Method and apparatus for motion detection in auto-focus applications

An auto-focus image capture device, comprising:

• an image sensor;
• a control circuit coupled to the image sensor configured to cause the image sensor to capture electronic image data;
• an auto-focus module, operable with the control circuit, and configured to execute an auto-focus operation such that images captured by the image sensor are substantially in focus;
• a data capture module configured to initiate multiple scanning sweeps of the image sensor to obtain sets of digital values corresponding to a predetermined characteristic of incident light upon the image sensor;
• a comparison module configured to determine a change in the sets of digital values from one scanning sweep to another scanning sweep;
• and
• an image stability mechanism, operable with the control circuit, and configured to provide an image stability indication to the control circuit, and comprising an indicator module configured to provide the image stability indication to the control circuit when the change in the sets of digital values is within a range indicative of image stability;
• wherein the control circuit is configured to actuate the auto-focus module upon receiving the image stability indication from the image stability mechanism.

A portable electronic device having an image capture system, the image capture system comprising:

• an image capture device having auto-focus capabilities;
• a control circuit coupled to the image capture device configured to selectively cause the image capture device to execute an auto-focus operation in the image capture device or cause the image capture device to capture an image;
• an image stability mechanism, operable with the control circuit, and configured to provide an image stability indication to the control circuit;
• a timer;
• wherein the control circuit is at least configured to execute the auto-focus operation upon receiving the image stability indication from the image stability mechanism or, upon on expiration of the timer regardless of whether the image stability indication has been received from the image stability mechanism.