QFile aFile("C:\\Users\\chaojunche\\Desktop\\1.jpeg");
aFile.open(QIODevice::ReadOnly | QIODevice::Truncate);
QByteArray file = aFile.readAll();
vector<char> vdata(file.data(), file.data() + file.size());
Mat img_decode = imdecode(cv::Mat(vdata), IMREAD_UNCHANGED);
imshow("test", img_decode);