Automatic focusing system for imaging-based bar code reader

A method of focusing an image of a target object on an imaging system of an automatic identification system including an aiming apparatus generating a beam to aid in aiming the system at a target object when the system is actuated and an imaging system including a pixel array, a focusing lens to focus an image of the target object onto the pixel array, the lens movable along a path of travel, the steps of the method comprising:

• a) providing an automatic focusing system operating to move the lens along the path of travel to a position suitable for properly focusing an image of the target object onto the pixel array;
• b) analyzing an image of the beam reflected from the target object and projected onto the pixel array by the lens and employing a distance algorithm to determine a distance between the imaging system and the target object;
• c) if the distance between the imaging system and the target object is determined, moving the lens along its path of travel to a suitable position for properly focusing the target object onto the pixel array;
• and
• d) if the distance between the imaging system and the target object is not determined, using a search routine and moving the lens along its path of travel in accordance with the search routine, analyzing images of the target object at different lens positions as the lens is moved along its path of travel and stopping the movement of the lens when a satisfactory lens position is found.

A bar code reader comprising:

• a) an aiming apparatus generating a beam to aid in aiming the system at a target object when the system is actuated;
• b) an imaging system including a pixel array, a focusing lens to focus an image of the target object onto the pixel array, the lens movable along a path of travel;
• and
• c) an automatic focusing system operating move the lens along the path of travel to a position suitable for properly focusing an image of the target object onto the pixel array, the automatic focusing system:
• 1) analyzing an image of the beam reflected from the target object and projected onto the pixel array by the lens and the employing a distance algorithm to determine a distance between the imaging system and the target object;
• 2) if the distance between the imaging system and the target object is determined, moving the lens along its path of travel to a suitable position for properly focusing the target object onto the pixel array;
• and
• 3) if the distance between the imaging system and the target object is not determined, using a search routine and moving the lens along its path of travel in accordance with the search routine, analyzing images of the target object at different lens positions as the lens is moved along its path of travel and stopping the movement of the lens when a satisfactory lens position is found.