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Calculating char gap by distance from midpoint (rather than edge).

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More accurate for characters like "1" that don't fill up the full area, but still have the same distance between overall characters
This commit is contained in:
Matt Hill
2015-09-25 20:34:11 -04:00
parent 022e191fb9
commit 3675cd82ab
2 changed files with 17 additions and 6 deletions
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21
src/openalpr/segmentation/charactersegmenter.cpp
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@@ -403,6 +403,11 @@ namespace alpr
}
}
}
int CharacterSegmenter::getCharGap(cv::Rect leftBox, cv::Rect rightBox) {
int right_midpoint = (rightBox.x + (rightBox.width / 2));
int left_midpoint = (leftBox.x + (leftBox.width / 2));
return right_midpoint - left_midpoint;
}
vector<Rect> CharacterSegmenter::combineCloseBoxes( vector<Rect> charBoxes)
{
@@ -410,7 +415,7 @@ namespace alpr
if (charBoxes.size() <= 2)
return charBoxes;
// First find the median char gap (the space between characters)
// First find the median char gap (the space from midpoint to midpoint of chars)
vector<int> char_gaps;
for (unsigned int i = 0; i < charBoxes.size(); i++)
@@ -419,8 +424,7 @@ namespace alpr
break;
// the space between charbox i and i+1
int char_gap = charBoxes[i+1].x - (charBoxes[i].x + charBoxes[i].width);
char_gaps.push_back(char_gap);
char_gaps.push_back(getCharGap(charBoxes[i], charBoxes[i+1]));
}
int median_char_gap = median(char_gaps.data(), char_gaps.size());
@@ -455,14 +459,14 @@ namespace alpr
if (i == 0)
left_gap = 999999999999;
else
left_gap = charBoxes[i].x - (charBoxes[i-1].x + charBoxes[i-1].width);
left_gap = getCharGap(charBoxes[i-1], charBoxes[i]);
right_gap = charBoxes[i+1].x - (charBoxes[i].x + charBoxes[i].width);
right_gap = getCharGap(charBoxes[i], charBoxes[i+1]);
int min_gap = (int) ((float)median_char_gap) * 0.75;
int max_gap = (int) ((float)median_char_gap) * 1.25;
int max_width = (int) ((float)biggestCharWidth) * 1.1;
int max_width = (int) ((float)biggestCharWidth) * 1.2;
bool has_good_gap = (left_gap >= min_gap && left_gap <= max_gap) || (right_gap >= min_gap && right_gap <= max_gap);
@@ -488,6 +492,11 @@ namespace alpr
else
{
newCharBoxes.push_back(charBoxes[i]);
if (this->config->debugCharSegmenter)
{
cout << "Not Merging 2 boxes -- " << i << " and " << i + 1 << " -- has_good_gap: " << has_good_gap <<
" bigWidth (" << bigWidth << ") > max_width (" << max_width << ")" << endl;
}
}
}

2
src/openalpr/segmentation/charactersegmenter.h
View File

@@ -68,6 +68,8 @@ namespace alpr
std::vector<cv::Rect> getHistogramBoxes(HistogramVertical histogram, float avgCharWidth, float avgCharHeight, float* score);
std::vector<cv::Rect> getBestCharBoxes(cv::Mat img, std::vector<cv::Rect> charBoxes, float avgCharWidth);
int getCharGap(cv::Rect leftBox, cv::Rect rightBox);
std::vector<cv::Rect> combineCloseBoxes( std::vector<cv::Rect> charBoxes);
std::vector<cv::Rect> get1DHits(cv::Mat img, int yOffset);