Automatic focusing device

An automatic focusing device for a camera, comprising:

• a phototaking lens for forming an image of an object on a predetermined plane;
• focus detecting means for detecting the amount of defocus of an image plane of said phototaking lens with respect to said predetermined plane;
• lens position detecting means for detecting the position of said phototaking lens;
• in-focus lens position determining means for intermittently determining an in-focus lens position to which said phototaking lens is to be focused, based on said defocus amount and the detected lens position;
• in-focus position memory means for storing plural in-focus lens positions and times generated time-sequentially;
• lens movement pattern memory means for storing, as lens movement pattern information, the relationship between the lens position and time for focusing said phototaking lens to a particular moving object;
• lens movement pattern compensating means for compensating said lens movement pattern information and generating compensated lens movement pattern information having reduced error relative to the in-focus lens position determined by said in-focus lens position determining means;
• and
• lens drive controller means for effecting drive control of said phototaking lens according to said compensated lens movement pattern information.

An automatic focusing device for a camera, comprising:

• a phototaking lens for forming an image of an object on a predetermined plane;
• focus detecting means for detecting the amount of defocus of an image plane of said phototaking lens with respect to said predetermined plane;
• lens position detecting means for detecting the position of said phototaking lens;
• in-focus lens position determining means for determining an in-focus lens position to which said phototaking lens is to be focused, based on said defocus amount and said lens position;
• lens movement pattern memory means for determining and storing lens movement pattern information indicating a relationship between the lens position and time for focusing said phototaking lens to a particular moving object, based on plural in-focus lens positions and times generated time-sequentially;
• and
• lens drive controller means for effecting drive control of said phototaking lens based on said lens movement pattern information.

An automatic focusing device for a camera, comprising:

• a phototaking lens for forming an image of an object on a predetermined plane;
• focus detecting means for detecting the amount of defocus of an image plane of said phototaking lens with respect to said predetermined plane;
• tracking means for generating a tracking signal indicating predicted movement of the object based on plural past defocus amounts;
• movement pattern determining means for determining a function representing a movement pattern of the object, based on information relating to the object movement and on said defocus amount;
• prediction means for generating a signal representing predicted movement of the object according to said function;
• deviation discrimination means for discriminating whether the latest defocus amount obtained by said focus detecting means is deviated from the movement represented by the predicted movement signal generated by said prediction means;
• prediction controller means for calculating a drive amount of said phototaking lens either based on said predicted movement signal when a deviated state is identified by said deviation discrimination means, or on said tracking signal when a non-deviated state is identified;
• and
• lens drive means for driving said phototaking lens according to said lens drive amount.

An automatic focus device for a camera, comprising:

• a phototaking lens for forming an image of an object on a predetermined plane;
• focus detection means for detecting the amount of defocus of an image plane of said phototaking lens with respect to said predetermined plane;
• lens movement pattern memory means for storing, as lens movement pattern information, the relationship between the lens position and time for focusing said phototaking lens to a particular moving object;
• means for modifying the relationship between the lens position and time of the stored lens movement pattern information on the basis of the amount of defocus detected by said focus detection means during driving of said phototaking lens;
• and
• lens drive controller means for controlling the driving of said phototaking lens according to the modified relationship between the lens position and time.