车牌尺寸识别

Author: lixiaoxu

OpenCVCarBoardDetect/.idea/workspace.xml

@@ -3,4 +3,17 @@ project(OpenCVCarBoardDetect)
 
 set(CMAKE_CXX_STANDARD 14)
 
-add_executable(OpenCVCarBoardDetect main.cpp)
+find_package(OpenCV REQUIRED)
+
+include_directories("/usr/local/Cellar/opencv/4.1.0_2/include/opencv4")
+link_libraries("/usr/local/Cellar/opencv/4.1.0_2/lib")
+
+
+add_executable(OpenCVCarBoardDetect main.cpp PlateRecognize.cpp PlateRecognize.h common.h PlateLocate.cpp PlateLocate.h SobelLocate.cpp SobelLocate.h)
+
+target_link_libraries(OpenCVCarBoardDetect
+        opencv_videoio
+        opencv_core
+        opencv_highgui
+        opencv_video
+        opencv_objdetect)

OpenCVCarBoardDetect/CMakeLists.txt

@@ -0,0 +1,159 @@
+//
+// Created by lixiaoxu on 2019-10-15.
+//
+
+#include "PlateLocate.h"
+
+PlateLocate::PlateLocate() {
+
+}
+
+PlateLocate::~PlateLocate() {
+
+}
+
+/**
+ * 尺寸校验（宽高比&面积）
+ * @param rotatedRect
+ * @return
+ */
+int PlateLocate::verifySizes(RotatedRect rotatedRect) {
+    //容错率
+    float error = 0.75f;
+    //理想宽高比
+    float aspect = float(136) / float(36);
+    //真实宽高比
+    float realAspect = float(rotatedRect.size.width) / float(rotatedRect.size.height);
+    if (realAspect < 1)
+        realAspect = float(rotatedRect.size.height) / float(rotatedRect.size.width);
+    //真实面积
+    float area = rotatedRect.size.height * rotatedRect.size.width;
+    //最小最大面积 不符合的丢弃
+    //给个大概就行，随时调整
+    //初步筛选
+    int areaMin = 44 * aspect * 14;
+    int areaMax = 440 * aspect * 140;
+
+    //比例浮动 error认为也满足
+    //最小宽高比
+    float aspectMin = aspect - aspect * error;
+    //最大宽高比
+    float aspectMax = aspect + aspect * error;
+
+    if ((area < areaMin || area > areaMax) || (realAspect < aspectMin || realAspect > aspectMax)) {
+        return 0;
+    }
+    return 1;
+}
+
+/**
+ * 矩形矫正
+ * @param src
+ * @param rects
+ * @param dst_plates
+ */
+void PlateLocate::tortuosity(Mat src, vector<RotatedRect> &rects, vector<Mat> &dst_plates) {
+    //循环要处理的矩形
+    for (RotatedRect roi_rect:rects) {
+        //矩形角度
+        float roi_angle = roi_rect.angle;
+        float r = (float) roi_rect.size.width / (float) roi_rect.size.height;
+        if (r < 1) {
+            roi_angle = 90 + roi_angle;
+        }
+
+        //矩形大小
+        Size roi_rect_size = roi_rect.size;
+
+        //让rect在一个安全范围内
+        Rect2f safe_rect;
+        safeRect(src, roi_rect, safe_rect);
+
+        //候选车牌
+        //抠图 这里不是产生一张新图片 而是在src上定位到一个Mat，来处理
+        //数据和src是同一份
+        Mat src_rect = src(safe_rect);
+        //真正的候选车牌
+        Mat dst;
+        //不需要旋转的 旋转角度小没必要旋转了
+        if (roi_angle - 5 < 0 && roi_angle + 5 > 0) {
+            dst = src_rect.clone();
+        } else {
+            //相对于roi的中心点，不见去左上角坐标是相对于整个图的
+            //减去左上角则是相对于候选车牌的中心点 坐标
+            Point2f roi_ref_center = roi_rect.center - safe_rect.tl();
+            Mat rotated_mat;
+            //矫正 rotated_mat 矫正后的图片
+            rotation(src_rect, rotated_mat, roi_rect_size, roi_ref_center, roi_angle);
+            dst = rotated_mat;
+        }
+
+        //调整大小
+        Mat plate_mat;
+        //高和宽
+        plate_mat.create(36, 136, CV_8UC3);
+        resize(dst, plate_mat, plate_mat.size());
+
+        dst_plates.push_back(plate_mat);
+        dst.release();
+    }
+}
+
+/**
+ * 转换安全矩形
+ * @param src
+ * @param rect
+ * @param safa_rect
+ */
+void PlateLocate::safeRect(Mat src, RotatedRect rect, Rect2f &safe_rect) {
+    //RotatedRect 没有坐标
+    //转为正常的带坐标的边框
+    Rect2f boundRect = rect.boundingRect2f();
+
+    //左上角x,y
+    float tl_x = boundRect.x > 0 ? boundRect.x : 0;
+    float tl_y = boundRect.y > 0 ? boundRect.y : 0;
+
+    //这里是拿坐标x,y从0开始的所以 - 1
+    //比如宽长度是10，x坐标最大是9，所以src.cols - 1
+    //右下角
+    float br_x = boundRect.x + boundRect.width < src.cols ? boundRect.x + boundRect.width - 1 : src.cols - 1;
+    float br_y = boundRect.y + boundRect.height < src.rows ? boundRect.y + boundRect.height - 1 : src.rows - 1;
+
+    float w = br_x - tl_x;
+    float h = br_y - tl_y;
+    if (w <= 0 || h <= 0) return;
+    safe_rect = Rect2f(tl_x, tl_y, w, h);
+}
+
+
+/**
+ * 旋转
+ * @param src
+ * @param dst
+ * @param rect_size
+ * @param center
+ * @param angle
+ */
+void PlateLocate::rotation(Mat src, Mat &dst, Size rect_size, Point2f center, double angle) {
+    //获得旋转矩阵
+    Mat rot_mat = getRotationMatrix2D(center, angle, 1);
+
+    //运用放射变换
+    Mat mat_rotated;
+    //矫正后 大小会不一样，但是对角线肯定能容纳
+    int max = sqrt(pow(src.rows, 2) + pow(src.cols, 2));
+    warpAffine(src, mat_rotated, rot_mat, Size(max, max), INTER_CUBIC);
+//    imshow("before rotate",src);
+//    imshow("after rotate",mat_rotated);
+    //截取 尽量吧车牌多余的区域截取掉
+    getRectSubPix(mat_rotated, Size(rect_size.width, rect_size.height), center, dst);
+//    imshow("cut" ,dst);
+//    waitKey();
+
+    mat_rotated.release();
+    rot_mat.release();
+}
+
+
+

OpenCVCarBoardDetect/PlateLocate.cpp

@@ -0,0 +1,37 @@
+//
+// Created by lixiaoxu on 2019-10-15.
+//
+
+#ifndef OPENCVCARBOARDDETECT_PLATELOCATE_H
+#define OPENCVCARBOARDDETECT_PLATELOCATE_H
+
+
+#include "common.h"
+
+class PlateLocate {
+public:
+    PlateLocate();
+
+    //作为父类加入虚构函数
+    virtual ~PlateLocate();
+
+    /**
+   * 车牌定位：1.原图，2.输出候选车牌
+   * @param src
+   * @param dst_plates
+   * @return
+   */
+    virtual void locate(Mat src, vector<Mat> &dst_plates) = 0;
+
+protected:
+    int verifySizes(RotatedRect rotatedRect);
+
+    void tortuosity(Mat src, vector<RotatedRect> &rect, vector<Mat> &dst_plates);
+
+    void safeRect(Mat src, RotatedRect rotatedRect, Rect2f& rect2f);
+
+    void rotation(Mat src, Mat &dst, Size rect_size, Point2f center, double angle);
+};
+
+
+#endif //OPENCVCARBOARDDETECT_PLATELOCATE_H

OpenCVCarBoardDetect/PlateLocate.h

@@ -0,0 +1,34 @@
+//
+// Created by lixiaoxu on 2019-10-15.
+//
+
+#include "PlateRecognize.h"
+
+
+PlateRecognize::PlateRecognize() {
+    sobelLocate = new SobelLocate();
+}
+
+PlateRecognize::~PlateRecognize() {
+    if (sobelLocate) {
+        delete sobelLocate;
+        sobelLocate = 0;
+    }
+}
+
+/**
+ * 车牌识别：车牌定位+检测+字符识别
+ * @param src
+ * @return
+ */
+string PlateRecognize::recognize(Mat src) {
+    //1.车牌定位
+    //sobel定位
+    vector<Mat> dst_plates;
+    sobelLocate->locate(src, dst_plates);
+
+    return string("12345");
+}
+
+
+

OpenCVCarBoardDetect/PlateRecognize.cpp

@@ -0,0 +1,27 @@
+//
+// Created by lixiaoxu on 2019-10-15.
+//
+
+
+
+#ifndef OPENCVCARBOARDDETECT_PLATERECOGNIZE_H
+#define OPENCVCARBOARDDETECT_PLATERECOGNIZE_H
+
+#include <string>
+#include "common.h"
+#include "SobelLocate.h"
+
+class PlateRecognize {
+public:
+    PlateRecognize();
+
+    //没有加入虚函数，因为没有作为父类
+    ~PlateRecognize();
+
+    string recognize(Mat src);
+private:
+    SobelLocate *sobelLocate = 0;
+};
+
+
+#endif //OPENCVCARBOARDDETECT_PLATERECOGNIZE_H

OpenCVCarBoardDetect/PlateRecognize.h

@@ -0,0 +1,95 @@
+//
+// Created by lixiaoxu on 2019-10-15.
+//
+
+#include "SobelLocate.h"
+
+SobelLocate::SobelLocate() {
+
+}
+
+SobelLocate::~SobelLocate() {
+
+}
+
+/**
+ * 车牌定位，1.原图，2.输出候选车牌
+ * @param src
+ * @param dst_plates
+ */
+void SobelLocate::locate(Mat src, vector<Mat> &dst_plates) {
+    //1.高斯模糊
+    Mat blur;
+    //Ksize:both must be positive and odd,正数的奇数
+    //半径越大越模糊
+    GaussianBlur(src, blur, Size(5, 5), 0);
+    imshow("origin", src);
+//    imshow("Gauss", blur);
+    //2.灰度化
+    Mat gray;
+    cvtColor(blur, gray, COLOR_BGR2GRAY);
+//    imshow("gray", gray);
+
+    //3.sobel运算
+    Mat sobel_16;
+    //输入
+    //Sobel函数求导后，导数可能得值会大于255，或小于0
+    Sobel(gray, sobel_16, CV_16S, 1, 0);
+//    imshow("sobel_16",sobel_16);//无法显示
+    //转回8位
+    Mat sobel;
+
+    convertScaleAbs(sobel_16, sobel);
+//    imshow("sobel", sobel);//无法显示,需要进行转换
+
+    //4.二值化（非黑即白）
+    Mat shold;
+    threshold(sobel, shold, 0, 255, THRESH_OTSU + THRESH_BINARY);
+//    imshow("shold", shold);
+
+    //5.形态学操作：闭操作
+    Mat close;
+//    Mat element = getStructuringElement(MORPH_RECT, Size(80, 30));//car4
+    Mat element = getStructuringElement(MORPH_RECT, Size(19, 3));
+    morphologyEx(shold, close, MORPH_CLOSE, element);
+    imshow("close", close);
+
+    //6.找轮廓
+    vector<vector<Point>> contours;
+    findContours(close, contours,
+                 RETR_EXTERNAL,//外轮廓
+                 CHAIN_APPROX_NONE //轮廓上所有的像素点
+    );
+    RotatedRect rotatedRect;
+    vector<RotatedRect> vec_sobel_rects;
+
+    //7.遍历判断矩形
+    for (vector<Point> points :contours) {
+        rotatedRect = minAreaRect(points);//带角度的矩形
+        rectangle(src, rotatedRect.boundingRect(), Scalar(0, 0, 255));
+        if (verifySizes(rotatedRect)) {
+            vec_sobel_rects.push_back(rotatedRect);
+        }
+    }
+
+    for (RotatedRect rect :vec_sobel_rects) {
+        rectangle(src, rect.boundingRect(), Scalar(0, 255, 0));
+    }
+//    imshow("轮廓图", src);
+    //8.矩形矫正
+    //角度判断，旋转，调整大小
+
+    tortuosity(src, vec_sobel_rects, dst_plates);
+    for (Mat m :dst_plates) {
+        imshow("定位候选车牌", m);
+        waitKey();
+    }
+
+
+    blur.release();
+    gray.release();
+    sobel_16.release();
+    sobel.release();
+    shold.release();
+    close.release();
+}