OpenCV C++, getting Region Of Interest (ROI) using cv::Mat

Question

I\'m very new to OpenCV (started using it two days ago), I\'m trying to cut a hand image from a depth image got from Kinect, I need the hand image for gesture recognition. I

Answer 1

Maybe an other approach could be:

//Create the rectangle
cv::Rect roi(10, 20, 100, 50);
//Create the cv::Mat with the ROI you need, where "image" is the cv::Mat you want to extract the ROI from
cv::Mat image_roi = image(roi)

I hope this can help.

Answer 2

You can use the overloaded function call operator on the cv::Mat:

cv::Mat img = ...;
cv::Mat subImg = img(cv::Range(0, 100), cv::Range(0, 100));

Check the OpenCV documentation for more information and for the overloaded function that takes a cv::Rect. Note that using this form of slicing creates a new matrix header, but does not copy the data.