An endoscope apparatus according to an aspect of the invention comprises an imaging unit, a detection unit, a process unit, and a measurement unit. The data classification system includes a fetch unit, a classification tree module, and a data repository. If the task scheduling request is granted, then the allocation manager adds the corresponding task to a prioritized task table. One lead of the current mirror is level-shifted by a transistor coupled to another current source, wherein the coupling of the transistor and the current source form the output of the amplifier.