1. A dynamic range three-dimensional image system, comprising: an optical detector including a gain control terminal capable of controlling an optical amplification gain; a pixel detecting module for detecting a pixel signal for configuring an image by receiving an output of the optical detector; a high dynamic range (HDR) generating module for acquiring a dynamic range image by generating a signal indicating a saturation degree of the pixel signal and combining the pixel signal based on the pixel signal detected by the pixel detecting module; and a gain control signal generating module generating an output signal for supplying required voltage to the gain control terminal of the optical detector based on a magnitude of the signal indicating the saturation degree of the pixel signal.