JP2019147065A - Optical coherence tomography device and optical coherence tomography control program - Google Patents

Abstract

To make it possible to easily and accurately acquire a plurality of OCT signals with respect to the same part.SOLUTION: An optical coherence tomography device comprises: control means for acquiring a first front image by means of a front observation optical system when acquiring a plurality of OCT signals in a first scanning region of a subject, and acquiring a second front image by means of the front observation optical system after acquiring the plurality of OCT signals in the first scanning region and after acquiring the first front image; and a determination means for determining quality of the plurality of OCT signals acquired in the first scanning region on the basis of a result of detection of a positional deviation between the first front image and the second front image, wherein the control means acquires each of a plurality of timewisely different OCT signals with respect to at least two scanning regions on the subject by means of an OCT optical system and, after acquiring a plurality of OCT signals in every scanning region, reacquiring a plurality of OCT signals in each scanning region whose plurality of OCT signals has been determined as poor by the determination means.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an optical coherence tomography apparatus that obtains motion contrast data of a subject, and an optical coherence tomography control program.

  Conventionally, as an apparatus for performing angiography, for example, a fundus camera, a scanning laser optometry apparatus, and the like are known. In this case, a contrast agent that emits light by specific excitation light is injected into the body. The apparatus obtains an angiographic image by receiving light from the contrast agent. That is, conventionally, injection of a contrast medium has been required.

  In recent years, there has been proposed an apparatus that obtains motion contrast (angiogram) without using a contrast agent by applying OCT technology (see, for example, Patent Document 1).

International Publication No. 2010/143601

  When acquiring motion contrast data using OCT, a plurality of OCT signals that are temporally different with respect to the same part of the subject are acquired, and the acquired plurality of OCT signals are processed to acquire motion contrast data in the subject. doing. However, while a plurality of OCT signals that are temporally different with respect to the same part of the subject are acquired, the acquired plurality of OCT signals may have been acquired at different positions due to the movement of the subject. is there. In this case, good motion contrast data cannot be acquired.

  In view of the above-described problems, the present disclosure has an object to provide an optical coherence tomography apparatus and an optical coherence tomography control program that can easily and accurately acquire a plurality of OCT signals for the same part. To do.

  In order to solve the above problems, the present disclosure is characterized by having the following configuration.

(1)
An optical coherence tomography device that detects an OCT signal by measurement light and reference light irradiated to a subject's eye, and acquires a tomographic image of the subject's eye by processing the OCT signal,
A front observation optical system for obtaining a front image of the eye to be examined;
An OCT optical system that acquires a plurality of OCT signals that are temporally different with respect to the same scanning region on the eye to be examined;
When a plurality of OCT signals are acquired by the OCT optical system in the first scanning region on the eye to be examined, a first front image is acquired by the front observation optical system, and the plurality of OCT signals are acquired in the first scanning region. A control means for acquiring a second front image by the front observation optical system after the acquisition of the first front image;
A positional deviation between the first front image and the second front image is detected by image processing, and the quality of the plurality of OCT signals acquired in the first scanning region is determined based on the detection result of the positional deviation. Determining means for determining
Arithmetic processing means for processing the plurality of OCT signals determined to be good by the determination means to obtain motion contrast data in the eye to be examined;
With
The control means acquires a plurality of OCT signals that are temporally different with respect to at least two or more scanning regions on the eye by the OCT optical system,
After the acquisition of the plurality of OCT signals is completed in all scanning regions, the plurality of OCT signals in the scanning region in which the plurality of OCT signals are determined to be unsatisfactory by the determination unit are re-acquired. Optical coherence tomography device.
(2)
Executed in a control device that controls the operation of an optical coherence tomography device that detects an OCT signal based on measurement light and reference light irradiated to the eye and processes the OCT signal to acquire a tomographic image of the eye to be examined. An optical coherence tomography control program,
By being executed by the processor of the control device,
A front image acquisition step of obtaining a front image of the eye to be examined;
An acquisition step of acquiring a plurality of OCT signals that are temporally different with respect to the same scanning region on the eye to be examined;
In the first scanning region on the eye to be examined, when acquiring the plurality of OCT signals by the acquiring step, the first front image is acquired by the front image acquiring step, and after acquiring the plurality of OCT signals in the first scanning region. A control step of acquiring a second front image by the front image acquisition step after acquisition of the first front image;
A positional deviation between the first front image and the second front image is detected by image processing, and the quality of the plurality of OCT signals acquired in the first scanning region is determined based on the detection result of the positional deviation. A determination step for determining
An arithmetic processing step of processing the plurality of OCT signals determined to be good by the determination step to obtain motion contrast data in the eye to be examined;
To the optical coherence tomography device,
The control step acquires, by the OCT optical system, a plurality of OCT signals that are temporally different with respect to at least two or more scanning regions on the eye to be examined,
After the acquisition of the plurality of OCT signals is completed in all scanning regions, the plurality of OCT signals in the scanning region in which the plurality of OCT signals are determined to be unsatisfactory by the determination unit are re-acquired. Optical coherence tomography control program.

It is a block diagram explaining the structure of the optical coherence tomography apparatus which concerns on this embodiment. It is a figure which shows the outline of the OCT optical system which concerns on this embodiment. It is an image figure of the fundus for explaining photographing of this embodiment. It is a figure explaining the relationship between the acquisition operation of an OCT signal, and the acquisition operation of a front image. The flowchart of the determination process is shown. It is a figure explaining the example of a change of the relationship between the acquisition operation of an OCT signal, and the acquisition operation of a front image.

  Hereinafter, one exemplary embodiment will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of an optical coherence tomography apparatus according to the present embodiment. FIG. 2 is a schematic diagram illustrating the OCT optical system.

  An optical coherence tomography apparatus (hereinafter referred to as an OCT device) 1 processes a detection signal acquired by an OCT optical system (interference optical system) 100. In the present embodiment, the OCT device 1 observes an image photographed by the OCT optical system 100 on a display means (for example, a monitor) 75. For example, the OCT device 1 includes an OCT optical system, a CPU (control unit) 70, a mouse (operation unit) 76, a memory (storage unit) 72, and a monitor 75. Each unit is connected via a bus or the like. Are electrically connected to the CPU 70. In the following description, the case where the fundus of the subject's eye is imaged by the OCT device 1 as an object will be described as an example. Of course, the OCT device 1 can photograph various living bodies. For example, ears, nose, various organs and the like can be mentioned. Further, for example, the OCT device 1 may be a device that images the anterior segment of the eye to be examined.

  The control unit 70 controls the operation of each unit based on an arithmetic program and various control programs stored in the memory 72 (details will be described later). In addition, as the control unit 70, the operation unit 76, the memory 72, and the monitor 75, various processing programs are installed on a commercially available PC by using an arithmetic processing unit, an input unit, a storage unit, and a display unit of a commercially available PC (personal computer). You may do it.

  In the present embodiment, the OCT optical system 100 has been described as an example of an apparatus in which the OCT optical system 100 and each unit are integrated, but the present invention is not limited thereto. For example, the OCT device 1 may be configured without the OCT optical system 100. In this case, the OCT device is connected to a separately provided OCT optical system or the like, receives an OCT signal or OCT image data, and performs various arithmetic processes based on the received information.

  For example, in the present embodiment, the OCT optical system 100 includes a front observation optical system 200. Of course, the OCT optical system and the front observation optical system 200 may not be integrated. The OCT optical system 100 irradiates the fundus Ef with measurement light. The OCT optical system 100 detects the interference state between the measurement light reflected from the fundus oculi Ef and the reference light by the light receiving element (detector 120). The OCT optical system 100 includes an irradiation position changing unit (for example, the optical scanner 108 and the fixation target projection unit 300) that changes the irradiation position of the measurement light on the fundus oculi Ef in order to change the imaging position on the fundus oculi Ef. The control unit 70 controls the operation of the irradiation position changing unit based on the set imaging position information, and acquires a tomographic image based on the light reception signal from the detector 120.

<OCT optical system>
The OCT optical system 100 will be described. The OCT optical system 100 has an apparatus configuration of a so-called ophthalmic optical tomography (OCT: Optical coherence tomography), and takes a tomographic image of the eye E to be examined. The OCT optical system 100 splits the light emitted from the measurement light source 102 into measurement light (sample light) and reference light by a coupler (light splitter) 104. The OCT optical system 100 guides the measurement light to the fundus oculi Ef of the eye E by the measurement optical system 106 and guides the reference light to the reference optical system 110. Thereafter, the detector 120 receives interference light obtained by combining the measurement light reflected by the fundus oculi Ef and the reference light.

  The detector 120 detects an interference signal between the measurement light and the reference light. In the case of Fourier domain OCT, the spectral intensity (spectral interference signal) of the interference light is detected by the detector 120, and a complex OCT signal is obtained by Fourier transform on the spectral intensity data.

  For example, in the Fourier domain OCT, the depth profile (A scan signal) in a predetermined range is acquired by calculating the absolute value of the amplitude in the complex OCT signal acquired by Fourier transform on the spectral intensity data. OCT image data (tomographic image data) is acquired by arranging the depth profiles at each scanning position of the measurement light scanned by the optical scanner 108. Furthermore, three-dimensional OCT image data (three-dimensional tomographic image data) may be acquired by scanning the measurement light two-dimensionally. Further, from the three-dimensional OCT image data, an OCT front (Enface) image (for example, an integrated image integrated in the depth direction, an integrated value of spectrum data at each XY position, and an XY position at a certain depth direction) Brightness data, retina surface layer image, etc.) may be acquired.

  Also, motion contrast data is acquired from at least two or more OCT signals at the same position (the same part) at different times. That is, at least two or more complex OCT signals are analyzed and motion contrast data is acquired. For example, a functional OCT signal is acquired from a complex OCT signal. The functional OCT image data is acquired by arranging the functional OCT signals at each scanning position of the measurement light scanned by the optical scanner 108. Furthermore, three-dimensional functional OCT image data (three-dimensional motion contrast data) is acquired by two-dimensionally scanning the measurement light in the XY directions. Further, an OCT function front image (for example, a Doppler front image, a signal image data speckle variance front image) is acquired from the three-dimensional function OCT image data. Each image data may be image data or signal data. Details of the motion contrast data will be described later.

  For example, examples of the Fourier domain OCT include Spectral-domain OCT (SD-OCT) and Swept-source OCT (SS-OCT). For example, Time-domain OCT (TD-OCT) may be used. In the case of SD-OCT, a low-coherent light source (broadband light source) is used as the light source 102, and the detector 120 is provided with a spectroscopic optical system (spectrometer) that separates interference light into each frequency component (each wavelength component). . The spectrometer includes, for example, a diffraction grating and a line sensor. In the case of SS-OCT, a wavelength scanning light source (wavelength variable light source) that changes the emission wavelength at a high speed with time is used as the light source 102, and a single light receiving element is provided as the detector 120, for example. The light source 102 includes, for example, a light source, a fiber ring resonator, and a wavelength selection filter. Examples of the wavelength selection filter include a combination of a diffraction grating and a polygon mirror, and a filter using a Fabry-Perot etalon.

  The light emitted from the light source 102 is split into a measurement light beam and a reference light beam by the coupler 104. Then, the measurement light flux passes through the optical fiber and is then emitted into the air. The luminous flux is condensed on the fundus oculi Ef via the optical scanner 108 and other optical members of the measurement optical system 106. Then, the light reflected by the fundus oculi Ef is returned to the optical fiber through a similar optical path.

  The optical scanner 108 scans the measurement light two-dimensionally (XY direction) on the fundus. The optical scanner 108 is arranged at a position substantially conjugate with the pupil. The optical scanner 108 is, for example, two galvanometer mirrors, and the reflection angle thereof is arbitrarily adjusted by the drive mechanism 50.

  As a result, the reflection (advance) direction of the light beam emitted from the light source 102 is changed and scanned at an arbitrary position on the fundus. Thereby, the imaging position on the fundus oculi Ef is changed. The optical scanner 108 may be configured to deflect light. For example, in addition to a reflective mirror (galvano mirror, polygon mirror, resonant scanner), an acousto-optic device (AOM) that changes the traveling (deflection) direction of light is used.

  The reference optical system 110 generates reference light that is combined with reflected light acquired by reflection of measurement light at the fundus oculi Ef. The reference optical system 110 may be a Michelson type or a Mach-Zehnder type. The reference optical system 110 is formed by, for example, a reflection optical system (for example, a reference mirror), and reflects light from the coupler 104 back to the coupler 104 by being reflected by the reflection optical system and guides it to the detector 120. As another example, the reference optical system 110 is formed by a transmission optical system (for example, an optical fiber), and guides the light from the coupler 104 to the detector 120 by transmitting the light without returning.

  The reference optical system 110 has a configuration in which the optical path length difference between the measurement light and the reference light is changed by moving an optical member in the reference optical path. For example, the reference mirror is moved in the optical axis direction. The configuration for changing the optical path length difference may be arranged in the measurement optical path of the measurement optical system 106.

<Front observation optical system>
The front observation optical system 200 acquires front image data of the eye to be examined. The front image data may be image data or signal data. For example, the front observation optical system 200 is provided to obtain a front image of the fundus oculi Ef. The front observation optical system 200 includes, for example, an optical scanner that two-dimensionally scans the fundus of measurement light (for example, infrared light) emitted from a light source, and a confocal aperture that is disposed at a position substantially conjugate with the fundus. And a second light receiving element that receives the fundus reflection light, and has a so-called ophthalmic scanning laser ophthalmoscope (SLO) device configuration.

  The configuration of the front observation optical system 200 may be a so-called fundus camera type configuration. Further, for example, an infrared imaging optical system that images a subject using infrared light may be used. Further, for example, the OCT optical system 100 may also serve as the front observation optical system 200. That is, the front image data (hereinafter referred to as a front image) may be acquired using data forming a tomographic image (OCT front image) obtained two-dimensionally.

  The front observation optical system 200 may not be integrated with the OCT device or the like. In this case, for example, front image data acquired by a front observation optical system 200 provided separately is received by an OCT device or the like.

<Fixation target projection unit>
The fixation target projecting unit 300 includes an optical system for guiding the line-of-sight direction of the eye E. The fixation target projection unit 300 has a fixation target to be presented to the eye E, and can guide the eye E in a plurality of directions.

  For example, the fixation target projection unit 300 has a visible light source that emits visible light, and changes the presentation position of the target two-dimensionally. Thereby, the line-of-sight direction is changed, and as a result, the imaging region is changed. For example, when the fixation target is presented from the same direction as the imaging optical axis, the center of the fundus is set as the imaging site. When the fixation target is presented upward with respect to the imaging optical axis, the upper part of the fundus is set as the imaging region. That is, the imaging region is changed according to the position of the target with respect to the imaging optical axis.

  As the fixation target projection unit 300, for example, a configuration in which the fixation position is adjusted by the lighting positions of LEDs arranged in a matrix, the light from the light source is scanned by an optical scanner, and the fixation position is controlled by lighting control of the light source. Various configurations such as a configuration to be adjusted are conceivable. The fixation target projection unit 300 may be an internal fixation lamp type or an external fixation lamp type.

<Control unit>
The control unit 70 includes a CPU (processor), a RAM, a ROM, and the like. The CPU of the control unit 70 controls the entire apparatus such as each member of each configuration 100 to 300. The RAM temporarily stores various information. The ROM of the control unit 70 stores various programs for controlling the operation of the entire apparatus, initial values, and the like. The control unit 70 may be configured by a plurality of control units (that is, a plurality of processors).

  A non-volatile memory (storage means) 72, an operation unit (control unit) 76, a display unit (monitor) 75, and the like are electrically connected to the control unit 70. The non-volatile memory (memory) 72 is a non-transitory storage medium that can retain stored contents even when power supply is interrupted. For example, a hard disk drive, a flash ROM, the OCT device 1, and a USB memory that is detachably attached to the OCT optical system 100 can be used as the nonvolatile memory 72. The memory 72 stores an imaging control program for controlling imaging of front images and tomographic images by the OCT optical system 100. The memory 72 stores a fundus analysis program that enables the OCT device 1 to be used. In addition, the memory 72 stores information on imaging positions of tomographic image data (OCT image data), three-dimensional tomographic image data (three-dimensional OCT image data), front image data (fundus frontal image data), and tomographic image data in a scanning line. Etc., various information relating to photographing is stored. Various operation instructions by the examiner are input to the operation unit 76.

  The operation unit 76 outputs a signal corresponding to the input operation instruction to the control unit 70. For the operation unit 74, for example, at least one of a mouse, a joystick, a keyboard, a touch panel, and the like may be used.

  The monitor 75 may be a display mounted on the apparatus main body or a display connected to the main body. A display of a personal computer (hereinafter referred to as “PC”) may be used. A plurality of displays may be used in combination. The monitor 75 may be a touch panel. When the monitor 75 is a touch panel, the monitor 75 functions as an operation unit. Various images including tomographic image data and front image data captured by the OCT optical system 100 are displayed on the monitor 75.

<Signal processing method>
In this embodiment, which describes an arithmetic processing method for acquiring motion contrast data from an OCT signal in this embodiment, in order to acquire motion contrast data, the control unit 70 has at least two frames having different times at the same position. The interference signal (OCT signal) is acquired.

  In the present embodiment, the control unit 70 acquires motion contrast data (for example, functional OCT image data) from a plurality of OCT signals by performing processing related to the Doppler phase difference method and processing related to the vector difference method. As a method of processing the complex OCT signal, for example, a method of calculating a phase difference of the complex OCT signal, a method of calculating a vector difference of the complex OCT signal, a method of multiplying the phase difference and the vector difference of the complex OCT signal, and the like are considered. It is done. In the present embodiment, a method of multiplying a phase difference and a vector difference will be described as an example.

  First, the control unit 70 performs a Fourier transform on the OCT signal acquired by the OCT optical system 100. The controller 70 obtains a complex OCT signal by Fourier transform. The complex OCT signal includes a real component and an imaginary component.

  In order to obtain a blood flow signal, it is necessary to compare images at the same position at different times. For this reason, it is preferable that the control unit 70 aligns images based on image information. Image registration is the process of aligning and arranging multiple images of the same scene. Possible causes of the image position shift include, for example, the movement of the subject's eye during imaging (for example, fixation fine movement, adjustment fine movement, and pulsation). Note that even if alignment between frames is performed, a phase shift may occur between A scan lines in the same image. Therefore, it is preferable to perform phase correction. Note that the registration and phase correction processes are intended to facilitate the process of the present embodiment, and are not essential.

  Next, the control unit 70 calculates a phase difference with respect to the complex OCT signal acquired at least two or more different times at the same position. The controller 70 removes a random phase difference that exists in a region where the S / N ratio (signal-to-noise ratio) is low.

  The controller 70 removes a portion having a small phase difference. This is to remove a reflection signal from a highly reflective portion such as NFL (nerve fiber layer). This makes it easy to distinguish whether the signal is from a highly reflective part or from a blood vessel. In the present embodiment, one frame for which the phase difference is calculated is acquired. When there are a plurality of frames for which the phase difference has been calculated, it is better that the control unit 70 performs an averaging process on the signals of the frames subjected to the above processing to remove noise.

  Next, the control unit 70 calculates a vector difference of the complex OCT signal. For example, the vector difference of the complex OCT signal detected by the OCT optical system is calculated. For example, a complex OCT signal can be represented as a vector on the complex plane. Therefore, by detecting two signals at the same position at different times and calculating a vector difference, contrast image data in the eye to be examined is generated. In addition, when imaging a vector difference, you may image based on phase information other than the magnitude | size of a difference, for example. In the present embodiment, one frame for which the vector difference is calculated is acquired. When there are a plurality of frames for which the vector difference is calculated, it is better that the control unit 70 performs an averaging process on the signal of the frame subjected to the above-described processing to remove noise.

  The control unit 70 uses the phase difference calculation result as a filter for the vector difference calculation result. In the description of the present embodiment, “filtering” means, for example, weighting a certain numerical value. For example, the control unit 70 performs weighting by multiplying the calculation result of the vector difference by the calculation result of the phase difference. That is, the vector difference of the portion having a small phase difference is weakened, and the vector difference of the portion having a large phase difference is strengthened. Thereby, the calculation result of the vector difference is weighted by the calculation result of the phase difference.

  In the process of the present embodiment, the control unit 70 multiplies the vector difference calculation result and the phase difference calculation result, for example. Thereby, the control unit 70 generates functional OCT image data weighted by the calculation result of the phase difference.

  By multiplying the calculation result of the vector difference and the calculation result of the phase difference, the disadvantages of the respective measurement methods can be negated, and the image data of the blood vessel part can be successfully acquired.

  The control unit 70 performs the above arithmetic processing for each scanning line, and acquires functional OCT image data for each scanning line. Then, by acquiring functional OCT image data at these multiple positions, it is possible to acquire three-dimensional functional OCT front image data used as a pseudo angiographic image.

  In the present embodiment, the control unit 70 has been described by taking as an example a configuration in which the vector difference calculation result and the phase difference calculation result are multiplied in order to obtain motion contrast data. However, the present invention is not limited to this. Not. For example, the motion contrast data may be acquired using a vector difference calculation result. Further, for example, the motion contrast data may be acquired using a phase difference calculation result. Further, for example, the motion contrast data may be acquired by an amplitude difference result, Amplitude-decorrelation, Speckle variance, Phase variance, or the like.

  In the present embodiment, the control unit 70 has been described with an example of a configuration in which motion contrast data is acquired using two OCT signals, but is not limited thereto. The motion contrast data may be acquired by two or more OCT signals.

<Shooting operation>
Hereinafter, a series of imaging operations using the OCT device 1 will be described. In addition, the following description is given taking as an example the case of acquiring three-dimensional functional OCT image data. Of course, the technique disclosed in the present invention can be applied when obtaining motion contrast data. For example, the present invention can be applied to a case where a function OCT signal is acquired or a function OCT image data is acquired.

  First, the examiner instructs the subject to gaze at the fixation target of the fixation target projection unit 300, and then monitors an anterior ocular segment observation image captured by an anterior ocular segment observation camera (not shown) on the monitor 75. , An alignment operation is performed using an operation unit 76 (for example, a joystick (not shown)) so that the measurement optical axis comes to the center of the pupil of the eye to be examined.

  For example, when the alignment operation is completed, the control unit 70 controls the OCT optical system 100 to acquire three-dimensional OCT image data corresponding to the set region, and also controls the front observation optical system 200 to obtain fundus image data. (Fundus frontal image data) is acquired. Then, the control unit 70 acquires three-dimensional OCT image data by the OCT optical system 100 and fundus image data by the front observation optical system 200 as needed. The three-dimensional OCT image data includes image data in which A scan signals are arranged two-dimensionally in the XY directions, a three-dimensional graphic image, and the like.

  The examiner sets the scanning position using the fundus front image of the front observation optical system 200. Then, when a photographing start signal is output from the operation unit 76, the control unit 70 controls the operation of the optical scanner 108 to cause the measurement light to scan two-dimensionally in the XY directions within a scanning range corresponding to the imaging region. Thus, acquisition of the three-dimensional functional OCT image data is started. As the scanning pattern, for example, a raster scan, a plurality of line scans, a circle shape, a refracted shape, a bent shape, and the like can be considered.

  Hereinafter, an imaging operation using the OCT device 1 will be described. FIG. 3 is a schematic diagram for explaining photographing according to the present embodiment. In the present embodiment, for example, when an imaging start signal is output, the control unit 70 acquires a plurality of OCT signals from the OCT optical system 100 in the first scanning region on the eye fundus. Further, the control unit 70 acquires the first front image by the front observation optical system 200 when the OCT optical system 100 acquires a plurality of OCT signals in the first scanning region. Then, the control unit 70 acquires the second front image by the front observation optical system 200 after the OCT optical system 100 acquires the plurality of OCT signals in the first scanning region. Next, the control unit 70 detects a positional deviation between the first front image and the second front image by image processing, and a plurality of OCT signals acquired in the first scanning region based on the detection result of the positional deviation. Judge the quality of the. The control unit 70 processes a plurality of OCT signals determined to be good and acquires motion contrast data in the fundus of the eye to be examined.

<OCT signal acquisition>
This will be described in more detail. For example, when an imaging start signal is output, the control unit 70 controls driving of the optical scanner 108 and scans the measurement light on the fundus in order to acquire the three-dimensional functional OCT image data. For example, according to the output of the imaging start signal, the control unit 70 controls the OCT optical system 100 to acquire the OCT signal at the set frame rate. Note that the frame rate for obtaining the OCT signal may or may not be changed before and after the acquisition of the OCT signal.

  The control unit 70 acquires a plurality of OCT signals in the same scanning region. The same scanning area does not have to be completely the same scanning area, and may be scanned in substantially the same scanning area. Therefore, the control unit 70 repeats scanning in the same scanning area on the fundus. By such a plurality of scans, the control unit 70 can obtain a plurality of OCT signals in the same scan region.

  For example, the control unit 70 scans the measurement light a plurality of times using the optical scanner 108 with respect to the set first scanning region. In the present embodiment, a case where one scanning position (first scanning position) is set as the first scanning region will be described as an example. Of course, a plurality of scanning positions (for example, two scanning positions of the first scanning position and the second scanning position) may be set as the scanning area (details will be described later).

  As shown in FIG. 3, for example, the control unit 70 scans the measurement light in the X direction along the first scanning position (scanning line) S1. Scanning the measurement light in any one of the XY directions (for example, the X direction) in this way is called “B scan”. Hereinafter, the one-frame interference signal is described as an OCT signal obtained by one B-scan. The control unit 70 acquires the OCT signal detected by the detector 120 during scanning. In FIG. 3, the direction of the Z axis is the direction of the optical axis of the measurement light. The direction of the X axis is a direction perpendicular to the Z axis and left and right. The direction of the Y axis is assumed to be perpendicular to the Z axis and up and down.

  When the first scan is completed, the control unit 70 performs the second scan at the same position as the first scan. For example, the control unit 70 scans the measurement light again after scanning the measurement light along the first scanning line S1 illustrated in FIG. The controller 70 acquires the OCT signal detected by the detector 120 during the second scan. Thus, the control unit 70 can acquire two frames of OCT signals at different times at the same scanning position. For example, the control unit 70 repeatedly acquires an OCT signal and acquires a 4-frame OCT signal at the same scanning position. In the present embodiment, a configuration in which an OCT signal of 4 frames is acquired at the same scanning position is described as an example, but the present invention is not limited to this. It suffices if the OCT signal of at least two frames is acquired at the same position. For example, the scanning at the same position may be repeated 8 times to acquire continuous 8 frames of OCT signals at different times, or the scanning at the same position may be repeated 2 times to obtain 2 frames of OCT signals at different times. May be obtained.

  Note that if the OCT signal at the same position at different times can be acquired by one scan, the second scan may not be performed. For example, when two measurement beams whose optical axes are shifted by a predetermined interval are scanned at a time, it is not necessary to scan a plurality of times, and it is only necessary to obtain OCT signals having different times at the same position in the subject. That is, the same position does not need to be completely the same position, and may be scanned at substantially the same position. When two measurement lights are scanned at a time, an arbitrary blood flow velocity can be detected as a target by the interval between the two measurement lights.

<Front image acquisition>
On the other hand, the control unit 70 controls the front observation optical system 200 in order to repeatedly obtain the front image at the set frame rate in response to the output of the imaging start signal. Note that the frame rate for obtaining the front image may or may not be changed before and after the start of capturing. In the embodiment, the frame rate for obtaining the OCT signal is four times the frame rate for obtaining the front image. That is, four frames of OCT signals can be acquired in the time to acquire one frame of the front image. In the present embodiment, the frame rate for acquiring the OCT signal and the frame rate for acquiring the front image are set so that at least two OCT signals are acquired while the front image of one frame is acquired. Just do it.

  Further, for example, in the present embodiment, the relationship between the frame rate for obtaining the OCT signal and the frame rate for obtaining the front image is that until acquisition of a plurality of OCT signals in at least one scanning region is completed. It is only necessary to set the time taken to be less than the time taken to complete the acquisition of one front image. For example, a frame rate for obtaining an OCT signal and a frame for obtaining a front image so that an OCT signal having a preset number of frames for obtaining motion contrast data in at least one scanning region is obtained. It is sufficient that the rate is set.

  The control unit 70 repeats the front image acquisition operation while a plurality of OCT signals are acquired. With such control, the control unit 70 monitors the movement (movement) of the eye while the OCT signal is acquired. For example, the control unit 70 receives reflected light from the front of the fundus by the operation of the front observation optical system 200. The control unit 70 acquires a front image by processing the received reflected light. The controller 70 stores the acquired plurality of front images in the memory 72 as needed. As described above, the control unit 70 makes the acquisition of the front image and the acquisition of the OCT signal in parallel.

<Parallel acquisition of OCT signal acquisition and front image acquisition>
FIG. 4 is a diagram illustrating the relationship between the OCT signal acquisition operation and the front image acquisition operation. In FIG. 4, the horizontal axis is the time axis (T). For example, the control unit 70 starts acquiring the first front image F1 in response to the output of the shooting start signal. When the acquisition of the first front image F1 is completed, the control unit 70 causes the memory 72 to store the first front image F1. In the present embodiment, the acquisition of the first front image (front image of one frame) F1 is completed when the time T1 has elapsed from the output timing (at the start of acquisition) T0 of the imaging start signal. To do. That is, the time T1 has elapsed until the first front image F1 is acquired.

  Next, the control unit 70 starts acquiring the second front image F2. Further, in parallel with the acquisition of the second front image F2, a plurality of OCT signals on the first scanning line S1 are acquired. In this embodiment, since the frame rate when acquiring the OCT signal is four times as high as the frame rate when acquiring the front image, 4 frames are required until the front image of one frame is acquired. The OCT signal for the frame can be acquired. For example, the control unit 70 performs a plurality of OCT signals O1, O2, O3, and O4 on the first scanning line S1 during the time T2 for acquiring the second front image F2 (the time between time T1 and time T2). Can be obtained. When the acquisition of the second front image F <b> 2 is completed, the control unit 70 stores it in the memory 72.

<OCT signal pass / fail judgment>
Next, the control unit 70 determines pass / fail (propriety) of the plurality of OCT signals O1, O2, O3, and O4 acquired in the first scan line S1. FIG. 5 shows a flowchart of the determination process. In the present embodiment, the quality of the OCT signal is determined in real time. The determination result is used to process a plurality of OCT signals and acquire motion contrast data.

  For example, the control unit 70 performs a determination process every time a front image and a plurality of OCT signals are acquired (A1). For example, the control unit 70 detects a positional deviation between the acquired front images (A2). For example, in the position shift detection, a front image at the time of obtaining a plurality of OCT signals and after obtaining a plurality of OCT signals is used. In the present embodiment, a front image acquired before acquiring a plurality of OCT signals is used as a front image when acquiring a plurality of OCT signals. Of course, the front image when acquiring a plurality of OCT signals is not limited to a front image acquired before acquiring a plurality of OCT signals. For example, a front image acquired during acquisition of a plurality of OCTs may be used as the front image when acquiring a plurality of OCT signals. In the present embodiment, the front image after the acquisition of the plurality of OCT signals is acquired, and the acquisition of the plurality of OCT signals is completed as the front image after the acquisition of the plurality of OCT signals. At the same time, the front image that has been acquired is used. Of course, the front image after the acquisition of the plurality of OCT signals is not limited to the front image that has been acquired simultaneously with the completion of the acquisition of the plurality of OCT signals. For example, the front image after acquisition of a plurality of OCT signals may be a front image acquired after acquisition of a plurality of OCT signals (preferably immediately after completion of acquisition of OCT signals).

  For example, when the control unit 70 determines the quality of the plurality of OCT signals O1, O2, O3, and O4 acquired in the first scanning line S1, the plurality of OCT signals O1, O2, and O4 in the first scanning line S1 are determined. The first front image F1 before acquisition of O3 and O4 and the second front image F2 that has been acquired at the same time as acquisition of the plurality of OCT signals O1, O2, O3, and O4 are used. The control unit 70 detects a positional shift between the first front image F1 and the second front image F2 by image processing. Accordingly, it is possible to detect the eye movement while the plurality of OCT signals O1, O2, O3, and O4 are acquired in the first scanning line S1. That is, it is possible to detect whether or not the scanning position has shifted when the plurality of OCT signals O1, O2, O3, and O4 are acquired.

  Next, for example, the control unit 70 determines pass / fail of the plurality of OCT signals O1, O2, O3, and O4 acquired in the first scan line S1 based on the detection result of the positional deviation. For example, the control unit 70 determines whether the positional deviation (deviation amount) satisfies an allowable range (for example, a predetermined threshold) (A3). For example, when the deviation amount satisfies the allowable range (in the case of YES in FIG. 5), the control unit 70 determines that the plurality of OCT signals are good. For example, the control unit 70 determines that the plurality of OCT signals are not good when the deviation amount does not satisfy the allowable range (NO in FIG. 5).

  For example, when it is determined that the plurality of OCT signals are good, the control unit 70 stores the plurality of OCT signals O1, O2, O3, and O4 acquired in the first scanning line S1 in the memory 72 (A5 ). Next, the control unit 70 determines whether imaging has been completed up to the final scanning line Sn. In other words, the control unit 70 determines whether or not imaging in all scanning regions (all scanning lines in the present embodiment) has been completed (A6). When it is determined that the imaging at all scanning lines (all scanning positions) has been completed, the control unit 70 ends the imaging (A9). Further, if it is determined that the imaging for all the scanning lines is not completed, the imaging is continued. For example, the control unit 70 sets a region from which the plurality of OCT signals O1, O2, O3, and O4 are acquired as a second scanning region (the main scanning line S1 in the present embodiment) that is different from the first scanning region. In the embodiment, the second scanning line S2) is changed (A7). That is, the control unit 70 ends the acquisition of the plurality of OCT signals O1, O2, O3, O4 in the first scanning line S1, and the plurality of OCT signals O1, O2, O3 acquired in the first scanning line S1. , O4 are stored in the memory 72. And the control part 70 starts acquisition of several OCT signal O1, O2, O3, O4 (for example, refer FIG. 4) in the 2nd scanning line (2nd scanning position) S2 (A8).

  For example, the control unit 70 controls the optical scanner 108 to change the sub-scanning position (Y-direction position), and scans the measurement light a plurality of times in the main scanning direction (X-direction) on the second scanning line S2. To do. Note that the change of the scanning position is not limited to the Y direction. You may make it change to a X direction. As a result, wide-angle shooting can be performed in the X direction. Of course, the configuration may be changed to both the X direction and the Y direction. As shown in FIG. 4, when acquiring the plurality of OCT signals O1, O2, O3, and O4 in the second scanning line S2, the control unit 70, as in the case of the first scanning line S1, Three front images F3 are acquired. And the control part 70 determines the quality of several OCT signal O1, O2, O3, O4 acquired in 2nd scanning line S2. In this case, for the determination, acquisition of the second front image F2 and the plurality of OCT signals O1, O2, O3, O4 before acquisition of the plurality of OCT signals O1, O2, O3, O4 in the second scanning line S2 ( The third front image F3 for which acquisition has been completed at the same time (time T3) is used. The control unit 70 detects a positional shift between the second front image F2 and the third front image F3 by image processing, and a plurality of OCT signals O1 acquired in the second scanning line S2 based on the detection result of the positional shift. , O2, O3, O4 are judged.

  Note that in the present embodiment, when determining the quality of a plurality of OCT signals, front images (for example, the first front image F1 and the second front image F2) acquired continuously are used for the determination process. Although the configuration has been described as an example, the configuration is not limited thereto. The front image for performing the OCT determination processing includes a front image before acquisition of a plurality of OCT signals in a scan line and a front image acquired after the front image before acquisition of the plurality of OCT signals. Any structure may be used as long as it uses a front image acquired after the acquisition of the OCT signal. For example, the first front image acquired with the start of shooting is set as the reference image. Then, at each scanning position, a plurality of OCT signals are acquired, and determination processing may be performed based on the positional deviation between the acquired front image and the reference image. More specifically, for example, when the plurality of OCT signals O1, O2, O3, and O4 in the second scanning line S2 are determined, a configuration in which the first front image F1 and the third front image F3 are used. .

  Similar to the operation after the determination in the first scanning line S1, the control unit 70 acquires the plurality of OCT signals O1, O2, O3, and O4 when the plurality of OCT signals are determined to be good. Is changed to the next scanning position (scanning line). Similarly, the control unit 70 performs a determination process while acquiring the OCT signal and the front image, and scans the measurement light a plurality of times in each scan line up to the final scan line Sn, thereby obtaining each scan line. A plurality of OCT signals are acquired. That is, as shown in FIG. 3, the control unit 70 performs raster scanning (scanning at the crossing position) of the measurement light, and at least two frames having different times in each scanning line (S1 to Sn) (in this embodiment, 4 frames) OCT signal is acquired. Thereby, three-dimensional information of the fundus can be acquired. Note that, even when the imaging has not been completed up to the final scanning position, if the examiner cancels the imaging, the imaging operation may be terminated at that time. In this way, it is possible to more quickly acquire a plurality of OCT signals in each scanning region by determining whether the acquired plurality of OCT signals are acceptable or not and changing the scanning region based on the determination result.

  On the other hand, for example, when it is determined that the plurality of OCT signals are not good, the control unit 70 re-acquires the plurality of OCT signals in the first scanning line S1. For example, the control unit 70 deletes the plurality of OCT signals O1, O2, O3, O4 and the first front image F1 acquired in the first scanning line S1 (A11), and starts re-acquisition. The control unit 70 controls the optical scanner 108 based on the shift amount between the first front image F1 and the second front image F2, and corrects the scanning position (A12). For example, the control unit 70 appropriately controls driving of the two galvanometer mirrors of the optical scanner 108 so that the shift of the scanning position is corrected. After correcting the scanning position, the control unit 70 again starts acquiring a plurality of OCT signals in the first scanning line S1 (A13).

  The control unit 70 acquires a front image after correcting the scanning position before acquiring a plurality of OCT signals. That is, for example, a front image at the time of reacquisition of a plurality of OCT signals is acquired. After re-acquisition of the plurality of OCT signals, the control unit 70 is based on the front image at the time of re-acquisition of the plurality of OCT signals, the front image that has been acquired simultaneously with the completion of re-acquisition of the plurality of OCT signals, and the positional deviation. Then, the quality of the re-acquired plurality of OCT signals is determined. Then, based on the determination result, the control unit 70 determines whether to shift to scanning at the next scanning position or to perform scanning at the same scanning position again. In addition, when the OCT signal is not successfully acquired a plurality of times, the control unit 70 performs error display (for example, display for prompting resetting of the shooting position, display for prompting readjustment of the shooting conditions), and the like, and ends the shooting. You may make it make it. As described above, when a plurality of OCT signals cannot be acquired satisfactorily, a plurality of OCT signals in each scanning region can be acquired with high accuracy by acquiring the plurality of OCT signals again.

<Acquisition of motion contrast data>
The control unit 70 processes a plurality of OCT signals determined to be good and acquires motion contrast data (acquires three-dimensional functional OCT image data in the present embodiment) in the fundus of the eye to be examined. For example, when the control unit 70 shifts to acquisition of a plurality of OCT signals in the next scanning line, the control unit 70 performs calculation processing of the plurality of OCT signals in each scanning line acquired before that.

  For example, after acquiring a plurality of OCT signals in the first scanning line S1, the control unit 70 scans (acquires) a plurality of OCT signals from the first scanning line S1 to the second scanning line S2. To move. When the acquisition of the plurality of OCT signals is started in the second scanning line S2, the control unit 70 starts arithmetic processing of the acquired plurality of OCT signals in the first scanning line S1. That is, the control unit 70 starts arithmetic processing of a plurality of OCT signals corresponding to the first scanning line S1 while acquiring the OCT signal in the second scanning line S2, and performs the first scanning. The function OCT image data in the line S1 is acquired. The control unit 70 performs the above processing for each scanning line, and acquires functional OCT image data for each scanning line while acquiring a plurality of OCT signals for each scanning line. Then, by acquiring functional OCT image data at these multiple positions (scanning lines), a three-dimensional functional OCT front image that is a pseudo angiographic image (an image that can be used as an angiographic image as an application). Data can be acquired. As described above, the motion contrast data can be acquired more quickly by performing the operation for acquiring the motion contrast data during the acquisition of the plurality of OCT signals. In the present embodiment, when shifting to the acquisition of a plurality of OCT signals in the next scanning line, the arithmetic processing of the plurality of OCT signals in each scanning line acquired before that is performed. However, it is not limited to this. For example, the control unit 70 may be configured to start arithmetic processing of a plurality of OCT signals in each scanning line after acquiring a plurality of OCT signals in each scanning line.

  As described above, in the predetermined scanning region, the image is acquired in the predetermined scanning region based on the detection result of the positional deviation between the front image at the time of acquiring the plurality of OCT signals and the front image after acquiring the plurality of OCT signals. By determining the quality of the plurality of OCT signals, the quality of the plurality of OCT signals acquired in the same part (the same scanning region) can be determined collectively. For this reason, it can be easily confirmed whether or not the acquired plurality of OCT signals have been successfully imaged. Thereby, a plurality of OCT signals in the same scanning region can be easily and accurately acquired.

<Transformation example>
In the present embodiment, the acquisition of the plurality of OCT signals in the first scanning line S1 is started after the acquisition of the first front image F1 is completed, but the present invention is not limited to this. A configuration may be adopted in which acquisition of a plurality of OCT signals is started in parallel with the acquisition of the first front image F1 in accordance with the output of the imaging start signal. In this case, when determining the quality of the plurality of OCT signals, the plurality of OCT signals acquired in parallel with the acquisition of the first front image F1 (obtained with the start of imaging) are deleted, and the second front image is acquired. Judgment processing for a plurality of OCT signals is started from a plurality of OCT signals acquired in parallel when F2 is acquired. For example, in the first scanning line S1, an OCT signal of 8 frames (an OCT signal for 4 frames at the time of acquiring the first front image F1 and an OCT signal for 4 frames at the time of acquiring the second front image F2) is acquired. The OCT signals for four frames at the time of acquiring the first front image F1 are deleted.

  In the present embodiment, the configuration in which the front image acquisition start timing and the plurality of OCT signal acquisition start timings in a predetermined scanning region are synchronized is described as an example, but the present invention is not limited to this. The acquisition start operation of the plurality of OCT signals and the acquisition start operation of the front image in a predetermined scanning region may be asynchronous. For example, as shown in FIG. 6, during the acquisition of the first front image F1 (for example, after half of the time T1 has elapsed), acquisition of a plurality of OCT signals in the first scan line S1 is started. In this case, the first front image F1 and the second front image F2 are acquired when the plurality of OCT signals O1, O2, O3, and O4 are acquired in the first scanning line S1. That is, the determination process for the plurality of OCT signals O1, O2, O3, and O4 in the first scanning line S1 is performed using the positional deviation between the first front image F1 and the second front image F2. In addition, the acquisition of the plurality of OCT signals O1, O2, O3, and O4 in the second scanning line S2 is started during the acquisition of the second front image F2 (for example, after half of the time T2 has elapsed). The plurality of OCT signals O1, O2, O3, and O4 in the second scanning line S2 are subjected to determination processing based on the second front image F2 and the third front image F3.

  Note that, in the present embodiment, predetermined detection is performed based on the detection result of the positional shift between the front image of one frame when acquiring a plurality of OCT signals in a predetermined scanning region and the front image of one frame after acquiring the plurality of OCT signals. However, the present invention is not limited to this. For example, when using a front observation optical system (for example, an infrared observation optical system) that can acquire a plurality of front images while acquiring a plurality of OCT signals, one front surface is selected from the plurality of front images. An image (for example, the latest front image) may be selected and the determination process may be performed. Further, for example, a plurality of OCT signal determination processes may be performed using all the plurality of front images.

  In the present embodiment, the case where one scanning position (first scanning position) is set as the first scanning region is described as an example, but the present invention is not limited to this. A configuration in which a plurality of scanning positions is set as the scanning region may be used. For example, the first scanning region may be set so that the measurement light is scanned at two scanning positions, a first scanning position and a second scanning position. In this case, for example, when the frame rate for acquiring the front image and the OCT signal is the frame rate described in the present embodiment (when the frame rate for acquiring the OCT signal is four times the frame rate for acquiring the front image), 1 While acquiring the front image of the frame, two frames of OCT signals are acquired at the first scanning position, and two frames of OCT signals are acquired at the second scanning position. That is, based on a detection result of a positional shift between a front image of one frame when acquiring a plurality of OCT signals and a front image of one frame after acquiring a plurality of OCT signals in a predetermined scanning region (for example, the first scanning region). In this case, the quality of the plurality of OCT signals at the two scanning positions can be determined collectively. Then, the control unit 70 processes each of the plurality of OCT signals acquired with respect to at least two or more (two in the present embodiment) scanning positions, and motion contrast data at each scanning position on the fundus of the eye to be examined. Get each. In this way, motion contrast data at a plurality of scanning positions is acquired during detection of a single positional shift between front images acquired after acquisition of a plurality of OCT signals and after acquisition of the plurality of OCT signals. Therefore, shooting can be completed more quickly.

  In the case where a plurality of scanning positions are set as the scanning region, an arbitrary order can be performed as the order of acquiring the plurality of OCT signals at each scanning position. For example, when the first scanning region is set so that the measurement light is scanned at two scanning positions, ie, a first scanning position and a second scanning position, one frame is obtained at the first scanning position. After acquiring the OCT signal, one frame of the OCT signal is acquired at the second scanning position. Thereafter, an OCT signal of one frame is acquired at the first scanning position, and an OCT signal of one frame is acquired at the second scanning position. That is, by acquiring OCT signals alternately at the first scanning position and the second scanning position, two frames of OCT signals are acquired at the respective scanning positions. For example, when an OCT signal of one frame is acquired at the first scanning position and the second scanning position, the OCT signal and the second scanning position at the first scanning position in one scan. The OCT signal may be acquired at the same time.

  In the present embodiment, when it is determined that the OCT signal is not good, imaging is performed again in the same scanning region, but the present invention is not limited to this. The configuration may be such that after the completion of all the scanning positions, the OCT signal in the scanning region in which it is determined that the OCT signal is not good is re-photographed. Further, the scan area where the OCT signal is not acquired well may be notified to the examiner. In this case, the examiner may execute re-imaging or the like based on the notified information.

  In the present embodiment, a case where a front image of the fundus is acquired is described as an example in order to detect a positional shift of the fundus of the eye to be examined. However, the present invention is not limited to this. For example, the front image of the anterior segment of the eye to be examined may be captured, and the fundus may be captured based on the positional shift between the front images of the anterior segment.

  Note that, in the present embodiment, the present invention is not limited to this described by taking an optical coherence tomography apparatus that acquires an OCT signal as an example. The technology of the present disclosure can be applied to any device that acquires motion contrast data from a plurality of signals (for example, imaging signals acquired by a fundus imaging device with a wavefront compensation function).

  Note that the present invention is not limited to the apparatus described in this embodiment. For example, optical coherence tomography calculation software (program) that performs the functions of the above embodiments is supplied to the system or apparatus via a network or various storage media. A computer of the system or apparatus (for example, a CPU) can also read and execute the program.

DESCRIPTION OF SYMBOLS 1 Optical coherence tomography device 70 Control part 72 Memory 75 Monitor 76 Operation part 100 Interference optical system (OCT optical system)
108 optical scanner 120 detector 200 front observation optical system 300 fixation target projection unit

Claims (4)

An optical coherence tomography device that detects an OCT signal by measurement light and reference light irradiated to a subject's eye, and acquires a tomographic image of the subject's eye by processing the OCT signal,
A front observation optical system for obtaining a front image of the eye to be examined;
An OCT optical system that acquires a plurality of OCT signals that are temporally different with respect to the same scanning region on the eye to be examined;
When a plurality of OCT signals are acquired by the OCT optical system in the first scanning region on the eye to be examined, a first front image is acquired by the front observation optical system, and the plurality of OCT signals are acquired in the first scanning region. A control means for acquiring a second front image by the front observation optical system after the acquisition of the first front image;
A positional deviation between the first front image and the second front image is detected by image processing, and the quality of the plurality of OCT signals acquired in the first scanning region is determined based on the detection result of the positional deviation. Determining means for determining
Arithmetic processing means for processing the plurality of OCT signals determined to be good by the determination means to obtain motion contrast data in the eye to be examined;
With
The control means acquires a plurality of OCT signals that are temporally different with respect to at least two or more scanning regions on the eye by the OCT optical system,
After the acquisition of the plurality of OCT signals is completed in all scanning regions, the plurality of OCT signals in the scanning region in which the plurality of OCT signals are determined to be unsatisfactory by the determination unit are re-acquired. Optical coherence tomography device. The optical coherence tomography apparatus according to claim 1, wherein the first scanning region includes at least two scanning positions on the eye to be examined. Executed in a control device that controls the operation of an optical coherence tomography device that detects an OCT signal based on measurement light and reference light irradiated to the eye and processes the OCT signal to acquire a tomographic image of the eye to be examined. An optical coherence tomography control program,
By being executed by the processor of the control device,
A front image acquisition step of obtaining a front image of the eye to be examined;
An acquisition step of acquiring a plurality of OCT signals that are temporally different with respect to the same scanning region on the eye to be examined;
In the first scanning region on the eye to be examined, when acquiring the plurality of OCT signals by the acquiring step, the first front image is acquired by the front image acquiring step, and after acquiring the plurality of OCT signals in the first scanning region. A control step of acquiring a second front image by the front image acquisition step after acquisition of the first front image;
A positional deviation between the first front image and the second front image is detected by image processing, and the quality of the plurality of OCT signals acquired in the first scanning region is determined based on the detection result of the positional deviation. A determination step for determining
An arithmetic processing step of processing the plurality of OCT signals determined to be good by the determination step to obtain motion contrast data in the eye to be examined;
To the optical coherence tomography device,
The control step acquires, by the OCT optical system, a plurality of OCT signals that are temporally different with respect to at least two or more scanning regions on the eye to be examined,
After the acquisition of the plurality of OCT signals is completed in all scanning regions, the plurality of OCT signals in the scanning region in which the plurality of OCT signals are determined to be unsatisfactory by the determination unit are re-acquired. Optical coherence tomography control program. 4. The optical coherence tomography control program according to claim 3, wherein the first scanning region includes at least two scanning positions on the eye to be examined.

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