OpenCV 和 MinGW 的运行时错误？

Question

我正在尝试在 OpenCV 的文档中运行一个示例，如下所示

#include <iostream>
#include <opencv2\core\core.hpp>
#include <opencv2\highgui\highgui.hpp>
#include <opencv\cv.h>


int main(int argc, char **argv)
{   
    cv::VideoCapture cap(0);
    if ( !cap.isOpened())
    {
        std::cout << "Error with opening Camera" << std::endl;
        return -1;
    }

    cv::Mat frame, edges;
    cv::namedWindow("edges", 1);
    for(;;)
    {
        cap >> frame;
        cvtColor(frame, edges, CV_BGR2GRAY);
        GaussianBlur(edges, edges, cv::Size(7,7), 1.5, 1.5);
        Canny(edges, edges, 0, 30, 3);
        cv::imshow("edges", edges);
        if ( cv::waitKey(30) >= 0) break;
    }

    return 0;
}

我有if statement 来检查相机是否有任何问题，它应该终止程序，但事实并非如此。这是我得到的错误

OpenCV Error: Assertion failed (scn == 3 || scn == 4) in cvtColor, file C:\opencv_2_4_8\opencv\sources\modules\imgproc\src\color.cpp, line 3737
terminate called after throwing an instance of 'cv::Exception'
  what():  C:\opencv_2_4_8\opencv\sources\modules\imgproc\src\color.cpp:3737: error: (-215) scn == 3 || scn == 4 in function cvtColor


This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

Answer 1

通过查看“color.cpp”中的OpenCV代码，看起来错误中提到的变量“scn”是帧的通道数，转换类型（BGR->灰度）需要有3 或 4 个通道：

断言失败（scn == 3 || scn == 4）

您确定您的相机默认不提供灰度图像吗？尝试注释掉处理框架的行并仅显示检索到的图像，看看你得到了什么。或者只是在帧捕获之后放置一个断点并检查“帧”变量 - 它是空的吗？是否有预期的大小等等？