Well, after some configuration, and re-flashing the firmware of optical flow camera. I used the analyzer of QGC without arming or taking off, I see that x, y value are changing in real time especially when moving the drone, or moving some objects under the camera, which mean that it does work, However. when starting a flight test, the log values for x and y are always 0.
I remember the last flight, i switched from stabilized to altitude control, and the drone increased the throttle and got up to 3 meter directly for no obvious reason.
http://logs.uaventure.com/view/E6RKa7RrjhSNBtGnNQ6Vxi
http://logs.uaventure.com/view/cFSYUvdKCB4rrypEYsA8n4
Any ideas???
Thanks