OpenCV试图将两个不同的图像统一为一个

Question

c++ (VS2013)使用OpenCV库(2.4.9)。在Kyle Hounslow教程的帮助下，OpenCV教程:无颜色的实时对象跟踪。我试过用2个摄像头添加too track功能。

    //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);
    }

我的问题是差异image1和差异image2被完美地显示。但是image3是灰色的

我做错了什么?

Answer 1

differenceImage1和differenceImage2是灰度图像，因此具有1个通道，并且您将differenceImage3分配为3个通道(使用标志CV_8UC3)。这导致两个copyTo调用在leftone和rightone中分配新的缓冲区，而不是使用从differenceImage3中预先分配的缓冲区，因此永远不会填充。

如果您替换:

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

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