초록 ▼

In a still video camera or the like which employs a solid-state image sensor, such as a CCD, a first calculation of the amount of correlation in an AF sensor is executed by using a smaller number of pixels and a larger amount of shifting, and second and subsequent calculations of the amount of corre

In a still video camera or the like which employs a solid-state image sensor, such as a CCD, a first calculation of the amount of correlation in an AF sensor is executed by using a smaller number of pixels and a larger amount of shifting, and second and subsequent calculations of the amount of correlation are executed by using a larger number of pixels and a smaller amount of shifting. Accordingly, it is possible to reliably detect a large-defocus state through the first calculation, whereby it is possible to omit an unnecessary calculation to reduce the required calculation time. The automatic focusing device uses a phase difference detection method in which a focus state is detected by detecting the deviation between two incident images. The device includes two sensor portions for receiving two images which are each a variable in their image forming portions according to a focus state. The device also includes a correlation computing device for computing the correlation between signals from the two sensor portions by relatively shifting the output signals with a predetermined pitch. The device also includes a driver for driving a focus lens to the in-focus point according to the outputs of the computing device and also includes a control for changing the predetermined pitch with which the output signals of the two sensor portions are shifted.

대표청구항 ▼

[ What is claimed is:] [1.] An automatic focusing device of phase-difference detection type, in which a focus state is detected by detecting deviation between two incident images, comprising:a) image sensing means composed of two sensor portions for receiving two images each variable in their image

[ What is claimed is:] [1.] An automatic focusing device of phase-difference detection type, in which a focus state is detected by detecting deviation between two incident images, comprising:a) image sensing means composed of two sensor portions for receiving two images each variable in their image forming positions according to the focus state,b) correlation computing means for computing correlation between output signals from the two sensor portions by relatively shifting the output signals with a predetermined pitch,c) driving means for driving a focus lens to an in-focus point according the outputs of the correlation computing means, andd) control means for changing a predetermined range with which the output signals of the two sensor portions are shifted and a unit of a shifting pitch between the two sensor portions between a rough focus detecting mode and a high accuracy focus detecting mode and changing shiftable ranges of the two sensor portions for computing the correlation on the image sensing means so that a number of pixels of the sensor portions operable in the high accuracy focus detecting mode is larger than that in the rough focus detecting mode and the unit of the shifting pitch in the high accuracy focus detecting mode is smaller than in the rough focus detecting mode.