问如何将三通道Mat转换为汇总的单通道Mat？

EN

    // sum up the channels of the image:
    // 1 .store initial nr of rows/columns
    int initialRows = frameVid1.rows;
    int initialCols = frameVid1.cols;

    // 2. check if matrix is continous
    if (!frameVid1.isContinuous())
    {
        frameVid1 = frameVid1.clone();
    }
    // 3. reshape matrix to 3 color vectors
    frameVid1 = frameVid1.reshape(3, initialRows*initialCols);
    // 4. convert matrix to store bigger values than 255
    frameVid1.convertTo(frameVid1, CV_32F);
    // 5. sum up the three color vectors
    reduce(frameVid1, frameVid1, 1, CV_REDUCE_SUM);
    // 6. reshape to initial size
    frameVid1 = frameVid1.reshape(1, initialRows);
    // 7. convert back to CV_8UC1
    frameVid1.convertTo(frameVid1, CV_8U);