版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/carloswc/article/details/76141587
接上文，我们通过一些列预处理获得了较为明显的车牌区域，接下来我们我们将车牌区域提取出来，利用的是中国车牌的大小长宽比，能够将车牌外接矩形与其他的外接矩形区分出来。代码如下：
vector<vector<Point>>contours1;
findContours(closeImg, contours1, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE);
Mat result(plate.size(), CV_8U, Scalar(255));
//drawContours(result, contours1, -1, 0, 2);
Mat contourPlate = threshImg.clone();
vector<RotatedRect>plateRects;
for (int i = 0; i < contours1.size(); i++)
{
RotatedRect rect = minAreaRect(contours1[i]);
if (verifySizes(rect)) {
plateRects.push_back(rect);
}
}
cout << plateRects.size();
Mat carPlate = threshPlate(plateRects[0].boundingRect());
imshow("plateArea", carPlate);车牌判断函数：
//-----------------------------------【verifySizes函数】----------------------------------
// 描述：判断是否为车牌区域
//-----------------------------------------------------------------------------------------------
bool verifySizes(RotatedRect mr)
{
float error = 0.4;
//Spain car plate size: 52x11 scale 4,7272
float scale = 3.667;
//Set a min and max area. All other patchs are discarded
int min = 150 * scale *100; // minimum area
int max = 200 * scale * 200; // maximum area
//Get only patchs that match to a respect ratio.
float rmin = scale - scale*error;
float rmax = scale + scale*error;
int area = mr.size.height * mr.size.width;
float r = (float)mr.size.width / (float)mr.size.height;
if (r<1)
r = (float)mr.size.height / (float)mr.size.width;
if ((area < min || area > max) || (r < rmin || r > rmax)) {
return false;
}
else {
return true;
}
}接下来我们对车牌区域进行处理，同样适用轮廓提取法，利用长款比及大小区分，原理与车牌提取类似，只是中文字符会出现上下或者左右分块的问题，我们单独列出来中文字符的处理
vector<vector<Point>> contours;
vector<Vec4i>hierarchy;
findContours(carPlate, contours, hierarchy, CV_RETR_EXTERNAL,
CV_CHAIN_APPROX_NONE);
Mat contour_plate = carPlate.clone();
vector<RotatedRect>rects;
vector<float>point_x;
vector<float>widths;
vector<float>heights;
Point2f tempPoint[4];
vector<Mat>chars;
Mat image_ROI;
float y0;
/*************************英文字符处理**************************/
for (int i = 0; i<contours.size(); i++)
{
//绘制轮廓的最小外结矩形
RotatedRect rect = minAreaRect(contours[i]);
Point2f P[4];
rect.points(P);
if ((P[0].y - P[1].y)>100 && (P[0].y - P[1].y) < 150
&& (P[2].x - P[1].x) > 50 && (P[2].x - P[1].x) < 100)
{
point_x.push_back(P[1].x);
widths.push_back(rect.size.width);
heights.push_back(rect.size.height);
rects.push_back(rect);
image_ROI = cut_plate(Rect(P[1], rect.size));
chars.push_back(image_ROI);
y0 = P[1].y;
}
for (int j = 0; j <= 3; j++)
{
line(contour_plate, P[j], P[(j + 1) % 4], Scalar(255), 2);
//cout << "P" << j << "(" << P[j].x << "," << P[j].y << ")" << endl;
}
}
cout << rects.size()<<endl;
/***************************中文字符处理*********************/
float sum = 0;
float x0 = point_x[0] - (point_x[5] - point_x[1]) / 4;
float aveWidth = (widths[0] + widths[1] + widths[2] + widths[3] + widths[4] + widths[5]) / 6;
float aveHeight = (heights[0] + heights[1] + heights[2] + heights[3] + heights[4] + heights[5]) / 6;
image_ROI = cut_plate(Rect(x0, y0, aveWidth + 10, aveHeight + 10));
chars.insert(chars.begin(), image_ROI);
imshow("chars1", chars[0]);
imshow("chars2", chars[1]);
imshow("chars3", chars[2]);
imshow("chars4", chars[3]);
imshow("chars5", chars[4]);
imshow("chars6", chars[5]);
imshow("chars7", chars[6]);
imshow("contours", contour_plate);
for (int i = 0; i < chars.size(); i++)
{
charRecognize(chars[i], i, i);
}
cout << "chars.size=" << chars.size() << '\n' << "车牌号码为" << endl;
showChars(G_PlateChar);
waitKey();
return 0;//*****************************字符识别函数*************************************/
void charRecognize(Mat src, int num, int char_num)
{
int k, i, j;
int char_begin, char_end;
int num_t[CHARACTER] = { 0 };
switch (num)
{
case 0:char_begin = 36; char_end = 42; break;
case 1:char_begin = 10; char_end = 35; break;
case 2:char_begin = 0; char_end = 35; break;
case 3:char_begin = 0; char_end = 35; break;
case 4:char_begin = 0; char_end = 35; break;
case 5:char_begin = 0; char_end = 35; break;
case 6:char_begin = 0; char_end = 35; break;
default:break;
}
for (k = 0; k<8; k++)
{
for (j = int(k / 2) * 15; j<int(k / 2 + 1) * 15; j++)
{
for (i = (k % 2) * 10; i<(k % 2 + 1) * 10; i++)
{
num_t[k] += src.at<uchar>(i, j) / 255;
}
}
num_t[8] += num_t[k]; // 第9个特征 前8个特征的和作为第9个特征值
}
for (i = 0; i<20; i++) //以下特征也是 固定算法得到的
num_t[9] += src.at<uchar>(10, i) / 255;
for (i = 0; i<20; i++)
num_t[10] += src.at<uchar>(20, i) / 255;
for (i = 0; i<20; i++)
num_t[11] += src.at<uchar>(30, i) / 255;
for (j = 0; j<40; j++)
num_t[12] += src.at<uchar>(j, 7) / 255;
for (j = 0; j<40; j++)
num_t[13] += src.at<uchar>(j, 10) / 255;
for (j = 0; j<40; j++)
num_t[14] += src.at<uchar>(j, 13) / 255;
int num_tt[CHARACTER] = { 0 };
int matchnum = 0; //可以说是 匹配度或 相似度
int matchnum_max = 0;
int matchcode = 0; // 匹配号
//int matchtempnum[10]={0};
j = 0;
for (k = char_begin; k <= char_end; k++)
//for(k=40;k<42;k++)
{
matchnum = 0;
for (i = 0; i<8; i++) //区域的匹配
{
// num_tt[i]= abs(num_t[i]-num[k][i]);
if (abs(num_t[i] - Num_Templete[k][i]) <= 2)//与模板里的相应值进行匹配
matchnum++;//两者相减，如果绝对值小于2，标记匹配成功一次
}
if (Num_Templete[k][i] - abs(num_t[i]) <= 8)//对第9个特征进行匹配
matchnum += 2;
for (i = 9; i<CHARACTER; i++) // 横竖的匹配
{
if (Num_Templete[k][i] >= 5) //特征值 大于5
{
if (abs(num_t[i] - Num_Templete[k][i]) <= 1)
matchnum += 2;
}
else if (num_t[i] == Num_Templete[k][i])
{
matchnum += 2;
}
}
if (matchnum>matchnum_max)
{
matchnum_max = matchnum; //保留最大的 匹配
matchcode = k; //记录 识别的字符的 索引
//matchtempnum[j]=matchnum_min
}
}
//识别输出 存放输出结果
cout << "templete";
for (i = 0; i < 15; i++)
{
cout << num_t[i] << " ";
}
cout << endl;
G_PlateChar[char_num] = PlateCode[matchcode]; //保存下该字符
}const int Num_Templete[TEMPLETENUM][CHARACTER] =
{
{ 16,19,10,12,10,10,15,18,110,3,2,2,3,3,3 }, //0
{ 9,11,10,10,10,10,9,10,79,2,2,2,0,2,12 }, //1
{ 18,19,3,18,10,10,23,22,123,4,2,2,7,6,8 }, //2
{ 119, 58, 150 ,61 ,150, 118 ,94, 87, 837, 18 ,0, 0 ,15, 15, 15 }, //3
{ 2,18,11,22,20,21,11,18,123,2,4,2,6,7,5 }, //4
{ 23,19,20,12,9,20,18,22,143,2,4,4,6,6,6 }, //5
{ 6,13,17,8,15,20,18,20,117,2,2,4,5,7,6 }, //6
{ 21,21,0,20,8,12,9,11,102,2,2,2,2,8,15 }, //7
{ 9 ,72 ,126, 116, 116, 118, 6, 70, 633 ,9 ,15 ,13 ,25, 29, 33 }, //8
{ 16,18,15,21,7,19,13,7,116,3,2,2,6,6,5 }, //9
{ 10,10,16,16,20,20,18,19,129,2,4,2,8,3,6 }, //A
{ 24,20,20,19,22,22,24,20,171,4,8,4,6,6,6 }, //B
{ 18,19,20,4,20,8,17,21,127,3,2,4,4,4,4 }, //C
{ 23,19,11,20,12,20,22,21,148,3,3,3,4,4,4 }, //D
{ 23,19,21,9,22,8,23,23,148,2,2,2,6,6,6 }, //E
{ 139,148,143,77,117,69,98,61,852,20,14,14,40,40,40 }, //F
{ 17,18,22,14,12,24,18,21,146,4,7,4,4,6,6 }, //G
{ 14,20,18,22,17,22,16,20,149,4,1,4,2,2,2 }, //H
{ 0,17,0,20,3,20,18,22,100,2,2,4,2,2,2 }, //J
{ 19,20,26,10,20,20,20,22,157,4,4,4,3,5,11 }, //K
{ 20,0,20,0,20,0,25,20,105,2,2,2,2,2,2 }, //L
{ 20,10,27,17,20,10,22,14,140,1,3,3,4,1,5 }, //M
{ 21,12,25,17,26,12,18,18,149,3,5,3,5,5,6 }, //N
{ 23,19,18,20,21,8,22,0,131,3,3,2,4,4,4 }, //P
{ 18,104,123, 117, 119 ,122, 13, 85, 701, 12, 16 ,14, 29 ,32 }, //Q
{ 26,19,21,18,21,17,20,21,163,4,3,4,4,6,5 }, //R
{ 18,18,18,10,8,17,17,22,128,4,3,4,6,6,6 }, //S
{ 22,18,10,10,10,10,10,10,100,2,2,2,33,2,2 }, //T
{ 18,12,20,10,20,10,19,21,130,3,3,3,2,2,2 }, //U
{ 20,19,20,20,15,14,9,10,127,4,4,2,9,1,8 }, //V
{ 21,25,26,28,16,16,21,19,172,6,2,4,13,0,7 }, //W
{ 21,21,13,13,12,11,22,21,134,4,2,4,8,0,10 }, //X
{ 21,20,10,11,10,10,10,11,103,3,2,2,5,2,6 }, //Y
{ 21,23,5,15,15,5,24,20,128,2,2,2,8,8,7 }, //Z
{ 13,14,10,10,10,10,13,13,93,2,2,2,29,2,29 }, //I
{ 20,20,13,20,19,12,17,20,141,3,3,4,4,4,4 }, //O //36
{ 14,15,17,17,16,10,25,24,138,0,2,4,12,8,9 }, //云 //37
{ 17,20,17,12,33,28,23,20,170,3,4,7,13,6,4 }, //苏
{ 21,21,23,24,24,25,31,27,196,0,9,6,8,6,7 }, //京
{ 19,27,20,34,19,36,24,37,216,4,4,7,13,28,3 }, //湘
{ 17,14,23,27,36,40,26,27,210,4,13,4,16,14,14 }, //鲁
{ 0,1,4,99,0,10,0,6,120,1,16,8,14,8,8 }, // 粤
{ 22,20,33,37,25,24,24,25,210,13,3,6,12,8,7 } //蒙
};
//车牌字符
char *PlateCode[TEMPLETENUM] =
{
"0", "1", "2", "3", "4" ,
"5","6", "7", "8", "9",
"A", "B", "C", "D","E",
"F", "G","H", "J", "K",
"L", "M", "N","P", "Q",
"R", "S", "T", "U", "V",
"W","X", "Y", "Z", "I", "O",
"云", "苏","京", "湘", "鲁","粤","蒙"
};