在linux下调用webcam（同样适用windows）

#include <opencv2/highgui/highgui.hpp>#include <opencv2/imgproc/imgproc.hpp>int main(){    cv::Mat img;    cv::Mat dst;    cv::VideoCapture input(0);    cv::VideoWriter output(        "Capture.avi",        CV_FOURCC('X', 'V', 'I', 'D'),        30,        cv::Size(input.get(CV_CAP_PROP_FRAME_WIDTH),                 input.get(CV_CAP_PROP_FRAME_HEIGHT))        );    for (;;)    {        if (!input.read(img))            break;        cv::Sobel(img, dst, CV_8U, 1, 1);        output.write(dst);        cv::imshow("img", dst);        char c = cv::waitKey(30);        if (c == ' ')            break;    }}