| 摘要 |
PURPOSE:To realize a focusing operation short in focusing time and high in focusing accuracy even if there are plural maximal points in a contrast characteristic. CONSTITUTION:This automatic focusing detector is constituted to have an imaging optical system which takes in the light image of a subject S placed on a stage 1 via an objective lens 3 and image a subject image, an image sensor 6 which reads the front focus image and rear focus image formed in the front and rear positions optically conjugate with the predetermined imaging plane of this imaging optical system, a contrast calculating means 12 which calculates a contrast value in accordance with an evaluation function from the respective image signals of the front focus image and the rear focus image from this image sensor 6, a contrast comparing means which compares the contrast value of the front focus image and the contrast value of the rear focus image, a image shape comparing means 8 which compares the shapes of the front focus image and rear focus image formed on the image sensor 6 and a driving control means which controls a driving direction and driving quantity in accordance with the respective results of the comparison. |
