1;
+  while (startI + i < maxI && centerJ + i < maxJ && image_->get(centerJ + i, startI + i)) {
+    stateCount[2]++;
+    i++;
+  }
+
+  // Ran off the edge?
+  if (startI + i >= maxI || centerJ + i >= maxJ) {
+     return false;
+  }
+
+  while (startI + i < maxI && centerJ + i < maxJ && !image_->get(centerJ + i, startI + i) &&
+         stateCount[3] < maxCount) {
+    stateCount[3]++;
+    i++;
+  }
+
+  if (startI + i >= maxI || centerJ + i >= maxJ || stateCount[3] >= maxCount) {
+    return false;
+  }
+
+  while (startI + i < maxI && centerJ + i < maxJ && image_->get(centerJ + i, startI + i) &&
+         stateCount[4] < maxCount) {
+    stateCount[4]++;
+    i++;
+  }
+
+  if (stateCount[4] >= maxCount) {
+    return false;
+ }
+
+  // If we found a finder-pattern-like section, but its size is more than 100% different than
+  // the original, assume it's a false positive
+  int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] + stateCount[4];
+  return
+      abs(stateCountTotal - originalStateCountTotal) < 2 * originalStateCountTotal &&
+          foundPatternCross(stateCount);
+}
+
+int *FinderPatternFinder::getCrossCheckStateCount() const
+{
+   memset(crossCheckStateCount, 0, sizeof(crossCheckStateCount));
+   return crossCheckStateCount;
 }