Problem with the number of matchings in FLANN OpenCV algorithm
My scenario is the following: i'm acquiring images streams from 8 simulated cameras in an simulated environment (V-Rep). Through the cv_bridge i read these images on a ROS topic and compute some image processing. Afterwards i send some data to Simulink and, after some processes, through some special S-Functions, i publish some data on ROS topics in order to control the position of the mentioned cameras.
In the image processing phase i use the OpenCV FLANN algorithm in order to compute the Homografy matrix between two consecutive frame of a single camera..
My problem is the following: even if the camera stays still (and so the two consecutive frames are the same) at every step of the node execution the number of matchings that FLANN manages to find is very oscillating: from about 350 matchings to about 2.
Furthermore i noticed, but i'm not sure, that this problem occurred as soon as the computational payload of the node increased.
What may it be due to?