A linear image sensor which has an enhanced image resolution, and requires reduced processing time, and is low in cost. The RFID system comprises an RFID reader and at least one antenna for transmitting and receiving RF signals to communicate with the RFID tags. The antenna module disposed in the axle is fixed to the main body. The optical fiber has a core that is doped. This exposure controller is adapted for down-sizing a software processor while eliminating the necessity of any complicated process such as functional operation.