Patent ID: 7652714

Claim:
An imaging device comprising: a focusing lens that focuses on an object; an image sensor that receives from the focusing lens a focused light reflected from the object, the image sensor converting the focused light to an image signal for reproducing an image of the object; a lens driver that moves the focusing lens to a plurality of focal points; and a processor subsystem in communication with the lens driver and the image sensor, the processor subsystem including a magnification-changing unit that obtains a magnification changing rate for each focal point of the plurality, a size changer unit that changes a size of the image of the object according to the magnification changing rate, and an automatic focus module that extracts a predetermined frequency component of a size-changed image that is output from the size changer unit and determines an optimal focal point of the focusing lens according to the predetermined frequency component; wherein the processor subsystem maintains constant a view angle for each image photographed of the object at each focal point of the focusing lens.