JP6535985B2 - Optical coherence tomography apparatus, optical coherence tomography computing method and optical coherence tomography computing program - Google Patents

Description

  The present invention relates to an optical coherence tomography apparatus for obtaining motion contrast data of an object, an optical coherence tomography computing method, and an optical coherence tomography computing program.

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

  In recent years, a device has been proposed that obtains motion contrast (a pseudo angiographic image) without applying a contrast agent by applying the OCT technology (see, for example, Patent Document 1).

International Publication No. 2010/143601

  However, when acquiring a functional OCT image such as a motion contrast using OCT, it takes a long time to calculate an OCT signal to acquire a functional OCT image. For this reason, after completion of the imaging of OCT, it takes a long time to be able to observe a functional OCT image, which is stress for the subject and the examiner.

  An object of the present invention is to provide an optical coherence tomography apparatus, an optical coherence tomography computing method, and an optical coherence tomography computing program capable of rapidly acquiring a functional OCT image in view of the above problems. .

  In order to solve the above-mentioned subject, the present invention is characterized by having the following composition.

(1) The optical coherence tomography apparatus according to the first aspect of the present disclosure detects an OCT signal from the measurement light and the reference light irradiated to the test object, and processes the OCT signal to detect a tomographic image of the test object. An optical coherence tomography apparatus for acquiring image data, the acquisition means for acquiring a plurality of OCT signals temporally different with respect to the same position on a subject, and the plurality of OCTs acquired by the acquisition means Arithmetic processing means for processing signals to acquire motion contrast data in the test object, the acquisition means scanning measurement light at a plurality of different transverse positions on the test object, in relation to the XY directions Acquiring an OCT signal for acquiring three-dimensional motion contrast data, and the arithmetic processing means performs OCT at the plurality of crossing positions by the acquiring means During acquisition of the signal, processing a plurality of OCT signals acquired by the acquisition unit, characterized in that you get the three-dimensional motion contrast data.
(2) The optical coherence tomography computing method according to the second aspect of the present disclosure detects an OCT signal from the measurement light and the reference light irradiated to the test object, and processes the OCT signal to detect the OCT signal. An optical coherence tomography calculation method executed in an optical coherence tomography apparatus for acquiring a tomographic image, the acquisition step for acquiring a plurality of temporally different OCT signals with respect to the same position on a subject. Acquiring the OCT signal for scanning the measurement light at different crossing positions on the test object and acquiring three-dimensional motion contrast data in the X and Y directions; and the plurality acquired by the acquiring step. Calculating the OCT signal of the subject to obtain motion contrast data in the test object, During acquisition of the OCT signal at said plurality of transverse position by the obtaining step, processing a plurality of OCT signals acquired by the acquisition step, and a processing step you get the three-dimensional motion contrast data It is characterized by
(3) The optical coherence tomography calculation program according to the third aspect of the present disclosure detects an OCT signal by the measurement light and the reference light irradiated to the test object, and processes the OCT signal to thereby process the test object. An optical coherence tomography calculation program that is executed in a control device that controls the operation of an optical coherence tomography device that acquires a tomographic image, which is executed by a processor of the control device to achieve the same position on a subject Acquisition step for acquiring a plurality of OCT signals temporally different with respect to the scanning direction, in which measurement light is scanned at a plurality of different crossing positions on the test object to acquire three-dimensional motion contrast data in the XY directions Acquiring an OCT signal of the image, and processing the plurality of OCT signals acquired by the acquiring step A plurality of OCT signals acquired by the acquisition step during the acquisition of the OCT signals at the plurality of crossing positions by the acquisition step. processing, and a processing step get the three-dimensional motion contrast data, characterized in that to be executed by the optical coherence tomography apparatus.

It is a block diagram explaining the composition of the optical coherence tomography device concerning this example. It is a figure which shows the outline of the OCT optical system which concerns on a present Example. It is an image figure of the fundus for demonstrating imaging | photography of a present Example. It is a figure explaining matching of three-dimensional function OCT image data. It is a schematic diagram which shows the example of functional OCT image data acquired by OCT optical system, and its luminance distribution. It is a figure explaining an analysis map and an analysis parameter. It is a figure which shows an example of the superposition display of motion contrast data and analysis information. It is a figure explaining the case where an eye fundus region is divided and analysis information is acquired.

  An exemplary embodiment of the present invention will be described based on the drawings. In the present embodiment, the depth direction of the subject's eye (the axial direction of the subject's eye E) is the Z direction (optical axis L1 direction), and is horizontal on a plane perpendicular to the depth direction (the same plane as the subject's face). The direction will be described as the X direction, and the vertical direction as the Y direction. The surface direction of the fundus may be considered as the XY direction.

<Overview>
The present apparatus (optical coherence tomography apparatus) 1 includes an interference optical system (OCT optical system) 100, a fundus illumination optical system (hereinafter sometimes referred to as an illumination optical system) 10, and a CPU (control unit) 70. A monitor 75, an operation unit 76, and a memory 72 are mainly provided (see FIG. 1). Each unit is electrically connected to the control unit 70 via a bus or the like. In the following description, a case where a tomographic image of the fundus oculi Ef of the eye to be examined E is taken as an example of the optical coherence tomography device 1 will be described. Of course, the optical coherence tomography apparatus 1 is applicable to imaging of various parts (for example, an anterior segment etc.) of an eye to be examined.
The optical coherence tomography apparatus 1 has been described by taking an apparatus in which the OCT optical system 100 and each part are integrated as an example, but the present invention is not limited to this. For example, the OCT device 1 may not have the OCT optical system 100. In this case, the OCT device is connected to an apparatus or the like provided with an OCT optical system provided separately, receives an OCT signal or OCT image data acquired by entering another apparatus, and various types of information based on the received information Perform arithmetic processing.

  For example, 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). It should be noted that various programs are installed on a commercially available PC using a processing unit, an input unit, a storage unit, and a display unit possessed by a commercially available PC (personal computer) as the control unit 70, operation unit 76, memory 72, and monitor 75. You may do so. For example, the control unit 70 may also serve as an acquisition unit, an arithmetic processing unit, an analysis processing unit, an image processing unit, and the like. The control unit 70 may also serve as a control unit (scan control unit) that controls a scanning unit for scanning the measurement light. Of course, configurations such as an acquisition unit, an arithmetic processing unit, an analysis processing unit, an image processing unit, and a scan control unit may be separately provided.

  For example, the OCT optical system 100 irradiates the fundus Ef with measurement light. The OCT optical system 100 detects an interference state between the measurement light reflected from the fundus oculi Ef and the reference light by a light receiving element (detector 120). The OCT optical system 100 includes an irradiation position change 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 tomographic image data based on the light reception signal from the detector 120. The tomographic image data may be image data or signal data.

  For example, as tomographic image data, B scan tomographic image data, three-dimensional tomographic image data (three-dimensional OCT image data) and the like can be mentioned. For example, the B scan tomographic image data is tomographic image data acquired by scanning the measurement light in any direction (for example, the X direction) in the X and Y directions along the scan line (cross position). . Also, for example, three-dimensional OCT image data is tomographic image data acquired by scanning measurement light two-dimensionally. For example, from three-dimensional OCT image data, OCT front (Enface) image (for example, integrated image integrated in the depth direction, integrated value of spectrum data at each XY position, XY each in a certain fixed depth direction) Brightness data at the position, retina surface image, etc.) may be acquired.

  For example, the OCT optical system 100 includes a front observation optical system 200. Of course, the front observation optical system 200 may be separately provided. In this case, for example, an apparatus including the front observation optical system 200 is connected to the optical coherence tomography apparatus 1 or the OCT optical system 100 or the like, and a front image acquired by an apparatus including the separately provided front observation optical system 200 Data is received, and various arithmetic processing is performed based on the received information.

  For example, the front observation optical system 200 acquires front image data of an 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. For example, as the front observation optical system 200, a configuration of an ophthalmic scanning laser ophthalmoscope (SLO) and a fundus camera type can be mentioned. Also, for example, the OCT optical system 100 may double as the front observation optical system 200. That is, front image data (hereinafter referred to as a front image) may be acquired using data for forming a two-dimensionally obtained tomographic image (OCT front image).

  For example, the control unit 70 acquires a plurality of temporally different OCT signals with respect to the same position on a test object (for example, an eye to be examined). The control unit 70 processes the plurality of acquired OCT signals to acquire motion contrast data in the subject.

  For example, motion contrast data is detection information such as movement of a test object or temporal change. For example, a flow image or the like is also a kind of motion contrast. The flow image is, for example, an image obtained by detecting the movement of a fluid or the like. For example, angiographic image data etc. in which the blood vessel position obtained by detecting the movement of blood is contrasted can be said to be a type of motion contrast data.

  For example, as the motion contrast data, functional OCT signals, functional OCT image data, three-dimensional functional OCT image data (three-dimensional motion contrast data), and the like can be given. That is, the motion contrast data may be image data or signal data. For example, the functional OCT signal is so-called A scan data. Also, for example, functional OCT image data is acquired by arranging functional OCT signals at each scanning position of measurement light. Also, for example, three-dimensional functional OCT image data is acquired by two-dimensionally scanning the measurement light in the XY directions. From the three-dimensional functional OCT image data, OCT functional front (Enface) image data (for example, an integrated image integrated in the depth direction, an integrated value of spectral data at each XY position, XY in a certain fixed depth direction Brightness data etc.) at each position may be acquired.

  For example, the control unit 70 scans the measurement light at least twice at the same position on the test object to acquire different OCT signals at different times at the same position. It is preferable that OCT signals different in time at the same position acquire signals at the same position. Note that a plurality of OCT signals different in time may not scan the measurement light at completely coincident positions. For example, scanning positions adjacent to each other may be used. Thus, the same position also includes scanning positions adjacent to each other.

<Operation processing operation>
For example, after acquiring a plurality of OCT signals at a first position on the test object, the control unit 70 acquires a plurality of OCT signals at a second position different from the first position. The control unit 70 processes a plurality of OCT signals acquired at the first position and acquires motion contrast data at the first position during acquisition of a plurality of OCT signals at at least one of the first position and the second position. Do. With such a configuration, processing of the OCT signal can be completed while processing of the OCT signal can be performed while acquiring a plurality of OCT signals, and motion contrast data can be acquired quickly. be able to.

  For example, as a calculation processing method for acquiring motion contrast data, a method using phase difference (PD) of a complex OCT signal, a method using vector difference (VD: Vector difference) of a complex OCT signal, speckle The method etc. which use a variance (SV: Speckle Variance) are mentioned. Also, for example, as the operation processing method, it may be obtained by a combination of these methods.

  For example, when at least two or more OCT signals are acquired at the first position, the control unit 70 may continue to acquire OCT signals at the first position, even if the OCT signal is acquired at the first position. Processing may be initiated between the acquired OCT signals. Also, for example, when acquisition of a plurality of OCT signals at the second position is started, the control unit 70 may start processing of the plurality of OCT signals at the first position. Also, for example, even when processing of a plurality of OCT signals at the first position is started, it is the timing at which acquisition of OCT signals at another position different from the first position (for example, the third position etc.) is started. Good. Although processing of a plurality of OCT signals at the first position is started, acquisition of a plurality of OCT signals at other positions (for example, the second position, the third position, etc.) is started. The start of acquisition of H may not be exactly the timing at which acquisition of the OCT signal is started. The start of processing of a plurality of OCT signals at the first position may be any timing during acquisition of OCT signals at other positions.

  For example, the first position and the second position include one position (A scan line), a crossing position, and the like. For example, when the first position is the first crossing position and the second position is the second crossing position, the control unit 70 determines the plurality of OCTs at at least one of the first crossing position and the second crossing position. During signal acquisition, the plurality of OCT signals detected at the first crossing position are processed to obtain motion contrast data at the first crossing position. As described above, when a plurality of OCT signals are acquired in units of crossing positions, processing can be performed in consideration of the deviation between the transverse direction and the depth direction by processing the OCT signals, which is better. Motion contrast data can be obtained.

  For example, the control unit 70 may display motion contrast data on the monitor 75 while acquiring motion contrast data at each position. With such a configuration, before completing acquisition of OCT signals at all set imaging positions, it is confirmed whether or not motion contrast data is accurately acquired at positions where acquisition of OCT signals is completed. be able to. For this reason, it is possible to reduce the chance of performing re-shooting again after completing the shooting.

<Correction process with three-dimensional function OCT image data>
For example, the control unit 70 aligns the three-dimensional function OCT image data with other front image data. For example, the three-dimensional functional OCT image data is acquired by processing a plurality of OCT signals acquired at a plurality of positions on the test object, and the control unit 70 determines the plurality of positions on the test object. In the plurality of acquired OCT signals, at least one or more OCT signals are processed at each of the plurality of positions to acquire reference front image data of the subject. The control unit 70 performs matching processing of the other front image data and the reference front image data to associate the other front image data with the three-dimensional functional OCT image data. As described above, since three-dimensional functional OCT image data and front image data for alignment (reference front image data) can be acquired from a common OCT signal, the correspondence between three-dimensional functional OCT image data and Even if the type of image data (e.g., luminance distribution, contrast, resolution, form of test object, etc.) is different from that of the other front image data to be attached, the association can be easily performed with high accuracy. In addition, information that is useful for diagnosis such that the relationship between the three-dimensional functional OCT image data and the other fundus image data can be easily confirmed by correlating the use as an angiographic image also with other fundus image data. You can get

  For example, as the three-dimensional functional OCT image data, in addition to the three-dimensional functional OCT image data, OCT functional front image data acquired from the three-dimensional functional OCT image data may be used.

  For example, as another front image data, a configuration using front image data acquired by a front observation optical system (for example, SLO, configuration of a fundus camera type, etc.) 200 may be mentioned. Of course, frontal image data separately acquired by another device may be used.

  For example, the reference front image data includes OCT front image data acquired based on at least one OCT signal among a plurality of OCT signals acquired at a plurality of positions on the test object. Also, for example, as the reference front image data, OCT function front image data acquired from three-dimensional function OCT image data may be used.

  For example, the control unit 70 superimposes a display indicating three-dimensional function OCT image data on the front image data by associating the front image data with the three-dimensional function OCT image data. In this way, by superimposing the front image data and the display showing the three-dimensional function OCT image data by associating them, the relationship between the both can be more easily confirmed, which is useful information for diagnosis. For example, when OCT functional front image data is used as three-dimensional functional OCT image data, the control unit 70 is an OCT that is front image data in a predetermined depth region of the subject based on the three-dimensional functional OCT image data. Function front image data is acquired. The control unit 70 superimposes a display indicating OCT function front image data on the front image data by associating the front image data with the three-dimensional function OCT image data. Of course, front image data, three-dimensional functional OCT image data, and OCT functional front image data may be superimposed and displayed.

<Analysis Information Acquisition Process>
For example, the control unit 70 may acquire analysis information on a blood vessel from the motion contrast data. For example, the control unit 70 processes motion contrast data of the eye to be examined, acquires blood vessel position information, and acquires analysis information on the blood vessel based on the position information. Thus, acquiring analysis information on blood vessels leads to early detection of retinal diseases and the like. Moreover, the activity state of the blood vessel can be confirmed with an easy configuration, and the effects of the drug, the laser treatment and the like can be confirmed.

  For example, as the analysis information, the control unit 70 processes motion contrast data, determines whether or not a blood vessel is present, and obtains analysis information based on the determination result. Such a configuration facilitates early detection of a lesion or the like that can be judged by the presence or absence of a blood vessel. Also, for example, as analysis information, the control unit 70 measures at least one of a dimension (length information), an area, and a volume (actually calculated volume, volume ratio, and the like) regarding the blood vessel site by image processing. There is a configuration for acquiring a blood vessel analysis parameter (analysis parameter) based on.

  For example, when processing motion contrast data to determine whether or not a blood vessel is present, the control unit 70 determines whether or not a blood vessel is present in a region in the depth direction of the motion contrast data and makes a determination. Obtain analysis information based on the results. With such a configuration, it is known that blood vessels in the depth direction do not exist at each position of the subject's eye, so it becomes easy to detect a lesion etc. at an early stage. For example, the region in the depth direction of the motion contrast data may be configured to be the entire region in the depth direction. In addition, for example, the region in the depth direction of the motion contrast data may be configured as a partial region in the depth direction of the motion contrast data. Such a configuration that performs determination in a partial region makes it possible to confirm the blood vessel state at a predetermined depth, and more detailed blood vessel analysis information can be provided to the examiner.

<Example>
One exemplary embodiment will now be described with reference to the drawings. FIG. 1 is a block diagram for explaining the arrangement of an optical coherence tomography apparatus according to this embodiment. FIG. 2 is a schematic view illustrating an 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 the fundus oculi image taken by the OCT optical system 100 on the 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, and each unit is via a bus or the like. Are electrically connected to the CPU 70. In the following description, a case where a tomographic image of the fundus oculi Ef of the eye to be examined E is taken as the OCT device 1 will be described as an example.

  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). It should be noted that various programs are installed on a commercially available PC using a processing unit, an input unit, a storage unit, and a display unit possessed by a commercially available PC (personal computer) as the control unit 70, operation unit 76, memory 72, and monitor 75. You may do so.

  In addition, in a present Example, although the apparatus with which the OCT optical system 100 and each part were united was mentioned as the example and demonstrated as the OCT device 1, it is not limited to this. For example, the OCT device 1 may not have 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 processing 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 an interference state between the measurement light reflected from the fundus oculi Ef and the reference light by a light receiving element (detector 120). The OCT optical system 100 includes an irradiation position change 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 coherence tomography (OCT), and captures a tomographic image of the eye to be examined E. The OCT optical system 100 splits the light emitted from the measurement light source 102 into a measurement light (sample light) and a reference light by a coupler (light splitter) 104. Then, 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. After that, the detector 120 receives interference light resulting from the combination of 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 of the interfering light (spectral interference signal) is detected by the detector 120, and a complex OCT signal is obtained by Fourier transformation on the spectral intensity data.
For example, in Fourier domain OCT, a depth profile (A scan signal) in a predetermined range is obtained by calculating the absolute value of the amplitude in the complex OCT signal obtained by Fourier transform on 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. Also, 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 spectral data at each XY position, and each XY position in a certain depth direction Luminance data, a retinal surface image, etc.) may be acquired.

  Also, motion contrast data is obtained from at least two or more OCT signals at the same position at different times. That is, motion contrast data is acquired by analyzing at least two or more complex OCT signals. For example, a functional OCT signal is obtained from a complex OCT signal. 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 scanning the measurement light two-dimensionally in the XY directions. In addition, an OCT function front (Enface) image (for example, a Doppler front (Enface) image, signal image data speckle variance front image) is acquired from three-dimensional function OCT image data. Each image data may be image data or signal data. The details of the motion contrast data will be described later.

  For example, Fourier-domain OCT includes Spectral-domain OCT (SD-OCT) and Swept-source OCT (SS-OCT). Also, 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 disperses interference light into each frequency component (each wavelength component). . The spectrometer comprises, 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 high speed temporally 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. Then, as the wavelength selection filter, for example, a combination of a diffraction grating and a polygon mirror, and one using a Fabry-Perot etalon can be mentioned.

  The light emitted from the light source 102 is divided by the coupler 104 into a measurement light beam and a reference light beam. Then, the measurement light flux is emitted into the air after passing through the optical fiber. 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 the same optical path.

  The optical scanner 108 two-dimensionally (XY direction) scans the measurement light on the fundus. The light scanner 108 is disposed at a position substantially conjugate to the pupil. The light 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 light beam emitted from the light source 102 changes its reflection (traveling) direction, and is scanned at an arbitrary position on the fundus. Thereby, the imaging position on the fundus oculi Ef is changed. The light scanner 108 may be configured to deflect light. For example, in addition to a reflection mirror (galvano mirror, polygon mirror, resonant scanner), an acousto-optic element (AOM) or the like that changes the traveling (deflection) direction of light is used.

  The reference optical system 110 generates reference light that is combined with the reflected light acquired by the reflection of the 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 reflective optical system (for example, a reference mirror), and the light from the coupler 104 is returned to the coupler 104 again by being reflected by the reflective optical system and guided to the detector 120. As another example, the reference optical system 110 is formed by transmission optical system (for example, an optical fiber) and is guided to the detector 120 by transmitting the light from the coupler 104 without returning it.

  The reference optical system 110 is configured to change the optical path length difference between the measurement light and the reference light by moving the optical member in the reference light path. For example, the reference mirror is moved in the optical axis direction. A configuration for changing the optical path length difference may be disposed 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 an 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 measurement light (for example, infrared light) emitted from a light source on the fundus, and a confocal aperture disposed at a substantially conjugate position with the fundus. And a second light receiving element for receiving the fundus reflected light, and has an apparatus configuration of a so-called ophthalmic scanning laser ophthalmoscope (SLO).

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

  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 the front observation optical system 200 provided separately is received by the OCT device or the like.

<Fixation target projection unit>
The fixation target projection unit 300 has an optical system for guiding the viewing direction of the eye E. The fixation target projection unit 300 has a fixation target 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 presenting position of the visual target two-dimensionally. Thereby, the sight line direction is changed, and as a result, the imaging region is changed. For example, when a fixation target is presented from the same direction as the imaging optical axis, the central portion of the fundus is set as an imaging region. Also, when the fixation target is presented above with respect to the imaging optical axis, the upper part of the fundus is set as an imaging region. That is, the imaging region is changed according to the position of the visual target with respect to the imaging optical axis.

  As the fixation target projection unit 300, for example, the fixation position is adjusted by the lighting positions of the LEDs arranged in a matrix, the light from the light source is scanned by the optical scanner, and the fixation position is controlled by the lighting control of the light source. Various configurations are conceivable, such as a configuration to be adjusted. The fixation target projection unit 300 may be of 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 the members of the configurations 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 nonvolatile memory (storage unit) 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 capable of holding stored contents even when the supply of power is shut off. For example, a hard disk drive, a flash ROM, the OCT device 1, and a USB memory detachably attached to the OCT optical system 100 can be used as the non-volatile memory 72. The memory 72 stores an imaging control program for controlling imaging of a front image and a tomographic image by the OCT optical system 100. The memory 72 also stores a fundus analysis program that enables the OCT device 1 to be used. In the memory 72, tomographic image data (OCT image data), three-dimensional tomographic image data (three-dimensional OCT image data), front image data (fundus front image data), and information of imaging positions of tomographic image data in a scanning line. Etc., various information related 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, and a touch panel may be used.

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

<Signal processing method>
In the present embodiment, which describes an arithmetic processing method for obtaining motion contrast data from an OCT signal in the present embodiment, in order to obtain motion contrast data, the control unit 70 performs at least two frames different in time at the same position. To obtain an interference signal (OCT signal) of

  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 the processing related to the Doppler phase difference method and the processing related to the vector difference method. As a method of processing the complex OCT signal, for example, a method of calculating the phase difference of the complex OCT signal, a method of calculating the vector difference of the complex OCT signal, a method of multiplying the phase difference of the complex OCT signal and the vector difference, etc. are considered Be In this embodiment, a method of multiplying the phase difference and the vector difference will be described as an example.

  First, the control unit 70 Fourier transforms the OCT signal acquired by the OCT optical system. The control unit 70 obtains a complex OCT signal by Fourier transform. The complex OCT signal includes real and imaginary components.

  In order to obtain a blood flow signal, it is necessary to compare the images at the same location that differ in time. For this reason, the control unit 70 preferably aligns the image based on the image information. Image registration is the process of aligning and aligning multiple images of the same scene. As a cause of the displacement of the position of the image, for example, movement of the eye to be examined during imaging (for example, involuntary eye movement, fine movement, pulse movement, etc.) can be considered. Note that, even when the frames are aligned, phase shift may occur between A scan lines in the same image. Therefore, it is preferable to perform phase correction. The processing of registration and phase correction is for facilitating the processing of the present embodiment, and is not essential.

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

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

  Next, the control unit 70 calculates the 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, the complex OCT signal can be represented as a vector on the complex plane. Therefore, two signals at the same position at different times are detected, and vector differences are calculated to generate contrast image data in the eye to be examined. In addition, when imaging a vector difference, you may image-form 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 has been calculated is acquired. If there are a plurality of frames for which vector differences have been calculated, the control unit 70 may perform averaging processing on the signals of the frames subjected to the above processing to remove noise.

  The control unit 70 uses the calculation result of the phase difference as a filter for the calculation result of the vector difference. 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 phase difference by the calculation result of the vector difference. That is, the vector difference of the part with a small phase difference is weakened, and the vector difference of the part with a large phase difference is intensified. Thus, the calculation result of the vector difference is weighted by the calculation result of the phase difference.

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

  By multiplying the calculation result of the vector difference and the calculation result of the phase difference, it is possible to cancel the demerit of each measurement method, and to obtain the image data of the blood vessel part well.

  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 plural positions, it is possible to acquire three-dimensional functional OCT front image data used as a pseudo angiographic image.

  In the present embodiment, in order to obtain motion contrast data, the control unit 70 has been described by way of example of a configuration in which the calculation result of the vector difference and the calculation result of the phase difference are taken as an example. I will not. For example, motion contrast data may be acquired using the calculation result of the vector difference. Also, for example, motion contrast data may be acquired using the calculation result of the phase difference.

  In the present embodiment, the control unit 70 has been described by way of an example in which motion contrast data is acquired using two OCT signals, but the present invention is not limited to this. 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, about the following description, the case where three-dimensional function OCT image data is acquired is mentioned as an example, and is demonstrated. Of course, the techniques disclosed in the present invention can be applied when acquiring motion contrast data. For example, the present invention can be applied to the case of acquiring a functional OCT signal or the case of acquiring functional OCT image data.

  First, after the examiner instructs the subject to gaze at the fixation target of the fixation target projection unit 300, the monitor 75 monitors the anterior eye observation image captured by the anterior segment observation camera (not shown). The alignment operation is performed using the 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 while looking at.

  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 controls the front observation optical system 200 to obtain fundus image data. Acquire (fundus front image data). 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 X and Y 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. When the imaging start signal is output from the operation unit 76, the control unit 70 controls the operation of the optical scanner 108 to two-dimensionally scan the measurement light in the XY direction in the scanning range corresponding to the imaging region. Thus, acquisition of three-dimensional functional OCT image data is started. For example, raster scan and plural line scans can be considered as the scan pattern.

  Hereinafter, the imaging operation using the OCT device 1 will be described. FIG. 3 is a schematic view for explaining photographing of the present embodiment.

For example, when the imaging start signal is output, the control unit 70 controls the drive of the optical scanner 108 to scan the measurement light on the fundus in order to acquire three-dimensional functional OCT image data. For example, measurement light is scanned in the X direction along the first scan line (crossing position) S1 shown in FIG. As described above, scanning the measurement light in any direction (for example, the X direction) in the XY directions is referred to as “B scan”. Hereinafter, an interference signal of one frame will be described as an OCT signal obtained by one B scan. The controller 70 acquires an 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 perpendicular to the Z axis and in the left and right direction. The direction of the Y axis is perpendicular to the Z axis and in the vertical direction.
When the first scan is completed, the control unit 70 performs the second scan at the same position as the first scan. For example, after scanning the measurement light along the first scan line S1 shown in FIG. 3, the control unit 70 scans the measurement light again. The control unit 70 acquires an OCT signal detected by the detector 120 during the second scan. Thus, the control unit 70 can acquire two frames of OCT signals different in time at the same position. In addition, in a present Example, although the structure which acquires the OCT signal of 2 frames in the same position is mentioned as an example, it is not limited to this. It may be a configuration in which at least two frames of OCT signals are acquired at the same position. For example, scanning at the same position may be repeated eight times to acquire OCT signals of consecutive eight frames different in time.

  In addition, when the OCT signal of the same position from which time differs can be acquired by one scan, it is not necessary to perform a second scan. For example, in the case where two measurement light beams whose optical axes are shifted by a predetermined interval are scanned at one time, it is not necessary to scan multiple times, as long as different OCT signals at different positions in the same position in the object can be obtained. That is, the same position does not have to be completely the same position, and may be scanned at substantially the same position. In addition, when making two measurement lights scan at once, arbitrary blood flow velocity can be detected as a target by the space | interval of two measurement lights.

  When scanning a plurality of times in the first scan line S1 is completed, the control unit 70 changes the sub-scanning position (the position in the Y direction) by controlling the light scanner 108, and performs measurement in the second scan line S2. The light is scanned a plurality of times in the main scanning direction (X direction). The control unit 70 performs scanning on the second scan line S2 until, for example, an OCT signal of a preset number of frames (in the present embodiment, an OCT signal of two frames) is obtained.

  Similarly, the control unit 70 acquires a plurality of OCT signals in each scan line by scanning the measurement light a plurality of times in each scan line up to the final scan line Sn. That is, the control unit 70 performs the scan a plurality of times for each scan line. That is, as shown in FIG. 3, the control unit 70 raster scans (scans at a cross position) the measurement light, and acquires OCT signals of at least two frames different in time in each scanning line (S1 to Sn). . This makes it possible to acquire three-dimensional information of the fundus. The control unit 70 may control the OCT optical system 100 to acquire an OCT signal, and may control the front observation optical system 200 to acquire fundus image data.

  Here, in the case where the plurality of OCT signals acquired in each scanning line are subjected to arithmetic processing to acquire functional OCT image data in each scanning line, the arithmetic processing takes time. For this reason, if calculation processing of a plurality of OCT signals in each scanning line is started after acquiring a plurality of OCT signals in each scanning line, it takes a long time to obtain functional OCT image data in each scanning line. .

  In the present embodiment, in the case of shifting to acquisition of the OCT signal in the next scanning line, processing of the OCT signal in each scanning line acquired up to that point is performed. The control unit 70 processes the plurality of OCT signals acquired at the first position during acquisition of the plurality of OCT signals at at least one of the first position and the second position, and the motion contrast at the first position Get data

  For example, after acquiring a plurality of OCT signals in the first scan line S1, the control unit 70 moves the acquisition position of the OCT signal from the first scan line S1 to the second scan line S2. When the acquisition of the OCT signal is started in the second scan line S2, the control unit 70 starts arithmetic processing of the plurality of acquired OCT signals in the first scan line S1. That is, while performing acquisition of the OCT signal in the second scan line S2, the control unit 70 starts arithmetic processing of a plurality of OCT signals corresponding to the first scan line S1, and the functional OCT image data Get the 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 plural positions (scanning lines), a three-dimensional functional OCT front image which is a pseudo angiographic image (an image that can be used as an angiographic image as an application) Data can be obtained.

  In the present embodiment, when acquisition of the OCT signal is started in the second scan line S2, the control unit 70 starts arithmetic processing of the plurality of acquired OCT signals in the first scan line S1. Although the case has been described as an example, the present invention is not limited to this. The timing to start the calculation of the plurality of OCT signals may be during the acquisition of another plurality of OCT signals different from the OCT signal to be subjected to the calculation process.

  For example, when at least two or more OCT signals are acquired in the first scan line S1, the control unit 70 may sequentially perform arithmetic processing of the OCT signal in the first scan line S1. In this case, for example, when the control unit 70 acquires two OCT signals at the first scanning line S1 and starts acquiring a third OCT signal at the first scanning line S1, the first scanning is performed. Arithmetic processing of the first OCT signal and the second OCT signal acquired in the line S1 is started. Also, for example, when the control unit 70 starts acquiring the OCT signal in the third scan line which is a scan at the position next to the second scan line S2, the plurality of OCTs in the first scan line S1 are generated. The arithmetic processing of the signal may be started.

  As described above, while acquiring an OCT signal at another imaging position, it is possible to complete the calculation processing of the OCT signal at the previous imaging position, and it is quick to take time-consuming motion contrast data to acquire It can be acquired. Further, as in the present embodiment, calculation is performed in consideration of the deviation between the cross direction (X direction) and the depth direction (Z direction) by performing calculation processing for each acquisition of the OCT signal at each cross position. It is possible to obtain accurate functional OCT image data that can be performed. The technique of the present disclosure is more useful when acquiring three-dimensional functional OCT image data. That is, since it is necessary to detect and process OCT signals at a plurality of crossing positions when acquiring three-dimensional functional OCT image data, it takes a long time to acquire three-dimensional functional OCT. The technology disclosed herein is more useful.

  In the present embodiment, the case of acquiring motion contrast data in the scanning line (crossing position) has been described as an example, but the present invention is not limited to this. The control unit 70 may be configured to process the plurality of OCT signals acquired at the first position and acquire motion contrast data at the first position during acquisition of the plurality of OCT signals at the second position. For example, the first position and the second position may be one position (A scan line).

  In the present embodiment, the motion contrast data may be displayed on the monitor 75 each time it is acquired. For example, the control unit 70 acquires functional OCT image data on the first scan line S1 and displays the functional OCT image data on the monitor 75. By adopting such a configuration, the examiner can accurately sequentially acquire motion contrast data at the imaging position at which the acquisition of the OCT signal is completed before completing acquisition of the OCT signal at all the set imaging positions. You can check if it has been acquired. Therefore, for example, the examiner can continuously perform re-shooting at a shooting position where good motion contrast data is not obtained during shooting, and after the shooting is completed, the shooting may be performed again. It is possible to reduce the time and effort to do.

  In the present embodiment, the control unit 70 may determine the appropriateness of the motion contrast data, and output the determination information based on the determination result. For example, the control unit 70 may determine the propriety of the motion contrast data based on the signal intensity (for example, the magnitude of the luminance value) of the acquired motion contrast data. Also, for example, the control unit 70 acquires OCT images corresponding to respective OCT signals from a plurality of OCT signals acquired in the same scanning line used to acquire motion contrast data, and acquires the OCT images. The propriety of the motion contrast data may be determined based on the correlation value (similarity) between the images. For example, as a configuration for outputting the determination information, a configuration for outputting a signal for shifting to the next operation may be mentioned. In this case, for example, the control unit 70 determines that the motion contrast data is not properly acquired when it is determined by the determination processing that there is a shooting position determined that the motion contrast data was not properly acquired. There is a configuration that performs an operation of performing re-shooting at the shooting position. Also, for example, as a configuration for outputting the determination information, output error information indicating the content in which the shooting position where the motion contrast data was not properly obtained exists (for example, display on the monitor 75 or the like, printing is performed) A configuration, a configuration for outputting guide information for prompting re-shooting, and the like can be mentioned. By adopting such a configuration, it is possible to smoothly shift to the next operation even if the motion contrast data can not be acquired satisfactorily. Also, the examiner can easily confirm that the motion contrast data could not be successfully obtained.

  The control unit 70 may update the motion contrast data each time the motion contrast data is acquired, and may display the motion contrast data of the moving image on the monitor 75. For example, the control unit 70 sequentially displays motion contrast data on the monitor 75 while acquiring motion contrast data at each position. For example, when updating three-dimensional functional OCT image data, the control unit 70 updates motion contrast data in each scanning line each time motion contrast data is acquired in each set scanning line. Of course, the OCT function front image data acquired based on the motion contrast data may be updated. In this case, for example, the control unit 70 sequentially acquires three-dimensional motion contrast data, and sequentially acquires OCT function front image data based on the three-dimensional motion contrast data, and each scanning line (each crossing position) Update the front image data of OCT function. As a result, the examiner can confirm moving image (real time) three-dimensional functional OCT image data and real time OCT functional front image data on the monitor 75.

  The position to be photographed may be set by confirming such motion contrast data or OCT function front image data updated in real time. For example, the control unit 70 can set the position at which imaging is performed on the real-time three-dimensional functional OCT image data or the OCT functional front image data displayed on the monitor 75. The control unit 70 controls a scanning unit for scanning the measurement light so that the image data at the set acquisition position is acquired. In this case, for example, the acquisition position of tomographic image data can be set on real-time three-dimensional functional OCT image data or OCT functional front image data so that tomographic images at the set acquisition position can be acquired. There is a configuration for controlling a scanning means for scanning the measurement light. With such a configuration, the examiner can easily acquire image data of a portion desired to be confirmed in more detail while confirming real-time motion contrast data or OCT functional front image data. Of course, the control unit 70 may automatically set the acquisition position of tomographic image data instead of the configuration in which the acquisition position of tomographic image data is set by the examiner. In this case, for example, the control unit 70 sets an acquisition position so as to acquire tomographic image data of an area or the like where there are many blood vessels based on analysis information of blood vessels described later. In addition, on the real-time three-dimensional function OCT image data or the OCT function front image data, display (for example, line display) indicating the acquisition position of tomographic image data may be performed.

<Association with Three-dimensional Function OCT Front Image Data>
As described above, when the three-dimensional functional OCT image data of the eye to be examined is acquired, the control unit 70 associates the three-dimensional functional OCT image data with other fundus image data. For example, the control unit 70 performs matching processing to associate the three-dimensional functional OCT image data with other fundus image data. Hereinafter, the correspondence between the images will be described. In the present embodiment, as another fundus oculi image data for associating three-dimensional function OCT image data, front image data (hereinafter, SLO front image data) acquired by SLO will be described as an example. Of course, various fundus oculi image data can be applied as three-dimensional functional OCT image data and other fundus oculi image data to be associated.

  FIG. 4 is a diagram for explaining the association of three-dimensional functional OCT image data. Hereinafter, an image analysis process for associating the positional relationship between the three-dimensional function OCT image data and the SLO front image data will be described with reference to FIG.

  In the following description of association, a case where OCT function front image data 24 acquired based on three-dimensional function OCT image data and SLO front image data 22 are associated will be described as an example. In the present embodiment, the control unit 70 acquires OCT function front image data 24 which is front image data in a predetermined depth region of the subject based on the three-dimensional function OCT image data. For example, when acquiring the OCT functional front image data 24, the control unit 70 acquires the OCT functional front image data 24 by integrating the three-dimensional functional OCT image data with respect to the depth direction. Of course, as described above, the OCT function front image data 24 may be acquired by integrating spectral data at each XY position, extracting luminance data at each XY position in a certain depth direction, or the like. . Note that, for example, the OCT functional front image data 24 in a predetermined depth region is the entire region in the depth direction of the three-dimensional functional OCT image data (for example, all the layers of each retinal layer), three-dimensional functional OCT image data OCT functional front image data acquired in a partial region in the depth direction (for example, at least one layer in each retinal layer, or a plurality of layers in each retinal layer) may be mentioned.

  In the present embodiment, matching processing is performed based on a plurality of OCT signals T that are temporally different with respect to the same position, which is used when acquiring three-dimensional functional OCT image data. For example, the control unit 70 processes a plurality of OCT signals T acquired at a plurality of positions on the subject's eye, processes at least one OCT signal at each position of the plurality of positions, and generates a reference image for matching processing. Front image data (reference front image data) 20 of the object to be used as the image sensor is acquired. For example, as the reference front image data 20, the control unit 70 uses OCT front image data (two-dimensionally obtained tomographic image data).

  For example, in the case of acquiring OCT front image data, the control unit 70 acquires OCT front image data by integrating three-dimensional OCT image data in the depth direction. Of course, as described above, the OCT front image data may be acquired by extracting the integrated value of the spectrum data at each position of XY, the luminance data at each position of XY in a certain depth direction, or the like.

  The control unit 70 performs matching processing between the reference front image data (hereinafter referred to as OCT front image data) 20 and the SLO front image data 22, and the OCT based on the SLO front image data 22 and the three-dimensional functional OCT image data. The function front image data 24 is associated with each other.

  For example, the control unit 70 detects the misalignment amount of the OCT front image data 20 and the SLO front image data 22 as matching processing, and based on the misalignment amount, the OCT function front image data 24 and the SLO front image The positional relationship with the data 22 is made to correspond.

  For example, various image processing methods (a method using various correlation functions, a method using Fourier transform, a method based on feature point matching) can be used as a method for detecting the positional displacement amount between two images. It is.

  For example, the predetermined reference image data (for example, OCT front image data 20) or the target image data (SLO front image data 22) is displaced by one pixel at a time, and the reference image and the target image are compared. A method is conceivable to detect the amount of positional deviation between the two data (when the correlation becomes the highest). In addition, a method may be considered in which a common feature point is extracted from a predetermined reference image and a target image, and positional deviation of the extracted feature point is detected.

  In addition, a phase limited correlation function may be used as a function for obtaining positional deviation between two image data. In this case, first, each image data is subjected to Fourier transform to obtain the phase and amplitude of each frequency component. The obtained amplitude component is normalized to 1 for each frequency component. Next, after calculating the phase difference for each frequency between two image data, they are subjected to inverse Fourier transform.

  Here, if there is no positional deviation between the two image data, only cosine waves are added, and a peak appears at the origin position (0, 0). In addition, when there is positional deviation, a peak appears at a position corresponding to the positional deviation. Therefore, the amount of positional deviation between the two image data can be obtained by finding the detected position of the peak. According to this method, it is possible to detect the misalignment amount between the OCT front image data 20 and the SLO front image data 22 with high accuracy and in a short time.

  In the present embodiment, the control unit 70 uses a method of extracting a feature point common to the OCT front image data 20 and the SLO front image data 22 and detecting the amount of positional deviation of the extracted feature point. When detecting the positional displacement amount, the control unit 70 associates the positional relationship between the OCT function front image data 24 and the SLO front image data 22 based on the positional displacement amount.

  Here, since the OCT front image data 20 and the OCT function front image data 24 are acquired based on the same OCT signal T, both data can be associated in a pixel-to-pixel relationship. For this reason, in the positional relationship between the OCT front image data 20 and the OCT function front image data 24, almost no positional deviation occurs. Therefore, since it is not necessary to associate the positional relationship between the OCT front image data 20 and the OCT function front image data 24 again, the positional shift amount between the OCT front image data 20 and the SLO front image data 22 It can be applied as the positional deviation amount between the image data 24 and the SLO front image data 22. For this reason, it is not necessary to associate a plurality of pieces of image data, and the OCT function front image data 24 and the SLO front image data 22 can be easily associated with high accuracy.

  When the association is completed, the control unit 70 superimposes and displays the OCT function front image data 24 and the SLO front image data 20. In the present embodiment, the configuration in which the OCT functional front image data 24 and the SLO front image data 20 are superimposed and displayed is described as an example, but the present invention is not limited to this. For example, the control unit 70 may display the OCT function front image data 24 and the SLO front image data 20 in parallel. In this case, for example, the position at which the OCT function front image data is acquired may be displayed (displayed by an electronic display mark or the like) on the SLO front image data.

  As described above, it is possible to acquire, from the OCT signal, the reference front image data used for matching processing and the three-dimensional functional OCT image data having a use as an angiographic image. Even if the type of image data (for example, luminance distribution, contrast, resolution, form of subject, etc.) is different from that of other fundus image data to be associated, it is possible to easily perform matching with high accuracy. it can. In addition, information that is useful for diagnosis such that the relationship between both can be easily confirmed by correlating three-dimensional functional OCT image data having a use as an angiographic image with other fundus image data. You can get

  In the present embodiment, the configuration in which the SLO front image data 22 and the OCT function front image data 24 are superimposed and displayed is described as an example, but the present invention is not limited to this. The technology of the present disclosure is applicable to any information acquired from three-dimensional functional OCT image data. For example, the three-dimensional function OCT image data and the SLO front image data 22 may be superimposed and displayed. Further, for example, analysis information (described in detail later) obtained by analyzing the three-dimensional functional OCT image data may be superimposed on the SLO front image data 22.

  In addition, in a present Example, although the structure which performs matching processing with SLO front image data 22 was mentioned as an example using OCT front image data 20 acquired from OCT signal T, it is not limited to this. Different types of front image data may be created from the OCT signal T, and reference front image data used for matching processing may be selected according to front image data to be associated with three-dimensional function OCT image data.

  For example, the control unit 70 generates OCT front image data or three-dimensional functional OCT image data acquired based on at least one of a plurality of OCT signals acquired at a plurality of positions on the eye to be examined. At least one image data of OCT function front image data acquired based on the image data is used as reference front image data. The control unit 70 performs at least one image of OCT front image data or OCT function front image data according to front image data (for example, other fundus image data) to be associated with the three-dimensional function OCT image data. The data is selected as reference front image data to be associated with other fundus image data. The control unit 70 performs a process of matching the front image data with at least one of the OCT front image data and the OCT function front image data. By this, association with three-dimensional functional OCT image data is performed. As described above, by switching the reference front image data used for the matching process according to the front image data to be associated with the three-dimensional functional OCT image data, the image data is similar (for example, similarity of luminance distribution, contrast) Similarity, similarity of resolution, similarity of form of test object, and the like) image data can be associated, so that the accuracy of the association can be further improved. Of course, the examiner may operate the operation unit 76 to select an image to be used as reference front image data.

  In addition, in a present Example, although the structure which matches three-dimensional function OCT image data and other fundus oculi image data was mentioned as an example, and demonstrated, it is not limited to this. For example, the technology of the present disclosure can be applied in association with motion contrast data (for example, functional OCT image data and the like) and other fundus image data.

  In the present embodiment, in order to obtain motion contrast data, better OCT image data and three-dimensional OCT image data can be obtained using at least two or more OCT signals at the same position obtained at different times. May be acquired. For example, since at least two or more OCT signals are acquired at the same site, these OCT signals are subjected to combined processing (for example, integration processing, addition processing, and the like). For example, when performing addition processing, the control unit 70 performs addition processing on a plurality of OCT signals acquired for each of a plurality of positions on the subject's eye, and adds processed image data at a plurality of positions on the subject's eye. get.

  In the present embodiment, when performing matching processing with a wide range of front image data (for example, panoramic image data acquired by a fundus camera) as other fundus image data, fixation position information and scanning position information It is better to perform the matching process based on at least one of the above information. In this case, since the region corresponding to the three-dimensional functional OCT image data is to be confirmed from the fundus image data of a wide range of regions, at least one of the fixation position information and the scanning position information is used. The scope of confirmation can be narrowed down more. This makes it possible to easily and accurately superimpose a display showing three-dimensional functional OCT image data even on a wider range of fundus images.

  In the present embodiment, the control unit 70 indicates the acquisition position of tomographic image data after correlating three-dimensional functional OCT image data having application as an angiographic image with other fundus image data. A display (for example, line display etc.) may be displayed on other fundus image data. By doing this, it is possible to confirm the acquisition position of tomographic image data in various frontal images, and information useful for diagnosis can be acquired.

<Acquisition of analysis information>
In the present embodiment, the acquired motion contrast data is analyzed, the position information of the blood vessel is acquired, and the analysis information on the blood vessel is acquired based on the position information. Hereinafter, analysis processing of motion contrast data to obtain analysis information on a blood vessel will be described. For example, the control unit 70 determines whether a blood vessel is present in the region in the depth direction of the acquired motion contrast data, and acquires analysis information based on the determination result. For example, in the region in the depth direction when determining the presence or absence of a blood vessel, the determination process is performed on the entire retinal layer region of the eye to be examined.

  Hereinafter, a case where analysis processing of three-dimensional functional OCT image data is performed as motion contrast data will be described as an example. For example, the control unit 70 analyzes and processes the acquired three-dimensional functional OCT image data, and acquires blood vessel position information. The control unit 70 acquires analysis information on the blood vessel based on the acquired positional information on the blood vessel.

  For example, the control unit 70 determines whether a blood vessel is present in the region in the depth direction of the three-dimensional functional OCT image data, and acquires analysis information based on the determination result. In the following description, in the case of analysis processing of three-dimensional functional OCT image data, which is image data at one crossing position in three-dimensional functional OCT image data, for example, three-dimensional functional OCT image data is constructed The analysis process of three-dimensional functional OCT image data is performed by sequentially analyzing each functional OCT image data being processed.

  FIG. 5 is a schematic view showing an example of the functional OCT image data A acquired by the OCT optical system 100 and the luminance distribution C thereof. The control unit 70 performs the blood vessel B determination process in each function OCT data A in the three-dimensional function OCT image data. The control unit 70 processes the functional OCT image data A to two-dimensionally determine whether or not the blood vessel B is present, and acquires analysis information based on the determination result. The control unit 70 detects the blood vessel B of the fundus in the acquired functional OCT image data A by image processing, and determines the presence or absence of the blood vessel B based on a predetermined determination condition (determination criterion). Then, the control unit 70 obtains analysis information on the functional OCT image data A based on the determination result.

  When the functional OCT image data is processed to perform determination processing, the control unit 70 may determine the presence or absence of a blood vessel by performing processing at each A scan line forming the functional OCT image data, or the function The entire OCT image data may be processed to determine the presence or absence of a blood vessel.

<Determination of the presence or absence of blood vessels>
When the blood vessel position is detected and the presence or absence of the blood vessel B is determined, for example, the luminance level is detected in the depth direction of the functional OCT image data A, and the blood vessel B present in the retinal layer is image processed (for example, edge detection) Extracted by

  When determining the presence or absence of the blood vessel B from the functional OCT image data A, for example, the control unit 70 detects the luminance distribution C (on the scanning line Z1 in FIG. 5) in the depth direction (Z direction) of each A scan signal. The presence or absence of the blood vessel B is determined depending on whether a luminance value exceeding a preset threshold is detected. For example, it is determined that a blood vessel is present at a position where the detected luminance value exceeds. Note that, for example, a configuration in which the luminance value corresponding to the blood vessel is calculated and set in advance may be mentioned as the threshold. With such a configuration, it is easy to identify the change in luminance caused by noise or the like and the change in luminance due to the blood vessel, and the blood vessel portion can be extracted with high accuracy. In addition, as a method of detecting a blood vessel position, it is not limited to the said structure. For example, the control unit 70 may determine the portion where the luminance value is detected as the portion where the blood vessel is present.

  FIG. 5A is an example showing the luminance distribution C in a state where the blood vessel B is present on the scanning line Z1, and FIG. 5B is an example showing the luminance distribution C in a state where the blood vessel B is not present. That is, when the blood vessel B is present, the luminance value corresponding to the blood vessel B is seen, but when the blood vessel B is not present, there is no luminance value corresponding to the blood vessel B. As described above, the control unit 70 obtains two-dimensional information of the fundus regarding the presence or absence of the blood vessel B by performing the determination regarding the presence or absence of the two-dimensional blood vessel B in the fundus of the eye to be examined.

  In addition, when acquiring analysis information in three-dimensional functional OCT image data, the control unit 70 analyzes and processes functional OCT image data acquired at each of a plurality of crossing positions of the eye to be analyzed and acquires analysis information on a blood vessel. Do. As a result, analysis information in the three-dimensional functional OCT image data is acquired. That is, in the determination process regarding the presence or absence of the blood vessel described above, the control unit 70 performs the determination process on a plurality of different positions on the fundus to obtain analysis information in the three-dimensional functional OCT image data.

<Creating Analysis Map>
FIG. 6 is a diagram for explaining an analysis map and analysis parameters acquired based on the determination result. In the present embodiment, for example, the control unit 70 controls the blood vessel region V in which the blood vessel is determined to be present and the avascular region N in which the blood vessel is determined to be absent based on the determination result acquired as described above. An analysis map indicating a distribution state (two-dimensional distribution) of is acquired as analysis information. Also, for example, the control unit 70 acquires an analysis parameter P as analysis information based on the blood vessel determination result acquired as described above. For example, when acquiring an analysis map and analysis parameters, the analysis map and analysis parameters are acquired based on the determination result of three-dimensional functional OCT image data.

  For example, the control unit 70 calculates an analysis parameter P based on the abundance of at least one of the blood vessel region V and the non-blood vessel region N in a predetermined fundus region based on the determination result. For example, the ratio of the blood vessel region V to the non-blood vessel region N in a predetermined imaging region is calculated as an analysis parameter P. Thereby, the abundance of blood vessels in a predetermined area is confirmed.

The analysis parameter is at least one of dimension information (length information), area information, and volume information (actually calculated volume, volume ratio, etc.) of the blood vessel area in a predetermined fundus area based on the determination result. May be The analysis parameter may be based on at least one of dimension information, area information, and volume information of the non-blood vessel region in a predetermined fundus region. For example, the area actually calculated may be displayed as the area information. Note that the number of pixels in which a blood vessel is present may be calculated as a parameter. In addition, volume information is calculated using three-dimensional functional OCT image data and information in the depth direction corresponding to the area for which the area is calculated (for example, the thickness of the blood vessel), using area and depth information . Then, using the volume information of each layer, a three-dimensional analysis map (color three-dimensional map) can be created and displayed. In addition, dimension information is calculated using information in the vertical direction and horizontal direction of the analysis map. Of course, all of the area information, the volume information, and the dimension information may be displayed. In the present embodiment, a numerical value is displayed as a parameter indicating the amount of blood vessels present, but the present invention is not limited to this. There is a method of displaying not only in numerical values but also in bar graphs, radar charts, etc. As described above, when analysis information on a blood vessel is obtained, the control unit 70 generates motion contrast data and analysis information on the blood vessel. And are displayed on the monitor 75 (see FIG. 7). For example, when the analysis information of the three-dimensional functional OCT image data is acquired, the control unit 70 acquires the OCT functional front image data in the area in the predetermined depth direction acquired based on the three-dimensional functional OCT image data and the analysis information And are superimposed and displayed. Of course, three-dimensional functional OCT image data and analysis information may be superimposed and displayed.

  Thus, by allowing analysis information of a blood vessel to be compared with motion contrast data, an examiner can make a diagnosis suitably while easily comparing various information. In addition, since an avascular region can be easily confirmed, early detection of retinal diseases such as ischemic conditions becomes possible.

In the present embodiment, the region in the depth direction when determining the presence or absence of a blood vessel has been described by way of an example in which the determination processing is performed in the entire retinal layer region of the eye to be examined. . It may be determined whether or not a blood vessel is present in a partial region in the depth direction of the motion contrast data, and analysis information may be acquired based on the determination result. For example, the control unit 70 analyzes and processes OCT image data or three-dimensional OCT image data acquired from an OCT signal and processes each retinal layer (eg, nerve fiber layer (NFL), ganglion cell (ganglion cell). layer: GCL), retinal pigment epithelium (RPE), etc. are detected. The control unit 70 determines whether or not a blood vessel is present between predetermined layer boundaries, and acquires analysis information. By adopting such a configuration, the examiner can confirm the blood vessel distribution between specific layers or layers, and can perform diagnosis more suitably. For example, since the presence of blood vessels can be confirmed in the RPE layer, it becomes easy to detect new blood vessels early and to make it easy to detect lesions. In addition, the examiner can confirm the effect of a drug in a specific layer or layer or the effect of laser treatment or the like.
In the present embodiment, the configuration in which the motion contrast data and the analysis information on the blood vessel are superimposed and displayed is described as an example, but the present invention is not limited to this. It may be a configuration in which motion contrast data and analysis information are displayed so as to be comparable. For example, a configuration in which motion contrast data and analysis information are displayed in parallel may be mentioned as a configuration in which comparisons are displayed.
In the present embodiment, the configuration for displaying the motion contrast data and the analysis information on the blood vessel on the monitor 75 has been described as an example, but the present invention is not limited to this. Any configuration may be used as long as it outputs motion contrast data and analysis information. For example, as a configuration that outputs the data in a comparable manner, a configuration that prints motion contrast data and analysis information, a configuration that transfers data of motion contrast data and analysis information, and the like can be given.

  In addition, in a present Example, although motion contrast data and the analysis information regarding a blood vessel were superimposed and displayed as an example and it demonstrated, it is not limited to this. The analysis information may be displayed comparably on the front image data acquired by the front observation optical system 200. In this case, for example, the front image data acquired by the front observation optical system 200 and the analysis information may be displayed comparably. Also, for example, the motion contrast data, the front image data acquired by the front observation optical system 200, and the analysis information may be displayed in a comparable manner. When the analysis information is superimposed on the front image data acquired by the front observation optical system 200, the control unit 70 generates an OCT front image based on the OCT signal used when acquiring the three-dimensional function OCT image data. Get data The control unit 70 matches the OCT front image data with the front image data acquired by the front observation optical system 200 by matching processing. Since the three-dimensional functional OCT image data and the OCT front image data are acquired from the same OCT signal, both data can be associated in a pixel-to-pixel relationship. Further, since the analysis information is acquired from the three-dimensional functional OCT image data, both data can be associated in a pixel-to-pixel relationship. By this, it is possible to associate the analysis information with the front image data acquired by the front observation optical system 200.

  In the present embodiment, the configuration for acquiring the analysis information of the three-dimensional functional OCT image data has been described as an example by performing the blood vessel determination process in A scan units, but the present invention is not limited to this. For example, three-dimensional functional OCT image data may be divided into a plurality of regions, and blood vessel determination processing may be performed for each of the divided regions to obtain analysis information of the three-dimensional functional OCT image data. FIG. 8 is a diagram for explaining the case of dividing the fundus area and acquiring analysis information. For example, the control unit 70 divides the three-dimensional functional OCT image data into a plurality of regions (for example, a plurality of regions on the XY plane (fundus surface)). The control unit 70 determines, for each divided area (for example, refer to the divided areas G1 and G2 in FIG. 8), whether or not a blood vessel exists in each divided area. The control unit 70 acquires analysis information based on the determination result based on the determination result. When the determination process is performed for each divided area, for example, when it is determined that a blood vessel is present at a plurality of positions in the divided area, the control unit 70 determines that the blood vessel is present in the divided area. Can be mentioned. In addition, for example, when it is determined that a blood vessel is continuously present in a predetermined range in a divided area, a configuration in which a blood vessel is determined to be present in the divided area may be mentioned. As described above, with the configuration in which the blood vessel determination process is performed for each divided area, it is possible to more accurately identify blood vessels, noise, and the like. That is, it is possible to suppress the decrease in the accuracy of blood vessel determination due to the influence of noise and the like.

  The analysis information of the blood vessel may be output so as to be comparable (for example, printing, display, data transmission, etc.) with the analysis map of the layer in which the retinal layer of the fundus is analyzed. For example, the control unit 70 detects layer information from an OCT signal acquired to acquire three-dimensional functional OCT image data, and analyzes a layer indicating a two-dimensional distribution regarding layer thickness information of the retinal layer of the subject's eye Obtain a map (eg, difference map, layer thickness map, etc.). The control unit 70 superimposes and displays the analysis information of the blood vessel and the analysis map of the layer in which the retinal layer of the fundus is analyzed. Of course, the analysis information of the blood vessel and the analysis map of the layer where the retinal layer of the fundus is analyzed may be displayed in parallel. With such a configuration, the examiner can easily confirm the relationship between the state of the retinal layer and the state of the blood vessel, and can diagnose more preferably.

  The present invention is not limited to the apparatus described in the present embodiment. For example, optical coherence tomography calculation software (program) for performing the functions of the above embodiments is supplied to a system or apparatus via a network or various storage media. Then, a computer (for example, a CPU or the like) of a system or an apparatus can read and execute a program.

  In addition, in a present Example, although the structure which makes a test object an eye was demonstrated, it is not limited to this. The technology of the present disclosure is also applicable to an optical coherence tomography apparatus for imaging an object such as a living body other than the eye (for example, skin, blood vessels) or a sample other than the living body.

DESCRIPTION OF SYMBOLS 1 optical coherence tomography apparatus 70 control part 72 memory 75 monitor 76 operation part 100 interference optical system 120 detector 200 front view optical system 300 fixation target projection unit

Claims (5)

An optical coherence tomography apparatus for detecting tomographic image data of a test object by detecting an OCT signal from measurement light and reference light irradiated to the test object and processing the OCT signal,
Acquisition means for acquiring a plurality of temporally different OCT signals with respect to the same position on the subject;
Operation processing means for processing the plurality of OCT signals acquired by the acquisition means to acquire motion contrast data of the subject;
The acquisition means scans the measurement light at a plurality of different crossing positions on the object to acquire an OCT signal for acquiring three-dimensional motion contrast data in the X and Y directions.
It said processing means, during the acquisition of the OCT signal at said plurality of transverse position by the acquisition means, processing the plurality of OCT signals acquired by the acquisition unit, it you get the three-dimensional motion contrast data Optical coherence tomography device characterized by In the optical coherence tomography of claim 1,
Motion contrast data at the plurality of crossing positions are sequentially acquired by the arithmetic processing means, and motion contrast data of each crossing position is sequentially displayed on the display means, thereby displaying real-time three-dimensional motion contrast data An optical coherence tomography apparatus comprising display control means for displaying on the screen. In the optical coherence tomography of claim 1,
The three-dimensional motion contrast data is sequentially acquired by the arithmetic processing means, and sequentially, based on the three-dimensional motion contrast data, an OCT function front which is front image data in a predetermined depth region of the test object An optical coherence tomography device comprising display control means for displaying real-time OCT function front image data on the display means by acquiring image data and displaying the OCT function front image data of each crossing position on the display means. Graphic equipment. Optical coherence tomography calculation performed in an optical coherence tomography apparatus that detects an OCT signal from a measurement light and a reference light irradiated to a test object and acquires a tomographic image of the test object by processing the OCT signal Method,
An acquisition step for acquiring a plurality of temporally different OCT signals with respect to the same position on the subject, wherein the measurement light is scanned at a plurality of different transverse positions on the subject, and three-dimensional in the XY directions Acquiring an OCT signal for acquiring motion contrast data;
An arithmetic processing step of processing the plurality of OCT signals acquired in the acquisition step to acquire motion contrast data in the subject, and during acquisition of OCT signals at the plurality of crossing positions in the acquisition step in processes a plurality of OCT signals acquired by the acquisition step, a processing step you get the three-dimensional motion contrast data,
An optical coherence tomography computing method comprising: Executed in the control device that controls the operation of the optical coherence tomography device that acquires the tomographic image of the test object by detecting the OCT signal from the measurement light and the reference light irradiated to the test object and processing the OCT signal Optical coherence tomography operation program,
Being executed by the processor of the controller,
An acquisition step for acquiring a plurality of temporally different OCT signals with respect to the same position on the subject, wherein the measurement light is scanned at a plurality of different transverse positions on the subject, and three-dimensional in the XY directions Acquiring an OCT signal for acquiring motion contrast data;
An arithmetic processing step of processing the plurality of OCT signals acquired in the acquisition step to acquire motion contrast data in the subject, and during acquisition of OCT signals at the plurality of crossing positions in the acquisition step in processes a plurality of OCT signals acquired by the acquisition step, a processing step you get the three-dimensional motion contrast data,
An optical coherence tomography computing program for causing the optical coherence tomography apparatus to execute the program.

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