OPTICAL TOMOGRAPHIC IMAGING APPARATUS

• US 20120293807A1
• Filed: 08/07/2012
• Published: 11/22/2012
• Est. Priority Date: 01/22/2009
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: SUGITA, Mitsuro
• Granted Patent: US 8,749,795 B2
• Time in Patent Office: Days
• US Class Current: 356/479
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: G01B 9/02044 Imaging in the frequency domain, e.g. by using a spectrometer
• CPC Class Codes: G01B 9/02048 Rough and fine measurement
• CPC Class Codes: G01B 9/02063 by particular alignment of focus position, e.g. dynamic focussing in optical coherence tomography
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence

Abstract

Provided is an optical tomographic imaging apparatus that is capable of shortening a period of time of focusing at multiple focus positions when images split in a depth direction are obtained by zone focusing. The optical tomographic imaging apparatus includes: a focus position setting device for splitting a zone within a predetermined imaging depth range into multiple focus zones so as to set multiple focus positions; a reference position setting device for setting at least two reference positions in an imaging depth direction within the predetermined imaging depth range; and a focus controlling device for performing control so as to perform focusing at the multiple focus positions sequentially based on focus position information generated by the focus position setting device and a focus condition of in-focus at the at least two reference positions set in advance by the reference position setting device.

Claims

1. An ophthalmologic apparatus that acquires a tomographic image of an eye by splitting light from a light source into a measuring light and a reference light, guiding the measuring light to the eye through scanning with a scanning optical system, and using a return light, which corresponds to the measuring light that is reflected or scattered by the eye and the reference light, the ophthalmologic apparatus comprising:

a focus position setting unit configured to set multiple focus positions within a predetermined imaging depth range of a tomographic image of the eye;

a reference position setting unit configured to set at least two reference positions in an imaging depth direction within the predetermined imaging depth range;

a focus detecting unit configured to detect positions of a focusing lens at the at least two reference positions;

a focus controlling unit configured to control the performance of focusing at the multiple focus positions based on the positions of the focusing lens at the at least two reference positions; and

a unit configured to reconstruct a new tomographic image from tomographic images acquired at the multiple focus positions.

2. The ophthalmologic apparatus according to claim 1, further comprising:

a focus controlling data converting unit configured to create one of a conversion equation and a conversion table, in which a focus position in the imaging depth direction within the tomographic image is an input and position information of a focusing mechanism is an output, based on the positions of the focusing lens at the at least two reference positions detected by the focus detecting unit, and storing the one of the conversion equation and the conversion table so as to convert the input into the output; and

a focus driving information calculating unit configured to calculate driving information of the focusing mechanism based on the one of the conversion equation and the conversion table created by the focus controlling data converting unit and on the focus position information from the focus position setting unit,

wherein the focusing mechanism is driven and controlled by the focus controlling unit according to the driving information.

3. The ophthalmologic apparatus according to claim 1, wherein the focus detecting unit detects the positions of the focusing lens at the at least two reference positions by determining an in-focus state for the at least two reference positions based on luminance of the image of the predetermined imaging depth range.

4. The ophthalmologic apparatus according to claim 1, wherein the focus detecting unit detects the positions of focusing lens at the at least two reference positions by determining an in-focus state for the at least two reference positions based on a definition of the image of the predetermined imaging depth range.

5. The ophthalmologic apparatus according to claim 1, further comprising:

a mode selecting unit configured to select at least one mode from among multiple modes including a horizontal resolution mode and a luminance mode,

wherein the luminance mode uses a pixel larger than that of the horizontal resolution mode, and

wherein the focus position setting unit sets the multiple focus positions based on the at least one mode that has been selected.

17. The ophthalmologic apparatus according to claim 1, wherein the reference position setting unit is configured to segment the tomographic image and automatically set an optic nerve fiber layer and a pigmented epithelial cells layer as the at least two reference positions.

6. An ophthalmologic method of acquiring a tomographic image of an eye by splitting a light from a light source into a measuring light and a reference light, guiding the measuring light to the eye through scanning with a scanning optical system, and using a return light corresponding to the measuring light that is reflected or scattered by the eye and the reference light, the ophthalmologic method comprising:

setting multiple focus positions within a predetermined imaging depth range of a tomographic image of the eye;

setting at least two reference positions in an imaging depth direction within the predetermined imaging depth range;

detecting a position of a focusing lens at the at least two reference positions; and

controlling the performance of focusing at the multiple focus positions based on the positions of the focusing lens at the at least two reference positions; and

;

reconstructing a new tomographic image from tomographic images acquired at the multiple focus positions.

7. A non-transitory computer-readable storage medium storing a program that causes a computer to execute the ophthalmologic method according to claim 6.

8. (canceled)

9. An ophthalmologic apparatus for acquiring a tomographic image of an eye by using combined light of (a) a return light from the eye irradiated with a measuring light and (b) a reference light corresponding to the measuring light, the ophthalmologic apparatus comprising:

a determining unit configured to determine at least two reference positions within a predetermined range in the tomographic image of the eye; and

a controlling unit configured to control a focusing unit to perform focusing at multiple focusing positions in the predetermined range, based on positions of a focusing lens at the at least two reference positions.

10. An ophthalmologic apparatus according to claim 9, further comprising a focus detecting unit configured to detect the positions of the focusing lens at the at least two reference positions.

11. An ophthalmologic apparatus according to claim 9, further comprising:

an imaging unit configured to acquire a tomographic image of the eye; and

a focus position determining unit configured to determine the multiple focusing positions in the imaging depth direction within the predetermined range in the tomographic image.

12. An ophthalmologic apparatus according to claim 11, wherein the focus position determining unit determines the multiple focusing positions based on aberration of the eye.

13. An ophthalmologic apparatus according to claim 9, wherein the determining unit is configured to segment the tomographic image and automatically determine an optic nerve fiber layer and a pigmented epithelial cells layer as the at least two reference positions.

18. The ophthalmologic apparatus according to claim 9, further comprising a unit configured to reconstruct a new tomographic image from tomographic images acquired at the multiple focus positions.

14. An ophthalmologic method for acquiring a tomographic image of an eye using combined light of (a) a return light from the eye irradiated with a measuring light and (b) a reference light corresponding to the measuring light, the ophthalmologic method comprising:

determining at least two reference positions within a predetermined range in the tomographic image of the eye; and

performing focusing at multiple focusing positions in the predetermined range, based on positions of a focusing lens at the at least two reference positions.

15. A computer-readable storage medium storing a program for causing a computer to execute the ophthalmologic method according to claim 14.

19. The ophthalmologic method according to claim 14, further comprising reconstructing a new tomographic image from tomographic images acquired at the multiple focus positions.

16. An ophthalmologic apparatus for acquiring a tomographic image of an eye using combined light of (a) a return light from the eye irradiated with a measuring light and (b) a reference light corresponding to the measuring light, the ophthalmologic apparatus comprising:

a determining unit configured to determine at least two reference positions within a predetermined range in the tomographic image of the eye; and

a controlling unit configured to control a focusing unit to perform focusing at multiple focusing positions in the predetermined range, based on an aberration of the eye.