| 摘要 |
PROBLEM TO BE SOLVED: To improve accuracy at a level for business use by extracting the high frequency components of the specified area of image signals, generating an evaluation value, cyclically calculating the acute angle rate of the change curve of the evaluation value from a present field to prescribed fields before and moving a focus to a position where the acute angle rate is relatively high. SOLUTION: An image pickup block converts incident light from a lens block to the electric image pickup signals of RGB(red, green and blue) and the CPU 138 of an AF block 137 extracts the high frequency components of the specified area of the image pickup signals, generates the evaluation value used for AF(automatic focusing) and stores the evaluation value and the position of a focus lens 111 corresponding to it in a RAM 143. Then, a main CPU 141 cyclically calculates the acute angle rate which is the index of how much the change curve of the evaluation value from the present field to the prescribed fields before is sharpened locally and moves the focus to a focus position where the acute angle rate is relatively high when the search of a prescribed area is ended. |
