Ophthalmic Device Pseudo Target Display for Alignment
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Solution Overview
Problem
Conventional fundus cameras face difficulties in automatic focusing and alignment operations due to out-of-focus optical images of split targets and alignment targets, especially when one target is blocked by the eye's pupil, leading to increased complexity and cost, and the need for additional mechanisms to handle inappropriate working distances.
Innovation Solution
An ophthalmic device with a pseudo target display processing unit that detects the positions of split and alignment targets in the observation video signal and displays pseudo targets on the monitor, allowing for easier manual operation and reliable automatic alignment and focusing, regardless of the display states of the optical image targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If automatic focusing is performed using optical images of split targets, then the burden on the examiner during focusing operation is reduced, but the automatic focusing operation cannot be completed when the optical images of the split targets are out of focus or when only one of the upper and lower split targets can be detected
Solution Approach 1:
The patent creates a pseudo alignment target that is a synthetic copy constructed from image data of the actual alignment target. This pseudo target is generated and displayed on the monitor to guide alignment operations, providing a reliable visual reference even when the actual alignment target is difficult to detect or blocked by the pupil. The pseudo target serves as a faithful reproduction that enables automatic alignment functionality to complete successfully under conditions where direct observation of the real target would fail.
2Ease of operation
If automatic alignment is performed using an optical image of an alignment target, then the burden on the examiner during alignment adjusting operation is reduced, but the automatic alignment operation cannot be completed when the optical image of the alignment target is out of focus or when only one of two alignment targets can be detected
Solution Approach 1:
The patent generates a pseudo alignment target by processing image data of the actual alignment target and displays it on the monitor. This pseudo target provides a reliable visual reference for alignment operations even when the actual alignment target is out of focus or partially blocked. The copying approach ensures that the alignment guidance information remains visible and usable under challenging optical conditions.
Solution Approach 2:
The pseudo alignment target acts as an intermediary between the actual alignment target and the examiner's visual system. When the actual target is difficult to detect directly, the pseudo target serves as a mediating representation that conveys the necessary alignment information. This intermediary enables the automatic alignment system to function reliably by providing visual feedback that is not constrained by the optical limitations affecting the real target.
3Adaptability or versatility
If conventional fundus camera is used with small pupil, then examination can be performed, but the focusing operation becomes difficult when one split target is blocked by the pupil of the eye to be examined
Solution Approach 1:
The patent creates a pseudo alignment target that is synthesized from image data and displayed on the monitor. This pseudo target provides reliable visual guidance for alignment operations even when the actual alignment target is blocked by the pupil or difficult to detect. The copying approach ensures continuous visibility of alignment references regardless of pupil size or optical obstructions.
Data Source
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AI summary
This object aims to provide an ophthalmic device in which an alignment adjusting manipulation or a focusing manipulation can be easily carried out at a manual operation and an alignment adjusting operation or a focusing operation can be surely achieved at an automatic operation regardless of a display condition of a target of an optical image used for carrying out the alignment adjusting manipulation and the focusing manipulation. An ophthalmic device is provided with a photographing optical system (20) that photographs an eye fundus (Ef); an illumination optical system (30) that illuminates the eye fundus (Ef); a split target projection optical system (60) that projects a split target (SL) for focusing the photographing optical system (20) on the eye fundus (Ef), an alignment target projection optical system (40) that projects an alignment target(AL) for aligning the photographing optical system (20) with an examining eye (E); an observation optical system (30) that displays optical images of the eye fundus (Ef), the split target (SL) and the alignment target (AL) on a monitor (31); and a quasi-target display processing unit (316) that takes an observation video signal output by the observation optical system in, detects at least one of positions of the split target (SL) and the alignment target (AL) in the observation video signal, and displays a quasi-target on the monitor (31) in accordance with the detected position.