Input image data is divided into blocks so as to make adjacent blocks partially overlap image data, and the divided image data is filtered in the unit of block. The electronic ballast system includes a circuit that allows for a fluorescent lamp to be energized without the preheating of its cathodes, a circuit for power factor correction that makes use of an average current mode implemented by a pulse-width modulator in order to derive a power factor that approaches unity for the electronic power circuit. The dummy gate electrode is formed to cover part of the active region within a region into which an N type dopant is to be implanted to form N sourcedrain regions. The memory unit records a previous voltage value of the LED. This method provides more flexibility when using optical switching in core networks, as it allows path optimization to new physical link connectivity, without requiring any change to the optical components such that, significant signal degradation tuning range for a WDM optical transport system is provided. When accessed, the error detection code is applicable to detect errors.