c – countNonZero函数在openCV中给出断言错误

我尝试使用COuntNonZero()函数进行水平投影,如下所示. @H_22_2@mat src = imread(INPUT_FILE,CV_LOAD_IMAGE_COLOR); Mat binaryImage = src.clone(); cvtColor(src,src,Cv_bGR2GRAY); Mat horizontal = Mat::zeros(1,binaryImage.cols,CV_8UC1); for (int i = 0; i<binaryImage.cols; i++) { Mat roi = binaryImage(Rect(0,1,binaryImage.rows)); horizontal.at<int>(0,i) = countNonZero(roi); cout << "Col no:" << i << " >>" << horizontal.at<int>(0,i); }

但是在调用countonZero()函数时出现错误.错误如下.

OpenCV Error: Assertion Failed (src.chAnnels() == 1 && func != 0) in cv::countNo
    nZero,file C:\builds\2_4_PackSlave-win32-vc12-shared\opencv\modules\core\src\st
    at.cpp,line 549

有人可以指出错误吗？