goodfeaturestoTrack with Mask

edit

what is Mat(frame,faces.back()) ? looks like some kind of ROI. ?

try this:

Mat mask(frame.size(),CV_8U,Scalar(0));
mask(faces.back()).setTo(Scalar(255));
goodFeaturesToTrack(grayframe, points, 500, 0.01, 10, mask, 3, 0, 0.04);

I tried what you suggested, but it gives out a error message saying.

OpenCV Error: Assertion failed (0 <= roi.x && 0 <= roi.width && roi.x + roi.width <= m.cols && 0 <= roi.y && 0 <= roi.height && roi.y + roi.height <= m.rows) in Mat, file /opt/local/var/macports/build/_opt_mports_dports_graphics_opencv/opencv/work/opencv-2.4.10/modules/core/src/matrix.cpp, line 323
libc++abi.dylib: terminating with uncaught exception of type cv::Exception: /opt/local/var/macports/build/_opt_mports_dports_graphics_opencv/opencv/work/opencv-2.4.10/modules/core/src/matrix.cpp:323: error: (-215) 0 <= roi.x && 0 <= roi.width && roi.x + roi.width <= m.cols && 0 <= roi.y && 0 <= roi.height && roi.y + roi.height <= m.rows in function Mat

Frame is a Mat, and faces.back() is a rect from a vector.

sorry, probably grayframe, not frame

The size of both frame is the same. Grayframe is just a copy of frame, converted to grayscale.

please check if faces actually contains something before.

ok.. I tried put something together but it seem not to work as expected.. For some reason it will not apply the Lukas kanade using the points.. I am bit confused on why this problem is occurring at all... http://pastebin.com/CtrTfFeA