Continuous autofocus mechanisms for image capturing devices

A method to implement a continuous autofocus mechanism for an image capturing device, the method comprising:

• performing an autofocus scan that positions a lens of the image capturing device in a plurality of positions;
• obtaining a plurality of focus scores with each focus score being associated with a respective lens position of the autofocus scan;
• determining an acceptable band of focus scores based on the obtained plurality of focus scores, wherein determining the acceptable band of focus scores comprises determining a lower limit and an upper limit of the acceptable band of focus scores;
• determining an intersection of the current score on a focus graph of focus scores versus lens positions if the current score is less than the lower limit of the acceptable band of scores;
• estimating a lens position based on the intersection;
• and
• starting a refocus scan, which is a new autofocus scan, at the lens position.

A method to implement a continuous autofocus mechanism for an image capturing device, the method comprising:

• performing an autofocus scan that positions a lens of the image capturing device in a plurality of positions;
• obtaining a plurality of focus scores with each focus score being associated with a respective lens position of the autofocus scan;
• determining an acceptable band of focus scores based on the obtained plurality of focus scores;
• determining whether a lens is focused close to infinity;
• and
• setting a starting position that corresponds to the lens focused at infinity for a refocus scan if the lens is focused close to infinity.

A machine readable medium containing executable computer program instructions which when executed by a data processing system cause said system to perform a method, the method comprising:

• performing an autofocus scan for a lens of the image capturing device;
• obtaining a plurality of focus scores associated with the autofocus scan;
• and
• determining an acceptable band of focus scores based on the obtained focus scores, wherein determining the acceptable band of focus scores comprises determining a lower limit and an upper limit of the acceptable band of focus scores, wherein determining the acceptable band of focus scores comprises determining a first derivative of a peak focus score value with respect to a first focus score value that is adjacent to the peak focus score value and determining a first derivative of the peak focus score value with respect to a second focus score value that is adjacent to the peak focus score value, wherein the first focus score value is associated with a different lens position than the second focus score value.

A machine readable medium containing executable computer program instructions which when executed by a data processing system cause said system to perform a method, the method comprising:

• performing an autofocus scan for a lens of the image capturing device;
• obtaining a plurality of focus scores associated with the autofocus scan;
• and
• determining an acceptable band of focus scores based on the obtained focus scores, wherein determining the acceptable band of focus scores comprises determining a lower limit and an upper limit of the acceptable band of focus scores;
• determining whether a frame is stable;
• determining a current lens position and a current focus score associated with the frame if the frame is stable;
• determining whether the current focus score associated with the frame is within the acceptable band of focus scores;
• setting the lens position to a new position in which the lens moves from the current position by a predetermined adjustment towards a lens position associated with the lens being focused near infinity if the current score is greater than the upper limit of the acceptable band of scores;
• and
• starting a refocus scan at the new position.

An image capturing device, comprising:

• a storage device to store a plurality of captured images;
• a lens to receive incident light associated with an image to be captured;
• and
• a processing system coupled to the storage device, the processing system is configured to perform an autofocus scan, to obtain a plurality of focus scores associated with the autofocus scan;
• and to determine an acceptable band of focus scores for the lens based on the obtained focus scores, wherein to determine the acceptable band of focus scores comprises determining a lower limit and an upper limit of the acceptable band of focus scores, wherein to determine the acceptable band of focus scores comprises determining a first derivative of a peak focus score value with respect to a first focus score value that is adjacent to the peak focus score value and determining a first derivative of the peak focus score value with respect to a second focus score value that is adjacent to the peak focus score value, wherein the first focus score value is associated with a different lens position than the second focus score value.

An image capturing device, comprising:

• a storage device to store a plurality of captured images;
• a lens to receive incident light associated with an image to be captured;
• and
• a processing system coupled to the storage device, the processing system is configured to perform an autofocus scan, to obtain a plurality of focus scores associated with the autofocus scan;
• and to determine an acceptable band of focus scores for the lens based on the obtained focus scores, wherein to determine the acceptable band of focus scores comprises determining a lower limit and an upper limit of the acceptable band of focus scores, wherein the processing system is configured to determine whether a refocus scan is needed and to start a refocus scan, wherein the processing system is configured to perform the refocus scan by positioning the lens in a plurality of positions, wherein the processing system is configured to detect that the lens has moved past a predetermined position and to abort the refocus scan without moving the lens to the remaining positions of the refocus scan.

A method, comprising:

• determining motion information for an image capturing device using one or more motion sensors;
• determining whether the device is moving based on the motion information;
• and
• filtering a plurality of focus scores based on the motion information, wherein each focus score is filtered by applying a dampening factor to each focus score based on the associated motion information with the dampening factor indicating how fast a filter reacts to changes in the focus scores.

A method, comprising:

• determining motion information for an image capturing device using a motion sensor;
• determining whether the device is moving based on the motion information;
• starting or stopping an autofocus mechanism based on the motion information;
• and
• parking a lens position of a lens of the device at a hyperfocal position if the device is moving for a period of time that compares in a predetermined manner with a threshold value.