What are qt+opencv marker recognition systems?

Question

Qt

Marker recognition. such as arrows for example (return some function when found).
3.1 Development of the architecture of the visual navigation system of an all-terrain reconnaissance robot
3.2. Development of mechanisms for access to the video camera and pre-processing of video information
3.4. Development and implementation of the navigation subsystem for an all-terrain reconnaissance robot using beacons (markers
). Regarding hardware. All processing is carried out on a PC. An ip camera is installed on the robot (so far it is D-Link DCS-932L).
Implemented on QT (mingw) with opencv. under Windows There are no strict restrictions on markers.The
only thing is that there should not be color binding, because the camera mostly shows in bw.The video.cpp project
which is responsible for video processing.
Development environment qt (mingw) + opencv under vin7
Thanks in advance.