我正在尝试使用opencv和curl在visual studio 2010中从网址加载图像。运行代码时我得到了上述错误。该错误意味着什么?如何更正我的代码。 这是我的代码
#include "curl/curl.h" // has to go before opencv headers
#include <iostream>
#include <vector>
using namespace std;
#include <opencv2/opencv.hpp>
using namespace cv;
//curl writefunction to be passed as a parameter
// we can't ever expect to get the whole image in one piece,
// every router / hub is entitled to fragment it into parts
// (like 1-8k at a time),
// so insert the part at the end of our stream.
size_t write_data(char *ptr, size_t size, size_t nmemb, void *userdata)
{
vector<uchar> *stream = (vector<uchar>*)userdata;
size_t count = size * nmemb;
stream->insert(stream->end(), ptr, ptr + count);
return count;
}
//function to retrieve the image as cv::Mat data type
cv::Mat curlImg(const char *img_url, int timeout=10)
{
vector<uchar> stream;
CURL *curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_URL, img_url); //the img url
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data); // pass the writefunction
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &stream); // pass the stream ptr to the writefunction
curl_easy_setopt(curl, CURLOPT_TIMEOUT, timeout); // timeout if curl_easy hangs,
CURLcode res = curl_easy_perform(curl); // start curl
curl_easy_cleanup(curl); // cleanup
return imdecode(stream, -1); // 'keep-as-is'
}
int main(void)
{
Mat image = curlImg("http://pimg.tradeindia.com/01063301/b/1/CRO-Oscilloscope.jpg");
// if (image.empty())
// return -1; // load fail
namedWindow( "Image output", CV_WINDOW_AUTOSIZE );
if (!image.empty())
imshow("Image output",image); // here's your car ;)
waitKey(0); // infinite
}
感谢您的帮助。
答案 0 :(得分:2)
此错误与传递给opencv imdecode()的流的大小有关。尝试检查流的大小,看看它是否正确,即非零或非空。