Ophthalmologic apparatus and auto-alignment method

• US 6,733,129 B2
• Filed: 03/26/2002
• Issued: 05/11/2004
• Est. Priority Date: 03/29/2001
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Masaki, Toshifumi
• Primary Examiner(s): Ruhl, Dennis W.
• Assistant Examiner(s): SANDERS JR, JOHN R
• Application Number:
  US10/107,467
• Publication Number:
  US 20020159028A1
• Time in Patent Office: 777 Days
• Field of Search: 351/200, 351/205, 351/206, 351/208, 351/210, 351/211-216, 351/221, 351/246, 128/898, 600/558
• US Class Current: 351/208
• CPC Class Codes: A61B 3/152 for aligning

Abstract

An aligning method for an ophthalmologic apparatus including a measurement optical system for measuring the eyes of an object to be examined and an illumination system for illuminating the eyes with extrinsic eye light is disclosed. When a reflected cornea image can be detected by irradiating an eye of the object with alignment light, alignment of the measurement optical system is executed on the basis of the reflected cornea image. If no reflected cornea image of the alignment light can be detected, a reflected cornea image formed by the extrinsic eye light is detected, and alignment of the measurement optical system is executed on the basis of the reflected cornea image formed by the extrinsic eye light. Thereafter, the reflected cornea image is detected again.

Claims

1. An ophthalmologic apparatus comprising:

(1) a movable measurement unit which includes a measurement optical system for measuring an eye to be examined;

(2) a first light source which irradiates the eye with first light from a direction different from that of an optical axis of said measurement optical system;

(3) a second light source which irradiates the eye with second light from an optical axis direction of said measurement optical system;

(4) image pickup means for obtaining image information of the eye;

(5) first detection means for detecting a positional relationship between said measurement unit and the eye on the basis of information of the first reflected cornea image formed by said first light source on the basis of image information from said image pickup means; and

(6) second detection means for detecting a positional relationship between said measurement unit and the eye on the basis of information of the second reflected cornea image formed by said second light source on the basis of image information from said image pickup means,

wherein said measurement unit is driven to be aligned with the eye on the basis of a detection result formed by said first detection means when said second detection means does not detect the positional relationship between said measurement unit and the eye.

2. An apparatus according to claim 1, further comprising:

(1) pupil position detection means for obtaining a position of a pupil on the basis of image information from said image pickup means; and

(2) further detection means for detecting a positional relationship between said measurement unit and the eye on the basis of pupil position information detected by said pupil position detection means.

3. An apparatus according to claim 1, further comprising control means for performing control to align said measurement unit with the eye on the basis of a detection result obtained by said second detection means after aligning said measurement unit with the eye on the basis of a detection result obtained by said first detection means.

4. An apparatus according to claim 3, wherein when a positional relationship between said measurement unit and the eye cannot be detected by said second detection means, said control means controls said measurement unit to align said measurement unit with the eye on the basis of a detection result obtained by said second detection means after driving said measurement unit on the basis of a detection result obtained by said first detection means.

5. An apparatus according to claim 1, wherein said unit can move in up-and-down, right-and-left, and forward-and-backward directions with respect to the eye, said first detection means performs position detection in the up-and-down, right-and-left, and forward-and-backward directions, and said second detection means performs at least detection in the forward-and-backward direction.

6. An apparatus according to claim 1, wherein each of said first and second detection means includes a process which processes the image information and computes a positional relationship between said measurement unit and the eye.

7. An auto-alignment method for an ophthalmologic apparatus including a measurement optical system which measures an eye to be examined, an illumination system which illuminates the eye with extrinsic eye light, and an image pickup device to obtain image information of the eye, comprising:

(1) the detection step of irradiating the eye with a light beam through the measurement optical system, and detecting a reflected cornea image of the light beam on the basis of the image information;

(2) the aligning step of, when a reflected cornea image can be detected in the detection step, aligning the measurement optical system with the eye on the basis of the reflected cornea image; and

(3) the step of, when no reflected cornea image can be detected in the detection step, detecting a reflected cornea image based on the illumination of extrinsic eye light from the image information, aligning the measurement optical system in accordance with the reflected cornea image, and then performing the detection step again.

9. A method according to claim 7, wherein the reflected cornea image formed by the illumination of extrinsic eye light and a pupil position are detected, and the alignment is executed on the basis of a positional relationship between the reflected cornea image and the pupil position.

14. A method according to claim 9, wherein in the first aligning step, alignment in up-and-down, right-and-left, and forward-and-backward directions is executed, in the second aligning step, alignment in the up-and-down and right-and-left directions is executed, and in the third aligning step, at least alignment in the forward-and-backward direction is executed.

8. An auto-alignment method for an ophthalmologic apparatus including a measurement optical system which measures an eye to be examined, an illumination system which illuminates the eye with extrinsic eye light, and image pickup means for obtaining image information of the eye, comprising:

(1) the detection step of irradiating the eye with a light beam through the measurement optical system, and detecting a reflected cornea image of the light beam on the basis of the image information from the image pickup means;

(2) the first aligning step of, when a reflected cornea image can be detected in the detection step, aligning the measurement optical system with the eye on the basis of the reflected cornea image;

(3) the second aligning step of, when no reflected cornea image can be detected in the detection step, detecting a pupil image of the eye, aligning the measurement optical system in accordance with the pupil image, and then shifting the detection step; and

(4) the third aligning step of, when the reflected cornea image cannot be detected even after the second aligning step, detecting a reflected cornea image based on the illumination of extrinsic eye light on the basis of image information from the image pickup means, aligning the measurement optical system in accordance with the reflected cornea image, and then shifting to the detection step.

10. A method according to claim 8, wherein in the first aligning step, alignment in up-and-down, right-and-left, and forward-and-backward directions is executed, in the second aligning step, alignment in the up-and-down and right-and-left directions is executed, and in the third aligning step, at least alignment in the forward-and-backward direction is executed.

13. A method according to claim 8, wherein the reflected cornea image formed by the illumination of extrinsic eye light and a pupil position are detected, and the alignment is executed on the basis of a positional relationship between the reflected cornea image and the pupil position.

11. An auto-alignment method for an ophthalmologic apparatus including a measurement optical system which measures an eye to be examined, and image pickup means for obtaining image information of the eye, comprising:

(1) the detection step of irradiating the eye with a light beam through the measurement optical system, and detecting a reflected cornea image of the light beam on the basis of the image information from the image pickup means;

(2) the aligning step of, when a reflected cornea image can be detected in the detection step, aligning the measurement optical system with the eye on the basis of the reflected cornea image; and

(3) the step of, when no reflected cornea image can be detected in the detection step, detecting a pupil image of the eye on the basis of an image signal from the image pickup means, aligning the measurement optical system in accordance with the pupil image, and performing the detection step again.

12. An auto-alignment method for an ophthalmologic apparatus including a measurement optical system which measures an eye to be examined, and image pickup means for obtaining image information of the eye, comprising:

(1) the detection step of irradiating the eye with a light beam through the measurement optical system, and detecting a reflected cornea image on the basis of image information from the image pickup means;

(2) the first aligning step of, when a reflected cornea image can be detected in the detection step, aligning the measurement optical system with the eye on the basis of a position of the eye which is discriminated based on the reflected cornea image;

(3) the second aligning step of, when no reflected cornea image can be detected in the detection step, detecting a pupil image of the eye on the basis of image information from the image pickup means, aligning the measurement optical system in accordance with the pupil image, and then shifting to the detection step; and

(4) the third aligning step of, when the reflected cornea image cannot be detected even after the second aligning step, detecting the reflected cornea image on the basis of the image information from the image pickup means, aligning the measurement optical system in accordance with the reflected cornea image, and then shifting the detection step.

15. An ophthalmologic apparatus comprising:

(1) a movable measurement unit which includes a measurement optical system for measuring an eye to be examined;

(2) a first light source which irradiates the eye with first light from a direction different from that of an optical axis of said measurement optical system;

(3) a second light source which irradiates the eye with second light from an optical axis direction of said optical measurement optical system;

(4) image pickup means for obtaining image information of the eye;

(5) first detection means for detecting a positional relationship between said measurement unit and the eye on the basis of information of the first reflected cornea image formed by said first light source on the basis of image information from said image pickup means;

(6) second detection means for detecting a positional relationship between said measurement unit and the eye on the basis of information of the second reflected cornea image formed by said second light source on the basis of image information from said image pickup means;

(7) pupil position detection means for obtaining a position of a pupil on the basis of image information from said image pickup means; and

(8) third detection means for detecting a positional relationship between said measurement unit and the eye on the basis of pupil position information detected by said pupil position detection means,

wherein said measurement unit is driven to be aligned with the eye on the basis of one of detection results formed by sequentially changing over said first detection means, second detection means, and third detection means.