| 摘要 |
PROBLEM TO BE SOLVED: To provide a focus determination technology in which the variations in determination is less. SOLUTION: The focus determination method of the present invention includes (1) an imaging step in which at least two kinds of patterns of different spatial frequencies are photographed by an optical device, and image data is captured; (2) a contract calculation step, in which the image data is processed, a low frequency contrast is obtained from the signal amplitude of the low frequency pattern, and a high-frequency contrast is obtained from the signal amplitude of the high-frequency pattern; (3) a difference calculation step in which a difference between the low-frequency contrast and high-frequency contrast is calculated; and (4) a focus determination step in which determination is made whether the difference is an extreme value or lies within the tolerance of the extreme value. COPYRIGHT: (C)2009,JPO&INPIT |
