去年七月份因为学校项目需要开始接触图像处理，但那时候只是到网上找车牌识别代码，然后加入到自己的项目中，不清楚细节原理。
现在自己重新一步步实现车牌识别。
高斯模糊：
1 Mat Gaussian(Mat &img) {
2 Mat out;
3 GaussianBlur(img, out, Size(3, 3),
4 0, 0, BORDER_DEFAULT);
5 return out;
6
7 }
灰度化：
1 Mat Grayscale(Mat &img) {
2 Mat out;
3 cvtColor(img, out, CV_RGB2GRAY);
4
5 return out;
6 }
Sobel算子（X方向）：
1 Mat Sobel(Mat &img) {
2 Mat out;
3 Mat grad_x, grad_y;
4 Mat abs_grad_x, abs_grad_y;
5
6 //X方向
7 //Sobel(img, grad_x, CV_16S, 1, 0, 3, 1, 1, BORDER_DEFAULT);
8 //convertScaleAbs(grad_x, abs_grad_x);
9 Sobel(img, img, CV_16S, 1, 0, 3, 1, 1, BORDER_DEFAULT);
10 convertScaleAbs(img, out);
11
12 //Y方向
13 //Sobel(img, grad_y, CV_16S, 0, 1, 3, 1, 1, BORDER_DEFAULT);
14 //convertScaleAbs(grad_y, abs_grad_y);
15 //convertScaleAbs(img, out);
16
17 //合并
18 //addWeighted(abs_grad_x, 0.5, abs_grad_y, 0.5, 0, out);
19
20 return out;
21 }
二值化：
1 Mat TwoValued(Mat &img) {
2 Mat out;
3 threshold(img, out, 0, 255, CV_THRESH_OTSU + CV_THRESH_BINARY);
4 //threshold(img, out, 100, 255, CV_THRESH_BINARY);
5
6 return out;
7 }
闭操作：
1 Mat Close(Mat &img) {
2 Mat out;
3 //Mat element(5, 5, CV_8U, cv::Scalar(1));
4 Mat element = getStructuringElement(MORPH_RECT, Size(17, 5));
5 morphologyEx(img, out, cv::MORPH_CLOSE, element);
6
7 return out;
8 }
取轮廓：
1 void Contour(Mat &img, Mat &out) {
2 RNG rng(12345);
3
4 vector< Mat > contours(1000);
5 vector<Vec4i> hierarchy(1000);
6 findContours(img, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0));
7
8
9 vector< Mat >::iterator itc = contours.begin();
10 vector<RotatedRect> rects;
11 int t = 0;
12 while (itc != contours.end()) {
13 //Create bounding rect of object
14 RotatedRect mr = minAreaRect(Mat(*itc));
15 //large the rect for more
16 if (!verifySizes(mr)) {
17 itc = contours.erase(itc);
18 }
19 else {
20 ++itc;
21 rects.push_back(mr);
22 }
23 }
24
25 cv::Mat result;
26 img.copyTo(result);
27 for (int i = 0; i< contours.size(); i++)
28 {
29 drawContours(result, contours, i, Scalar(0, 0, 255), 2, 8, vector<Vec4i>(), 0, Point());
30 //drawContours(result, contours, i, Scalar(255), 2);
31 }
32
33 //imshow("MASK11", result);
34
35 for (int i = 0; i < rects.size(); i++) {
36 circle(result, rects[i].center, 3, Scalar(0, 255, 0), -1);
37
38 float minSize = (rects[i].size.width < rects[i].size.height) ? rects[i].size.width : rects[i].size.height;
39 //minSize = minSize - minSize*0.5;
40
41 srand(time(NULL));
42 Mat mask;
43 mask.create(out.rows + 2, out.cols + 2, CV_8UC1);
44 mask = Scalar::all(0);
45 int loDiff = 30;
46 int upDiff = 30;
47 int connectivity = 4;
48 int newMaskVal = 255;
49 int NumSeeds = 10;
50 Rect ccomp;
51 int flags = connectivity + (newMaskVal << 8) + CV_FLOODFILL_FIXED_RANGE + CV_FLOODFILL_MASK_ONLY;
52
53 for (int j = 0; j < NumSeeds; j++) {
54 Point seed;
55 seed.x = rects[i].center.x + rand() % (int)minSize - (minSize / 2);
56 seed.y = rects[i].center.y + rand() % (int)minSize - (minSize / 2);
57 circle(result, seed, 1, Scalar(0, 255, 255), -1);
58 int area = floodFill(out, mask, seed, Scalar(255, 0, 0), &ccomp, Scalar(loDiff, loDiff, loDiff), Scalar(upDiff, upDiff, upDiff), flags);
59 }
60
61 //imshow("MASK", mask);
62
63 vector<Point> pointsInterest;
64 Mat_<uchar>::iterator itMask = mask.begin<uchar>();
65 Mat_<uchar>::iterator end = mask.end<uchar>();
66 for (; itMask != end; ++itMask)
67 if (*itMask == 255)
68 pointsInterest.push_back(itMask.pos());
69
70 RotatedRect minRect = minAreaRect(pointsInterest);
71
72 if (verifySizes(minRect)) {
73 // rotated rectangle drawing
74 Point2f rect_points[4]; minRect.points(rect_points);
75 for (int j = 0; j < 4; j++)
76 line(result, rect_points[j], rect_points[(j + 1) % 4], Scalar(0, 0, 255), 1, 8);
77
78 //Get rotation matrix
79 float r = (float)minRect.size.width / (float)minRect.size.height;
80 float angle = minRect.angle;
81 if (r < 1)
82 angle = 90 + angle;
83 Mat rotmat = getRotationMatrix2D(minRect.center, angle, 1);
84
85 //Create and rotate image
86 Mat img_rotated;
87 warpAffine(out, img_rotated, rotmat, out.size(), CV_INTER_CUBIC);//实现旋转
88
89 //Crop image
90 Size rect_size = minRect.size;
91 if (r < 1)
92 swap(rect_size.width, rect_size.height);
93 Mat img_crop;
94 getRectSubPix(img_rotated, rect_size, minRect.center, img_crop);
95
96 Mat resultResized;
97 resultResized.create(33, 144, CV_8UC3);
98 resize(img_crop, resultResized, resultResized.size(), 0, 0, INTER_CUBIC);;
99
100 ////Equalize croped image
101 Mat grayResult;
102 cvtColor(resultResized, grayResult, CV_BGR2GRAY);// CV_RGB2GRAY
103 blur(grayResult, grayResult, Size(3, 3));
104 grayResult = histeq(grayResult);
105
106 if (1) {
107 stringstream ss(stringstream::in | stringstream::out);
108 ss << "haha" << "_" << i << ".jpg";
109 imwrite(ss.str(), grayResult);
110 }
111
112 }
113 }
114 }
主函数：
1 int main() {
2 Mat img;
3 Mat out;
4 //Mat result;
5
6 //载入图片
7 img = imread("test1.jpg");//, CV_LOAD_IMAGE_GRAYSCALE);
8 img.copyTo(out);
9 //imshow ("原始图", img);
10
11 img = Gaussian(img);
12 //imshow ("高斯模糊", img);
13
14 img = Grayscale(img);
15 //imshow("灰度化", img);
16
17 img = Sobel(img);
18 //imshow("Sobel_X", img);
19
20 img = TwoValued(img);
21 //imshow("二值化", img);
22
23 img = Close(img);
24 //imshow("闭操作", img);
25
26 //
27 Contour(img, out);
28
29 waitKey(0);
30 cvDestroyAllWindows();
31 }
学习自——http://www.cnblogs.com/subconscious/p/3979988.html
时间： 2024-10-12 21:45:03