The investigations of systems which allow to avoid obstacles by the unmanned aerial vehicles (UAV) are presented in the paper. The systems are designed to enable the full autonomous UAV flight in unknown, dynamic environment. Presented solutions enable to real-time control of the image brightness, without significantly disturbing the objectivity of the vision system. Single board ADSP-BF537 computer with built-in CMOS camera was used in the experimental studies. The final stage of the task is to perform fully autonomous missions of flying object with the real obstacles on its trajectory.