c++ - OpenCV imwrite 不工作

Question

我有一个简单的 OpenCV 应用程序，它从网络摄像头获取视频流，当按下 spacebar 时，它会捕获当前图像并卡住在该图像上。当我尝试使用 cv::imwrite() 方法将图片保存到磁盘时，它不起作用。代码成功编译，但不保存图像。它也从调用中返回一个假值。我不确定这是图像类型问题还是其他问题，但我似乎被难住了。

这是我当前的 cpp 类的代码:

#include <iostream>

#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"

using namespace std;
using namespace cv;

Mat picture;
char key;

class FacialRec {

};

int main() {
    //Starting the video
    VideoCapture videoCapture(0);

    if (!videoCapture.isOpened()) {
        cout << "Unable to open video file." << endl;
        return 1;
    }

    namedWindow("Webcam", CV_WINDOW_AUTOSIZE);

    while(true) {
        Mat frame;
        videoCapture.retrieve(frame);
        bool success = videoCapture.read(frame);

        if (!success) {
            cout << "Could not read from video file" << endl;
            return 1;
        }

        imshow("Webcam", frame);
        key = waitKey(30);

        if (key == 27) { //escape key pressed: stop program
            cout << "ESC pressed. Program closing..." << endl;
            break;
        }else if (key == ' ') { //spacebar pressed: take a picture
            picture = frame;
            key = -1;

            while (true) {
                imshow("Webcam", picture);

                key = waitKey(30);

                if (key == 27 || key == 32) {
                    cout << "ESC or SPACE pressed. Returning to video..." << endl;
                    break;
                }

                if (key == 115) {
                    //trying to save to current directory
                    bool maybe = imwrite("/testimage.jpg", picture);
                    // maybe bool is always getting value of 0, or false
                   cout << "s was pressed. saving image " << maybe << endl;
                }   
            }
        }

    }

    return 0;
}

Answer 1

您正在尝试将 testimage.jpg 写入 / 目录。正在执行的程序可能没有足够的权限写入该目录。根据您的评论，您可能想要

//trying to save to current directory
bool maybe = imwrite("./testimage.jpg", picture);

因为 . 表示当前工作目录。