opencv 入门代码

//#define USINGAT
//#define USINGITERATOR
//#define USINGPOINTER
//#define SHOWIMG
#include<opencv2\opencv.hpp>
#include<iostream>
using namespace cv;
using namespace std;

int main(int argc, char** argv)
{
    /* Mat mat(3, 2, CV_8UC3, Scalar(0, 0, 200)); cout << "mat=" << mat << endl; Mat z = Mat::zeros(2, 2, CV_8UC2); cout << "z=" << z << endl; Mat o = Mat::eye(2, 2, CV_8UC3); cout << "o=" << o << endl; */
    Mat      grayim(600, 800, CV_8UC1);
    Mat      colorim(600, 800, CV_8UC3);
#ifdef USINGAT

    /*traversal all item,and assign the item*/
    for (int i = 0; i < grayim.rows; i++){
        for (int j = 0; j < grayim.cols; j++){
            grayim.at<uchar>(i, j) = (i + j * 10) % 255;
        }
    }
    Vec3b  pixel;
    /*traversal all pixel,and set the pix's value*/
    for (int i = 0; i < colorim.rows; i++){
        for (int j = 0; j < colorim.cols; j++){
            pixel[0] = i % 255 & 10;
            pixel[1] = j % 255 & 10;
            pixel[2] = ((i + j) & 100) % 255;
            colorim.at<Vec3b>(i, j) = pixel;
        }
    }

#endif 
#ifdef USINGITERATOR
    /*using iterator to traversal the image mat*/
    MatIterator_<uchar> grayit,grayend;
    for (grayit = grayim.begin<uchar>(), grayend = grayim.end<uchar>();
        grayit != grayend; grayit++){
        *grayit = rand() % 255;//this is a pointer..
    }

    MatIterator_<Vec3b> colorit, colorend;
    for (colorit = colorim.begin<Vec3b>(), colorend = colorim.end<Vec3b>();
        colorit != colorend; colorit++){
        /*BGR*/
        (*colorit)[0] = rand() % 255;
        (*colorit)[1] = rand() % 255;
        (*colorit)[2] = rand() % 255;
    }
#endif
#ifdef USINGPOINTER
    /*using the data pointer to traversal the img*/
    for (int i = 0; i < grayim.rows; i++){
        //get the pointer of i-th rows
        uchar* p = grayim.ptr<uchar>(i);
        //set this rows
        for (int j = 0; j < grayim.cols; j++){
            p[j] = (i + j) % 255;
        }
    }

    for (int i = 0; i < colorim.rows; i++){
        Vec3b* p = colorim.ptr<Vec3b>(i);
        for (int j = 0; j < colorim.cols; j++){
            p[j][0] = i % 255;//B
            p[j][1] = j % 255;//G
            p[j][2] = (i + j) % 255;//R
        }
    }
#endif
#ifdef SHOWIMG
    //show the image
    imshow("grayim", grayim);
    imshow("colorim", colorim);
    waitKey(0);
#endif

//#define pp
#ifdef pp
    for (int i = 0; i < colorim.rows; i++){
        Vec3b* p = colorim.ptr<Vec3b>(i);
        for (int j = 0; j < colorim.cols; j++){
            p[j][0] = (i) % 255;
            p[j][1] = (j) % 255;
            p[j][2] = (i + j*i) % 255;
        }
    }
    //imshow("colorimage", colorim);
    //change something
    Mat    line;
    for (int i = 0; i < colorim.rows; i++){
        line = colorim.row(i);
        colorim.row(i) = (2 * line);
    }
    //imshow("change", colorim);
    //waitKey(0);

    /*get some area*/
    Mat  rect;
    //rect = colorim(Range(1,20), Range(1, 30));
    //imshow("rect", rect);
    //waitKey(0);
    /*get the area*/
    //Mat roi(grayim, Rect(10, 10, 100, 200));
    //imshow("im", roi);
    //waitKey(0);
    //Mat roi2 = grayim(Rect(10, 10, 200, 300));

    //cout << colorim << endl;

#endif

//#define hj
#ifdef hj
    Mat A = Mat::eye(4, 4, CV_32SC1);
    Mat B = A * 3 + 1;
    /* diag is the daig of the mat =0 means the main diag >0 means the main-down diag =1 means the item with main-down <0 means the main-up diag */
    Mat C = B.diag(0) + B.col(1);
    cout << "A=" << A << endl;
    cout << "B=" << B << endl;
    cout << "C=" << C << endl;
    cout << "C.*diag(B)=" << C.dot(B.diag(0)) << endl;
#endif

//#define _mat
#ifdef _mat
    Vec3b*  p;
    for (int i = 0; i < colorim.rows; i++){
        p = colorim.ptr<Vec3b>(i);
        for (int j = 0; j < colorim.cols; j++){
            p[j][0] = i % 255;
            p[j][1] = j % 255;
            p[j][2] = (i + j) % 255;
        }
    }
    //show the image
    //imshow("color", colorim);
    //waitKey(0);
    //using the Mat_
    Mat_<Vec3b> mm = (Mat_<Vec3b>&)colorim;
    for (int i = 0; i < mm.rows; i++){
        Vec3b* pp = mm.ptr<Vec3b>(i);
        for (int j = 0; j < mm.cols; j++){
            double   d = (double)((i + j) % 255);
            mm(i, j) = d;
        }
    }
    //imshow("hit", mm);
    //waitKey(0);

#endif
#define memofcv_
#ifdef memofcv
    /* let the colorim's pixel range[0..255] */
    Mat r = Mat(3, 2, CV_8UC3);
    randu(r, Scalar::all(0), Scalar::all(255));
    cout << "r(default) = " << "\n" << r << " , " << endl << endl;
    cout << "r(matlab) = " << "\n" << format(r,1) << " , " << endl << endl;
    cout << "r(csv) = " << "\n" << format(r,2) << " , " << endl << endl;
    cout << "r(python) = " << "\n" << format(r,3) << " , " << endl << endl;
    cout << "r(numpy) = " << "\n" << format(r,4) << " , " << endl << endl;

#endif

//#define trans
#ifdef trans
    /* trans Mat to IpLImage */
    //Mat img(Size(320, 240), CV_8UC3);
    //IplImage iplimg = img;//hehe,just assign is ok.
    /* trans Mat to CvMat */
    //CvMat cvimg = img;//hehe,just assign is ok.

    IplImage * iplimg = cvLoadImage("1.jpg"); 
    Mat img = cvarrToMat(iplimg);
    CvMat*     cvimg = cvLoadImageM("2.jpg");
    Mat img1 = cvarrToMat(cvimg);


    imshow("cvarray", img);
    imshow("cv2", img1);
    waitKey(2000);//wait 2 seconds

#endif


//#define imrw
#ifdef imrw
    /* using imread and imwrite imread(filename,flag) flag>0 means return 3 chunnel image,and if not 3,trans to 3 flag=0 means return 1 chunnel image,and if not 1,trabs to 1 flag<0 means return the source image,not trans it. imwrite(filename,image,params) param->for image jpeg:means the images's quility,0...100,95 is the default png:means the level of compress,0..9,bigger means smaller 3 is default ppm,pgm,pbm:text or binary?1 means binary,0 means text,1 is default */

    //ok,read image to memory
    Mat myimg = imread("3.jpg", 0);//0 means return 1 channel
    //empty?
    if (myimg.empty()){
        printf_s("Can not open image\n");
        return -1;
    }
    //Canny operator
    Mat result;
    Canny(myimg, result, 50, 150);
    //store image
    imwrite("3_ex.png", result,std::vector<int,allocator<int>>(5));

    //show the image
    imshow("s", myimg);
    imshow("d", result);
    waitKey(0);

#endif


//#define movier
#ifdef movier
    /* VideoCaptute and VideoWriter read->read one frame */
    //open video
    VideoCapture cap("xx.mp4");
    //check
    if (!cap.isOpened()){
        printf_s("Can not open video\n");
        return -1;
    }
    Mat  edges,frame;
    //create the windows
    namedWindow("edges", 1);
    while (true){
        //read frame
        cap >> frame;
        //check
        if (frame.empty()){
            break;
        }
        //cvtColor(frame, edges, CV_BGR2GRAY);
        //Canny(edges, edges, 0, 30, 3);
        imshow("edges", frame);
        if (waitKey(10) >= 0)
            break;
    }


#endif



//#define moview
#ifdef moview
    //define the video's size
    Size s(320, 240);
    //create the writer
    VideoWriter writer = VideoWriter("hj.avi", CV_FOURCC('M', 'J', 'P', 'G'), 25, s);
    //check
    if (!writer.isOpened()){
        printf_s("Can not create video\n");
        return -1;
    }
    //video frame
    Mat frame(s, CV_8UC3);
    for (int i = 100; i >=0; i--){
        //set the frame's color
        frame = Scalar::all(0);
        //get the number
        char  text[128];
        sprintf_s(text, "%d", i);
        putText(frame, text, Point(s.width / 3, s.height / 3), 
            FONT_HERSHEY_SCRIPT_SIMPLEX, 3,Scalar(0,0,255),3,8);
        //write to video
        writer << frame;
    }

    //open video
    VideoCapture cap("hj.avi");
    //check
    if (!cap.isOpened()){
        printf_s("Can not open video\n");
        return -1;
    }
    Mat hj;
    while (true){
        //read frame
        cap >>hj;
        //check
        if (hj.empty()){
            break;
        }
        imshow("hj",hj);
        if (waitKey(100) >= 0)
            break;
    }
#endif
    exit(EXIT_SUCCESS);
}