Automatic focus system calibration for image capture systems

A method for calibrating a scene image capture system having a taking lens system that focuses light from a field of view onto an image sensor and that can be set to a range of different focus settings to provide different focus distances said image capture system being mounted to a common body with a rangefinder that determines distances from the scene image capture system to portions of a scene within the field of view without using the scene image capture system, the method comprising the steps of:

• capturing a set of images with the taking lens system automatically set to a range of different focus settings for each image;
• and
• identifying captured images that were captured with the lens system at different settings than others of the captured images and that depict a portion of the field of view in focus, and obtaining for each identified image a rangefinder determined distance from the scene image capture system to the portion of the field of view depicted in the identified image that has a predetermined degree of focus;
• and
• storing correlation data that associates the rangefinder determined distance for the image and setting of the taking lens system at the time that the additional image was captured, so that a focus correlation can be established associating distance values with corresponding focus settings over the range of different focus settings.

An imaging system comprising

• a body,
• a scene image capture system mounted to the body, said scene image capture system capturing images using a taking lens system that can be set to a plurality of different focus distances;
• a rangefinder mounted to the body, said rangefinder being adapted to determine a distance between the rangefinder and a portion of a scene within a field of view of the scene image capture system;
• and
• a controller adapted to automatically capture a first calibration image through the taking lens system with the taking lens system set to a first focus distance setting, to identify a portion of the first calibration image having a predetermined degree of focus and to use the rangefinder to measure a first calibration distance from the imaging device to the identified portion;
• wherein said controller determines a focus correlation based upon the first calibration distance and the first focus distance setting used to capture the first image, said focus correlation associating different rangefinder determined distances with the plurality of focus distance settings;
• said controller further being adapted to detect a capture condition indicating that the image capture system is to be used to capture an archival image of a scene, and, when the capture condition is detected, the controller causes the rangefinder to determine a capture distance from the imaging system to a portion of the field of view of the taking lens system, and the focus distance setting for the taking lens system is set for the capture of the image based upon the determined focus correlation and the determined capture distance.