Optical tomographic imaging method and apparatus

• US 7,954,948 B2
• Filed: 12/11/2009
• Issued: 06/07/2011
• Est. Priority Date: 12/26/2008
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sugita, Mitsuro, Nozato, Koji, Katayama, Akihiro, Hirose, Futoshi
• Primary Examiner(s): MAI, HUY KIM
• Application Number:
  US12/636,607
• Publication Number:
  US 20100165289A1
• Time in Patent Office: 543 Days
• Field of Search: 351/205, 351/206, 351/210, 351/221, 351/246, 356/450, 356/477, 356/479, 356/496, 356/497
• US Class Current: 351/206
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: G01B 9/02002 using two or more frequencies
• CPC Class Codes: G01B 9/02063 by particular alignment of focus position, e.g. dynamic focussing in optical coherence tomography
• CPC Class Codes: G01B 9/02085 Combining two or more images of different regions
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence

Abstract

An optical tomographic imaging method is provided in which light from a light source is split into a measuring beam and a reference beam, the measuring beam being moved by a scanning optical system and guided to an object to be examined, the reference beam being guided to a reference mirror, and in which a tomogram of the object is generated from a return beam of the measuring beam reflected or scattered by the object and the reference beam reflected by the reference mirror. The method includes acquiring longitudinal sectional information on the object, calculating depth-position information on the object from the longitudinal sectional information, and acquiring a three-dimensional surface image of the object by controlling a reference-path length defined by the reference mirror and a scanning operation of the scanning optical system in accordance with the depth-position information on the object.

Claims

1. An optical tomographic imaging method in which light from a light source is split into a measuring beam and a reference beam, the measuring beam being moved by a scanning optical system and guided to an object to be examined, the reference beam being guided to a reference mirror, and in which a tomogram of the object is generated from a return beam of the measuring beam reflected or scattered by the object and the reference beam reflected by the reference mirror, the method comprising:

acquiring longitudinal sectional information on the object;

calculating depth-position information on the object from the longitudinal sectional information; and

acquiring a three-dimensional surface image of the object by controlling a reference-path length defined by the reference mirror and a scanning operation of the scanning optical system in accordance with the depth-position information on the object.

2. The optical tomographic imaging method according to claim 1, wherein the longitudinal sectional information on the object is a longitudinal sectional image of the object.

3. The optical tomographic imaging method according to claim 2, wherein the longitudinal sectional image of the object includes at least two longitudinal sectional images of the object substantially orthogonal to each other.

4. The optical tomographic imaging method according to claim 2, wherein the longitudinal sectional image of the object includes at least two longitudinal sectional images of the object substantially parallel to each other.

5. The optical tomographic imaging method according to claim 1, wherein the longitudinal sectional information on the object is calculated from a plurality of pieces of one-dimensional information on the object.

6. The optical tomographic imaging method according to claim 1, wherein, in acquiring the three-dimensional surface image of the object, a point in the object at which the measuring beam is incident is controlled instead of controlling the reference-path length defined by the reference mirror.

7. The optical tomographic imaging method according to claim 1, wherein the object is a set of retinal cells in an eye, and the depth-position information on the object is position information on a three-dimensional surface in the retinal cells.

8. An optical tomographic imaging apparatus in which light from a light source is split into a measuring beam and a reference beam, the measuring beam being guided to an object to be examined, the reference beam being guided to a reference mirror, and in which a tomogram of the object is generated from a return beam of the measuring beam reflected or scattered by the object and the reference beam reflected by the reference mirror, the apparatus comprising:

a scanning optical system capable of moving the measuring beam in one-dimensional and two-dimensional manners;

a reference-path-length adjuster provided to the reference mirror and configured to adjust an optical-path length of the reference beam; and

a control unit configured to control the reference-path-length adjuster and the scanning optical system so that a three-dimensional surface image of the object is acquired in accordance with depth-position information on the object estimated in advance.

9. The optical tomographic imaging apparatus according to claim 8,

wherein the reference-path-length adjuster includes

a stage capable of coarse adjustment and used in acquiring the depth-position information;

and

a stage capable of fine adjustment and used in acquiring the three-dimensional surface image.