opencv测试的基本代码

开始一直运行不正确,发现和标准代码有出入。发现是使用img.empty() == 0这个用法是错误的。

#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/opencv.hpp>
#include "opencv2/highgui/highgui.hpp"
#include <iostream>

// using namespace std;
using namespace cv;

int main()
{
	std::string path = "basketBall.jpg";
	Mat img = imread(path,IMREAD_COLOR);
	// Mat img = imread("basketBall.jpg",IMREAD_COLOR);
	if (img.empty())
	{
		std::cout << "打开图像失败！" <<std::endl;
		return -1;
	}
	namedWindow("image", CV_WINDOW_AUTOSIZE);
	cv::imshow("image", img);
	waitKey();

	return 0;
}

empty()函数提示

bool cv::Mat::empty() const
Returns true if the array has no elements. The method returns true if Mat::total() is 0 or if Mat::data is NULL. Because of pop_back() and resize() methods M.total() == 0 does not imply that M.data == NULL.

官方给出的样例

#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <iostream>
using namespace cv;
int main()
{
    std::string image_path = samples::findFile("basketBall.jpg");
    Mat img = imread(image_path, IMREAD_COLOR);
    if(img.empty())
    {
        std::cout << "Could not read the image: " << image_path << std::endl;
        return 1;
    }
    imshow("Display window", img);
    int k = waitKey(0); // Wait for a keystroke in the window
    if(k == 's')
    {
        imwrite("starry_night.png", img);
    }
    return 0;
}