Cho bạn cái hàm để bạn tham khảo
int FindPlate()
{
Mat src1 = imread("images\\BienSo.jpg", CV_LOAD_IMAGE_COLOR);
if(!src1.data)
return 0;
Mat src2 = src1.clone(); // copy anh
Mat gray, binary;
cvtColor(src1, gray, CV_BGR2GRAY);
threshold(gray, binary, 100, 255, CV_THRESH_BINARY);
imshow("Anh nhi phan goc", binary);
Mat morpho;
Mat element = getStructuringElement(MORPH_CROSS, Size(3,3), Point(1,1));
erode(binary, morpho, element, Point(-1,-1), 3);
imshow("Anh sau khi thuc hien phep gian no", morpho);
vector<vector<Point> > contours1;
findContours(binary, contours1, CV_RETR_LIST, CV_CHAIN_APPROX_NONE );
for(size_t i = 0; i < contours1.size(); i++)
{
Rect r = boundingRect(contours1[i]);
if(r.width/(double)r.height > 3.5f && r.width/(double)r.height < 4.5f)
rectangle(src1, r, Scalar(0, 0, 255), 2, 8, 0);
else
rectangle(src1, r, Scalar(0, 255, 0), 1, 8, 0);
}
imshow("Ket qua phat hien truoc phep gian no", src1);
vector<vector<Point> > contours2;
findContours(morpho, contours2, CV_RETR_LIST, CV_CHAIN_APPROX_NONE );
for(size_t i = 0; i < contours2.size(); i++)
{
Rect r = boundingRect(contours2[i]);
if(r.width/(double)r.height > 3.5f && r.width/(double)r.height < 4.5f)
rectangle(src2, r, Scalar(0, 0, 255), 2, 8, 0);
else
rectangle(src2, r, Scalar(0, 255, 0), 1, 8, 0);
}
imshow("Ket qua phat hien sau khi phep gian no", src2);
}