Opencv笔记8——XML和YAML文件

XML和YAML文件

XML（eXtensible Markup Lauguage）是一种元标记语言，所谓的“元标记”就是开发者可以根据自身需要定义自己的标记。XML时一种语义/结构化语言，它描述了文档的结构和语义
YAML（Ain’t a Markup Language）强调这种语言是以数据为中心的。YAML是一种可读性高，用来表示资料序列的格式

FileStorage 类操作文件的使用引导

1. 实例化一个FileStorage类的对象，用默认带参数的构造函数完成初始化。或者用FileStorage::open()成员函数辅助初始化
2. 使用流操作<<进行文件写入操作，或者>>进行文件读取操作。类似c++中的文件输入输出流
3. 使用FileStorage::release()函数折构掉FileStorage类对象，同时关闭文件。

FileStorage::FileStorage()
FileStorage::FileStorage(const string& source ,int flags,const string& encoding=string)

XML和YAML文件的写入

#include 
#include 
using namespace cv;
int main()
{
       //初始化
       FileStorage fs("test.yaml", FileStorage::WRITE);
       //开始文件写入
       fs << "frameCount" << 5;
       time_t rawtime;
       time(&rawtime);
       fs << "calibrationDate" << asctime(localtime(&rawtime));
       Mat cameraMatrix = (Mat_<double>(3, 3) << 1000, 0, 320, 0, 1000, 240, 0, 0, 1);
       Mat disCoeffs = (Mat_<double>(5, 1) << 0.1, 0.01, -0.001, 0, 0);
       fs << "cameraMatrix" << cameraMatrix << "disCoeffs" << disCoeffs;
       fs << "features" << "[";
       for (int i = 0; i < 3; i++)
       {
              int x = rand() % 640;
              int y = rand() % 480;
              uchar lbp = rand() % 256;
              fs << "{:" << "x" << x << "y" << y << "lbp" << "[:";
              for (int j = 0; j < 8; j++)
              {
                     fs << ((lbp >> j) & 1);
              }
              fs << "]" << "}";
       }
       fs << "]";
       fs.release();
       printf("文件读写完毕，请在工程目录下查看生成的文件~");
       getchar();
       return 0;
}

%YAML:1.0
---
frameCount: 5
calibrationDate: "Wed Aug  1 11:13:44 2018\n"
cameraMatrix: !!opencv-matrix
   rows: 3
   cols: 3
   dt: d
   data: [ 1000., 0., 320., 0., 1000., 240., 0., 0., 1. ]
disCoeffs: !!opencv-matrix
   rows: 5
   cols: 1
   dt: d
   data: [ 1.0000000000000001e-01, 1.0000000000000000e-02,
       -1.0000000000000000e-03, 0., 0. ]
features:
   - { x:41, y:227, lbp:[ 0, 1, 1, 1, 1, 1, 0, 1 ] }
   - { x:260, y:449, lbp:[ 0, 0, 1, 1, 0, 1, 1, 0 ] }
   - { x:598, y:78, lbp:[ 0, 1, 0, 0, 1, 0, 1, 0 ] }

XML和YAML文件读取

#include 
#include 
using namespace std;
using namespace cv;
int main()
{
       // 改变console字体颜色
       system("color 6F");
       //初始化
       FileStorage fs2("test.yaml", FileStorage::READ);
       // 第一种方法 对FileNote操作
       int frameCount = (int)fs2["frameCount"];
       std::string date;
       //第二种方法:使用 FileNote运算符
       fs2["calibrationDate"] >> date;
       Mat cameraMatrix2, disCoeffs2;
       fs2["cameraMatrix"] >> cameraMatrix2;
       fs2["disCoeffs"] >> disCoeffs2;
       cout << "framCount: " << frameCount << endl
              << "calibration date: " << date << endl
              << "camera matrix: " << cameraMatrix2 << endl
              << "distortion coeffs: " << disCoeffs2 << endl;
       FileNode features = fs2["features"];
       FileNodeIterator it = features.begin(), it_end = features.end();
       int idx = 0;
       std::vector lbpval;
       //使用FileNoteIterator 遍历序列
       for (; it != it_end; ++it, ++idx)
       {
              cout << "feature #" << idx << ": ";
              cout << "x=" << (int)(*it)["x"] << ", y =" << (int)(*it)["y"] << ", lbp: (";
              (*it)["lbp"] >> lbpval;
              for (int i = 0; i < (int)lbpval.size(); i++)
              {
                     cout << " " << (int)lbpval[i];
              }
              cout << ")" << endl;
       }
       fs2.release();
       printf("\n文件读取完毕，请输入任意键结束程序~");
       getchar();
       return 0;
}