Detecting compositional change in image

摘要

A method obtains an electrical signal from the photoelectric detector, which signal corresponds to the illumination of the image formed by the focusing lens. The image screen is divided into a plurality of subdivision areas. The method then calculates for the respective subdivision areas a focus evaluation value representative of a high frequency component contained in the electrical signal and a brightness value representative of a brightness of the image. The subdivision areas are sorted in accordance with a object distance classification. The method weights with different weights the subdivision areas on the basis of the subdivision area to which a main object belongs. Variations in the focus evaluation and brightness values are calculated by comparing the values after a focus and the values for an in-focus image. Compositional changes are detected based on the weights and the variation in the focus evaluation and brightness values.