// OK, we have at least 3 confirmed centers, but, it's possible that one is a "false positive"\r
// and that we need to keep looking. We detect this by asking if the estimated module sizes\r
// vary too much. We arbitrarily say that when the total deviation from average exceeds\r
- // 15% of the total module size estimates, it's too much.\r
+ // 5% of the total module size estimates, it's too much.\r
float average = totalModuleSize / (float) max;\r
float totalDeviation = 0.0f;\r
for (int i = 0; i < max; i++) {\r
* @throws ReaderException if 3 such finder patterns do not exist\r
*/\r
private FinderPattern[] selectBestPatterns() throws ReaderException {\r
- Collections.insertionSort(possibleCenters, new CenterComparator());\r
- int size = 0;\r
- int max = possibleCenters.size();\r
- while (size < max) {\r
- if (((FinderPattern) possibleCenters.elementAt(size)).getCount() < CENTER_QUORUM) {\r
- break;\r
- }\r
- size++;\r
- }\r
\r
- if (size < 3) {\r
+ int startSize = possibleCenters.size();\r
+ if (startSize < 3) {\r
// Couldn't find enough finder patterns\r
throw ReaderException.getInstance();\r
}\r
\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
+ // Filter outlier possibilities whose module size is too different\r
+ if (startSize > 3) {\r
+ // But we can only afford to do so if we have at least 4 possibilities to choose from\r
+ float totalModuleSize = 0.0f;\r
+ for (int i = 0; i < startSize; i++) {\r
+ totalModuleSize += ((FinderPattern) possibleCenters.get(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
+ float average = totalModuleSize / (float) startSize;\r
+ for (int i = 0; i < possibleCenters.size() && possibleCenters.size() > 3; i++) {\r
+ FinderPattern pattern = (FinderPattern) possibleCenters.get(i);\r
+ if (Math.abs(pattern.getEstimatedModuleSize() - average) > 0.2f * average) {\r
+ possibleCenters.remove(i);\r
+ i--;\r
+ }\r
+ }\r
+ }\r
+\r
+ if (possibleCenters.size() > 3) {\r
+ // Throw away all but those first size candidate points we found.\r
+ Collections.insertionSort(possibleCenters, new CenterComparator()); \r
+ possibleCenters.setSize(3);\r
}\r
\r
return new FinderPattern[]{\r
}\r
}\r
\r
- /**\r
- * <p>Orders by variance from average module size, ascending.</p>\r
- */\r
- private static class ClosestToAverageComparator implements Comparator {\r
- private final float averageModuleSize;\r
-\r
- private ClosestToAverageComparator(float averageModuleSize) {\r
- this.averageModuleSize = averageModuleSize;\r
- }\r
-\r
- public int compare(Object center1, Object center2) {\r
- return Math.abs(((FinderPattern) center1).getEstimatedModuleSize() - averageModuleSize) <\r
- Math.abs(((FinderPattern) center2).getEstimatedModuleSize() - averageModuleSize) ?\r
- -1 :\r
- 1;\r
- }\r
- }\r
-\r
}\r