OPTICAL TOMOGRAPHIC IMAGING APPARATUS

• US 20100181462A1
• Filed: 01/07/2010
• Published: 07/22/2010
• 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 8,274,660 B2
• Time in Patent Office: Days
• US Class Current: 250/201.800
• 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 focusing at the multiple focus positions sequentially based on focus position information generated by the focus position setting device and determining a focus condition of an in-focus state for the at least two reference positions set in advance by the reference position setting device.

Claims

1. An optical tomographic imaging apparatus that takes a tomographic image of an object by splitting a light beams from a light source into a measuring beams and a reference beams, guiding the measuring beams to the object through scanning with a scanning optical system, and using a return beams corresponding to the measuring beams that is one of reflected and scattered by the object and the reference beams, the optical tomographic imaging apparatus comprising:

a focus position setting device that splits a zone within a predetermined imaging depth range into multiple focus zones so as to set multiple focus positions;

a reference position setting device that sets at least two reference positions in an imaging depth direction within the predetermined imaging depth range; and

a focus controlling device that performs focusing at the multiple focus positions sequentially based on focus position information generated by said focus position setting device and a focus condition of an in-focus state for the at least two reference positions set in advance by said reference position setting device.

2. The optical tomographic imaging apparatus according to claim 1, further comprising:

a focus detecting device that detects the focus condition of the in-focus state;

a focus controlling data converting device that creates 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 focus condition of the in-focus state, 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 device that calculates driving information of the focusing mechanism based on the one of the conversion equation and the conversion table created by said focus controlling data converting device and on the focus position information from said focus position setting device,

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

3. The optical tomographic imaging apparatus according to claim 1, wherein the in-focus state for the at least two reference positions is determined based on luminance of a tomographic image of the predetermined imaging depth range.

4. The optical tomographic imaging apparatus according to claim 1, wherein the in-focus state for the at least two reference positions is determined based on a definition of a tomographic image of the predetermined imaging depth range.

5. The optical tomographic imaging apparatus according to claim 1, further comprising a mode selecting device that selects at least one mode from among multiple modes including a horizontal resolution mode and a luminance mode,

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

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

a first setting step of splitting a zone within a predetermined imaging depth range into multiple focus zones so as to set multiple focus positions;

a second setting step of setting at least two reference positions in an imaging depth direction within the predetermined imaging depth range; and

a control step of performing focusing at the multiple focus positions sequentially based on focus position information set in said first setting step and determining a focus condition of an in-focus state for the at least two reference positions set in advance in the second setting step.

7. A non-transitory computer-readable storage medium storing a program for causing a computer to execute the imaging method according to claim 6.

8. A program for causing a computer to execute the imaging method according to claim 6.