JP2016055122A - Optical coherence tomography device, oct analysis processor and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve at least one issue of a conventional art.SOLUTION: An optical coherence tomography device comprises: a Fourier domain OCT optical system; and analysis processing means that acquires OCT data based on an A scan signal at each scanning position, applies segmentation processing to the acquired OCT data and analyzes a specimen on the basis of a result of the segmentation processing. The analysis processing means changes at least part of the segmentation processing between: first OCT data that is OCT data obtained in a state where a front face of the specimen is arranged on a deep side rather than a zero delay position; and second OCT data that is OCT data obtained in a state where a reverse face of the specimen is arranged on a front side rather than the zero delay position.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to optical coherence tomography for obtaining OCT data of a subject.

  An optical coherence tomography (OCT) is known as an apparatus for taking a tomographic image of a subject.

  In an optical tomographic interferometer, Fourier domain OCT is known in which spectral information acquired by a light receiving element is subjected to Fourier analysis to obtain a tomographic image of a test object (see Patent Document 1). As the Fourier domain OCT, SD-OCT having a spectroscopic optical system in a light receiving system and SS-OCT having a variable wavelength light source in a light projecting system are known.

  By the way, the tomogram obtained by the interference optical system based on the Fourier domain OCT has the highest sensitivity (interference sensitivity) at the depth position (zero delay position) where the optical path lengths of the measurement light and the reference light coincide with each other. Sensitivity decreases as the distance from the zero delay position increases. As a result, a high-sensitivity and high-resolution image can be obtained at a portion close to the zero delay position, but the sensitivity and resolution of the image are lowered at a portion away from the zero delay position.

  In Patent Documents 1 to 3, a tomographic image (normal image) acquired in a state where the fundus is arranged on the back side from a depth position where the optical path lengths of the measurement light and the reference light coincide with each other, and optical paths of the measurement light and the reference light It has a mode (retinal mode, choroid mode) that outputs tomographic images (reverse images) acquired with the fundus positioned in front of the depth position where the lengths coincide with each other.

JP 2010-29648 A JP 2007-215733 A JP 2013-156229 A

  However, when an analysis result is obtained based on the acquired tomographic image, a good analysis result may not be obtained. Alternatively, there may be a case where sufficient analysis is not performed on the acquired tomographic image.

  An object of the present disclosure is to solve at least one problem of the prior art.

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

(1)
A Fourier domain OCT optical system for detecting an A scan signal caused by interference between the measurement light scanned on the object by the scanning means and the reference light corresponding to the measurement light;
Analysis processing means for acquiring OCT data based on the A scan signal at each scanning position, performing segmentation processing on the acquired OCT data, and analyzing a subject based on a result of the segmentation processing;
An optical coherence tomography device comprising:
The analysis processing means includes first OCT data, which is OCT data acquired in a state where the surface of the test object is arranged on the back side with respect to the zero delay position, and the back side of the test object is arranged on the front side with respect to the zero delay position. At least a part of the segmentation process is changed with respect to the second OCT data which is the OCT data acquired in the processed state.
(2)
An OCT analysis processing apparatus for processing OCT data obtained by an optical coherence tomography apparatus including a Fourier domain OCT optical system,
An analysis processing means for performing a segmentation process on the OCT data and analyzing a subject based on a result of the segmentation process;
The analysis processing means includes first OCT data, which is OCT data acquired in a state where the surface of the test object is arranged on the back side with respect to the zero delay position, and the back side of the test object is arranged on the front side with respect to the zero delay position. At least a part of the segmentation process is changed with respect to the second OCT data which is the OCT data acquired in the processed state.
(3)
An OCT data processing program executed in an OCT data processing apparatus that processes OCT data obtained by an optical coherence tomography apparatus including a Fourier domain OCT optical system,
By being executed by the processor of the OCT data processor,
An analysis processing step for performing a segmentation process on the OCT data and analyzing a subject based on a result of the segmentation process,
First OCT data, which is OCT data acquired when the surface of the test object is arranged at the back side from the zero delay position, and data obtained when the back surface of the test object is arranged at the front side from the zero delay position An analysis processing step for changing at least a part of the segmentation processing with respect to the second OCT data that is the processed OCT data;
Is executed by the OCT data processing apparatus.
(4)
OCT obtained by an optical coherence tomography apparatus including a Fourier domain OCT optical system for detecting an A scan signal caused by interference between measurement light scanned on a subject by scanning means and reference light corresponding to the measurement light An OCT data processing apparatus for processing data,
An analysis processing means for performing a segmentation process on the OCT data and analyzing a subject based on a result of the segmentation process;
The analysis processing means changes at least a part of the segmentation process according to a difference in conditions when OCT data is acquired by the optical coherence tomography apparatus.

It is a block diagram which shows an example of the optical coherence tomography apparatus (it may hereafter be called this apparatus) concerning this embodiment. It is a figure shown about an example of the OCT optical system which concerns on this embodiment. It is a figure which shows an example of the OCT data acquired (formed) by the OCT optical system. It is a figure which shows an example of the OCT data memorize | stored in the memory 72 as analysis data.

  Hereinafter, one exemplary embodiment will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of an optical coherence tomography apparatus (hereinafter also referred to as this apparatus) according to the present embodiment. As an example, the apparatus 10 shows an application example to a fundus imaging apparatus that acquires a tomographic image of the fundus of a subject eye.

<First embodiment>
The OCT device 1 shown in FIG. 1 processes a detection signal acquired by the OCT optical system 100, for example. The OCT optical system 100 obtains, for example, OCT data (for example, fundus tomographic image) of the fundus oculi Ef of the eye E to be examined. The OCT optical system 100 is connected to the control unit 70, for example.

  Next, an example of the OCT optical system 100 will be described with reference to FIG.

<OCT optical system>
The OCT optical system 100 has, for example, an ophthalmic optical tomography (OCT: Optical coherence tomography) apparatus configuration, and may be provided to obtain OCT data of the eye to be examined. As an example of a more detailed configuration, the OCT optical system 100 divides light emitted from the light source 102 into measurement light and reference light by a light splitter (for example, a coupler or a circulator) 104. The OCT optical system 100 guides the measurement light to the fundus oculi Ef of the eye E by the measurement optical system 106 and guides the reference light to the reference optical system 110. The OCT optical system 100 causes the detector (light receiving element) 120 to receive interference light obtained by combining the measurement light reflected by the fundus oculi Ef and the reference light. The detector 120 detects an interference signal between the measurement light and the reference light.

  In the case of Fourier domain OCT, the spectral intensity (spectral interference signal) of the interference light is detected by the detector 120, and a complex OCT signal is obtained by Fourier transform on the spectral intensity data. For example, an A scan signal (for example, a depth profile) is acquired by calculating the absolute value of the amplitude in the complex OCT signal. The measurement light is scanned on the fundus by the optical scanner 108. OCT data (for example, tomographic image data) is acquired by arranging the A scan signals at each scanning position.

  The OCT optical system 100 may be a spectral domain type OCT optical system, or a swept source type (SS-OCT) that detects a spectrum of interference light using a wavelength variable light source. May be.

  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 (spectrum meter) that separates interference light into each frequency component (each wavelength component). . The spectrum meter includes, for example, a diffraction grating and a line sensor.

  In the case of SS-OCT, a wavelength scanning light source (wavelength variable light source) that changes the emission wavelength at a high speed in time is used as the light source 102, and a single light receiving element is provided as the detector 120, for example. The light source 102 includes, for example, a light source, a fiber ring resonator, and a wavelength selection filter. Examples of the wavelength selection filter include a combination of a diffraction grating and a polygon mirror, and a filter using a Fabry-Perot etalon.

  The light emitted from the light source 102 is split into measurement light and reference light by the light splitter 104. The measurement light may be emitted into the air after passing through the optical fiber. The measurement light may be collected on the fundus oculi Ef via the optical scanner 108 and other optical members of the measurement optical system 106. The light reflected by the fundus oculi Ef may be returned to the optical fiber through a similar optical path.

  The optical scanner 108 may scan the measurement light in the transverse direction on the fundus or may cause the measurement light to scan two-dimensionally on the fundus. The optical scanner 108 may be disposed at a position substantially conjugate with the pupil. The optical scanner 108 is, for example, two galvanometer mirrors, and the reflection angle thereof may be arbitrarily adjusted by the drive mechanism 50. As the optical scanner 108, for example, an acousto-optic device (AOM) that changes the traveling (deflection) direction of light is used in addition to a reflection mirror (galvano mirror, polygon mirror, resonant scanner).

  The reference optical system 110 can generate reference light that is combined with reflected light acquired by reflection of measurement light on the fundus oculi Ef. The reference optical system 110 may be a Michelson type or a Mach-Zehnder type. The reference optical system 110 is formed by, for example, a reflection optical system (for example, a reference mirror), and returns the light from the light splitter 104 to the light splitter 104 again by reflecting the light from the light splitter 104 and guides it to the detector 120. May be. As another example, the reference optical system 110 may be formed by a transmission optical system (for example, an optical fiber), and may be guided to the detector 120 by transmitting the light from the light splitter 104 without returning it.

  The reference optical system 110 may include a drive unit 112 for changing the optical path length difference between the measurement light and the reference light, for example, by moving an optical member in the reference light path. For example, the reference mirror is moved in the optical axis direction. The configuration for changing the optical path length difference may be arranged in the measurement optical path of the measurement optical system 106. That is, the apparatus of this embodiment may be provided with a structure for changing the optical path length of at least one of the measurement light and the reference light.

<Front observation optical system>
The front observation optical system 200 may be provided to obtain a front image of the fundus oculi Ef. The observation optical system 200 may include, for example, a so-called ophthalmic scanning laser ophthalmoscope (SLO) device configuration. Note that the configuration of the observation optical system 200 may be a so-called fundus camera type configuration. The OCT optical system 100 may also serve as the observation optical system 200.

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

<Control system>
The control unit 70 may include a CPU (processor), a RAM, a ROM, and the like. More specifically, the CPU of the control unit 70 controls the entire apparatus (OCT device 1, OCT optical system 100) such as each member of each component. The RAM temporarily stores various information. The ROM of the control unit 70 stores various programs for controlling the operation of the entire apparatus, initial values, and the like. The control unit 70 may be configured by a plurality of control units (that is, a plurality of processors).

  A non-volatile memory (hereinafter referred to as a memory) 72, an operation unit (control unit) 76, a display unit (monitor) 75, and the like as an example of a storage unit may be electrically connected to the control unit 70. The memory 72 may be a non-transitory storage medium that can retain stored contents even when power supply is interrupted. For example, any of a hard disk drive, flash ROM, OCT device 1, and USB memory may be used as the memory 72.

  The memory 72 may store an analysis processing program for analyzing the eye to be examined based on the OCT data obtained by the OCT device 1. Further, the memory 72 may store an imaging control program for controlling imaging of front images and tomographic images by the OCT optical system 100. The memory 72 may store various types of information related to imaging such as OCT data, fundus front images, and information on tomographic imaging positions. Various operation instructions by the examiner may be input to the operation unit 76.

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

  The display unit 75 may be a display mounted on the apparatus main body or a display connected to the main body. A display of a personal computer (hereinafter referred to as “PC”) may be used. A plurality of displays may be used in combination. The display unit 75 may be a touch panel. Note that when the display unit 75 is a touch panel, the display unit 75 functions as an operation unit. The display unit 75 displays OCT data acquired from the OCT optical system 100, front image data, and the like.

  FIG. 3 is a diagram illustrating an example of OCT data acquired (formed) by the OCT optical system. The zero delay position S is a position corresponding to the optical path length of the reference light in the OCT data, and corresponds to a position where the optical path lengths of the measurement light and the reference light match. The OCT data is formed from a first image area G1 corresponding to the back side from the zero delay position S and a second image area corresponding to the front side from the zero delay position S. The first image region G1 and the second image region G2 have a symmetric relationship with respect to the zero delay position S.

  FIG. 3 is an example of OCT data when the dispersion correction process is performed by software. That is, the control unit 70 may perform dispersion correction processing by software on the spectrum data output from the detector 120, or may obtain an A scan signal based on the spectrum data after dispersion correction. As a result, a difference in image quality occurs between the real image and the virtual image. In this regard, for example, refer to Japanese Patent Application Laid-Open No. 2012-223264. Note that the present invention is not limited to dispersion correction by software, and optical dispersion correction may be used. In this case, there is no difference in image quality between the real image and the virtual image.

  FIG. 3A is an example of OCT data when a normal image with high sensitivity on the retinal side is acquired. In the above configuration, the first OCT data is acquired when the optical path length difference is adjusted such that the retina surface of the eye E is arranged on the back side with respect to the zero delay position S. The first OCT data includes, for example, a fundus tomogram (normal image) having higher sensitivity on the retinal surface Rt side than the choroid Ch side portion.

  In this case, the tomographic images formed in the first image region and the second image region are in a state of facing each other. In this case, a real image R is formed in the first image region G1, and a virtual image M (mirror image) is formed in the second image region G2.

  FIG. 3B is an example of OCT data when a reverse image with high sensitivity on the choroid side is acquired. When the optical path length difference is adjusted such that the back surface of the choroid is arranged in front of the zero delay position, second OCT data is acquired. The second OCT data includes, for example, a fundus tomographic image (reverse image) having higher sensitivity on the choroid Ch side than on the retina surface Rt side.

  In this case, the tomographic images formed in the first image region G1 and the second image region G2 are in opposite states. In this case, a real image R is formed in the second image region G2, and a virtual image M (mirror image) is included in the first image region G1.

  In the example of FIG. 3, the first OCT data and the second OCT data have a normal / reverse relationship of the acquired fundus image depending on whether the fundus is located on the near side or the far side with respect to the zero delay position S. Is different.

  For example, the control unit 70 extracts image information of one of the first image region G1 and the second image region G2 from the OCT data, and displays the extracted image information on the screen of the display unit 75. For example, the control unit 70 may cut out the image area from the OCT data, or may newly create an image from the luminance information corresponding to the image area.

<Description of operation>
Next, an example of the operation of the apparatus according to the present embodiment will be described. The examiner instructs the subject to gaze at the fixation target, and then performs alignment with the fundus. When the fundus front image is displayed on the display unit 75, OCT data is acquired by the OCT optical system 100 based on a preset scanning pattern, and an OCT image is displayed on the display unit 75.

  The control unit 70 controls the driving of the driving mechanism 112 based on the detection signal output from the detector 120, and adjusts the optical path length difference between the measurement light and the reference light so that a fundus tomographic image is acquired. Note that the retina mode is set as an initial setting, and the control unit 70 adjusts the optical path length so that the retina Rt is disposed on the back side of the zero delay position S, for example. In this case, the first OCT data is obtained. On the other hand, when observing a fundus tomography in the choroid mode, the control unit 70 adjusts the optical path length difference between the measurement light and the reference light so that the choroid Ch is disposed in front of the zero delay position S. In this case, the second OCT data is obtained.

  <Storing Tomographic Image> In a state where the first OCT data or the second OCT data is displayed as a moving image, a scanning position / pattern desired by the examiner is set. Thereafter, a predetermined trigger signal is output automatically or manually. With this as a trigger, the control unit 70 controls the optical scanner 108 based on the set imaging conditions (for example, scanning position / pattern). The control unit 70 acquires OCT data as a still image based on the output signal from the detector 120 at each scanning position. The control unit 70 stores the acquired OCT data in the memory 72. In this case, the control unit 70 may store determination information on whether the OCT data is the first OCT data or the second OCT data in the memory 72 in association with the stored OCT data. The discrimination information can be acquired by a mode switching signal between the retinal mode and the choroid mode, a real image acquisition position, or the like.

  When storing the OCT data in the memory 72, the control unit 70 extracts, for example, image information of either the first image region G1 or the second image region G2 from the OCT data and stores the image information in the memory 72. Also good. For example, in the first OCT data, the OCT data corresponding to the first image region G1 is stored in the memory 72 (see FIG. 4A), and in the second OCT data, the second image region G2 corresponds. OCT data to be stored may be stored in the memory 72 (see FIG. 4B).

<Segmentation>
In this embodiment, when performing analysis, the control unit 70 may perform segmentation processing on the OCT data stored in the memory 72 and analyze the fundus oculi Ef based on the result of the segmentation processing. In this case, the control unit 70 is used as an example of an analysis processing unit. The segmentation process is used, for example, as an image process for performing feature extraction in OCT data as a preparation for obtaining a fundus analysis result.

  For example, the control unit 70 may detect (extract) at least one of the boundaries of a plurality of layers as a segmentation process. More specifically, the control unit 70 includes a specific layer (for example, nerve fiber layer (NFL), ganglion cell layer (GCL), retinal pigment epithelium (RPE), etc. ), A layer boundary corresponding to the choroid may be detected (extracted) by a segmentation process. When a layer boundary corresponding to a specific layer is detected, a detection method is set based on the position of the specific layer based on the anatomical viewpoint, the layer order, the luminance level in the A scan signal, and the like. For example, edge detection is used for the segmentation.

<Change in segmentation processing>
The control unit 70 may change at least a part of the segmentation process for the OCT data between the first OCT data and the second OCT data having different fundus positional relationships with respect to the zero delay position S. Here, the first OCT data is, for example, OCT data acquired in a state where the fundus surface is arranged on the back side from the zero delay position S. Further, the second OCT data is, for example, OCT data acquired in a state where the back surface of the fundus is arranged in front of the zero delay position S.

  In the present embodiment, both the first OCT data and the second OCT data include OCT data regarding the same part (for example, the fundus) of the eye to be examined. In the following description, the vertical direction in the OCT data will be described by defining the fundus surface (retinal surface layer) side as the upward direction (front side) and the fundus back surface (choroid layer) side as the downward direction (back side).

  Here, the control unit 70 may change the segmentation area, for example. As an example, the control unit 70 may change the segmentation region in consideration of the difference in noise position with respect to the fundus tomographic image between the first OCT data and the second OCT data. In this case, the area excluded from the segmentation process in the OCT data may be changed.

  FIG. 4 is a diagram illustrating an example of OCT data stored in a memory as analysis data. In the acquired OCT data, in addition to OCT data of the eye to be examined such as a fundus tomogram, a noise component NZ caused by the apparatus may be generated. Such a noise component is, for example, noise remaining in the OCT data without being removed by noise removal processing such as DC subtraction. Possible causes of such noise include, for example, light fluctuation from the light source 102, apparatus vibration / vibration, internal lens reflection, light from external illumination, and the like.

  The noise component NZ often has a certain periodicity, and is formed at a predetermined position with respect to the zero delay position, for example. As a result, the noise component NZ generated on the first OCT data is formed at a position that is a predetermined distance D away from the upper end of the OCT data (that is, the retina surface side end). That is, the noise component NZ is generated above the OCT data of the fundus of the eye to be examined. The noise component NZ generated on the second OCT data is formed at a position away from the lower end of the OCT data (that is, the choroid side end) by a predetermined distance D. That is, the noise component NZ is generated below the OCT data of the fundus of the eye to be examined.

  In the present embodiment, the region where the segmentation process is executed is changed in consideration of the difference in the generation position of the noise component NZ with respect to the OCT data of the fundus oculi to be examined. In FIG. 4, a segmentation execution area (hereinafter, execution area) SG is an area where segmentation is executed on OCT data. When the execution region SG is set, for example, the coordinate position in the depth direction from the start point SG1 at which segmentation is started to the end point SG2 at which segmentation is ended may be stored in the memory 72 in advance. Thus, segmentation is performed from the start point SG1 to the end point SG2 in each A scan signal, and segmentation is not performed for other regions.

  When segmentation is performed on the first OCT data, for example, the start point SG1 is set further below the position away from the upper end of the OCT data (that is, the end portion on the retinal surface layer) by a predetermined distance D. The lower end of the OCT data (that is, the choroid side end) is set as the end point SG2 (see FIG. 3A). As a result, segmentation is performed so as to exclude the noise component NZ included in the first OCT data.

  On the other hand, when segmentation is performed on the second OCT data, for example, the upper end of the OCT data (that is, the retina surface layer side) is set as the start point SG1, and the upper end from the lower end of the OCT data (that is, the choroid side end portion) The end point SG2 is set further above the position separated by the predetermined distance D. As a result, segmentation is performed so as to exclude the noise component NZ included in the second OCT data.

  As described above, by performing segmentation so that the noise component NZ is excluded according to the generation position of the noise component NZ with respect to the OCT data of the fundus of the eye to be examined, the influence of noise can be reduced regardless of the characteristics of the OCT data. Can be reduced appropriately. Subsequent analysis can be performed satisfactorily.

<Analysis based on segmentation results>
In the case of the first OCT data, the fundus surface side (for example, the retina portion) is clearly formed. As a result of the segmentation, the control unit 70 acquires layer boundary information in each layer of the retinal layer (for example, the retinal surface layer to the retinal pigment information layer), and calculates the thickness information of each layer based on the acquired layer boundary information. It may be. When the choroid can be segmented, the thickness of the choroid may be obtained in addition to the measurement of the thickness of the retinal layer.

  In the case of the second OCT data, the back side of the fundus (for example, the choroid portion) is clearly formed. As a result of the segmentation, the control unit 70 may acquire layer boundary information in the choroid layer and calculate choroid layer thickness information based on the acquired layer boundary information. When each layer of the retina can be segmented, the thickness of each layer of the retina may be obtained in addition to the measurement of the thickness of the choroid layer.

  The fundus analysis based on the result of the segmentation process is not limited to the above. For example, size measurement, lesion detection, or the like may be performed on a characteristic part of the fundus (for example, macular or nipple). Moreover, you may make it the control part 70 acquire the En-face image (OCT front image) in each layer using the segmentation result.

  Of course, the OCT data may be three-dimensional OCT data. The three-dimensional OCT data is acquired by, for example, two-dimensional scanning (for example, raster scanning) of measurement light. Moreover, an analysis map may be acquired as a result of segmentation on the three-dimensional OCT data. As the analysis map, for example, a retinal thickness map, a choroid thickness map, and the like can be considered.

  The control unit 70 may display the analysis result acquired as described above on the display unit 75.

<Transformation example>
In the above embodiment, the retinal surface layer side is set to the start point SG1, but the present invention is not limited to this, and the choroid side may be set to the start point SG1. Note that the execution area SG may be set in the manufacturing stage of the apparatus. In addition, the position of the execution region SG may be set for each device in consideration of individual differences between the devices.

  In the above example, the region where the segmentation is executed is changed according to the generation position of the noise component NZ with respect to the OCT data of the eye to be examined. However, the method for changing the segmentation region is not limited to this. For example, the present embodiment can be applied even when OCT data for performing segmentation processing is extracted and segmentation is performed on the extracted OCT data. For example, the control unit 70 may change the extraction region for performing the segmentation process according to the generation position of the noise component NZ. Further, the control unit 70 may exclude the noise component from the segmentation process in advance by storing the OCT data in the memory 75 so that the noise component NZ is excluded. In this case, a storage area on the OCT data may be set in advance so that the noise component NZ is excluded.

  In the above description, the image area stored in the memory 72 is changed between the first OCT data and the second OCT data. However, the present invention is not limited to this. The image areas stored in the memory 72 may be the same. Such a storage method may be used when OCT data is obtained by optical dispersion correction, or when dispersion correction data is switched between first OCT data and second OCT data. In this case, the OCT data corrected by the software dispersion correction process may be switched between a real image and a virtual image (for details, refer to Japanese Patent Application Laid-Open No. 2012-223264). Even in such a case, the vertical position of noise with respect to the eye image to be examined is different between the first OCT data and the second OCT data, so that the above embodiment can be applied.

  The controller 70 changes the display area of the OCT data between the first OCT data and the second OCT data when displaying a part of the OCT data based on the segmentation result. Also good.

  For example, when displaying a three-dimensional graphic image on the display unit 75 based on the three-dimensional OCT data, the control unit 70 changes a region to be displayed as a three-dimensional graphic image based on the layer boundary region detected by the segmentation. You may do it. More specifically, when displaying the first three-dimensional OCT data, the control unit 70 removes the region above the retina surface layer and displays a graphic image with respect to the region below the retina surface layer. May be. Further, when displaying the second three-dimensional OCT data, the control unit 70 may remove a region below the choroid layer and display a graphic image regarding the region above the choroid layer. Thereby, unnecessary noise information in the three-dimensional graphic image is preferably reduced.

  Note that the processing of the present embodiment may be performed on full-range OCT data from which either a real image or a virtual image has been removed by image processing.

  In the above description, at least a part of the segmentation process for the OCT data (for example, the segmentation region) is performed between the first OCT data and the second OCT data having different positional relationships of the fundus with respect to the zero delay position. Although it changed, it is not limited to this. In the present embodiment, at least a part of the segmentation process may be changed according to a difference in conditions when the OCT data is acquired by the optical coherence tomography apparatus.

  As a first example, the control unit 70 may change the segmentation process according to the difference in the imaging method of the optical coherence tomography apparatus. For example, the first OCT data is OCT data acquired by the spectral domain OCT (SD-OCT), and the second OCT data is OCT data acquired by the sweep source OCT (SS-OCT). In some cases, the brightness of the acquired image is different. Possible causes include differences in imaging principles and differences in light source wavelengths. Therefore, for example, the control unit 70 may change the threshold for performing segmentation between the first OCT data and the second OCT data. As a result, proper segmentation is executed. Such processing is also applicable in the first embodiment.

  In addition, the appearance image may be different depending on the sensitivity in the depth direction. An appearance image means an image that appears as an eye image to be examined in OCT data, and a difference in appearance image means a difference in eye data that appears in OCT data according to a difference in acquisition conditions. Here, the appearance image may be defined as an image imaged to such an extent that segmentation is possible, for example.

  Therefore, the control unit 70 may change the segmentation area between the first OCT data and the second OCT data. That is, in the present embodiment, the segmentation area may be changed according to the difference in the appearance image in the OCT data. This makes it possible to perform appropriate analysis processing. Such processing is also applicable in the first embodiment.

  As a second example, the control unit 70 may change the segmentation process according to the difference in the exposure time of the light receiving element when acquiring the OCT data. For example, it is acquired when the first OCT data is OCT data acquired at the first exposure time and the second OCT data is OCT data acquired at the second exposure time. The brightness of images differs. Therefore, the control unit 70 may change a threshold value when performing segmentation between the first OCT data and the second OCT data.

  In the above description, the case of acquiring a morphological tomographic image of the eye to be examined has been described. However, the control unit 70 measures changes between signals in a plurality of A scan signals (for example, phase change, intensity change). Thus, a blood flow measurement image (Doppler OCT image) may be acquired. Further, the control unit 70 may acquire an image (polarized OCT image) indicating the polarization characteristics of the eye to be examined by measuring the polarization components (S-polarized light and P-polarized light) in the plurality of A scan signals. That is, this embodiment can also be applied to OCT such as Doppler OCT and polarization-sensitive OCT.

  In the above description, the device for obtaining fundus OCT data has been described as an example. However, the present invention is not limited to this, and the present embodiment can be applied to any device that obtains OCT data for a predetermined part of the eye to be examined. Is possible. For example, it is used in an apparatus that obtains OCT data of the anterior segment of the eye to be examined.

  Further, the present embodiment is not limited to application to an ophthalmologic imaging apparatus, and the application of the present embodiment is also applicable to an OCT apparatus that acquires a tomographic image of a living body other than the eye (for example, skin, blood vessels) or a sample other than the living body. Is possible.

1 OCT Device 70 Control Unit 100 OCT Optical System S Zero Delay Position NZ Noise SG Segmentation Execution Area

Claims (7)

A Fourier domain OCT optical system for detecting an A scan signal caused by interference between the measurement light scanned on the object by the scanning means and the reference light corresponding to the measurement light;
Analysis processing means for acquiring OCT data based on the A scan signal at each scanning position, performing segmentation processing on the acquired OCT data, and analyzing a subject based on a result of the segmentation processing;
An optical coherence tomography device comprising:
The analysis processing means includes first OCT data, which is OCT data acquired in a state where the surface of the test object is arranged on the back side with respect to the zero delay position, and the back side of the test object is arranged on the front side with respect to the zero delay position. An optical coherence tomography apparatus characterized in that at least a part of the segmentation process is changed with respect to second OCT data which is OCT data acquired in the processed state.   The analysis processing unit changes a region to be excluded from the segmentation processing in consideration of a difference in noise position with respect to the subject image between the first OCT data and the second OCT data. The optical coherence tomography apparatus according to claim 1.   Display control means for displaying a part of the OCT data based on a result of segmentation by the analysis processing means, wherein a display area of OCT data is provided between the first OCT data and the second OCT data. The optical coherence tomography apparatus according to claim 1, wherein the optical coherence tomography apparatus is changed.   The optical coherence tomography apparatus according to claim 1, wherein the subject is an eye to be examined. An OCT analysis processing apparatus for processing OCT data obtained by an optical coherence tomography apparatus including a Fourier domain OCT optical system,
An analysis processing means for performing a segmentation process on the OCT data and analyzing a subject based on a result of the segmentation process;
The analysis processing means includes first OCT data, which is OCT data acquired in a state where the surface of the test object is arranged on the back side with respect to the zero delay position, and the back side of the test object is arranged on the front side with respect to the zero delay position. An OCT analysis processing apparatus characterized in that at least a part of the segmentation process is changed with respect to second OCT data that is OCT data acquired in the processed state. An OCT data processing program executed in an OCT data processing apparatus that processes OCT data obtained by an optical coherence tomography apparatus including a Fourier domain OCT optical system,
By being executed by the processor of the OCT data processor,
An analysis processing step for performing a segmentation process on the OCT data and analyzing a subject based on a result of the segmentation process,
First OCT data, which is OCT data acquired when the surface of the test object is arranged at the back side from the zero delay position, and data obtained when the back surface of the test object is arranged at the front side from the zero delay position An analysis processing step for changing at least a part of the segmentation processing with respect to the second OCT data that is the processed OCT data;
Is executed by the OCT data processing apparatus. OCT obtained by an optical coherence tomography apparatus including a Fourier domain OCT optical system for detecting an A scan signal caused by interference between measurement light scanned on a subject by scanning means and reference light corresponding to the measurement light An OCT data processing apparatus for processing data,
An analysis processing means for performing a segmentation process on the OCT data and analyzing a subject based on a result of the segmentation process;
The analysis processing unit changes at least a part of the segmentation process according to a difference in conditions when OCT data is acquired by the optical coherence tomography apparatus.

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