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Issue 520

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git-svn-id: https://zxing.googlecode.com/svn/trunk@1545 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
smparkes@smparkes.net 2010-08-17 20:12:10 +00:00
parent d70e368ef0
commit 3f8639c67e
1 changed files with 41 additions and 16 deletions
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57
cpp/core/src/zxing/qrcode/detector/FinderPatternFinder.cpp
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@ -31,27 +31,35 @@ namespace qrcode {
using namespace std;
class ClosestToAverageComparator {
class FurthestFromAverageComparator {
private:
float averageModuleSize_;
const float averageModuleSize_;
public:
ClosestToAverageComparator() : averageModuleSize_(0.0f) { }
ClosestToAverageComparator(float averageModuleSize) :
averageModuleSize_(averageModuleSize) {
FurthestFromAverageComparator(float averageModuleSize) :
averageModuleSize_(averageModuleSize) {
}
bool operator()(Ref<FinderPattern> a, Ref<FinderPattern> b) {
float dA = abs(a->getEstimatedModuleSize() - averageModuleSize_);
float dB = abs(b->getEstimatedModuleSize() - averageModuleSize_);
return dA < dB;
return dA > dB;
}
};
class CenterComparator {
const float averageModuleSize_;
public:
CenterComparator(float averageModuleSize) :
averageModuleSize_(averageModuleSize) {
}
bool operator()(Ref<FinderPattern> a, Ref<FinderPattern> b) {
// N.B.: we want the result in descending order ...
return a->getCount() > b->getCount();
if (a->getCount() != b->getCount()) {
return a->getCount() > b->getCount();
} else {
float dA = abs(a->getEstimatedModuleSize() - averageModuleSize_);
float dB = abs(b->getEstimatedModuleSize() - averageModuleSize_);
return dA < dB;
}
}
};
@ -311,12 +319,21 @@ vector<Ref<FinderPattern> > FinderPatternFinder::selectBestPatterns() {
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 (size_t i = 0; i < startSize; i++) {
totalModuleSize += possibleCenters_[i]->getEstimatedModuleSize();
float size = possibleCenters_[i]->getEstimatedModuleSize();
totalModuleSize += size;
square += size * size;
}
float average = totalModuleSize / (float) startSize;
float stdDev = (float)sqrt(square / startSize - average * average);
sort(possibleCenters_.begin(), possibleCenters_.end(), FurthestFromAverageComparator(average));
float limit = max(0.2f * average, stdDev);
for (size_t i = 0; i < possibleCenters_.size() && possibleCenters_.size() > 3; i++) {
if (abs(possibleCenters_[i]->getEstimatedModuleSize() - average) > 0.2f * average) {
if (abs(possibleCenters_[i]->getEstimatedModuleSize() - average) > limit) {
possibleCenters_.erase(possibleCenters_.begin()+i);
i--;
}
@ -325,7 +342,13 @@ vector<Ref<FinderPattern> > FinderPatternFinder::selectBestPatterns() {
if (possibleCenters_.size() > 3) {
// Throw away all but those first size candidate points we found.
sort(possibleCenters_.begin(), possibleCenters_.end(), CenterComparator());
float totalModuleSize = 0.0f;
for (size_t i = 0; i < startSize; i++) {
float size = possibleCenters_[i]->getEstimatedModuleSize();
totalModuleSize += size;
}
float average = totalModuleSize / (float) startSize;
sort(possibleCenters_.begin(), possibleCenters_.end(), CenterComparator(average));
}
if (possibleCenters_.size() > 3) {
@ -464,11 +487,13 @@ Ref<FinderPatternInfo> FinderPatternFinder::find(DecodeHints const& hints) {
}
}
} else {
// Advance to next black pixel
do {
j++;
} while (j < maxJ && !image_->get(j, i));
j--; // back up to that last white pixel
stateCount[0] = stateCount[2];
stateCount[1] = stateCount[3];
stateCount[2] = stateCount[4];
stateCount[3] = 1;
stateCount[4] = 0;
currentState = 3;
continue;
}
// Clear state to start looking again
currentState = 0;