OpenCV findContours crash

Question

I've got this code: ``` mat.copyTo(tmpMat); cvtColor(tmpMat, tmpMat, CV_BGR2GRAY); cv::equalizeHist(tmpMat, tmpMat); cv::Mat browMat = tmpMat(eyebrowRect); std::vector > contours; cv::findContours(browMat, contours, cv::RETR_LIST, cv::CHAIN_APPROX_NONE); ``` but it crashes with this error: OpenCV Error: Assertion failed (type == type0 || (CV_MAT_CN(type) == CV_MAT_CN(type0) && ((1 << type0) & fixedDepthMask) != 0)) in create, file /Users/robin/Projects/OpenCVForiPhone/opencv/opencv/modules/core/src/matrix.cpp, line 1249 terminate called throwing an exception I think my Mat is already in 1-channel gray-scale because of cvtColor call... How can I fix this?

Accepted Answer

Instead of: ``` std::vector > contours; ``` have you tried? ``` std::vector > contours; ```

OpenCV findContours crash

Solution

Problem