opencv structured forest edge detection and findcontours

问题

I am trying to use opencv via visual c++ to extract contours of an image. I was able to do that using the opencv tutorial for findcontours. findcontours works in two steps

Detect edges using canny edge detector.
Feed the output of canny to findcontours.

I want to try out the same with 'Structured Forest Edge Detection' (Zitnick et al). I am able to extract the edges and display them, but when I try to feed the output to findcontours. I am getting a 'cv::Exception at memory location 0x0020EE9C' error. (see code below). What am I doing wrong?

Mat src = imread("image.jpg");

src.convertTo(src, CV_32F, 1.0 / 255.0);

Mat edges(src.size(), src.type());

Ptr<StructuredEdgeDetection> pDollar = createStructuredEdgeDetection("model.yml.gz");

pDollar->detectEdges(src, edges);

findContours(edges, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0));