import com.google.zxing.DecodeHintType;\r
import com.google.zxing.MonochromeBitmapSource;\r
import com.google.zxing.ReaderException;\r
-import com.google.zxing.ResultPoint;\r
import com.google.zxing.common.BitArray;\r
import com.google.zxing.common.Collections;\r
import com.google.zxing.common.Comparator;\r
+import com.google.zxing.common.GenericResultPoint;\r
\r
import java.util.Hashtable;\r
import java.util.Vector;\r
*\r
* <p>This class is not thread-safe and should not be reused.</p>\r
*\r
- * @author srowen@google.com (Sean Owen)\r
+ * @author Sean Owen\r
*/\r
final class FinderPatternFinder {\r
\r
private final MonochromeBitmapSource image;\r
private final Vector possibleCenters;\r
private boolean hasSkipped;\r
+ private final int[] crossCheckStateCount;\r
\r
/**\r
* <p>Creates a finder that will search the image for three finder patterns.</p>\r
FinderPatternFinder(MonochromeBitmapSource image) {\r
this.image = image;\r
this.possibleCenters = new Vector();\r
+ this.crossCheckStateCount = new int[5];\r
}\r
\r
FinderPatternInfo find(Hashtable hints) throws ReaderException {\r
\r
boolean done = false;\r
int[] stateCount = new int[5];\r
+ BitArray blackRow = new BitArray(maxJ);\r
for (int i = iSkip - 1; i < maxI && !done; i += iSkip) {\r
// Get a row of black/white values\r
- BitArray blackRow = image.getBlackRow(i, null, 0, maxJ);\r
+ blackRow = image.getBlackRow(i, blackRow, 0, maxJ);\r
stateCount[0] = 0;\r
stateCount[1] = 0;\r
stateCount[2] = 0;\r
if (foundPatternCross(stateCount)) { // Yes\r
boolean confirmed = handlePossibleCenter(stateCount, i, j);\r
if (confirmed) {\r
- iSkip = 1; // Go back to examining each line\r
+ // Start examining every other line. Checking each line turned out to be too\r
+ // expensive and didn't improve performance.\r
+ iSkip = 2;\r
if (hasSkipped) {\r
done = haveMulitplyConfirmedCenters();\r
} else {\r
}\r
\r
FinderPattern[] patternInfo = selectBestPatterns();\r
- patternInfo = orderBestPatterns(patternInfo);\r
+ GenericResultPoint.orderBestPatterns(patternInfo);\r
\r
return new FinderPatternInfo(patternInfo);\r
}\r
Math.abs(moduleSize - (stateCount[4] << INTEGER_MATH_SHIFT)) < maxVariance;\r
}\r
\r
+ private int[] getCrossCheckStateCount() {\r
+ crossCheckStateCount[0] = 0;\r
+ crossCheckStateCount[1] = 0;\r
+ crossCheckStateCount[2] = 0;\r
+ crossCheckStateCount[3] = 0;\r
+ crossCheckStateCount[4] = 0;\r
+ return crossCheckStateCount;\r
+ }\r
+\r
/**\r
* <p>After a horizontal scan finds a potential finder pattern, this method\r
* "cross-checks" by scanning down vertically through the center of the possible\r
MonochromeBitmapSource image = this.image;\r
\r
int maxI = image.getHeight();\r
- int[] stateCount = new int[5];\r
+ int[] stateCount = getCrossCheckStateCount();\r
\r
// Start counting up from center\r
int i = startI;\r
MonochromeBitmapSource image = this.image;\r
\r
int maxJ = image.getWidth();\r
- int[] stateCount = new int[5];\r
+ int[] stateCount = getCrossCheckStateCount();\r
\r
int j = startJ;\r
while (j >= 0 && image.isBlack(j, centerI)) {\r
// How far down can we skip before resuming looking for the next\r
// pattern? In the worst case, only the difference between the\r
// difference in the x / y coordinates of the two centers.\r
- // This is the case where you find top left first. Draw it out.\r
+ // This is the case where you find top left last.\r
hasSkipped = true;\r
- return (int) Math.abs(Math.abs(firstConfirmedCenter.getX() - center.getX()) -\r
- Math.abs(firstConfirmedCenter.getY() - center.getY()));\r
+ return (int) (Math.abs(firstConfirmedCenter.getX() - center.getX()) -\r
+ Math.abs(firstConfirmedCenter.getY() - center.getY())) / 2;\r
}\r
}\r
}\r
FinderPattern pattern = (FinderPattern) possibleCenters.elementAt(i);\r
totalDeviation += Math.abs(pattern.getEstimatedModuleSize() - average);\r
}\r
- return totalDeviation <= 0.15f * totalModuleSize;\r
+ return totalDeviation <= 0.05f * totalModuleSize;\r
}\r
\r
/**\r
\r
if (size < 3) {\r
// Couldn't find enough finder patterns\r
- throw new ReaderException("Could not find three finder patterns");\r
- }\r
-\r
- if (size == 3) {\r
- // Found just enough -- hope these are good!\r
- return new FinderPattern[]{\r
- (FinderPattern) possibleCenters.elementAt(0),\r
- (FinderPattern) possibleCenters.elementAt(1),\r
- (FinderPattern) possibleCenters.elementAt(2)\r
- };\r
+ throw ReaderException.getInstance();\r
}\r
\r
- possibleCenters.setSize(size);\r
-\r
- // Hmm, multiple found. We need to pick the best three. Find the most\r
- // popular ones whose module size is nearest the average\r
-\r
- float averageModuleSize = 0.0f;\r
- for (int i = 0; i < size; i++) {\r
- averageModuleSize += ((FinderPattern) possibleCenters.elementAt(i)).getEstimatedModuleSize();\r
+ if (size > 3) {\r
+ // Throw away all but those first size candidate points we found.\r
+ possibleCenters.setSize(size);\r
+ // We need to pick the best three. Find the most\r
+ // popular ones whose module size is nearest the average\r
+ float averageModuleSize = 0.0f;\r
+ for (int i = 0; i < size; i++) {\r
+ averageModuleSize += ((FinderPattern) possibleCenters.elementAt(i)).getEstimatedModuleSize();\r
+ }\r
+ averageModuleSize /= (float) size;\r
+ // We don't have java.util.Collections in J2ME\r
+ Collections.insertionSort(possibleCenters, new ClosestToAverageComparator(averageModuleSize));\r
}\r
- averageModuleSize /= (float) size;\r
-\r
- // We don't have java.util.Collections in J2ME\r
- Collections.insertionSort(possibleCenters, new ClosestToAverageComparator(averageModuleSize));\r
\r
return new FinderPattern[]{\r
(FinderPattern) possibleCenters.elementAt(0),\r
};\r
}\r
\r
- /**\r
- * <p>Having found three "best" finder patterns we need to decide which is the top-left, top-right,\r
- * bottom-left. We assume that the one closest to the other two is the top-left one; this is not\r
- * strictly true (imagine extreme perspective distortion) but for the moment is a serviceable assumption.\r
- * Lastly we sort top-right from bottom-left by figuring out orientation from vector cross products.</p>\r
- *\r
- * @param patterns three best {@link FinderPattern}s\r
- * @return same {@link FinderPattern}s ordered bottom-left, top-left, top-right\r
- */\r
- private static FinderPattern[] orderBestPatterns(FinderPattern[] patterns) {\r
-\r
- // Find distances between pattern centers\r
- float abDistance = distance(patterns[0], patterns[1]);\r
- float bcDistance = distance(patterns[1], patterns[2]);\r
- float acDistance = distance(patterns[0], patterns[2]);\r
-\r
- FinderPattern topLeft;\r
- FinderPattern topRight;\r
- FinderPattern bottomLeft;\r
- // Assume one closest to other two is top left;\r
- // topRight and bottomLeft will just be guesses below at first\r
- if (bcDistance >= abDistance && bcDistance >= acDistance) {\r
- topLeft = patterns[0];\r
- topRight = patterns[1];\r
- bottomLeft = patterns[2];\r
- } else if (acDistance >= bcDistance && acDistance >= abDistance) {\r
- topLeft = patterns[1];\r
- topRight = patterns[0];\r
- bottomLeft = patterns[2];\r
- } else {\r
- topLeft = patterns[2];\r
- topRight = patterns[0];\r
- bottomLeft = patterns[1];\r
- }\r
-\r
- // Use cross product to figure out which of other1/2 is the bottom left\r
- // pattern. The vector "top-left -> bottom-left" x "top-left -> top-right"\r
- // should yield a vector with positive z component\r
- if ((bottomLeft.getY() - topLeft.getY()) * (topRight.getX() - topLeft.getX()) <\r
- (bottomLeft.getX() - topLeft.getX()) * (topRight.getY() - topLeft.getY())) {\r
- FinderPattern temp = topRight;\r
- topRight = bottomLeft;\r
- bottomLeft = temp;\r
- }\r
-\r
- return new FinderPattern[]{bottomLeft, topLeft, topRight};\r
- }\r
-\r
- /**\r
- * @return distance between two points\r
- */\r
- static float distance(ResultPoint pattern1, ResultPoint pattern2) {\r
- float xDiff = pattern1.getX() - pattern2.getX();\r
- float yDiff = pattern1.getY() - pattern2.getY();\r
- return (float) Math.sqrt((double) (xDiff * xDiff + yDiff * yDiff));\r
- }\r
-\r
/**\r
* <p>Orders by {@link FinderPattern#getCount()}, descending.</p>\r
*/\r
projects / zxing.git / blobdiff