| 摘要 |
PROBLEM TO BE SOLVED: To focus a lens for picking up the image of an object without using the conventional range-finder. SOLUTION: This lens focusing device F1 focusing the lens 1 by using the difference of a picture element data value, for example, is provided with a focusing device 3 having a lens position moving means for changing a distance between the lens 1 and the object by moving the lens 1 along an optical axis, a CCD 11 having an image pickup means for picking up the image of the object through the lens 1, an A/D converter 5, a frame memory 6, a strain calculator 7 having an arithmetic means and a strain comparator 8 having a focusing means. In the case of focusing the lens 1, the image pickup means of the CCD 4 picks up the image of the object through the lens 1, and the arithmetic means of the calculator 7 calculates the difference of the picture element data value of plural adjacent minute areas out of the image data of the object the image of which is picked up, then the focusing means of the comparator 8 allows the lens position moving means of a focusing unit 3 to move the lens 1 in a direction where the difference of the picture element data value calculated gets larger. |
