Image capturing apparatus and an image capturing method

1. An image capturing apparatus comprising:

an image capturing unit for capturing an image of an object;

a focal length storing unit for storing a focal length of the object which is outside of an image capturing region of the image being captured by said image capturing unit by corresponding to a positional relationship between said image capturing unit and the object;

an image capturing region variation detecting unit for detecting variation in the image capturing region of said image capturing unit;

a positional relationship predicting unit for predicting a positional relationship between said image capturing unit and the object after the image capturing region of said image capturing unit is varied on the basis of the variation in the image capturing region detected by said image capturing region variation detecting unit; and

a focus adjustment control unit for controlling focus adjustment by said image capturing unit on the basis of the focal length stored by said focal length storing unit, wherein the focal length is corresponded to the positional relationship predicted by said positional relationship predicting unit.

2. An image capturing apparatus as claimed in claim 1 , wherein said image capturing region variation detecting unit detects the variation in the image capturing region of said image capturing unit by detecting movement of said image capturing unit.

3. An image capturing apparatus as claimed in claim 1 , wherein

said image capturing unit captures a plurality of images successively, and

said image capturing region variation detecting unit detects the variation in the image capturing region of said image capturing unit by comparing the plurality of images captured by said image capturing unit.

4. An image capturing apparatus as claimed in claim 1 , wherein

said focal length storing unit stores the focal length of the object which is outside of the image capturing region of the image being captured by said image capturing unit by corresponding a direction of said image capturing unit,

said image capturing region variation detecting unit detects variation in the direction of said image capturing unit on the basis of the variation in the image capturing unit of said image capturing unit,

said positional relationship predicting unit predicts the direction of said image capturing unit after the direction of said image capturing unit is varied on the basis of the variation of the direction of said image capturing unit detected by said image capturing region variation detecting unit, and

said focus adjustment control unit controls the focus adjustment by said image capturing unit on the basis of the focal length to the object which is outside of the image capturing region of said image capturing unit stored by said focal length storing unit and corresponded to the direction of said image capturing unit predicted by said positional relationship predicting unit.

5. An image capturing apparatus as claimed in claim 1 further comprising:

a focal length measuring unit for measuring the focal length of the object,

wherein said focal length storing unit stores the focal length measured by said focal length measuring unit in the past and corresponded to the positional relationship between said image capturing unit and the object, and

said focus adjustment control unit controls the focus adjustment by said image capturing unit on the basis of the focal length measured in the past and stored by said focal length storing unit in case the image capturing region of said image capturing unit is varied.

6. An image capturing apparatus as claimed in claim 1 further comprising:

a focal length measuring unit for measuring the focal length of the object which is outside of the image capturing region of the image being captured by said image capturing unit,

wherein said focal length storing unit stores the focal length measured by said focal length measuring unit and corresponded to the positional relationship between said image capturing unit and the object, and

said focus adjustment control unit controls the focus adjustment by said image capturing unit on the basis of the focal length of the object which is outside of the image capturing region of said image capturing unit stored by said focal length storing unit in case the image capturing region of said image capturing unit is varied.

7. An image capturing apparatus as claimed in claim 6 , wherein

said focal length measuring unit measures a focal length of an object which is outside of an image capturing region of an image captured by said image capturing unit by using electronic zooming,

said focal length storing unit stores the focal length measured by said focal length measuring unit by corresponding it to a positional relationship between said image capturing unit and the object; and

said focus adjustment control unit controls the focus adjustment by said image capturing unit on the basis of the focal length of the object which is outside of the image capturing region of said image capturing unit stored by said focal length storing unit in case the image capturing region of said image capturing unit is varied.

8. An image capturing method comprising the steps of:

storing a focal length of an object which is outside of an image capturing region of an image being captured by an image capturing apparatus in a focal length storing unit by corresponding the focal length to a positional relationship between the image capturing apparatus and the object;

detecting variation in the image capturing region of the image capturing apparatus;

predicting the positional relationship between the image capturing apparatus and the object after the image capturing region of the image capturing apparatus is varied on the basis of the detected variation in the image capturing region;

controlling focus adjustment by the image capturing apparatus on the basis of the focal length stored in the focal length storing unit and corresponded to the predicted positional relationship; and

capturing an image of the object after the focus adjustment is performed.