mirror of
https://github.com/kerberos-io/openalpr-base.git
synced 2025-10-07 00:02:52 +08:00
Reorganized the detection interface to simplify code and reduce boilerplate
This commit is contained in:
Matt Hill
@@ -47,171 +47,160 @@ namespace alpr {
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}
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vector<PlateRegion> DetectorMorph::detect(Mat frame, std::vector<cv::Rect> regionsOfInterest) {
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Mat frame_gray,frame_gray_cp;
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if (frame.channels() > 2)
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{
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cvtColor( frame, frame_gray, CV_BGR2GRAY );
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}
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else
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{
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frame.copyTo(frame_gray);
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}
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std::vector<cv::Rect> DetectorMorph::find_plates(cv::Mat frame_gray, cv::Size min_plate_size, cv::Size max_plate_size)
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{
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Mat frame_gray_cp(frame_gray.size(), frame_gray.type());
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frame_gray.copyTo(frame_gray_cp);
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blur(frame_gray, frame_gray, Size(5, 5));
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vector<PlateRegion> detectedRegions;
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for (int i = 0; i < regionsOfInterest.size(); i++) {
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Mat img_open, img_result;
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Mat element = getStructuringElement(MORPH_RECT, Size(30, 4));
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morphologyEx(frame_gray, img_open, CV_MOP_OPEN, element, cv::Point(-1, -1));
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vector<Rect> plates;
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Mat img_open, img_result;
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Mat element = getStructuringElement(MORPH_RECT, Size(30, 4));
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morphologyEx(frame_gray, img_open, CV_MOP_OPEN, element, cv::Point(-1, -1));
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img_result = frame_gray - img_open;
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img_result = frame_gray - img_open;
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if (config->debugDetector && config->debugShowImages) {
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imshow("Opening", img_result);
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if (config->debugDetector && config->debugShowImages) {
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imshow("Opening", img_result);
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}
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//threshold image using otsu thresholding
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Mat img_threshold, img_open2;
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threshold(img_result, img_threshold, 0, 255, CV_THRESH_OTSU + CV_THRESH_BINARY);
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if (config->debugDetector && config->debugShowImages) {
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imshow("Threshold Detector", img_threshold);
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}
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Mat diamond(5, 5, CV_8U, cv::Scalar(1));
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diamond.at<uchar>(0, 0) = 0;
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diamond.at<uchar>(0, 1) = 0;
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diamond.at<uchar>(1, 0) = 0;
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diamond.at<uchar>(4, 4) = 0;
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diamond.at<uchar>(3, 4) = 0;
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diamond.at<uchar>(4, 3) = 0;
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diamond.at<uchar>(4, 0) = 0;
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diamond.at<uchar>(4, 1) = 0;
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diamond.at<uchar>(3, 0) = 0;
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diamond.at<uchar>(0, 4) = 0;
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diamond.at<uchar>(0, 3) = 0;
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diamond.at<uchar>(1, 4) = 0;
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morphologyEx(img_threshold, img_open2, CV_MOP_OPEN, diamond, cv::Point(-1, -1));
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Mat rectElement = getStructuringElement(cv::MORPH_RECT, Size(13, 4));
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morphologyEx(img_open2, img_threshold, CV_MOP_CLOSE, rectElement, cv::Point(-1, -1));
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if (config->debugDetector && config->debugShowImages) {
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imshow("Close", img_threshold);
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waitKey(0);
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}
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//Find contours of possibles plates
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vector< vector< Point> > contours;
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findContours(img_threshold,
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contours, // a vector of contours
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CV_RETR_EXTERNAL, // retrieve the external contours
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CV_CHAIN_APPROX_NONE); // all pixels of each contours
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//Start to iterate to each contour founded
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vector<vector<Point> >::iterator itc = contours.begin();
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vector<RotatedRect> rects;
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//Remove patch that are no inside limits of aspect ratio and area.
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while (itc != contours.end()) {
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//Create bounding rect of object
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RotatedRect mr = minAreaRect(Mat(*itc));
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if (mr.angle < -45.) {
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mr.angle += 90.0;
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swap(mr.size.width, mr.size.height);
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}
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if (!CheckSizes(mr))
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itc = contours.erase(itc);
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else {
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++itc;
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rects.push_back(mr);
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}
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}
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//Now prunning based on checking all candidate plates for a min/max number of blobsc
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Mat img_crop, img_crop_b, img_crop_th, img_crop_th_inv;
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vector< vector< Point> > plateBlobs;
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vector< vector< Point> > plateBlobsInv;
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double thresholds[] = { 10, 40, 80, 120, 160, 200, 240 };
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const int num_thresholds = 7;
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int numValidChars = 0;
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Mat rotated;
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for (int i = 0; i < rects.size(); i++) {
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numValidChars = 0;
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RotatedRect PlateRect = rects[i];
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Size rect_size = PlateRect.size;
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// get the rotation matrix
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Mat M = getRotationMatrix2D(PlateRect.center, PlateRect.angle, 1.0);
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// perform the affine transformation
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warpAffine(frame_gray_cp, rotated, M, frame_gray_cp.size(), INTER_CUBIC);
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//Crop area around candidate plate
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getRectSubPix(rotated, rect_size, PlateRect.center, img_crop);
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if (config->debugDetector && config->debugShowImages) {
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imshow("Tilt Correction", img_crop);
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waitKey(0);
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}
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//threshold image using otsu thresholding
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Mat img_threshold, img_open2;
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threshold(img_result, img_threshold, 0, 255, CV_THRESH_OTSU + CV_THRESH_BINARY);
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for (int z = 0; z < num_thresholds; z++) {
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if (config->debugDetector && config->debugShowImages) {
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imshow("Threshold Detector", img_threshold);
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}
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cv::threshold(img_crop, img_crop_th, thresholds[z], 255, cv::THRESH_BINARY);
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cv::threshold(img_crop, img_crop_th_inv, thresholds[z], 255, cv::THRESH_BINARY_INV);
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Mat diamond(5, 5, CV_8U, cv::Scalar(1));
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findContours(img_crop_th,
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plateBlobs, // a vector of contours
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CV_RETR_LIST, // retrieve the contour list
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CV_CHAIN_APPROX_NONE); // all pixels of each contours
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diamond.at<uchar>(0, 0) = 0;
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diamond.at<uchar>(0, 1) = 0;
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diamond.at<uchar>(1, 0) = 0;
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diamond.at<uchar>(4, 4) = 0;
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diamond.at<uchar>(3, 4) = 0;
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diamond.at<uchar>(4, 3) = 0;
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diamond.at<uchar>(4, 0) = 0;
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diamond.at<uchar>(4, 1) = 0;
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diamond.at<uchar>(3, 0) = 0;
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diamond.at<uchar>(0, 4) = 0;
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diamond.at<uchar>(0, 3) = 0;
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diamond.at<uchar>(1, 4) = 0;
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morphologyEx(img_threshold, img_open2, CV_MOP_OPEN, diamond, cv::Point(-1, -1));
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Mat rectElement = getStructuringElement(cv::MORPH_RECT, Size(13, 4));
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morphologyEx(img_open2, img_threshold, CV_MOP_CLOSE, rectElement, cv::Point(-1, -1));
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findContours(img_crop_th_inv,
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plateBlobsInv, // a vector of contours
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CV_RETR_LIST, // retrieve the contour list
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CV_CHAIN_APPROX_NONE); // all pixels of each contours
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if (config->debugDetector && config->debugShowImages) {
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imshow("Close", img_threshold);
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waitKey(0);
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}
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int numBlobs = plateBlobs.size();
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int numBlobsInv = plateBlobsInv.size();
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//Find contours of possibles plates
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vector< vector< Point> > contours;
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findContours(img_threshold,
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contours, // a vector of contours
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CV_RETR_EXTERNAL, // retrieve the external contours
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CV_CHAIN_APPROX_NONE); // all pixels of each contours
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float idealAspect = config->avgCharWidthMM / config->avgCharHeightMM;
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for (int j = 0; j < numBlobs; j++) {
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cv::Rect r0 = cv::boundingRect(cv::Mat(plateBlobs[j]));
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//Start to iterate to each contour founded
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vector<vector<Point> >::iterator itc = contours.begin();
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vector<RotatedRect> rects;
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if (ValidateCharAspect(r0, idealAspect))
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numValidChars++;
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}
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//Remove patch that are no inside limits of aspect ratio and area.
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while (itc != contours.end()) {
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//Create bounding rect of object
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RotatedRect mr = minAreaRect(Mat(*itc));
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if (mr.angle < -45.) {
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mr.angle += 90.0;
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swap(mr.size.width, mr.size.height);
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}
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if (!CheckSizes(mr))
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itc = contours.erase(itc);
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else {
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++itc;
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rects.push_back(mr);
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}
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}
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//Now prunning based on checking all candidate plates for a min/max number of blobsc
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Mat img_crop, img_crop_b, img_crop_th, img_crop_th_inv;
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vector< vector< Point> > plateBlobs;
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vector< vector< Point> > plateBlobsInv;
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double thresholds[] = { 10, 40, 80, 120, 160, 200, 240 };
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const int num_thresholds = 7;
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int numValidChars = 0;
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Mat rotated;
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for (int i = 0; i < rects.size(); i++) {
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numValidChars = 0;
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RotatedRect PlateRect = rects[i];
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Size rect_size = PlateRect.size;
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// get the rotation matrix
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Mat M = getRotationMatrix2D(PlateRect.center, PlateRect.angle, 1.0);
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// perform the affine transformation
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warpAffine(frame_gray_cp, rotated, M, frame_gray_cp.size(), INTER_CUBIC);
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//Crop area around candidate plate
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getRectSubPix(rotated, rect_size, PlateRect.center, img_crop);
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if (config->debugDetector && config->debugShowImages) {
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imshow("Tilt Correction", img_crop);
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waitKey(0);
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}
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for (int z = 0; z < num_thresholds; z++) {
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cv::threshold(img_crop, img_crop_th, thresholds[z], 255, cv::THRESH_BINARY);
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cv::threshold(img_crop, img_crop_th_inv, thresholds[z], 255, cv::THRESH_BINARY_INV);
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findContours(img_crop_th,
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plateBlobs, // a vector of contours
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CV_RETR_LIST, // retrieve the contour list
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CV_CHAIN_APPROX_NONE); // all pixels of each contours
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findContours(img_crop_th_inv,
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plateBlobsInv, // a vector of contours
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CV_RETR_LIST, // retrieve the contour list
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CV_CHAIN_APPROX_NONE); // all pixels of each contours
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int numBlobs = plateBlobs.size();
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int numBlobsInv = plateBlobsInv.size();
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float idealAspect = config->avgCharWidthMM / config->avgCharHeightMM;
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for (int j = 0; j < numBlobs; j++) {
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cv::Rect r0 = cv::boundingRect(cv::Mat(plateBlobs[j]));
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if (ValidateCharAspect(r0, idealAspect))
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numValidChars++;
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}
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for (int j = 0; j < numBlobsInv; j++) {
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cv::Rect r0 = cv::boundingRect(cv::Mat(plateBlobsInv[j]));
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if (ValidateCharAspect(r0, idealAspect))
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numValidChars++;
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}
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}
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//If too much or too lcittle might not be a true plate
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//if (numBlobs < 3 || numBlobs > 50) continue;
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if (numValidChars < 4 || numValidChars > 50) continue;
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PlateRegion PlateReg;
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// Ensure that the rectangle isn't < 0 or > maxWidth/Height
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Rect bounding_rect = PlateRect.boundingRect();
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PlateReg.rect = expandRect(bounding_rect, 0, 0, frame.cols, frame.rows);
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detectedRegions.push_back(PlateReg);
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for (int j = 0; j < numBlobsInv; j++) {
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cv::Rect r0 = cv::boundingRect(cv::Mat(plateBlobsInv[j]));
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if (ValidateCharAspect(r0, idealAspect))
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numValidChars++;
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}
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}
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//If too much or too lcittle might not be a true plate
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//if (numBlobs < 3 || numBlobs > 50) continue;
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if (numValidChars < 4 || numValidChars > 50) continue;
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PlateRegion PlateReg;
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// Ensure that the rectangle isn't < 0 or > maxWidth/Height
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Rect bounding_rect = PlateRect.boundingRect();
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Rect rect_expanded = expandRect(bounding_rect, 0, 0, frame_gray.cols, frame_gray.rows);
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plates.push_back(rect_expanded);
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}
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return detectedRegions;
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return plates;
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}
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bool DetectorMorph::CheckSizes(RotatedRect& mr) {
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