We have developing an intelligent mobile robot for service use which can be utilized as a "secretary or helper robot" during the day and "security guard or maintenance including floor-cleaning robot" at night in office buildings. When the service robot works or moves autonomously in an enviromnent including human beings, it should be able to recognize its environment on real time. In this paper, new biological object extraction method is developed. In order to extract objects from a frame image taken by a camera, many Virtual Flies (VFs) scattered in the CRT display are utilized. An individual VF composed of 3×3 pixels can freely fly in the display. Fundamental object extraction method is to detect objects just like flies sensing foods and swarming around them. Methodology and experimental results together with its application of Hand-Eye system using a robot manipulator are described in detail.