Patent ID: 7990460

Claim:
A method of focusing a digital camera module with an image sensor, the method comprising: capturing images of a test target with the digital camera module; determining a focus quality of each respective captured image with the image sensor in accordance with a variance in a spatial first derivative generated based on overlapping and offset first and second portions of the respective captured image, the variance determined by analyzing only one or more regions of interest of the respective captured image, the one or more regions of interest collectively defining less than 50% of an entirety of the respective image, the first and second portions of the respective captured image encompassed within the one or more regions of interest; generating, from the digital camera module, a binary output signal, indicative of whether the focus quality is increasing as subsequent images are captured; sending the binary output signal to a focusing station external to the digital camera module; and changing, by the focusing station, a position of a lens from the image sensor within the digital camera module to adjust the focus quality of the subsequently captured images in accordance with the binary output signal.