초록 ▼

A focus detecting device is provided with first and second line sensors and first and second image forming lenses which are located behind a predetermined focal plane of the objective lens to receive the object lights for forming first and second images on the first and second line sensors, respecti

A focus detecting device is provided with first and second line sensors and first and second image forming lenses which are located behind a predetermined focal plane of the objective lens to receive the object lights for forming first and second images on the first and second line sensors, respectively. The image signal generated by the first line sensor is divided into a plurality of block signals each consisting of a predetermined number of picture element outputs and each block signal is compared with groups of picture element outputs of the second line sensor, with the groups shifted sequentially, to find a group which best coincides therewith and the distance between the first and second images on the line sensors is calculated in accordance with the shift position of the group thus determined, for calculation of the amount and direction of defocus of the object image on the focal plane. The calculated distance between the first and second images may be corrected in accordance with manual adjustment of adjustable means and magnification data of the first and second images stored in storage means.

대표청구항 ▼

A focus detecting device for a camera having an objective lens with an optical axis, comprising: optical means for receiving light from an object which has passed through said objective lens at two portions of said objective lens distant from the optical axis of said objective lens, to form first an

A focus detecting device for a camera having an objective lens with an optical axis, comprising: optical means for receiving light from an object which has passed through said objective lens at two portions of said objective lens distant from the optical axis of said objective lens, to form first and second object images in such a manner that the distance between said first and second object images in a direction perpendicular to said optical axis varies with the focus condition of an object image formed by said objective lens on its predetermined focal plane equivalent to a film exposure plane; first and second line sensors disposed to receive said first and second object images for generating first and second image signals corresponding to the light intensity distributions of said first and second object images on said first and second line sensors, respectively, each of said line sensors having a plurality of picture element and said first and second image signals being the collective of picture element outputs of said first and second line sensors, respectively; signal dividing means for dividing said picture element outputs of said first line sensor into a plurality of blocks such that the number of the picture element outputs belonging to each of said blocks is smaller than the number of said picture element outputs of said second line sensor; correlation calculating means for calculating correlations represented by an equation [Figure] wherein Lk+ni represents the (k+ni)-th picture element output of said first line sensor, Rk+j-1 represents the (k+j-1)-th picture element output of said second line sensor, j represents the number of shifts, mi represents a number inherent to the i-th block, and ni represents a number inherent to the i-th block and varying with the value of i; best correlation finding means for finding a best correlation having a minimum value among the correlations Hi(j) for each of said blocks; image distance calculating means for determining which of the best correlations found by said best correlation finding means is smallest and calculating the distance between said first and second images on said first and second line sensors in accordance with the number of shifts j which provides the best correlation; and defocus amount calculating means for calculating the amount of defocus of said object image with respect to said predetermined focal plane in accordance with the distance calculated by said distance calculating means.