Patent ID: 8269856

Claim:
An automatic focusing system in a low-illumination setting, comprising: a lens module for taking an image; an image sensor connected with the lens module for converting the taken image into digital image signals; a gain adjustment unit connected to the image sensor for adjusting a gain of the digital image signals in order to reduce a noise associated with the digital image signals; a memory bits retrieving unit connected with the gain adjustment unit for retrieving data in memory bits of the digital image signals after the noise associated with the digital image signals has been reduced; a tone adjustment unit connected with the memory bits retrieving unit for performing a tone adjustment for the digital image signals, thereby increasing a contrast of the digital image signals; a focused image generating unit connected with the tone adjustment unit for receiving the digital image signals, and converting the digital image signals into a focused image; and a focusing unit connected to the focused image generating unit and the lens module, wherein the focusing unit firstly calculates a definition of the focused image, and automatically adjusts the lens module for further photographing according to a focus associated with the definition.