JP2018051177A - Ophthalmic imaging apparatus and operation method for ophthalmic imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform the rendering of both a vascular structure and an anatomical structure and lesion of a subject eye.SOLUTION: Provided is an ophthalmic imaging apparatus, including: detection means 141, 142 for detecting light beams of different polarization obtained by splitting light obtained by multiplexing return light from a subject eye irradiated with measurement light and reference light corresponding to the measurement light; scan means 114 for scanning the subject eye with the measurement light; and control means for controlling the scan means such that the same site of the subject eye is scanned with the measurement light by a plurality of times. The ophthalmic imaging apparatus acquires motion contrast information in the subject eye using light beams of different polarization detected under control of the control means. When different sites of the subject eye corresponding to a movement of the subject eye are scanned with the measurement light under control of the control means, the ophthalmic imaging apparatus acquires information indicating the depolarization of the subject eye using light beams of different polarization detected in regions corresponding to between the different sites in the scan direction of the scan means and the depth direction of the subject eye.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an ophthalmologic photographing apparatus, and more particularly to an ophthalmic photographing apparatus that efficiently draws both a blood vessel structure and an anatomical structure / lesion of an eye to be examined, and a method for operating the ophthalmic photographing apparatus.

  In recent years, an optical coherence tomography (hereinafter referred to as OCT) using interference by low-coherence light has been put into practical use as an ophthalmic examination apparatus. Although the OCT apparatus can depict the three-dimensional structure of the retina, in recent years, not only the retinal structure but also the retinal blood vessels are rendered non-invasively using signal changes between successively acquired tomographic images. OCT angiography (hereinafter referred to as OCTA) and polarization-sensitive OCT (Polarization Sensitive OCT: hereinafter referred to as PS-OCT) that depicts specific anatomical structures and lesions using polarization characteristics of the retina. ) Has been developed (see Patent Document 1).

US2014 / 0228681 A1

  Here, OCT is considered to be effective for diagnosis and treatment management of diseases that may cause blindness such as age-related macular degeneration and diabetic retinopathy. In particular, in order to perform appropriate diagnosis and treatment management of these diseases, it is important to grasp lesions that occur with the development of retinal neovascularization. Therefore, an imaging apparatus that can efficiently perform both the above-described depiction of the vascular structure of the retina by OCTA and the depiction of the anatomical structure / lesion by PS-OCT is desired.

  Accordingly, in view of the above problems, one of the objects of the present invention is to efficiently perform both the depiction of the blood vessel structure of the eye to be examined and the depiction of the anatomical structure / lesion.

One of the ophthalmologic photographing apparatuses according to the present invention is
Detection means for detecting light of different polarizations obtained by dividing light obtained by combining return light from the eye to be examined irradiated with measurement light and reference light corresponding to the measurement light;
Scanning means for scanning the measurement light with respect to the eye to be examined;
Control means for controlling the scanning means so as to scan the measurement light multiple times with respect to the same position of the eye to be examined;
First information acquisition means for acquiring motion contrast information in the eye to be examined using the detected lights of different polarizations under the control of the control means;
When the measurement light is scanned at different positions of the eye corresponding to the movement of the eye under control by the control means, the different positions in the scanning direction by the scanning means and the depth direction of the eye to be examined 2nd information acquisition means which acquires the information which shows the depolarization property of the said to-be-tested eye using the light of the mutually detected mutually different polarized light of the area | region corresponding to between.

  According to one aspect of the present invention, it is possible to efficiently perform both the depiction of the blood vessel structure of the eye to be examined and the depiction of the anatomical structure / lesion.

Schematic configuration diagram of an ophthalmologic photographing apparatus according to the present embodiment Configuration diagram of interferometer according to this embodiment Configuration diagram of an image generation unit according to the present embodiment Schematic explanatory diagram of the display form by the display control unit according to the present embodiment Flow chart of image generation and display according to this embodiment Explanatory drawing of shooting data according to this embodiment Illustration of luminance tomogram according to this embodiment Explanatory drawing of DOPU calculation by this embodiment Illustration of depolarizing substance according to this embodiment Explanatory drawing of the map showing the lesion by this embodiment Explanatory drawing of the characteristic of the filter by this embodiment Display example of each image according to this embodiment

  The ophthalmologic imaging apparatus according to the present embodiment is configured to divide the light obtained by combining the return light from the eye to be examined that has been irradiated with the measurement light and the reference light corresponding to the measurement light, and having different polarization lights. Detection means (for example, detectors 141 and 142). In addition, the ophthalmologic photographing apparatus according to the present embodiment includes a scanning unit (for example, a galvano scanner 114) that scans the measurement eye with measurement light. Further, the ophthalmologic photographing apparatus according to the present embodiment includes a control unit (for example, the control unit 200) that controls the scanning unit so that the measurement light is scanned a plurality of times with respect to the same position of the eye to be examined. In addition, the ophthalmologic imaging apparatus according to the present embodiment acquires first information acquisition for acquiring motion contrast information in the eye to be examined using light of different polarizations detected under control by the control unit (during execution of control). Means (for example, a decorrelation calculation unit 315). Here, the motion contrast information is information relating to the contrast between a highly uncorrelated region (for example, a blood vessel region) and a highly correlated region (for example, a region other than a blood vessel). It is a non-correlated tomographic image showing the non-correlation of. Further, the ophthalmologic photographing apparatus according to the present embodiment is assumed to be a case where the measurement light is scanned at different positions of the subject eye corresponding to the movement of the subject eye under the control of the control unit. At this time, the ophthalmologic photographing apparatus according to the present embodiment is between the different positions (for example, different positions in the Y direction) in the scanning direction by the scanning unit and the depth direction (for example, the X direction and the Z direction) of the eye to be examined. Second information acquisition means (for example, DOPU, for example) that acquires information indicating the depolarization property of the eye to be inspected using light of different polarizations detected in corresponding regions (for example, r1, r2, r3 in FIG. 8). A calculation unit 304). Here, the information indicating the depolarization property is, for example, DOPU data whose pixel value is DOPU (Degree Of Polarization Uniformity).

  As a result, it is possible to acquire both motion contrast information and information indicating depolarization using light of different polarizations detected at the same timing. For this reason, both the retinal vascular structure and the anatomical structure / lesion can be efficiently depicted. The ophthalmologic photographing apparatus according to the present embodiment can be executed as its operating method. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[Overall configuration of ophthalmic imaging apparatus]
FIG. 1 shows an embodiment of an ophthalmologic photographing apparatus according to the present invention. First, the interferometer 100 controlled by the control unit 200 irradiates the test eye 118 with measurement light, detects return light from the test eye 118, and generates two types of signals S ₀ and S ₁ as the image generation unit 300. Output to. The image generation unit 300 processes the two types of signals S ₀ and S ₁ to generate a map M and a tomographic image T, and outputs them to the display control unit 400. The display control unit 400 includes a display device (not shown) such as a liquid crystal display, and displays an input image. The generated image is stored together with information for specifying the eye to be examined in a storage device (not shown).

  The ophthalmologic photographing apparatus shown in FIG. 1 can be realized by a PC (personal computer) connected to hardware having a specific function. For example, the interferometer 100 can be realized by hardware, and the control unit 200, the image generation unit 300, and the display control unit 400 can be realized by software modules that can be mounted on a PC connected to the hardware. In this embodiment, the arithmetic processing unit CPU of the PC implements the function by executing the software module, but the present invention is not limited to such a method. The image generation unit 300 may be realized by dedicated hardware such as an ASIC, for example, and the display control unit may be a dedicated processor such as a GPU different from the CPU. In addition, the connection between the interferometer 100 and the PC can be realized by a configuration via a network without changing the gist of the present invention. Next, a detailed configuration of each unit will be described.

<Configuration of Interferometer 100>
Next, the configuration of the interferometer 100 will be described with reference to FIG. The light source 101 is a swept source (SS) light source, and emits light while sweeping at a sweep center wavelength of 1050 nm and a sweep width of 100 nm, for example. The light emitted from the light source 101 is a single mode fiber (hereinafter referred to as SM fiber) 102, a polarization controller 103, a connector 104, an SM fiber 105, a polarizer 106, a polarization maintaining (PM) fiber (hereinafter PM fiber). The light is guided to the beam splitter 110 via the connector 107, the PM fiber 109, and branched into measurement light (also referred to as OCT measurement light) and reference light (also referred to as reference light corresponding to the OCT measurement light). .

  The branching ratio of the beam splitter 110 is 90 (reference light): 10 (measurement light). The polarization controller 103 can change the polarization of the light emitted from the light source 101 to a desired polarization state. On the other hand, the polarizer 106 is an optical element having a characteristic of passing only a specific linearly polarized light component. Usually, light emitted from the light source 101 has a high degree of polarization, and light having a specific polarization direction is dominant, but light that does not have a specific polarization direction, which is called a random polarization component, is included. This random polarization component is known to deteriorate the image quality of the polarized OCT image, and the random polarization component is cut by a polarizer. Since only light in a specific linear polarization state can pass through the polarizer 106, the polarization controller 103 adjusts the polarization state so that a desired amount of light enters the eye to be examined 118.

  The branched measurement light is emitted through the PM fiber 111 and converted into parallel light by the collimator 112. The measurement light that has become parallel light passes through the quarter-wave plate 113, and then passes through the galvano scanner 114, the dichroic mirror 148, the scan lens 115, and the focus lens 116 that scans the measurement light on the fundus Er of the eye 118 to be examined. The light enters the optometry 118. Here, although the galvano scanner 114 is described as a single mirror, actually, the galvano scanner 114 is configured by two galvano scanners so as to raster scan the fundus Er of the eye 118 to be examined. Of course, a single mirror capable of scanning light in a two-dimensional direction may be used. Two galvano scanners may be arranged close to each other, or both may be arranged at a position optically conjugate with the anterior eye portion of the eye 118 to be examined.

  The focus lens 116 is fixed on the stage 117, and the focus can be adjusted by moving in the optical axis direction. The galvano scanner 114 and the stage 117 are controlled by the control unit 200 and can scan the measurement light in a desired range of the fundus Er of the eye 118 to be examined. The quarter-wave plate 113 is an optical element having a characteristic of delaying the phase between the optical axis of the quarter-wave plate and an axis orthogonal to the optical axis by a quarter wavelength. In this embodiment, the optical axis of the quarter-wave plate is rotated by 45 ° around the optical axis as the rotation axis with respect to the direction of linear polarization of the measurement light emitted from the PM fiber 111, and the light incident on the eye 118 to be examined is circular. Let it be polarized light. The measurement light is incident on the eye 118 to be examined and focused on the fundus Er by the focus lens 116 mounted on the stage 117. The measurement light irradiated on the fundus Er is reflected and scattered by each retinal layer and returns to the beam splitter 110 through the optical path L101. The return light of the measurement light incident on the beam splitter 110 enters the beam splitter 128 via the PM fiber 126.

  On the other hand, the reference light branched by the beam splitter 106 is emitted through the PM fiber 119 and converted into parallel light by the collimator 120. The reference light is incident on the PM fiber 127 through the half-wave plate 121, the dispersion compensation glass 122, the ND filter 123, and the collimator 124. One end of the collimator lens 124 and the PM fiber 127 is fixed on the coherence gate stage 125, and is controlled by the control unit 200 so as to be driven in the optical axis direction corresponding to the difference in the eye axis length of the subject. Is done. The half-wave plate 121 is an optical element having a characteristic of delaying the phase between the optical axis of the half-wave plate and an axis orthogonal to the optical axis by a half wavelength. In the present embodiment, the linearly polarized light of the reference light emitted from the PM fiber 119 is adjusted so as to have a polarization state in which the major axis is inclined by 45 ° in the PM fiber 127. In the present embodiment, the optical path length of the reference light is changed, but it is only necessary to change the optical path length difference between the optical path of the measurement light and the optical path of the reference light.

  The reference light that has passed through the PM fiber 127 enters the beam splitter 128. In the beam splitter 128, the return light of the reference light and the reference light are combined into interference light and then divided into two. The divided interference light is interference light having phases inverted from each other (hereinafter referred to as a positive component and a negative component). The positive component of the divided interference light enters the polarization beam splitter 135 via the PM fiber 129, the connector 131, and the PM fiber 133. On the other hand, the negative polarization component of the interference light enters the polarization beam splitter 136 via the PM fiber 130, the connector 132, and the PM fiber 134.

  In the polarization beam splitters 135 and 136, the interference light is split along two orthogonal polarization axes, and a horizontal (Horizontal) polarization component (hereinafter referred to as an H polarization component) and a vertical (Vertical) polarization component (hereinafter referred to as a V polarization component). Are divided into two lights. The positive interference light incident on the polarization beam splitter 135 is split into two interference lights of a positive V polarization component and a positive H polarization component in the polarization beam splitter 135. The divided positive H-polarized component enters the detector 141 via the PM fiber 137, and the positive V-polarized component enters the detector 142 via the PM fiber 138.

On the other hand, the negative interference light incident on the polarization beam splitter 136 is split into a negative H polarization component and a negative V polarization component in the polarization beam splitter 136. The negative H-polarized component is incident on the detector 141 via the PM fiber 139, and the negative V-polarized component is incident on the detector 142 via the PM fiber 140. The detectors 141 and 142 are both differential detectors. When two interference signals whose phases are inverted by 180 ° are input, the DC components are removed and only the interference components are output. The H polarization component of the interference signal detected by the detector 141 and the V polarization component of the interference signal detected by the detector 142 are output as signals S ₀ and S ₁ corresponding to the light intensity, respectively, and input to the image generation unit 300. The

The detectors 141 and 142 detect the signals S ₀ and S ₁ described above in synchronization with a trigger signal (not shown) output from the light source 101. The trigger signal output from the light source 101 is synchronized with the wave number of the measurement light to be swept, and the signals S ₀ and S ₁ are output as signals that are linear with respect to the wave number.

(SLO configuration)
An SLO light source 150 is a fundus imaging light source having a center value near 780 nm, and an APD (Avalanche Photodiode) 152 is a fundus imaging sensor having sensitivity near 780 nm. On the other hand, the fixation lamp 149 generates visible light to promote fixation of the subject. Reference numerals 151 and 157 denote lenses. Reference numerals 154, 156, 158, 162, and 163 denote mirrors. The light beams emitted from the light sources 149 and 150 once form an image in the vicinity of the scanner 153 and form an image again in the vicinity of the fundus Er of the eye 118 to be examined. The scanner 153 is controlled by the control unit 200 and can scan the measurement light in a desired range of the fundus Er of the eye 118 to be examined.

  Here, although the scanner 153 is described as a single mirror, it is actually configured by a resonant scanner that performs main scanning with SLO measurement light in the X direction and a galvano scanner that performs sub-scanning with SLO measurement light in the Y direction. You may comprise with the single mirror which can scan light to a two-dimensional direction. Two galvano scanners may be arranged close to each other, or both may be arranged at a position optically conjugate with the anterior eye portion of the eye 118 to be examined. Similarly to the OCT, the lens 117 is driven and controlled so that the second imaging position coincides with the fundus oculi of the eye 118 to be examined. A dichroic mirror 148 positioned on the optical axis of the lens 117 branches the optical path L101 of the OCT optical system and the optical path L102 of the fixation lamp and SLO optical system for each wavelength band. The optical path L102 is an optical axis through which light from the SLO light source 150 and the fixation lamp 149 enters the fundus Er, and reflected light from the fundus enters the SLO optical system. The light from the fundus reflected in the direction of the optical path L102 is reflected by the mirror 156 and detected by the APD 152.

<Control unit 200>
Next, the control unit 200 will be described. As described above, in the present embodiment, the control unit 200 is a software module executed by the CPU, and controls each unit of the interferometer 100 and controls the operation of the entire ophthalmologic photographing apparatus according to the present embodiment. The control unit 200 also receives input from a user who operates the ophthalmologic photographing apparatus. Specifically, information such as a patient ID for specifying an eye to be examined, parameters necessary for imaging, selection of a pattern for scanning the fundus, and the like are input to the control unit 200 from a device such as a keyboard or a mouse (not shown). And a function of saving the obtained data such as signals and images in a storage device (not shown). That is, the control unit 200 inputs information on the eye to be examined, controls the interferometer 100 to output two types of signals S ₀ and S ₁ , and displays the image generated by the image generation unit 300 as a display control unit 400. Controls the overall flow displayed by. The operation flow of the control unit 200 will be described later.

<Image Generation Unit 300>
FIG. 3 shows the configuration of the image generation unit 300. The image generation unit 300 generates and outputs the following images related to the eye to be examined by performing various processes on the two signals S ₀ and S ₁ output from the interferometer 100.

(1) Image depicting polarization characteristics of eye to be examined: T _δ , T _θ , M _δ , M _θ
(2) the subject's eye retinal structure and lesion information representative of the location and _{image: P R, P L, T} I, M R, M L, M I
(3) Images depicting the blood vessel structure of the eye to be examined: T _D , M _V
Details of each image and a generation method thereof will be described in a flow of imaging operation described later.

<Display control unit 400>
Next, the display control unit 400 will be described. As described above, the display control unit 400 includes a display device such as a liquid crystal display, and displays an image input from the image generation unit 300. FIG. 4 shows the configuration of the screen displayed by the display control unit 400. In addition, in addition to the screen shown in the figure, an input screen for specific information of the eye to be examined such as a patient ID input by the control unit 200 is necessary. Since it is not a central part, description is omitted.
In FIG. 4, the display device 401 displays a screen including a display area 403 for eye information and an image display area 402. In the eye information display area 403, information such as patient ID, name, and age is displayed. In the image display area 402, various types of image display areas 404, 405, and 406, which will be described later, and user interfaces 407, 408, 409, and 410 for selecting them are arranged. FIG. 4 shows an example of the implementation form of these user interfaces, and the present invention is not limited to this. That is, for selecting an image, elements of a user interface such as a radio button or a text box may be used instead of the pull-down menu and slider shown in FIG. The image displayed in each display area and the function of the user interface will be described in the flow of the photographing operation described later.

[Imaging operation]
Next, the operation of the ophthalmologic photographing apparatus according to the present invention controlled by the control unit 200 will be described with reference to the flowchart shown in FIG.

<Step S510: OCT scan>
The control unit 200 controls the interferometer 100 by the method described above to output signals S ₀ and S _{1 in} which different polarization components from the eye to be examined are detected. FIG. 6 shows a measurement region on the fundus oculi Er and a signal output from the interferometer 100. In FIG. 6A, reference numeral 601 denotes a measurement region on the fundus Er of the eye 118 to be examined. The control unit 200 controls the galvano scanner 114 of the interferometer 100 to perform a plurality of measurement light scans in the measurement region 601 and acquire signals. Reference numeral 602 in FIG. 6A shows an example of the scanning trajectory of the measurement light by the galvano scanner 114.

In the present embodiment, the control unit 200 controls the interferometer 100 to scan the measurement light with respect to the same Y coordinate a plurality of times, and obtains signals S ₀ and S ₁ in each scan. By repeating this for all the Y-direction ranges of the measurement region 602, the volume data 603 shown in FIG. 6B is acquired. 604 in the figure represents a signal obtained as a single plane corresponding to N scans at a certain Y coordinate position. 6C and 6D show N signals obtained by one scan, FIG. 6C shows a signal of a horizontal polarization component, and FIG. 6D shows a vertical signal. It corresponds to the signal of the polarization component. That is, the data indicated by 604 in FIG. 6B is composed of the data indicated in FIGS. 6C and 6D.

  Although details will be described later, in the present embodiment, a plurality of types of images corresponding to 604 in FIG. 6B, that is, the eye of the eye to be examined, are obtained from the N times of signals shown in FIGS. 6C and 6D. Generate images related to polarization characteristics, lesions, vascular structures, etc. In the following description, the signal obtained by the above-mentioned scanning is called a B scan. Further, N B scan groups acquired at the same Y coordinate are referred to as B scan groups. In the following description, it is assumed that the operation of each processing unit is entirely controlled by the control unit 200, and necessary data is input / output.

  Here, the control unit 200 detects the movement of the eye to be examined when the scanning unit is controlled to scan the measurement light multiple times with respect to the same position of the eye by detecting the movement of the eye to be examined. It is difficult to accurately scan the measurement light with respect to the same position of the eye to be inspected due to a delay or the like until the scanning means is controlled. Therefore, actually, the measurement light is scanned at different positions of the subject eye corresponding to the movement of the subject eye. That is, in this embodiment, the measurement light is scanned so that the position where the N B scan groups are acquired is the “same position”, but it is affected by the movement of the eye to be examined. In this case, it is assumed that the measurement light is scanned at “different positions” of the eye to be examined corresponding to the movement of the eye to be examined. However, this is not the case when the measurement light can be scanned with the above-described delay being zero.

<Step S520: Reconfiguration>
The reconstruction unit 301 converts the signals S ₀ and S ₁ of each polarization component output from the interferometer 100 into tomographic signals r ₀ and r ₁ . For this processing, a known technique of wavelength sweep type OCT can be used. That is, tomographic signals r ₀ and r ₁ are generated by performing Fourier transform after performing fixed noise removal, window processing, and the like on S ₀ and S ₁ . Further, phase correction such as dispersion compensation may be performed as necessary. The signal generated in this step is a spatial distribution of each polarization component of the backscattered light of the eye to be examined shown below.
(Formula 1)
r ₀ = {r ₀ (x, y, z, n) | (x, y, z, n) ∈T}
= {A ₀ (x, y, z, n) exp
{IΦ ₀ (x, y, z, n)} | (x, y, z, n) ∈T}
r ₁ = {r ₁ (x, y, z, n) | (x, y, z, n) ∈T}
= {A ₁ (x, y, z, n) exp
{IΦ ₁ (x, y, z, n)} | (x, y, z, n) ∈T}

  However, x, y, z are coordinates in the measurement range (length W in the X direction, length H in the Y direction, and size D in the Z direction) shown in FIGS. 6 (A) and 6 (B). Value of

である。

It is.

  N is the n-th B scan in the N scans described in step S510,

である。

It is.

FIGS. 6E and 6F show the two types of generated tomographic signals. T represents a range of subscripts of scanning repeated N times in the X, Y, Z directions and each Y coordinate position of data obtained in one photographing. The tomographic signals r ₀ and r ₁ reconstructed as described above are the Stokes vector calculation unit 303, the B scan alignment unit 302, the band pass filter H0 (313), the band pass filter H1 (314), and the B scan alignment unit. 302 is output.

<Step S530: B-scan alignment>
The control unit 200 controls the B scan alignment unit 302 to calculate alignment parameters between the B scans in the reconfigured B scan group. In other words, there is a positional shift between the N B scans shown in FIGS. 6 (E) and 6 (F) due to the fixation eye movement of the eye to be examined. The amount is detected and output as a subsequent processing parameter.

First, the B scan alignment unit 302 calculates the luminance signal I from the input tomographic signals r ₀ and r _{1 of} each polarization component by the following equation.
(Formula 2)
I = {I (x, y, z, n) | (x, y, z, n) ∈T}
= {A ₀ (x, y, z, n) ² + A ₁ (x, y, z, n) ² | (x, y, z, n) ∈T}

  Next, the B scan alignment unit 302 selects a B scan (hereinafter referred to as a reference B scan) that serves as an alignment reference from the same B scan group. For the reference B scan, a specific position (for example, N / 2nd) may be selected from N B scans, or a B scan with the highest contrast of the luminance signal may be selected for each B scan. .

  Next, the B scan alignment unit 302 calculates the relative positional deviation amount of the other B scans in the B scan group with respect to the reference B scan. The B scan alignment unit 302 sets a region of interest 702 in the selected reference B scan 701 as shown in FIG. In the present embodiment, the region of interest 702 selects a region where the variance of the luminance signal is highest in the reference B scan 701. The size of the region of interest 702 is determined in advance in consideration of the size of the eye movement and the time required for calculation, and is stored in a memory (not shown) in the image generation unit 500.

  The B scan alignment unit 302 detects the relative position of each B scan with respect to the reference B scan by known template matching using the region of interest 702 in the reference B scan as a template, and alignment parameter Δ = Δ (y) = {( Δx, Δz)} is generated and output. In the present embodiment, the alignment parameter Δ is an offset for converting the coordinates of each pixel in each B scan into the coordinates of the reference B scan. That is, the pixel in the corresponding reference B scan of the pixel I (x, y, z, n) in the B scan is calculated as I (x + Δx, y, z + Δz, n).

  It should be noted that other forms can be used as the alignment parameters. For example, a matrix for performing a affine transformation between a reference B scan and another B scan by setting a plurality of regions of interest may be calculated as an alignment parameter, or nonlinear based on matching of a plurality of regions of interest A parameter for performing coordinate conversion may be used as an alignment parameter.

In any case, the B scan alignment unit 302 stores the luminance signal I, the alignment parameter Δ (y), and the reference B scan number n _ref (y in the B scan group) in a memory (not shown) in the image generation unit 500. ).

<Step S540: Average Luminance Tomographic Image Calculation>
The control unit 200 controls the average luminance tomographic image generation unit 310 to generate an average luminance image. The average luminance tomogram generation unit 310 performs each B scan from the luminance signal I output from the B scan alignment unit 302, the alignment parameter Δ (y), and the reference B scan number n _ref (y) in the B scan group. Average luminance tomogram averaged over B scans within the group

を計算する。

Calculate

但し、上式においてＸ方向およびＺ方向の座標値は、前述した位置合わせパラメータΔ（ｙ）で補正されているものとする。すなわち、参照Ｂスキャン以外の各Ｂスキャンにおける座標値は（ｘ，ｙ，ｚ）は（ｘ＋Δｘ，ｙ，ｚ＋Δｚ）として補正されている。

However, in the above equation, the coordinate values in the X direction and the Z direction are corrected by the alignment parameter Δ (y) described above. That is, the coordinate values in each B scan other than the reference B scan are corrected as (x + Δx, y, z + Δz).

<Step S550: Retina Structure Tomographic Image Calculation>
Control unit 200, by controlling the layer recognition unit 311, Stokes vector calculating unit 303 to depolarizing material classification unit 305, the tomographic image _T I to render retinal structure of the eye, RPE and lesion position information _{P R} and to generate a P _L. The retinal layer recognition unit 311 is configured to display an average luminance tomogram.

のＺ方向のデータ列（以降Ａスキャンと呼ぶ）から内境界膜（ＩＬＭ）を検出する。具体的には、層認識部３１１は、各Ａスキャンに対し硝子体側からエッジを抽出し、当該エッジの座標をＡスキャン毎に画像生成部５００内の不図示のメモリにＩＬＭ境界位置情報Ｂ_ＩＬＭとして記憶する。さらに、網膜層認識部３１１は、網膜層の内網状層（ＩＰＬ）と内顆粒層（ＩＮＬ）の境界Ｂ_ＩＰＬを抽出し、ＩＰＬ境界位置情報として記憶する。

The inner boundary film (ILM) is detected from the Z-direction data string (hereinafter referred to as A scan). Specifically, the layer recognizing unit 311 extracts an edge from the vitreous side for each A scan, and the coordinates of the edge are stored in a memory (not shown) in the image generating unit 500 for each A scan in the ILM boundary position information B _ILM. Remember as. Further, the retinal layer recognition unit 311 extracts the boundary B _IPL between the inner reticular layer (IPL) and the inner granular layer (INL) of the retinal layer and stores it as IPL boundary position information.

また、網膜層認識部３１１は、平均輝度断層像

In addition, the retinal layer recognition unit 311 performs an average luminance tomogram.

とＩＬＭ境界位置情報Ｂ_ＩＬＭ、およびＩＰＬ境界位置情報Ｂ_ＩＰＬを関連付けて輝度断層像Ｔ_Ｉとして記憶すると共に、表示制御部４００に出力する。なお、上記抽出処理はこれに限定されることなくエッジ抽出に先立ちメディアンフィルタ等によりノイズ抑制を行ってもよい。また、ＩＬＭの平均的な境界位置、輝度情報を特徴量とした識別器を用いるようにしてもよい。次に、Ｓｔｏｋｅｓベクトル計算部３０３は、入力した各偏光成分の断層信号ｒ_０およびｒ_１から被検眼内の各座標位置におけるＳｔｏｋｅｓベクトルＳ＝Ｓ（ｘ，ｙ，ｚ，ｎ）を次式により計算する。

, ILM boundary position information B _ILM , and IPL boundary position information B _IPL are stored in association with each other as a luminance tomographic image T _I and output to the display control unit 400. The extraction process is not limited to this, and noise suppression may be performed by a median filter or the like prior to edge extraction. In addition, a discriminator having an average boundary position of ILM and luminance information as a feature amount may be used. Next, the Stokes vector calculation unit 303 calculates a Stokes vector S = S (x, y, z, n) at each coordinate position in the eye to be examined from the input tomographic signals r ₀ and r _{1 of} each polarization component by the following equation. calculate.

計算されたＳｔｏｋｅｓベクトルＳは、Ｓｔｏｋｅｓベクトル平均部３０７およびＤＯＰＵ計算部３０４に出力される。ＤＯＰＵ計算部３０４は、Ｓｔｏｋｅｓベクトル計算部３０３で計算したＳｔｏｋｅｓベクトルＳから被写体の偏光解消性を示す情報であるＤＯＰＵ（Ｄｅｇｒｅｅ Ｏｆ Ｐｏｌａｒｉｚａｔｉｏｎ Ｕｎｉｆｏｒｍｉｔｙ）を画素値とするＤＯＰＵデータであるＤＯＰＵを次式により計算する。ここで、ＤＯＰＵ計算部３０４は、互いに異なる偏光の光を用いて被検眼の偏光解消性を示す情報を取得する第２の情報取得手段の一例である。

The calculated Stokes vector S is output to the Stokes vector averaging unit 307 and the DOPU calculation unit 304. The DOPU calculation unit 304 calculates DOPU, which is DOPU data whose pixel value is DOPU (Degree Of Polarization Uniformity), which is information indicating the depolarization property of the subject, from the Stokes vector S calculated by the Stokes vector calculation unit 303 by the following equation. To do. Here, the DOPU calculation unit 304 is an example of a second information acquisition unit that acquires information indicating the depolarization property of the eye to be examined using light of different polarizations.

但し、上式においてＸ方向およびＺ方向の座標値は、ステップＳ５４０で説明したと同様、座標値は（ｘ，ｙ，ｚ）は（ｘ＋Δｘ，ｙ，ｚ＋Δｚ）として補正されているものとする。

However, in the above equation, the coordinate values in the X direction and the Z direction are corrected as (x + Δx, y, z + Δz) in the coordinate values (x, y, z) as described in step S540.

  FIG. 8 schematically shows the calculation at the specific position Y = y of the DOPU in (Equation 6) as the number of repeated scans N = 3. In FIG. 8, r1 to r3 are regions of interest set at the same position in each B scan, R in (Expression 6) is a range of coordinates for all three regions of interest, and M is a region R. The number of all pixels in That is, DOPU calculation section 304 calculates DOPU from all Stokes vector elements in R according to (Equation 6), and outputs the result to depolarization substance classification section 305. That is, DOPU corresponds to one B-scan as shown in (Formula 6). In this case, although the scanning means is controlled to scan the measurement light with respect to the “same position” of the eye to be examined a plurality of times, as described above, it is affected by the movement of the eye to be examined. Actually, the measurement light is scanned at “different positions” of the eye to be examined corresponding to the movement of the eye to be examined.

  Next, the depolarizing substance classification unit 305 divides the input DOPU into retinal pigment epithelium (RPE), depolarizing substance in the choroid, lesions, and other regions. First, the depolarizing substance classification unit 305 performs threshold processing on DOPU. The pixel value of DOPU indicates the degree of depolarization at the position (x, y, z) of the subject, and the smaller the value, the greater the depolarization. Therefore, the depolarizing substance classification unit 305 extracts pixels having a threshold value of, for example, 0.75 or less by threshold processing.

FIG. 9 shows an example of DOPU data after threshold processing, in which RPE 901, choroid depolarization substance 902, and lesion 903 showing strong depolarization properties are extracted in the retinal layer. Reference numeral 904 denotes an area that does not belong to any of these. Next, the depolarizing substance classification unit 305 classifies these three types of subjects. First, the depolarizing substance classification unit 305 extracts pixel groups connected to each other from the threshold-processed DOPU data, and determines a curve 905 that passes through the center of the pixel group. Next, depolarizing material classification unit 305 classifies the depolarization substance retinal inner layer side away from the curve 905 above d _u lesion 903, the depolarization substances or more away d _l choroidal side as choroidal depolarizing material 902 . Next, depolarizing material classification unit 305, a list P _R of the three coordinate values shown _below, and stores the P _L and P _C in a memory (not shown) in the image generation unit 300 further retinal structure map generator The data is output to 306 and output to the display control unit 400.
(Formula 7)
P _R = {(x, y, z) | (x, y, z) ∈V}
P _L = {(x, y, z) | (x, y, z) ∈V}
P _C = {(x, y, z) | (x, y, z) ∈V}
Here, P _R, P _L and P _C is a list of each RPE, lesion, the coordinate values of the pixels detected by depolarizing agent in the choroid. Incidentally, the d _u and d ₁ is set in advance from the distribution of the position of the depolarizing agent in the lesions and choroid of hard exudates or the like generated on the inner side of the RPE, stored in a memory (not shown) in the image generation unit 300 ing. In the present embodiment, in particular, the P _L representing the form of a lesion, such as P _R and hard exudates showing the form of the RPE is an important observation target in macular diseases including age-related macular degeneration, below Use as described to generate a retinal structure map.

<Step S560: Retinal structure map generation>
Retinal structure map generation unit 306, the _{P R} and _{P L} input from depolarizing material classification unit 305, generates the RPE thickness map _{M R} and lesion map _{M L,} which is an example of the depolarization map. First, the retinal structure map generation unit 306, as for all A-scan in the volume data 603 shown in FIG. 6 (B), counting the number of coordinates of each pixel in the A-scan is included in the coordinate list P _R and outputs the image M _R to the count number as the pixel value as RPE thickness map. Similarly, retinal structure map generating unit 306 counts the number contained in the coordinate list P _L, and outputs the count number of the image M _L to the pixel value as a lesion map. Here, it is preferable that the image generation unit 300 includes a layer extraction unit (not shown) that extracts a plurality of layers of the eye to be inspected using lights having different polarizations. At this time, it is preferable that a specific depth range is selected using at least one layer selected from the plurality of extracted layers. Thereby, since the user can select a specific depth range easily, the convenience of the user can be improved. In addition, as a method for selecting a specific depth range, any method may be used as long as a part of information in the depth direction can be selected from information indicating depolarization.

Figure 10 is an illustration of a RPE thickness map M _R and lesion map M _L, both of which are displayed at a high luminance level larger the number of counts mentioned above. Figure 10 (A) is shows the RPE thickness map _{M R,} DOPU data position indicated by the broken line is illustrated in FIG. 905 is a portion RPE is partially atrophy, this portion corresponds to 1001 in RPE thickness map _{M R.} Further, FIG. 10 (B) is an illustration of a lesion map _{M L,} similarly lesion 903 extracted from DOPU data position indicated by a broken line is depicted as 1002. The retinal structure map generation unit 306 outputs these maps to the display control unit 400.

<Step S570: Generation of polarization characteristic tomographic image>
The Stokes vector averaging unit 307 obtains the following (formula 7) from the Stokes vector S and the alignment parameter Δ (y) stored in step S530 and the reference n-scan number n _ref (y) in the B-scan group: The average Stokes vector according to (Equation 8)

を計算する。

Calculate

  However, in the above equation, it is assumed that (x, y, z) is corrected as (x + Δx, y, z + Δz) in the coordinate values in the B scan other than the reference B scan.

  Here, V represents a subscript range of data in the X, Y, and Z directions corresponding to the volume data 603 shown in FIG. The Stokes vector average unit 307 generates the generated average Stokes vector

を偏光特性計算部３０８に出力する。偏光特性計算部３０８は、平均Ｓｔｏｋｅｓベクトル

Is output to the polarization characteristic calculator 308. The polarization characteristic calculator 308 calculates the average Stokes vector

から被写体が有する位相遅延および進相軸方位の２種類の偏光特性を計算し、その値を画素値とする位相遅延断層像Ｔ_δおよび進相軸方位断層像Ｔ_θを、次式により生成する。

The phase delay tomogram T _δ and the fast axis azimuth tomographic image T _θ having the values as pixel values are calculated from the following equations by calculating two types of polarization characteristics of the subject from the phase delay and the fast axis azimuth. .

Pixel value of phase delay tomogram _Tδ

は、被写体がその線維構造等により複屈折性を有する場合、位置（ｘ，ｙ，ｚ）における偏光間の位相遅延量を表しており、網膜においては視神経繊維層で直線的に変化する。また、進相軸方位断層像Ｔ_θの画素値

Represents the amount of phase delay between polarized light at the position (x, y, z) when the subject has birefringence due to its fiber structure or the like, and linearly changes in the optic nerve fiber layer in the retina. Further, the fast axis azimuth pixel values of the tomographic image T _theta

は被写体がその線維構造によって複屈折性を有する場合にその繊維質の方向を表しており、網膜内層の病変が瘢痕となり線維化すると、周期的な変化が観察されるようになる。偏光特性計算部３０８は、位相遅延断層像Ｔ_δおよび進相軸方位断層像Ｔ_θを偏光特性マップ生成部３０９および表示制御部４００に出力する。

Represents the direction of the fiber when the subject has birefringence due to its fiber structure, and when the lesion in the inner retina becomes a scar and becomes fibrotic, a periodic change is observed. The polarization characteristic calculator 308 outputs the phase delay tomogram T _δ and the fast axis azimuth tomogram T _θ to the polarization characteristic map generator 309 and the display controller 400.

<Step S580: Polarization Characteristic Map Generation>
The polarization characteristic map generation unit 309 generates a phase delay map M _δ and a fast axis orientation map M _θ from the phase delay tomogram T _δ and the fast axis azimuth tomogram T _θ . In other words, polarization characteristic map generating unit 309 in each A-scan phase delay in the tomographic image T _[delta], between the ILM boundary position held in the position coordinates _{P R} and ILM boundary position information _{B ILM} of the stored RPE in step S550 between, to produce a histogram of the phase delay at the position of the a-scan (x, y), and the mode value as the pixel value of the phase delay map M _[delta]. Similarly, the polarization characteristic map generation unit 309 sets the mode value of the histogram between the RPE and the ILM as the pixel value of the fast axis orientation map M _θ in each A scan of the fast axis orientation tomographic image T _θ . The polarization characteristic map generation unit 309 outputs the two maps generated in this way to the display control unit 400.

<Step S590: Brightness Map Generation>
Luminance map generation unit 312, a luminance tomographic image T _I of retinal layer recognition unit 311 has generated to generate a luminance map M _I obtained by integrating in the Z direction, and outputs to the display control unit 400. In the present embodiment, the range of integration is the between the positions _{P R} of the ILM boundary and RPE represented by ILM boundary position information _{B ILM.} However, the present invention is not limited to this, and the integration may be performed over the entire range in the Z direction of the B scan.

<Step S600: Blood vessel map generation>
The image generation unit 300 uses the two types of tomographic signals r ₀ and r ₁ generated by the reconstruction unit 301 in step S520 as the tomographic signals rf ₀ and rf ₀ having different spatial frequency bands by the filters 313 and 314 having different pass bands. It is preferable to have a conversion unit (not shown) for converting to rf ₁ . At this time, the converted tomographic signal is output to the decorrelation calculation unit 315. Here, the decorrelation calculation unit 315 is an example of a first information acquisition unit that acquires motion contrast information in the eye to be examined using light of different polarizations. The motion contrast information is information relating to the contrast between a highly uncorrelated region (for example, a blood vessel region) and a highly correlated region (for example, a region other than a blood vessel). FIG. 11 schematically shows the pass characteristics of 313 (H0) and 314 (H1), and has a portion (A in the figure) where the passbands overlap each other. Next, the decorrelation calculation unit 315 obtains decorrelation tomographic images T _D (an example of motion contrast information) representing non-correlation between temporally different B scans from the input tomographic signals rf ₀ and rf _{1 according} to the following equation. Calculate

However, in the above equation, the coordinate values in the B scan other than the reference B scan are corrected as (x + Δx, y, z + Δz). Non-correlation calculating unit 315 outputs a decorrelated tomographic image T _D in the blood vessel map generation unit 316.

Vascular map generation unit 316, uncorrelated tomographic image _{T D} and structure of the retina that is generated in step S550 and the information _B ILM representing the position of the _{lesion, B IPL, P R, P} L and _{P C,} and in step S570 Using the generated phase delayed tomogram T _δ and fast axis azimuth tomogram T _θ , a blood vessel map M _V = {M _S , M _D , M _C } in a specific depth range in the retinal layer is generated, The data is stored in an internal memory (not shown) and output to the display control unit 400. Here, it is preferable that the image generation unit 300 includes a layer extraction unit (not shown) that extracts a plurality of layers of the eye to be inspected using lights having different polarizations. At this time, it is preferable that a specific depth range is selected using at least one layer selected from the plurality of extracted layers. Thereby, since the user can select a specific depth range easily, the convenience of the user can be improved. As a method for selecting a specific depth range, any method can be used as long as a part of information in the depth direction can be selected from motion contrast information. Vascular map generation unit 316, by using the above information to generate a plurality of blood vessel map as shown below, and outputs to the display control unit 400 sums it as a vascular map M _V.

(Retina shallow blood vessel map M _S )
The blood vessel map generation unit 316 determines the region of the retinal optic nerve fiber layer (RNFL) from the ILM boundary position information B _ILM and the phase delay tomogram T _δ . Since RNFL has birefringence, the amount of phase delay increases in proportion to the distance in that region. Therefore, the vascular map generation unit 316 each pixel position of the retinal superficial vascular map M _S (x, y) from the ILM boundary position z _L in the pixels of the phase delay in the tomographic image T _[delta] toward the Z-direction

が一定の割合で変化する範囲をＲＮＦＬの領域として決定する。一方、ＲＮＦＬが網膜層内では比較的高い輝度レベルを有する事から、平均輝度断層像

Is determined as a region of the RNFL. On the other hand, since the RNFL has a relatively high luminance level in the retinal layer, the average luminance tomogram

の画素

Pixels

が平均的なＲＮＦＬ周辺の輝度レベルより高い範囲をＲＮＦＬの範囲としてもよい。次に、血管マップ生成部３１６は、非相関断層像Ｔ_Ｄの当該領域内において非相関値

A range that is higher than the luminance level around the average RNFL may be set as the RNFL range. Next, the vascular map generation unit 316, the non-correlation value in the region of the non-correlation tomographic image T _D

が閾値以下の画素をＺ方向に積算投影し、網膜浅層血管マップＭ_Ｓを生成する。この閾値は、予め構造的に血管が存在しない領域の非相関値に基づいて決定されているものとする。

There the following pixel threshold integrated projected in the Z direction, to produce a retinal superficial vascular map M _S. This threshold value is determined in advance based on a non-correlation value of a region where a blood vessel does not exist structurally.

(Retina deep blood vessel map M _D )
Vascular map generation unit 316, the _{P R} representing the position of the IPL boundary position information _{B IPL} and RPE, determining a deep region of the retina. That is, the blood vessel map generation unit 316 each pixel position of the retinal superficial vascular map _{M D} (x, y) position in the _{P R} toward the IPL boundary position _{z L} in the Z direction in the (x, y) the smallest Z coordinate in Up to the deep region. Next, the vascular map generation unit 316 uncorrelated values in the region of the non-correlation tomographic image T _D

が閾値以下の画素をＺ方向に積算投影し、網膜浅層血管マップＭ_Ｄを生成する。

There the following pixel threshold integrated projected in the Z direction, to produce a retinal superficial vascular map M _D.

(Choroidal capillary plate map M _C )
Vascular map generation unit 316 determines from P _R representing the position of the RPE to a position spaced 10μm comprising anatomically choroidal capillaries plate in the Z direction as choroidal capillaries plate region. Next, the vascular map generation unit 316 uncorrelated values in the region of the non-correlation tomographic image T _D

が閾値以下の画素をＺ方向に積算投影し、網膜浅層血管マップＭ_Ｃを生成する。

There the following pixel threshold integrated projected in the Z direction, to produce a retinal superficial vascular map M _C.

<Step S610: Image Display>
The display control unit 400 displays various images input from the image generation unit 300 in the image display area 402 of the display device 401 shown in FIG. In the image display area 402, 404 and 405 are areas for displaying a planar image (Enface image) stretched by the X axis and the Y axis shown in FIG. 6, and the area 404 includes M _I , M _R , M _L , M _δ , _Mθ is displayed. The display control unit 400 switches and displays these maps in accordance with a user operation on the pull-down menu 408. A region 405 is a display region of the blood vessel map M _V = {M _S , M _D , M _C }, and the display control unit 400 switches and displays these maps according to the user's operation on the pull-down menu 409. . That is, the pull-down menus 408 and 409 are examples of the first display form and the second display form for selecting at least one layer from the plurality of extracted layers. At this time, partial information in the depth direction is selected from the motion contrast information using at least one layer selected in the first display form. Further, a part of the information in the depth direction is selected from the information indicating the depolarization property using at least one layer selected in the second display form. Thereby, the user can easily select partial information in the depth direction from the motion contrast information and the information indicating the depolarization property. For this reason, a user's convenience can be improved and the diagnostic efficiency improves as a result. In the present embodiment, 408 and 409 are pull-down menus, but any user interface such as a radio button having the same function may be used. An area 406 is a tomographic image display area in which tomographic images of the XZ cross section and the YZ cross section are displayed in the volume data. Fault display control unit 400 in response to selection of the pull-down menu _{410, T I, T δ,} T θ, T D, and their tomographic image and RPE, superimposed information _{P R} and _{P L} represents the position of the lesion Display an image. The slider 407 designates a tomographic image to be displayed in each area 406 in the volume data.

FIG. 12 shows a display example. In FIG. 12A, the region 404 has an RPE thickness map M _R , the region 405 has a retinal shallow blood vessel map M _S , and the region 406 has an average luminance. Tomogram

が、ＸＺ断面（水平Ｈ）およびＹＺ断面（垂直Ｖ）の各々に表示されている。また、ライン１２１および１２２は、各マップ上において断層像の取得位置を示すもので、各マップ上に重畳表示されている。ユーザは、ライン１２１および１２２をマウスで操作する事で各マップ上のラインを移動することができる。これにより、領域４０６に表示される断層像の位置を変更する事が出来る。ここで、ライン１２１および１２２は、点線である必要はなく、直線でも良いし、点滅させても良い。このとき、血管マップ及び偏光解消マップに重ねて表示された２つのラインのうち一方の移動に他方の移動を連動させることが好ましい。これにより、ユーザの利便性を向上することができる。また、図１２（Ｂ）は、別の表示例である。この例においては、ＲＰＥ厚マップＭ_Ｒ、領域４０５には網膜浅層血管マップＭ_Ｓ、領域４０６には平均輝度断層像

Are displayed in each of the XZ cross section (horizontal H) and the YZ cross section (vertical V). Lines 121 and 122 indicate tomographic image acquisition positions on each map, and are superimposed on each map. The user can move the lines on each map by operating the lines 121 and 122 with a mouse. Thereby, the position of the tomographic image displayed in the area 406 can be changed. Here, the lines 121 and 122 do not need to be dotted lines, and may be straight lines or blinking. At this time, it is preferable that one of the two lines displayed superimposed on the blood vessel map and the depolarization map is linked to the other movement. Thereby, a user's convenience can be improved. FIG. 12B shows another display example. In this example, the RPE thickness map M _R , the region 405 has a shallow retinal blood vessel map M _S , and the region 406 has an average luminance tomogram.

の各々に病変部の位置情報Ｐ_Ｌが重畳表示されている。図１２（Ｂ）においては、１２３および１２４が病変部を表している。また、ＲＰＥ厚マップＭ_ＲにはＲＰＥの委縮領域１２５が描出されている。

Each location P _L of the lesion is displayed superimposed on the. In FIG. 12B, reference numerals 123 and 124 denote lesions. Further, the RPE thickness map _{M R} atrophy region 125 of the RPE is depicted.

  As described above, according to the present embodiment, it is possible to efficiently generate and display a plurality of types of images, that is, anatomical structures and lesions of the retina including vascular structures, from the signals obtained by the OCT scan. I can do it. In the present embodiment, when a blood vessel image is generated, signals in different spatial frequency bands are generated from signals obtained from different polarization components, and the uncorrelation calculation is performed as shown in (Equation 11). As a result, the number of repeated scans N can be substantially doubled, and further, the resolution in the depth direction can be reduced to reduce the effect of slight positional deviation due to the movement of the eye to be uncorrelated. Thus, it is possible to improve the image quality of the blood vessel image.

In the present embodiment, the imaging data is obtained by the wavelength sweep type polarization OCT adjusted to be circularly polarized with respect to the eye to be examined 118, but the present invention is not limited to this. As the OCT method, a spectral domain method using a broadband light source may be used, or the polarization state of measurement light may be dynamically changed by a polarization modulator. In any configuration, any configuration can be used as long as an image can be generated and displayed in the same manner as the present embodiment by detecting different polarization components r ₀ and r ₁ from the scattered light from the eye to be examined. .
Here, although the case where the scanning position of the measurement light is actually scanned at a different position has been described as this embodiment, as another embodiment, the tomogram used for generation by a different method depending on the type of image to be generated An image may be selected. In other words, in depolarization imaging, it is necessary to calculate DOPU from data in a range with a certain spatial extent, so there is no need for the scanning positions to be perfectly matched, but acquisition of motion contrast information In this case, it is desirable that the tomographic signal acquisition position error is as small as possible.
Therefore, the non-correlation calculation unit 315 At step S600, the time of calculating decorrelation tomographic image T _D from the tomographic signal rf ₀ and rf ₁ entered excludes fault signal which can be regarded as the scanning position deviation is large. That is, when performing correlation calculation between the n-th and n + 1-th tomographic signals in Equation 11, if the scan position deviation is small enough to be ignored, the non-correlation value increases only in the blood vessel portion. Blood vessels can be extracted. However, if the scanning position deviation is large, the decorrelation value has a large value over the entire B scan regardless of the presence or absence of blood vessels, and it is impossible to extract only the blood vessel portion. For this reason, the decorrelation calculation unit 315 analyzes the distribution of the decorrelation values in the B scan, and determines that the scan position deviation is large if pixels with a high decorrelation value are uniformly distributed throughout the B scan. Te, the combination of the tomographic signal is excluded from the calculation of the decorrelation tomographic image T _D.
For the analysis of this distribution, the number of pixels outside the range of the decorrelation value corresponding to the blood vessel set experimentally in advance and the distribution of the coordinates can be used. For example, if the uncorrelated value is outside the range of the value that a normal blood vessel has, the B scan is binarized and the number of extracted regions is larger than the number predicted from the normal anatomical structure, or the area or center of the region If the coordinate distribution is continuous, it is determined that the spread is large. If the delay of the control unit 200 varies the scanning position of the measuring light, because the distribution of the non-correlation values over the entire B-scan, is possible to generate a decorrelation tomographic image T _D from only the appropriate fault signal by the method described above I can do it. On the other hand, in the calculation of DOPU which is information indicating the depolarization property, the selection of the B scan is not performed for the reason described above, and all acquired tomographic signals are used. Of course, in the calculation of DOPU, it is not necessary to select a tomographic image having a large scan position shift inappropriate to the DOPU calculation. At this time, the second threshold value used when selecting a tomographic image used for DOPU calculation is larger than the first threshold value used when selecting a tomographic image used for acquiring motion contrast information. preferable.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (10)

Detection means for detecting light of different polarizations obtained by dividing light obtained by combining return light from the eye to be examined irradiated with measurement light and reference light corresponding to the measurement light;
Scanning means for scanning the measurement light with respect to the eye to be examined;
Control means for controlling the scanning means so as to scan the measurement light multiple times with respect to the same position of the eye to be examined;
First information acquisition means for acquiring motion contrast information in the eye to be examined using the detected lights of different polarizations under the control of the control means;
When the measurement light is scanned at different positions of the eye corresponding to the movement of the eye under control by the control means, the different positions in the scanning direction by the scanning means and the depth direction of the eye to be examined Second information acquisition means for acquiring information indicating the depolarization property of the eye to be inspected using the detected lights of different polarizations in the corresponding region between
An ophthalmologic photographing apparatus comprising:   Using the partial information in the depth direction selected from the motion contrast information, a blood vessel map of the eye to be examined is generated, and the partial information in the depth direction selected from the information indicating the depolarization property The ophthalmologic photographing apparatus according to claim 1, further comprising: an image generating unit that generates a depolarization map of the eye to be examined using a lens.   The ophthalmologic photographing apparatus according to claim 2, further comprising display control means for displaying the blood vessel map, the depolarization map, and a luminance tomographic image of the eye to be examined on a display means.   The display control unit causes the display unit to display a line indicating the acquisition position of the luminance tomographic image on the blood vessel map and the depolarization map, and displays the line on the blood vessel map and the depolarization map. The ophthalmologic photographing apparatus according to claim 3, wherein the movement of one of the two lines is linked to the movement of the other. A layer extraction means for extracting a plurality of layers of the eye to be examined using the detected lights of different polarizations;
The display control means includes a first display form for selecting at least one layer among the plurality of extracted layers, and a first display mode for selecting at least one layer among the plurality of extracted layers. 2 is displayed on the display means,
A part of the information in the depth direction is selected from the motion contrast information using at least one layer selected in the first display form, and at least one layer selected in the second display form is selected. The ophthalmologic photographing apparatus according to claim 3 or 4, wherein a part of information in the depth direction is selected from information indicating the depolarization property. Conversion means for converting the detected light of different polarizations into a plurality of tomographic signals having different spatial frequency bands under the control of the control means;
The ophthalmologic imaging apparatus according to claim 1, wherein the first information acquisition unit acquires the motion contrast information using the converted plurality of tomographic signals.   The first information acquisition unit is configured to detect the different polarized lights corresponding to a plurality of scans selected from the plurality of scans based on a positional shift of different positions of the eye to be examined corresponding to the movement of the eye to be examined. The ophthalmologic photographing apparatus according to claim 1, wherein the motion contrast information is acquired by using the light of. The first information acquisition unit is configured to output the detected lights of different polarizations corresponding to a plurality of scans in which positional shifts of different positions of the subject eye corresponding to the movement of the subject eye are smaller than a first threshold. To obtain the motion contrast information,
The second information acquisition unit is configured to detect the detection corresponding to a plurality of scans in which a positional shift of a different position of the eye to be examined corresponding to the movement of the eye to be examined is smaller than a second threshold value that is larger than the first threshold value. 7. The ophthalmologic photographing apparatus according to claim 1, wherein information indicating the depolarization property is acquired using the light beams having different polarizations. Detecting means for detecting light of different polarizations obtained by dividing light obtained by combining return light from the eye to be examined irradiated with measurement light and reference light corresponding to the measurement light; and the eye to be examined Scanning means for scanning the measurement light, and an operation method of an ophthalmologic photographing apparatus comprising:
Controlling the scanning means to scan the measurement light multiple times with respect to the same position of the eye to be examined;
Using the detected lights of different polarizations during the controlling step to obtain motion contrast information in the eye to be examined;
When the measurement light is scanned at different positions of the subject eye corresponding to the movement of the subject eye during the execution of the controlling step, the different in the scanning direction by the scanning unit and the depth direction of the subject eye Obtaining information indicating the depolarization of the eye to be examined using the differently polarized light detected in the corresponding regions between positions;
A method of operating an ophthalmologic photographing apparatus comprising: A program for causing a computer to execute each step of the operation method of the ophthalmologic photographing apparatus according to claim 9.

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