如何解决错误 LNK2019：imwrite() 函数无法解析的外部符号？

Question

我在 c:/../Opencv 3.0 和 ms Visual Studio 2012 安装（解压）opencv。我使用 cmake 来创建库。 cmake -> c:/opencv/build custom/ 中构建二进制文件的路径，与 opencv 路径不同。我在cmake中选择Visual Studio 11 2012。 还设置环境路径。 在属性管理器中，我设置 c/c++ > 常规 > ExtraIncludeDirectories :
C:\lazy\opencv uild\include;% 链接器 > 常规 > 附加库目录：C:\opencv uild_custom\lib\Debug;%

链接器>输入>附加依赖项：opencv_calib3d300d.lib;opencv_core300d.lib;opencv_features2d300d.lib;opencv_flann300d.lib;opencv_highgui300d.lib;opencv_imgproc300d.lib;opencv_ml300d.lib;opencv_objdetect300d.lib; opencv_photo300d.lib;opencv_stitching300d.lib;opencv_superres300d.lib ;opencv_ts300d.lib;opencv_video300d.lib;opencv_videostab300d.lib;

我在 ms Visual Studio 中使用下面的 svm 代码：

#include <stdio.h>
#include <math.h>
#include <opencv\cv.h>
#include <opencv\highgui.h>
#include <opencv2\objdetect\objdetect.hpp>
#include <opencv2\highgui\highgui.hpp>
#include <opencv2\imgproc\imgproc.hpp>
#include <vector>
#include <windows.h>
#include <atlstr.h>
#include <iostream>
#include <sstream>
#include <iomanip>
//#include <opencv2\imgproc\imgproc.hpp>
#include <opencv2\core\core.hpp>
//#include <opencv2\highgui\highgui.hpp>
#include <opencv\cvaux.hpp>

using namespace cv;
using namespace std;

#include <opencv2\ml.hpp>

using namespace cv;

int main()
{
    // Data for visual representation
    int width = 512, height = 512;
    Mat image = Mat::zeros(height, width, CV_8UC3);


    // Set up training data
    int labels[4] = { 1, -1, -1, -1 };
    Mat labelsMat(4, 1, CV_32FC1, labels);

    float trainingData[4][2] = { { 501, 10 }, { 255, 10 }, { 501, 255 }, { 10, 501 } };
    Mat trainingDataMat(4, 2, CV_32FC1, trainingData);

    // Set up SVM's parameters

    Ptr<ml::SVM> svm = ml::SVM::create();
    // edit: the params struct got removed,
    // we use setter/getter now:
    svm->setType(ml::SVM::C_SVC);
    svm->setKernel(ml::SVM::LINEAR);
    svm->setGamma(3);

    svm->train(trainingDataMat, ml::ROW_SAMPLE, labelsMat);

    Mat res;   // output

    Vec3b green(0, 255, 0), blue(255, 0, 0);
    // Show the decision regions given by the SVM
    for (int i = 0; i < image.rows; ++i)
        for (int j = 0; j < image.cols; ++j)
        {
        Mat sampleMat = (Mat_<float>(1, 2) << j, i);
        float response = svm->predict(sampleMat, res);

        if (response == 1)
            image.at<Vec3b>(i, j) = green;
        else if (response == -1)
            image.at<Vec3b>(i, j) = blue;
        }


    // Show the training data
    int thickness = -1;
    int lineType = 8;
    circle(image, Point(501, 10), 5, Scalar(0, 0, 0), thickness, lineType);
    circle(image, Point(255, 10), 5, Scalar(255, 255, 255), thickness, lineType);
    circle(image, Point(501, 255), 5, Scalar(255, 255, 255), thickness, lineType);
    circle(image, Point(10, 501), 5, Scalar(255, 255, 255), thickness, lineType);

    // Show support vectors
    thickness = 2;
    lineType = 8;
    Mat sv = svm->getSupportVectors();

    for (int i = 0; i < sv.rows; ++i)
    {
        const float* v = sv.ptr<float>(i);
        circle(image, Point((int)v[0], (int)v[1]), 6, Scalar(128, 128, 128), thickness, lineType);
    }

    imwrite("result.png", image);        // save the image

    imshow("SVM Simple Example", image); // show it to the user
    waitKey(0);

}

调试时出现错误。 这是我在运行程序时遇到的错误

如何解决？

Answer 1

imwrite

函数在

opencv_imgcodecs300d.lib

中，将其添加到AdditionalDependencies