1 int CPlateLocate::sobelOper(const Mat &in, Mat &out, int blurSize, int morphW,int morphH) {
 2   Mat mat_blur;
 3   mat_blur = in.clone();
 4   GaussianBlur(in, mat_blur, Size(blurSize, blurSize), 0, 0, BORDER_DEFAULT);
 5
 6   Mat mat_gray;
 7   if (mat_blur.channels() == 3)
 8     cvtColor(mat_blur, mat_gray, CV_RGB2GRAY);
 9   else
10     mat_gray = mat_blur;
11
12   int scale = SOBEL_SCALE;
13   int delta = SOBEL_DELTA;
14   int ddepth = SOBEL_DDEPTH;
15
16   Mat grad_x, grad_y;
17   Mat abs_grad_x, abs_grad_y;
18
19
20   Sobel(mat_gray, grad_x, ddepth, 1, 0, 3, scale, delta, BORDER_DEFAULT);
21   convertScaleAbs(grad_x, abs_grad_x);
22
23   Mat grad;
24   addWeighted(abs_grad_x, SOBEL_X_WEIGHT, 0, 0, 0, grad);
25
26   Mat mat_threshold;
27   double otsu_thresh_val =
28       threshold(grad, mat_threshold, 0, 255, CV_THRESH_OTSU + CV_THRESH_BINARY);
29
30
31   Mat element = getStructuringElement(MORPH_RECT, Size(morphW, morphH));
32   morphologyEx(mat_threshold, mat_threshold, MORPH_CLOSE, element);
33
34   out = mat_threshold;
35
36   return 0;
37 }

 1 int CPlateLocate::sobelFrtSearch(const Mat &src,
 2                                  vector<Rect_<float>> &outRects) {
 3   Mat src_threshold;
 4
 5   sobelOper(src, src_threshold, m_GaussianBlurSize, m_MorphSizeWidth,
 6             m_MorphSizeHeight);
 7
 8   vector<vector<Point>> contours;
 9   findContours(src_threshold,
10                contours,               // a vector of contours
11                CV_RETR_EXTERNAL,
12                CV_CHAIN_APPROX_NONE);  // all pixels of each contours
13
14   vector<vector<Point>>::iterator itc = contours.begin();
15
16   vector<RotatedRect> first_rects;
17
18   while (itc != contours.end()) {
19     RotatedRect mr = minAreaRect(Mat(*itc));
20
21
22     if (verifySizes(mr)) {
23       first_rects.push_back(mr);
24
25       float area = mr.size.height * mr.size.width;
26       float r = (float) mr.size.width / (float) mr.size.height;
27       if (r < 1) r = (float) mr.size.height / (float) mr.size.width;
28     }
29
30     ++itc;
31   }
32
33   for (size_t i = 0; i < first_rects.size(); i++) {
34     RotatedRect roi_rect = first_rects[i];
35
36     Rect_<float> safeBoundRect;
37     if (!calcSafeRect(roi_rect, src, safeBoundRect)) continue;
38
39     outRects.push_back(safeBoundRect);
40   }
41   return 0;
42 }