c++ - OpenCV 试图将两个不同的图像合二为一

Question

C++ (VS2013) 使用 OpenCV 库 (2.4.9)。在 Kyle Hounslow OpenCV 教程的帮助下:无颜色实时对象跟踪。我尝试使用 2 个摄像头添加功能太跟踪。

    //read first frame
    stream1.read(frame1);
    //read first frame
    stream2.read(frame11);

    //convert frame1 to gray scale for frame differencing
    cv::cvtColor(frame1, grayImage1, COLOR_BGR2GRAY);
    //convert frame1 to gray scale for frame differencing
    cv::cvtColor(frame11, grayImage11, COLOR_BGR2GRAY);


    //copy second frame
    stream1.read(frame2);
    //copy second frame
    stream2.read(frame22);

    //convert frame2 to gray scale for frame differencing
    cv::cvtColor(frame2, grayImage2, COLOR_BGR2GRAY);
    //convert frame2 to gray scale for frame differencing
    cv::cvtColor(frame22, grayImage22, COLOR_BGR2GRAY);

    //perform frame differencing with the sequential images. This will output an "intensity image"
    //do not confuse this with a threshold image, we will need to perform thresholding afterwards.
    cv::absdiff(grayImage1, grayImage2, differenceImage1);
    cv::absdiff(grayImage11, grayImage22, differenceImage2);


    // Match the 2 Images in one
    Size sz1 = differenceImage1.size();                                         //get the size from cam 1
    Size sz2 = differenceImage2.size();                                         //get the size from cam 2

    Mat differenceImage3(sz1.height, sz1.width + sz2.width, CV_8UC3);           //create image 1 and 2

    Mat leftone(differenceImage3, Rect(0, 0, sz1.width, sz1.height));           //parameters for the left side one
    differenceImage1.copyTo(leftone);                                           //copy image 1 in leftone

    Mat rightone(differenceImage3, Rect(sz1.width, 0, sz2.width, sz2.height));  //parameters for the right side one
    differenceImage2.copyTo(rightone);                                          //copy image 2 in rightone


    //threshold intensity image at a given sensitivity value
    cv::threshold(differenceImage3, thresholdImage, SENSITIVITY_VALUE, 255, THRESH_BINARY);
    if (debugMode == true){
        //show the difference image and threshold image
        cv::imshow("Difference Image3", differenceImage3);
        cv::imshow("Difference Image2", differenceImage2);
        cv::imshow("Difference Image1", differenceImage1);
    }

我的问题是 differenceImage1 和 differenceImage2 完美显示。但是 differenceImage3 是灰色的。

我做错了什么？

Answer 1

differenceImage1和 differenceImage2是灰度图像，因此有 1 个 channel ，并且您正在分配 differenceImage3有 3 个 channel (使用标志 CV_8UC3 )。这导致两个 copyTo在 leftone 中分配新缓冲区的调用和 rightone而不是使用来自 differenceImage3 的预分配缓冲区，因此永远不会被填充。

如果您更换:

Mat differenceImage3(sz1.height, sz1.width + sz2.width, CV_8UC3);

与

Mat differenceImage3(sz1.height, sz1.width + sz2.width, CV_8UC1);