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US 5,856,663 AGranted
Focus detecting apparatus with virtual centering of line sensor
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorsShinichi Suzuki, Masahiro Nakata
Life of this patent
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Abstract
A focus detecting apparatus includes a focus detecting device which forms an image through a telephotographic system, onto a line sensor, and which detects a focus state of the telephotographic system based on an output from a predetermined portion of the line sensor. An assigning device which assigns the pixels to be used in detecting the focusing state in the case where the actual center of the line sensor deviates from the reference position of the telephotographic system.
Claims11
A focus detecting apparatus, comprising:
- a line sensor having a physical center in a horizontal direction;
- a telephotographic system having a reference horizontal position, said telephotographic system forming an image onto said line sensor;
- a focus detecting device that detects a focus state of said telephotographic system based on an output from a predetermined portion of said line sensor;
- and
- an assigning device that assigns which pixels are to be used as said predetermined portion for detecting a focusing state when the physical center of the line sensor deviates in the horizontal direction from the reference horizontal position of the telephotographic system.
2 more elements
A focus detecting apparatus, comprising:
- a line sensor having a physical center in a horizontal direction;
- a telephotographic system having a reference horizontal position, said telephotographic system forming an image onto said line sensor;
- a focus detecting device that detects a focus state of said telephotographic system based on an output from a predetermined portion of said line sensor;
- and
- an assigning device that assigns which pixels are to be used as said predetermined portion for detecting a focusing state where the physical center of the line sensor deviates in the horizontal direction from the reference horizontal position of the telephotographic system.
2 more elements
A focus detecting apparatus of a surveying instrument, comprising:
- a telephotographic optical system including an objective lens group, a focusing lens group, a focusing plate having a reticle, and an eyepiece lens group for observing an image formed on said focusing plate;
- a beam splitting optical system positioned between said focusing lens group and said focusing plate for splitting an image of said telephotographic system along two optical paths;
- a light receiving device, said reticle being near the horizontal center of the light receiving device and positioned to span each of the two optical paths, said light receiving device having a focus detecting portion on which an image corresponding to the image formed on said focusing plate;
- a calculating device for calculating a defocus amount in accordance with phase difference values detected by said light receiving device;
- and
- a shifting device for shifting the portion of said light receiving portion defined as said focus detecting portion within said line sensor so that the center of said focus detecting portion aligns with said reticle.
3 more elements
A focus detecting apparatus of a surveying instrument, comprising:
- a telephotographic optical system;
- a focusing device including a focus plate having a reticle, and a line sensor having a focus detecting portion, said focusing device being arranged to form an optical image, transmitted through said telephotographic optical system, on said focus detecting portion;
- a shifting means for shifting said focus detecting portion within said line sensor so that the center of said focus detecting portion aligns with said reticle.
A focus detecting apparatus, comprising:
- a line sensor extending in a horizontal direction;
- a telephotographic system that forms an image on said line sensor, said telephotographic system having a horizontal center along said horizontal direction;
- an assigning system for setting a virtual center of said line sensor, said virtual center being defined by a set of pixels bracketing said horizontal center of said telephotographic system, said virtual center of said line sensor differing from an actual center of said line sensor by the displacement of the physical center of said line sensor in said horizontal direction from said horizontal center of said telephotographic system;
- and
- a focus detecting device that detects a focus state of said telephotographic system based on an output from pixels of said line sensor bracketing the virtual center.
2 more elements
Dependencies are inferred from the claim text.