Signal processing method, information processing apparatus, optical coherence tomography apparatus, and program

Abstract

To provide a technique for acquiring a shape of an interface having a strong diffusion degree.SOLUTION: The present signal processing method is a signal processing method executed by an information processing apparatus including a control unit, the control unit inputting an optical coherence tomography signal obtained by optical coherence tomography, the signal processing method including: In the optical coherence tomographic signal, a target signal region corresponding to only the second interface is specified among a first interface between a first layer group including one or more layers and a second layer group including one or more layers and a second interface between the second layer group and a third layer group including one or more layers, and information on a shape of the second interface acquired based on the target signal region is output.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a signal processing method, an information processing device, an optical coherence tomography apparatus, and a program. [Background technology]

[0002] Optical coherence tomography (OCT) is used in the medical field for tomography of biological organs such as the eyeball.

[0003] For example, Patent Document 1 discloses an optical coherence tomography apparatus that includes an objective lens that focuses light from a light source onto a sample, and through which both sample light, which is light reflected from the sample, and reference light, which is light reflected from a reference surface provided between the objective lens and the sample, pass. Patent Document 2 also discloses an optical coherence tomography apparatus that uses a high-speed wavelength swept light source as a light source. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-052751 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-024677 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique for obtaining information about the shape of a highly diffuse interface with high accuracy. [Means for solving the problem]

[0006] A signal processing method according to a first aspect includes: A signal processing method executed by an information processing device having a control unit, The control unit An optical coherence tomography signal obtained by optical coherence tomography is input, In the optical coherence tomography signal, a target signal region corresponding only to a first interface between a first layer group including one or more layers and a second layer group including one or more layers, and a second interface between the second layer group and a third layer group including one or more layers is identified; and outputting information about the shape of the second interface obtained based on the target signal region.

[0007] According to the signal processing method of the first aspect, by specifying a target signal region corresponding only to the second interface in the optical coherence tomography signal, it is possible to acquire information about the shape of the second interface, which has a high degree of diffusion, with high accuracy.

[0008] A signal processing method according to a second aspect of the present invention comprises: The control unit identifying a first peak position in the target signal region where the signal intensity is highest in a stacking direction in which the first layer group, the second layer group, and the third layer group are stacked; The signal processing method according to a first aspect outputs information relating to the shape of the second interface based on the first peak position.

[0009] According to the signal processing method of the second aspect, by identifying the first peak position of the signal intensity corresponding to the second interface with high accuracy, it is possible to acquire information about the shape of the second interface with a high degree of diffusion with high accuracy.

[0010] A signal processing method according to a third aspect comprises: This is the signal processing method according to the first or second aspect, wherein the control unit corrects distortion in the target signal region.

[0011] According to the signal processing method of the third aspect, by correcting distortion in the target signal region, it is possible to obtain information about the shape of the second interface, which has a high degree of diffusion, with high accuracy.

[0012] A signal processing method according to a fourth aspect comprises: The control unit identifying a reference signal region in the optical coherence tomography signal that includes the first interface; identifying a second peak position in the reference signal region where the signal intensity is highest in a stacking direction in which the first layer group, the second layer group, and the third layer group are stacked; obtaining information about the shape of the first interface based on the second peak position; A signal processing method according to a third aspect corrects distortion of the target signal region by subtracting the shape of the first interface from the shape of the second interface.

[0013] According to the signal processing method of the fourth aspect, by correcting distortion in the target signal region, it is possible to obtain information about the shape of the second interface, which has a high degree of diffusion, with high accuracy.

[0014] A signal processing method according to a fifth aspect comprises: The signal processing method according to any one of the first to fourth aspects, wherein the control unit outputs information relating to a thickness of the third layer group.

[0015] According to the signal processing method of the fifth aspect, information relating to the thickness of the third layer group can be obtained.

[0016] A signal processing method according to a sixth aspect of the present invention comprises: A fifth aspect of the signal processing method is a signal processing method in which the control unit acquires information about the thickness of the third layer group based on predetermined correspondence information between the shape of the second interface and the thickness of the third layer group.

[0017] According to the signal processing method of the sixth aspect, information relating to the thickness of the third layer group can be obtained.

[0018] A signal processing method according to a seventh aspect comprises: This is a signal processing method according to any one of the first to sixth aspects, wherein the laminated structure including the second layer group and the third layer group has a transmittance of 20% or less for light having a wavelength of 960 nm or more and 2000 nm or less.

[0019] According to the signal processing method of the seventh aspect, in a laminated structure having low transmittance for light having a wavelength of 960 nm or more and 2000 nm or less, information about the shape of the second interface having a high degree of diffusion can be acquired with high accuracy.

[0020] The signal processing method according to an eighth aspect comprises: A seventh aspect of the present invention provides a signal processing method, wherein the laminated structure includes a layer made of at least one of resin, metal oxide, metal, carbon, glass, ceramics, and cement.

[0021] According to the signal processing method of the eighth aspect, it is possible to obtain information regarding the shape of a second interface having a high degree of diffusion in a layered structure including a layer made of at least one of metal oxide, metal, carbon, glass, ceramics, and cement with high accuracy.

[0022] A signal processing method according to a ninth aspect comprises: The signal processing method according to any one of the first to eighth aspects, wherein the third layer group includes a layer made of rust.

[0023] According to the signal processing method of the ninth aspect, information relating to the shape of the second interface, which contains rust and has a high degree of diffusion, can be acquired with high accuracy.

[0024] A signal processing method according to a tenth aspect comprises: In the signal processing method according to any one of the first to ninth aspects, the second layer group includes a layer made of paint.

[0025] According to the signal processing method of the tenth aspect, it is possible to obtain information regarding the shape of the second interface between the paint and the metal where the degree of diffusion is strong with high precision.

[0026] A signal processing method according to an eleventh aspect comprises: In the signal processing method according to any one of the first to tenth aspects, the first layer group includes a gas or liquid layer.

[0027] According to the signal processing method of the eleventh aspect, when the first layer group includes a gas or liquid layer, information on the shape of the second interface, which has a high degree of diffusion, can be acquired with high precision.

[0028] An information processing device according to a twelfth aspect comprises: An information processing device having a control unit, The control unit An optical coherence tomography signal obtained by optical coherence tomography is input, In the optical coherence tomography signal, a target signal region corresponding only to a first interface between a first layer group including one or more layers and a second layer group including one or more layers, and a second interface between the second layer group and a third layer group including one or more layers is identified; The information processing device outputs information about the shape of the second interface obtained based on the target signal region.

[0029] According to the information processing device of the twelfth aspect, by specifying a target signal region corresponding only to the second interface in the optical coherence tomographic signal, it is possible to acquire information about the shape of the second interface, which has a high degree of diffusion, with high accuracy.

[0030] An optical coherence tomography apparatus according to a thirteenth aspect of the present invention comprises: An information processing device according to a twelfth aspect, and a signal acquisition device that acquires the optical coherence tomography signal of the laminated structure by optical coherence tomography.

[0031] According to the optical coherence tomography apparatus of the thirteenth aspect, by identifying a target signal region in the optical coherence tomography signal that corresponds only to the second interface, information about the shape of the second interface, which has a high degree of diffusion, can be obtained with high accuracy.

[0032] An optical coherence tomography apparatus according to a fourteenth aspect of the present invention comprises: In a thirteenth aspect of the optical coherence tomography apparatus, the signal acquisition device emits light having a wavelength of 960 nm or more and 2000 nm or less.

[0033] According to the optical coherence tomography device of the fourteenth aspect, by using light having a wavelength of 960 nm or more and 2000 nm or less, it is possible to obtain information with high accuracy about the shape of the second interface, which has a high degree of diffusion, in a layered structure made up of layers of various materials.

[0034] An optical coherence tomography apparatus according to a fifteenth aspect thereof, In the optical coherence tomography apparatus according to the thirteenth or fourteenth aspect, the signal acquisition device emits linearly polarized, circularly polarized, or elliptically polarized light.

[0035] According to the optical coherence tomography device of the 15th aspect, by using linearly polarized, circularly polarized, or elliptically polarized light, it is possible to obtain information with high accuracy about the shape of the second interface, which has a high degree of diffusion, in a laminated structure made up of layers of various materials.

[0036] An optical coherence tomography apparatus according to a sixteenth aspect of the present invention comprises: A control unit of the information processing device includes: An optical coherence tomography signal obtained by optical coherence tomography is input, identifying a signal region of interest corresponding only to a first interface between a first layer group including one or more layers and a second layer group including one or more layers, and a second interface between the second layer group and a third layer group including one or more layers; The program executes a process of outputting information about the shape of the second interface obtained based on the target signal region.

[0037] According to the program of the sixteenth aspect, by identifying a target signal region in the optical coherence tomography signal that corresponds only to the second interface, information regarding the shape of the second interface, which has a high degree of diffusion, can be obtained with high accuracy based on the optical coherence tomography signal. [Brief explanation of the drawings]

[0038] [Figure 1] 1 is a schematic diagram of an optical coherence tomography apparatus having an information processing apparatus according to a first embodiment. [Figure 2]1 is a block diagram showing a hardware configuration of an information processing device according to a first embodiment. [Figure 3] 1 is a block diagram showing a functional configuration of an information processing device according to a first embodiment. [Figure 4] 1 is a schematic cross-sectional view of a laminated structure including a metal material, paint, and rust. [Figure 5] FIG. 10 is a schematic diagram of an optical coherence tomography signal and its intensity obtained at an interface with a high degree of diffusion. [Figure 6] FIG. 10 is a schematic diagram of an optical coherence tomography signal and its intensity obtained at an interface with a weak degree of diffusion. [Figure 7] FIG. 10 is a diagram showing an optical coherence tomography signal of a laminated structure including a first interface and a second interface. [Figure 8] FIG. 10 is a diagram showing a target signal region corresponding to only the second interface and its first peak position. [Figure 9] FIG. 10 is a diagram showing the results of acquiring information about the shape of the second interface including rust. [Figure 10] FIG. 10 is a diagram showing the results of acquiring information about the shape of the second interface that does not contain rust. [Figure 11] 4 is a flowchart showing processing by the information processing device according to the first embodiment. [Figure 12] FIG. 10 is a block diagram showing the functional configuration of an information processing device according to a second embodiment. [Figure 13] FIG. 10 is a diagram showing the shape of a first interface obtained by an information processing device according to a second embodiment. [Figure 14] FIG. 10 is a diagram showing the shape of a second interface obtained by the information processing device according to the second embodiment. [Figure 15] 15 is a diagram showing the result of correcting distortion by subtracting information about the shape of the first interface in FIG. 13 from information about the shape of the second interface in FIG. 14. FIG. [Figure 16] 10 is a flowchart showing processing by an information processing device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0039] Hereinafter, embodiments for carrying out the present disclosure will be described in detail with reference to the drawings. However, the embodiments described below exemplify a signal processing method, an information processing device, an optical coherence tomography apparatus, and a program for realizing the technical concept of the embodiments of the present disclosure, and are not limited to the following. Note that the size, positional relationship, etc. of components shown in each drawing may be exaggerated for clarity. In each drawing, the same components are assigned the same reference numerals, and duplicate explanations will be omitted as appropriate.

[0040] In the drawings, an XYZ Cartesian coordinate system may be used to represent directions. The Z direction along the Z axis corresponds to the stacking direction of each layer of the laminated structure to be imaged in an optical coherence tomography apparatus having an information processing device according to the embodiment. The Z direction also corresponds to the direction along the optical axis of the probe optical system of the optical coherence tomography apparatus. The galvanometer mirror of the optical coherence tomography apparatus scans light in the X and Y directions.

[0041] In this specification, for ease of explanation, "optical coherence tomography" will be referred to as OCT (Optical Coherence Tomography), "optical coherence tomography method" will be referred to as OCT method, and an optical coherence tomography apparatus will be referred to as an OCT apparatus.

[0042] [First embodiment] <Configuration of OCT device having information processing device according to first embodiment> FIG. 1 is a schematic diagram showing the configuration of an OCT device 100 having an information processing device 1 according to the first embodiment.

[0043] 1, the OCT device 100 includes an information processing device 1 that executes the signal processing method according to the first embodiment and a signal acquisition device 2 that acquires an optical coherence tomography signal of a laminated structure by the OCT method. The OCT device 100 also includes an operation device 3 that accepts operation inputs to the OCT device 100 and a display device 4 that displays an optical coherence tomography image generated by the information processing device 1. The signal acquisition device 2 includes a frequency scanning light source 101, a coupler 102, a circulator 103, a probe optical system 104, a galvanometer mirror driver 121, a variable optical attenuator 122, and a differential optical detection amplifier 123. The probe optical system 104 includes a collimator 105, a galvanometer mirror 106, an objective lens 107, and a reference member 108.

[0044] The OCT device 100 performs tomography of a sample, a laminated structure 110, based on interference between sample light and reference light. The sample light is light that is irradiated onto the laminated structure 110 through an objective lens 107 and a reference member 108 and is reflected or scattered at interfaces between layers in the laminated structure 110. The reference light is light that passes through the objective lens 107 and is then reflected by a reference surface 109 of the reference member 108. The reflected light includes specularly reflected light and diffusely reflected light.

[0045] In this embodiment, the laminated structure 110 is a structure including a first layer group including one or more layers, a second layer group including one or more layers, and a third layer group including one or more layers. The laminated structure 110 will be described in detail later with reference to FIG. 7. The optical coherence tomography signal is a signal obtained by Fourier transforming an interference signal including interference fringes between the sample light and the reference light. In this embodiment, the OCT device 100 performs tomography of the laminated structure 110 to obtain information about the three-dimensional shape of the second interface between the first layer group and the second layer group.

[0046] The frequency scanning light source 101 outputs light L0 used for OCT. The frequency scanning light source 101 outputs a trigger signal each time frequency scanning begins. The frequency scanning light source 101 also detects light using a Mach-Zehnder interferometer and outputs a K clock signal for sampling at equal frequency intervals. The light L0 output from the frequency scanning light source 101 is split by a coupler 102 at an intensity ratio of 95:5 into a first divided light L1 used to generate sample light and reference light, and a second divided light L2 used to remove the DC component of the interference signal. The first divided light L1 is input to a port SP1 of a circulator 103, output from a port SP2, and transmitted to a probe optical system 104 via an optical fiber.

[0047] 1, the probe optical system 104 includes a Fizeau interferometer. However, the interferometer included in the probe optical system 104 is not limited to a Fizeau interferometer as long as it allows both the sample light and the reference light to pass through the objective lens 107 in principle. The probe optical system 104 may include other types of interferometers, such as a Michelson interferometer or a Mirau interferometer.

[0048] 1, the first divided light L1 is converted into parallel light by a collimator 105, and then reflected by a galvanometer mirror 106 to enter an objective lens 107. The galvanometer mirror 106 is driven by a galvanometer mirror driver 121, and scans the parallel light converted by the collimator 105 in the X and Y directions. The galvanometer mirror 106 may be a polygon mirror, a MEMS mirror, or the like.

[0049] The parallel light incident on the objective lens 107 passes through the reference member 108, is focused on the layered structure 110 that is the subject of imaging, is reflected on the sample surface, and is incident as sample light on the objective lens 107. Furthermore, a part of the parallel light incident on the objective lens 107 is reflected on a reference surface 109 provided on the reference member 108, and is incident as reference light on the objective lens 107.

[0050] The sample light and reference light incident on the objective lens 107 pass through the galvanometer mirror 106 and collimator 105, then enter port SP2 of the circulator 103 through an optical fiber, exit port SP3, and then enter a differential light detection amplifier 123. The differential light detection amplifier 123 detects and amplifies an interference signal based on the interference between the sample light and the reference light. The second split light L2 split in the coupler 102 is attenuated by a variable optical attenuator 122 and then enters the differential light detection amplifier 123.

[0051] The differential photodetector amplifier 123 removes the DC component contained in the interference signal by using the signal of the second divided light L2. The interference signal from which the DC component has been removed and amplified by the differential photodetector amplifier 123 is collected by a DAQ device (A / D converter) provided in the information processing device 1 and converted into digital data. Collection of the interference signal is started by a trigger signal emitted by the frequency scanning light source 101 and is performed in synchronization with the K clock signal. An anti-aliasing filter that attenuates unnecessary frequency components beyond the measurable distance is provided between the differential photodetector amplifier 123 and the DAQ device.

[0052] The information processing device 1 generates an optical coherence tomography signal by Fourier transforming the interference signal converted by the DAQ device. The information processing device 1 also converts the generated optical coherence tomography signal into 8 bits, i.e., 256 gradations, and generates an optical coherence tomography image composed of multiple pixels, each having 256 gradations. The information processing device 1 transmits the generated optical coherence tomography image of the laminated structure 110 to the display device 4.

[0053] The operation device 3 is an input interface including a keyboard with multiple keys for inputting characters, numbers, various instructions, etc., and a pointing device or mouse for selecting and executing various instructions, selecting a processing target, moving a cursor, etc. The display device 4 is a display that displays various information such as optical coherence tomographic images received from the information processing device 1. The OCT device 100 may have a touch panel in which the operation device 3 and the display device 4 are integrated.

[0054] A wavelength-swept laser using a wavelength-swept filter can be used as the frequency-swept light source 101. The wavelength-swept filter can be one that sweeps the wavelength by driving a polygon mirror or a galvanometer mirror. However, a Fourier Domain Mode Locking (FDML) laser, a Micro Electro Mechanical Systems (MEMS) wavelength-swept light source, a Sampled Grating Distributed Bragg Reflector (SGDBR) laser, or the like can also be used as the frequency-swept light source 101. Furthermore, a MEMS VCSEL (Vertical Cavity Surface Emitting Laser), an external cavity MEMS Fabry-Perot laser, or the like can be used as the MEMS wavelength-swept light source.

[0055] The light L0 output from the frequency scanning light source 101 is, for example, near-infrared light. The light L0 preferably has a central wavelength of 600 nm or more and 2000 nm or less. Among these, light with a central wavelength of 1060±100 nm, 1310±100 nm, 1550±100 nm, or 1750±100 nm is more preferable in terms of light source stability and sensor reliability.

[0056] The frequency scanning light source 101 may be, for example, a high-speed wavelength sweep light source manufactured by Excelitas (center wavelength: 1310 nm, sweep width: 100 nm, A-scan rate: 50 kHz, output: 25 mW, coherence length: 12 mm).

[0057] Types of OCT that can be used in the OCT device 100 include time domain OCT (TD-OCT), Fourier domain OCT (FD-OCT), and polarization sensitive OCT (PS-OCT). Examples of FD-OCT include spectral domain OCT (SD-OCT) and swept source OCT (SS-OCT). Among these, SS-OCT is preferred because of its high sensitivity and large measurable depth. Furthermore, derivative high-resolution specifications of FD-OCT include full-field (FF-OCT) and line-field confocal (LC-OCT).

[0058] <Hardware configuration of information processing device 1> Fig. 2 is a block diagram showing the hardware configuration of the information processing device 1. As shown in Fig. 2, the information processing device 1 includes a control unit 11, a read-only memory (ROM) 12, and a random access memory (RAM) 13. The information processing device 1 also includes a hard disk drive (HDD) / solid state drive (SSD) 14, a DAQ device 15, an external I / F 16, and an operation unit 17. The control unit 11, the ROM 12, the RAM 13, the HDD / SSD 14, the DAQ device 15, the external I / F 16, and the operation unit 17 are each connected to a bus B.

[0059] The control unit 11 is a computing device that reads a program from a storage device such as the ROM 12 or HDD / SSD 14 onto the RAM 13 and executes the processing. The control unit 11 executes various processes by executing instruction codes stored in the memory using an electronic circuit, or by an electronic circuit designed for a specific purpose, thereby realizing each function of the information processing device 1. The electronic circuit is an electronic circuit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). However, the electronic circuit may also be an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). The control unit 11, ROM 12, and RAM 13 constitute a computer that controls the OCT device 100.

[0060] The ROM 12 is a non-volatile semiconductor memory that can retain programs and the like even when the power is turned off. The ROM 12 stores programs such as the BIOS (Basic Input / Output System) that is executed at startup, and information regarding various settings such as OS (Operating System) settings and network settings. The RAM 13 is a volatile semiconductor memory that temporarily stores programs, applications, data, and the like. The HDD / SSD 14 is a non-volatile memory that stores data such as optical coherence tomographic images.

[0061] The DAQ device 15 is an A / D (Analog-to-Digital) converter that collects the optical coherence tomographic signals from which the DC component has been removed and amplified by the differential photodetector amplifier 123, and converts them into digital data.

[0062] The external I / F 16 is an interface that connects the signal acquiring device 2 and the display device 4 with the information processing device 1. Via the external I / F 16, the information processing device 1 connects with devices other than the information processing device 1. The devices other than the information processing device 1 are the signal acquiring device 2, the display device 4, a PC (Personal Computer), a server, etc.

[0063] <Functional configuration of information processing device 1> The functional configuration of the information processing device 1 will be described with reference to FIGS. 3 to 10. FIG. 3 is a block diagram showing the functional configuration of the information processing device 1. FIG. 4 is a schematic cross-sectional view of a laminated structure including a metal material 41, a paint 42, and rust 43. FIG. 5 is a schematic diagram of an optical coherence tomography signal and its signal intensity obtained at an interface with a high degree of diffusion. FIG. 6 is a schematic diagram of an optical coherence tomography signal and its signal intensity obtained at an interface with a low degree of diffusion. FIG. 7 is a diagram showing an optical coherence tomography signal of a laminated structure including a first interface 114 and a second interface 115. FIG. 8 is a diagram showing a target signal region Tg corresponding only to the second interface 115 and its first peak position Ps1. FIG. 9 is a diagram showing the acquired information regarding the shape of the second interface including rust. FIG. 10 is a diagram showing the acquired information regarding the shape of the second interface not including rust.

[0064] As shown in FIG. 3, the information processing device 1 includes an input unit 20, a target signal region specifying unit 21, a first peak position specifying unit 22, a shape acquiring unit 23, and an output unit 24.

[0065] The functions of the input unit 20 and the output unit 24 are realized by the external I / F 16 or the control unit 11 executing processing defined in a program stored in the ROM 12 or the like. The functions of the target signal region identifying unit 21, the first peak position identifying unit 22, and the shape acquiring unit 23 are realized by the control unit 11 executing processing defined in a program stored in the ROM 12 or the like. Some of the above functions of the information processing device 1 may be realized by a device other than the information processing device 1, such as a server, or may be realized by distributed processing between the information processing device 1 and a device other than the information processing device 1.

[0066] For example, vehicles such as automobiles and structures such as fences and guardrails may have a laminated structure in which paint is applied to the surface of a metal material, as shown in FIG. 4. If metal oxides such as rust occur at the interface between the paint and the metal material in such a laminated structure, the paint may peel off, damaging the aesthetic appearance of the vehicle or structure, or the metal material may deteriorate, resulting in a deterioration in the strength, etc., of the vehicle or structure. The example shown in FIG. 4 is a schematic diagram showing a state in which paint 42 is applied to the surface of metal material 41, and rust 43 has occurred between the metal material 41 and the paint 42. Understanding the state of metal oxide generation at the interface between the paint and the metal material is effective from the perspective of maintaining the aesthetic appearance, strength, etc., of the vehicle or structure.

[0067] OCT devices can obtain information about the three-dimensional shape of the interface between layers in a laminated structure, so by using an OCT device, it may be possible to understand the occurrence of metal oxides such as rust at the interface between paint and metal materials.

[0068] However, for example, as shown in FIG. 5, if the interface 50 has a rough shape and the degree of diffusion of incident light onto the interface 50 is high, the light L irradiated from the signal acquisition device 2X is multiple-scattered by the interface 50. This multiple scattering causes the optical path length of the return light R to become non-uniform. When the return light R with a non-uniform optical path length is detected by the differential photodetector amplifier 123, the width W1 of the signal region corresponding to the interface 50 in the optical coherence tomography signal Sg becomes wider, and the slope near the first peak P1 of the first signal intensity distribution S1 becomes gentler. On the other hand, as shown in FIG. 6, if the interface 60 has a smooth shape and the degree of diffusion of incident light onto the interface 60 is low, the light L irradiated from the signal acquisition device 2X is almost specularly reflected by the interface 50, and the optical path length of the return light R becomes almost uniform. When the return light R having a uniform optical path length is detected by the differential optical detection amplifier 123, the width W2 of the signal region corresponding to the interface 60 in the optical coherence tomography signal Sg becomes narrower, and the slope near the second peak P2 of the second signal intensity distribution S2 becomes steeper.

[0069] 5 and 6, the width W1 of the signal region is wider than the width W2 of the signal region, and the slope of the first signal intensity distribution S1 near the first peak P1 is gentler than the slope of the second signal intensity distribution S2 near the second peak P2. Because the slope of the first signal intensity distribution S1 near the first peak P1 is gentle, the accuracy of identifying the position of the first peak P1 in the Z direction in which paint, metal material, etc. are layered decreases, which may result in a decrease in the accuracy of acquiring information about the shape of the interface obtained based on the position of the first peak P1.

[0070] 3 and 7 , the control unit 11 of the information processing device 1 receives an optical coherence tomography signal Sg obtained by the OCT method via the input unit 20. The control unit 11 uses the target signal region identifying unit 21 to identify, in the optical coherence tomography signal Sg, a target signal region Tg that corresponds only to the second interface 115, out of a first interface 114 between a first layer group 111 including one or more layers and a second layer group 112 including one or more layers, and a second interface 115 between the second layer group 112 and a third layer group 113 including one or more layers.

[0071] 3 and 8 , in the present embodiment, the control unit 11 uses the first peak position identifying unit 22 to identify a first peak position Ps1 in the target signal region Tg where the signal intensity is highest in the Z direction where the first layer group 111, the second layer group 112, and the third layer group 113 are stacked. The control unit 11 then uses the shape acquiring unit 23 to acquire information about the shape of the second interface 115 through calculation, based on the first peak position Ps1 identified by the first peak position identifying unit 22. The control unit 11 then outputs the information about the shape of the second interface 115 acquired by the shape acquiring unit 23 to a device other than the information processing device 1 through the output unit 24.

[0072] The first interface 114 is an interface located closer to the reference member 108 than the second interface 115. In other words, the first interface 114 is an interface located on the frequency scanning light source 101 side of the second interface 115. In the example shown in FIG. 7 , of the first layer group 111, the second layer group 112, and the third layer group 113 in the stacked structure 110, the first layer group 111 is located closer to the reference member 108. The second layer group 112 and the third layer group 113 are located farther from the reference member 108 in this order.

[0073] The optical coherence tomographic signal Sg is a signal having a dynamic range corresponding to a bit number greater than 8 bits. The bit number greater than 8 bits is 12 bits, 16 bits, etc. However, in the examples shown in Figures 7 and 8, for convenience of illustration, the optical coherence tomographic signal Sg is represented as an optical coherence tomographic image composed of multiple pixels, each having an 8-bit gradation value.

[0074] The input unit 20 controls communication between the information processing device 1 and the signal acquiring device 2, and thereby inputs the optical coherence tomographic signal Sg obtained by the signal acquiring device 2 from the signal acquiring device 2.

[0075] In identifying the target signal region Tg by the target signal region identifying unit 21, for example, the OCT device 100 displays an optical coherence tomographic image corresponding to the optical coherence tomographic signal Sg on the display device 4, as shown in FIG. 7 . While visually viewing the optical coherence tomographic image corresponding to the optical coherence tomographic signal Sg displayed on the display device 4, the operator of the OCT device 100 uses the operation device 3, such as a mouse, to move a cursor on the display device 4 and select an image region in the optical coherence tomographic image that does not include the first interface 114 but includes only the second interface 115. Information about the selected image region is passed from the operation device 3 to the information processing device 1. The target signal region identifying unit 21 identifies the target signal region Tg by receiving information about the selected image region from the operation device 3 via the input unit 20. However, the method for identifying the target signal region Tg by the target signal region identifying unit 21 is not limited to the above method. For example, the target signal region identifying unit 21 may automatically recognize an image region corresponding to the target signal region Tg in the optical coherence tomographic image by performing image processing on the optical coherence tomographic image corresponding to the optical coherence tomographic signal Sg, and identify the target signal region Tg. In this case, the operator does not need to perform a selection operation using the operation device 3. The reference signal region Rf in FIG. 7 will be described in the second embodiment.

[0076] In FIG. 8, the first signal intensity distribution S1 shown next to the target signal region Tg represents the signal intensity distribution along the Z direction in the target signal region Tg. The first peak position Ps1 is the position in the Z direction where the signal intensity of the second interface 115 peaks. The position of the first peak position Ps1 in the Z direction changes depending on the position in the X direction. The first peak position identifying unit 22 identifies the first peak position Ps1 for each position in the X direction. The first peak position identifying unit 22 also identifies the first peak position Ps1 for each position in the Y direction. The first peak position identifying unit 22 passes the identified first peak position Ps1 to the shape acquiring unit 23.

[0077] The shape acquiring unit 23 connects the first peak positions Ps1 received from the first peak position identifying unit 22 along the X and Y directions and converts them into height data corresponding to the shape. In this way, the shape acquiring unit 23 acquires information about the three-dimensional shape of the second interface 115 by calculation. Note that the process of connecting the first peak positions Ps1 along the X and Y directions may be performed by a unit other than the shape acquiring unit 23, such as the first peak position identifying unit 22.

[0078] The output unit 24 controls communication between the information processing device 1 and devices other than the information processing device 1, thereby outputting information relating to the three-dimensional shape of the second interface 115 to devices other than the information processing device 1.

[0079] 9 and 10 show the three-dimensional shape of second interface 115. In the example shown in Fig. 9, second interface 115 contains rust, and therefore irregularities corresponding to the rust occur on second interface 115. On the other hand, in the example shown in Fig. 10, second interface 115 contains almost no rust, and therefore almost no irregularities corresponding to the rust occur on second interface 115.

[0080] In the present embodiment, the target signal region Tg identified by the target signal region identifying unit 21 is narrower than the region corresponding to the entire optical coherence tomographic signal Sg. Therefore, the first peak position identifying unit 22 can identify the first peak position Ps1 with higher accuracy compared to when determining the first peak position Ps1 of the first signal intensity distribution S1 from information on the region corresponding to the entire optical coherence tomographic signal Sg. In the present embodiment, information on the shape of the second interface 115 is acquired based on the target signal region Tg, thereby enabling information on the shape of the second interface 115 to be acquired with high accuracy. Furthermore, in the present embodiment, identifying the target signal region Tg allows information on the shape of the first interface 114 and information on the shape of the second interface 115 to be acquired separately.

[0081] In this embodiment, the optical coherence tomography signal Sg is a signal having a dynamic range corresponding to a bit number greater than 8 bits. Therefore, the first peak position identifying unit 22 can identify the first peak position Ps1 with higher accuracy compared to when information about the shape of the second interface 115 is acquired based on an 8-bit optical coherence tomography image. As a result, in this embodiment, information about the shape of the second interface 115 can be acquired with high accuracy. Note that the identification accuracy of the first peak position Ps1 based on the optical coherence tomography signal Sg depends on the data interval in FFT (Fast Fourier Transform) calculation, and the larger the FFT size, the higher the identification accuracy.

[0082] In this embodiment, the first layer group 111 includes only an air layer. The second layer group 112 includes a layer made of paint. The third layer group 113 includes a layer made of rust. In this embodiment, even with the first layer group 111, the second layer group 112, and the third layer group 113 as described above, information about the shape of the second interface 115 can be acquired with high accuracy. However, the first layer group 111 is not limited to only an air layer and may include multiple gas layers of different types. Furthermore, the first layer group 111 may include only a liquid layer, multiple liquid layers of different types, or one or more gas layers and one or more liquid layers. The liquid included in the first layer group 111 is a liquid used to reduce reflection at the first interface 114, and has a refractive index approximately the same as that of the second layer group 112. Furthermore, the second layer group 112 may include multiple paint layers of different types.

[0083] In this embodiment, the laminated structure 110 including the second layer group 112 and the third layer group 113 has a transmittance of 20% or less for light having a wavelength of 960 nm or more and 2000 nm or less. In this embodiment, in a laminated structure having low transmittance for light having a wavelength of 960 nm or more and 2000 nm or less, information about the shape of the second interface, which has a high degree of diffusion, can be acquired with high accuracy.

[0084] In this embodiment, the layered structure 110 includes a layer made of at least one of resin, metal oxide, metal, carbon, glass, ceramics, and cement. In this embodiment, even in such a layered structure 110, information about the shape of the second interface 115 can be obtained with high accuracy.

[0085] In this embodiment, it is preferable that the signal acquiring device 2 emits light having a wavelength of 960 nm or more and 2000 nm or less. By using light having a wavelength of 960 nm or more and 2000 nm or less, it is possible to acquire information about the shape of the second interface, which has a high degree of diffusion, with high accuracy in a laminated structure made up of layers of various materials.

[0086] In this embodiment, the signal acquiring device 2 may emit linearly polarized, circularly polarized, or elliptically polarized light. By using linearly polarized, circularly polarized, or elliptically polarized light, it is possible to acquire information about the shape of the second interface, which has a high degree of diffusion, with high accuracy in a laminated structure made up of layers of various materials.

[0087] <Processing by information processing device 1> 11 is a flowchart showing processing by the information processing device 1. The information processing device 1 starts the processing shown in Fig. 11 when an optical coherence tomographic signal Sg is input via the input unit 20, which serves as a starting condition. Note that the optical coherence tomographic signal Sg input by the information processing device 1 as a starting condition refers to the optical coherence tomographic signal Sg corresponding to the entire optical coherence tomographic image shown in Fig. 7.

[0088] First, in step S11, the information processing device 1 causes the target signal region identifying unit 21 to identify, in the optical coherence tomographic signal Sg, a target signal region Tg that corresponds only to the second interface 115 out of the first interface 114 and the second interface 115. The target signal region identifying unit 21 passes information about the identified target signal region Tg to the first peak position identifying unit 22.

[0089] Next, in step S12, the information processing device 1 uses the first peak position identifying unit 22 to identify a first peak position Ps1 in the target signal region Tg where the signal intensity is highest in the Z direction. The first peak position identifying unit 22 identifies a two-dimensional distribution of the first peak positions Ps1 over the entire second interface 115 along the X and Y directions. The first peak position identifying unit 22 passes information about the identified two-dimensional distribution of the first peak positions Ps1 to the shape acquiring unit 23.

[0090] Subsequently, in step S13, the information processing device 1 causes the shape acquisition unit 23 to connect the first peak positions Ps1 along the X and Y directions and convert them into height data corresponding to the shape, thereby acquiring information about the three-dimensional shape of the second interface 115. The shape acquisition unit 23 passes the acquired information about the three-dimensional shape of the second interface 115 to the output unit 24.

[0091] Subsequently, in step S14, the information processing device 1 outputs information relating to the three-dimensional shape of the second interface 115 to a device other than the information processing device 1 via the output unit 24.

[0092] In this manner, the information processing device 1 can obtain information about the three-dimensional shape of the second interface 115 of the laminated structure 110 and output the information to a device other than the information processing device 1.

[0093] [Second embodiment] Next, an information processing device according to a second embodiment will be described. Note that the same names and symbols as those in the already described embodiments indicate the same or similar members or configurations, and detailed descriptions thereof will be omitted as appropriate.

[0094] <Functional configuration of information processing device according to second embodiment> The functional configuration of an information processing device according to the second embodiment will be described with reference to Fig. 12 to Fig. 15. Fig. 12 is a block diagram showing the functional configuration of an information processing device 1a according to the second embodiment. Fig. 13 is a diagram showing the shape of a first interface 114 obtained by the information processing device 1a. Fig. 14 is a diagram showing the shape of a second interface 115 obtained by the information processing device 1a. Fig. 15 is a diagram showing the result of correcting distortion by subtracting information about the shape of the first interface 114 in Fig. 13 from information about the shape of the second interface 115 in Fig. 14.

[0095] As shown in FIG. 12, the information processing device 1 a includes a reference signal region specifying unit 25, a second peak position specifying unit 26, a correcting unit 27, a thickness acquiring unit 28, and a storing unit 29.

[0096] The function of the storage unit 29 can be realized by the HDD / SSD 14 or the like. The functions of the reference signal region identifying unit 25, the second peak position identifying unit 26, the correcting unit 27, and the thickness acquiring unit 28 can be realized by the control unit 11 executing processing defined in a program stored in the ROM 12 or the like. Some of the above functions of the information processing device 1a may be realized by a device other than the information processing device 1a, such as a server, or may be realized by distributed processing between the information processing device 1a and a device other than the information processing device 1a.

[0097] Here, for example, in a typical OCT device, distortion of the optical coherence image signal may occur. Distortion of the optical coherence image signal refers to spatial distortion of the optical coherence image signal due to various factors. These factors include the inclination of the laminated structure relative to the objective lens when the laminated structure is installed. Other factors include deviation from a predetermined distance between the objective lens and the laminated structure in the Z direction along the optical axis of the objective lens, or aberration of the objective lens. When distortion occurs in the optical coherence image signal, shape errors occur in the acquired information about the shape of the interface due to the inclination of the laminated structure or aberration of the objective lens. This may reduce the accuracy of acquiring information about the shape of the interface.

[0098] In this embodiment, the control unit 11 of the information processing device 1a corrects distortion of the target signal region Tg using the correction unit 27. For example, the control unit 11 causes the reference signal region specifying unit 25 to specify a reference signal region Rf (see FIG. 7 ) including the first interface 114 in the optical coherence tomography signal Sg. Note that the method for specifying the reference signal region Rf by the reference signal region specifying unit 25 can be the same as the method for specifying the target signal region Tg by the target signal region specifying unit 21. The control unit 11 causes the second peak position specifying unit 26 to specify a second peak position Ps2 in the reference signal region Rf where the signal intensity is highest in the Z direction where the first layer group 111, the second layer group 112, and the third layer group 113 are stacked. The control unit 11 then causes the shape acquisition unit 23 to acquire information about the shape of the first interface 114 based on the second peak position Ps2. The control unit 11 corrects the distortion of the target signal region Tg by subtracting the shape of the first interface 114 from the shape of the second interface 115 using the correction unit 27.

[0099] Assuming that the thickness of the second layer group 112 is approximately uniform, the shape of the first interface 114 between the first layer group 111 and the second layer group 112 is considered to be approximately equal to the distortion of the target signal region Tg. The corrector 27 subtracts the shape of the first interface 114 from the shape of the second interface 115 to obtain information about the shape of the second interface 115 after correcting the distortion of the target signal region Tg. By correcting the distortion of the target signal region Tg, this embodiment can obtain information about the shape of the second interface 115 with high accuracy. Note that the thickness of the second layer group 112 corresponds to the length of the second layer group 112 in the Z direction.

[0100] FIG. 13 shows an example of the shape of the first interface 114 acquired by an OCT device having the information processing device 1a. FIG. 14 shows an example of the shape of the second interface 115 acquired by an OCT device having the information processing device 1a. In the examples shown in FIGS. 13 and 14, the laminated structure 110 is installed at an angle with respect to the objective lens, and the shapes of the first interface 114 and the second interface 115 each include an inclination error of the laminated structure 110. The correction unit 27 subtracts the shape of the first interface 114 from the shape of the second interface 115, thereby reducing the inclination error from the second interface 115. As a result, as shown in FIG. 15, highly accurate information on the shape of the second interface 115 with reduced inclination error is obtained.

[0101] 12 , control unit 11 acquires information about the thickness of third layer group 113 through calculation using thickness acquisition unit 28. For example, control unit 11 acquires information about the thickness of third layer group 113 based on predetermined correspondence relationship information 290 between the shape of second interface 115 and the thickness of third layer group 113.

[0102] Correspondence information 290 is information in which the shape of second interface 115 and the thickness of third layer group 113 are associated with each other, as shown in Table 1 below.

[0103] [Table 1]

[0104] The correspondence information 290 can be acquired by, for example, measuring the shape and thickness of rust in association with each other using the OCT device 100 or a measurement device other than the OCT device 100. The correspondence information 290 is stored in the storage unit 29. Note that if the shape and thickness of rust are measured in advance without the first layer group 111 when acquiring the correspondence information 290, acquisition of information about the shape of the second interface 115 via the first layer group 111 will be affected by the thickness and refractive index of the first layer group 111. Therefore, if the shape and thickness of rust are measured in advance without the first layer group 111, it is necessary to correct the measurement results of the shape of the rust based on the thickness and refractive index of the first layer group 111.

[0105] The thickness acquisition unit 28 acquires information regarding the thickness of the third layer group 113 by referring to the correspondence information 290 based on the information regarding the shape of the second interface 115 received from the correction unit 27, and outputs the information regarding the thickness of the third layer group 113 via the output unit 24 to a device other than the information processing device 1a.

[0106] In this embodiment, by acquiring information about the thickness of third layer group 113, it is possible to quantitatively evaluate, for example, the amount of rust generated and changes in the amount of rust generated over time. Note that the method of acquiring the thickness of third layer group 113 by thickness acquisition unit 28 is not limited to using correspondence information 290. For example, the shape of second interface 115 may be used as the thickness of third layer group 113, or the shape of second interface 115 may be multiplied by a predetermined coefficient to obtain the thickness of third layer group 113.

[0107] <Processing by Information Processing Device 1a> Fig. 16 is a flowchart showing processing by the information processing device 1a. The information processing device 1a starts the processing shown in Fig. 16 when an optical coherence tomographic signal Sg is input via the input unit 20. Note that the processing from step S21 to step S23 in Fig. 16 is the same as the processing from step S11 to step S13 shown in Fig. 11, and therefore description thereof will be omitted here.

[0108] In step S24, the information processing device 1a causes the reference signal region specifying unit 25 to specify, in the optical coherence tomographic signal Sg, a reference signal region Rf including the first interface 114. The reference signal region specifying unit 25 passes information about the specified reference signal region Rf to the second peak position specifying unit 26.

[0109] Next, in step S25, the information processing device 1a causes the second peak position identifying unit 26 to identify a second peak position Ps2 in the reference signal region Rf where the signal intensity is highest in the Z direction. The second peak position identifying unit 26 identifies a two-dimensional distribution of the second peak positions Ps2 over the entire first interface 114 along the X and Y directions. The second peak position identifying unit 26 passes information related to the identified two-dimensional distribution of the second peak positions Ps2 to the shape acquiring unit 23.

[0110] Subsequently, in step S26, the information processing device 1a causes the shape acquisition unit 23 to connect the first peak positions Ps1 along the X and Y directions and convert them into height data corresponding to the shape, thereby acquiring information about the three-dimensional shape of the second interface 115. The shape acquisition unit 23 also connects the second peak positions Ps2 along the X and Y directions and converts them into height data corresponding to the shape, thereby acquiring information about the three-dimensional shape of the first interface 114. The shape acquisition unit 23 passes the acquired information about the three-dimensional shapes of the second interface 115 and the first interface 114 to the correction unit 27.

[0111] Next, in step S27, the information processing device 1a acquires information about the shape of the second interface 115 after correcting the distortion of the target signal region Tg by subtracting the shape of the first interface 114 from the shape of the second interface 115 using the correction unit 27. The correction unit 27 passes the information about the corrected shape of the second interface 115 to the thickness acquisition unit 28 and the output unit 24.

[0112] Subsequently, in step S28, the information processing device 1a causes the thickness acquisition unit 28 to acquire information about the thickness of the third layer group 113 by referring to the correspondence information 290 based on the information about the shape of the second interface 115. The thickness acquisition unit 28 passes the information about the thickness of the third layer group 113 to the output unit 24.

[0113] Subsequently, in step S29, information processing device 1a outputs information relating to the three-dimensional shape of second interface 115 and information relating to the thickness of third layer group 113 to a device other than information processing device 1 via output unit 24.

[0114] In this way, information processing device 1a can obtain information about the three-dimensional shape of second interface 115 of stacked structure 110 and information about the thickness of third layer group 113, and output the information to a device other than information processing device 1a.

[0115] Although the preferred embodiments have been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments of the present disclosure without departing from the scope of the claims.

[0116] All numbers such as ordinal numbers and quantities used in the description of the embodiments of the present disclosure are provided as examples to specifically explain the technology of the present disclosure, and the present disclosure is not limited to the illustrated numbers. Furthermore, the connection relationships between components are provided as examples to specifically explain the technology of the present disclosure, and do not limit the connection relationships that realize the functions of the present disclosure.

[0117] The signal processing method, information processing device, optical coherence tomography device, and program disclosed herein can be suitably used in optical coherence tomography in general, regardless of the field, and particularly in the industrial field. Furthermore, the signal processing method, information processing device, optical coherence tomography device, and program disclosed herein can acquire the shape of an interface with a high degree of diffusion based on an optical coherence tomography signal, thereby accurately understanding the occurrence of metal oxides such as rust at the interface between paint and metal materials, which can lead to activities to maintain the appearance and strength of vehicles and structures. [Explanation of symbols]

[0118] 1, 1a Information processing device 2 Signal acquisition device 3 Operating device 4 Display device 11 Control section 12 ROM 13 RAM 14 HDD / SSD 15 DAQ devices 16 External I / F 20 Input section 21 Target signal area identification unit 22 First peak position identification unit 23 Shape acquisition section 24 Output section 25 Reference signal area identification section 26 Second peak position identification unit 27 Correction section 28 Thickness acquisition unit 29 Storage area 290 Correspondence Information 41 Metal materials 42 Paint 43 Rust 50, 60 interface 100 OCT equipment 101 Frequency-Scanning Light Source 102 Coupler 103 Circulator 104 Probe Optical System 105 Collimator 106 Galvanometer Mirror 107 Objective Lens 108 Reference Material 109 Reference plane 110 Laminated structure 111 First Group 112 Second Group 113 Third Group 114 1st interface 115 2nd interface 121 Galvanometer mirror driver 122 Variable Optical Attenuator 123 Differential Photodetector Amplifier B Bus L0 light L1 1st split light L2 2nd split light P1 First peak P2 Second peak Ps1 First peak position R Return light Rf reference signal area S1 1st signal strength distribution S2 2nd signal strength distribution Sg Optical coherence tomography signal SP1, SP2, SP3 ports Tg Target signal region W1, W2 width

Claims

1. A signal processing method executed by an information processing device having a control unit, The control unit An optical coherence tomography signal obtained by optical coherence tomography is input, In the optical coherence tomography signal, a target signal region corresponding only to a first interface between a first layer group including one or more layers and a second layer group including one or more layers, and a second interface between the second layer group and a third layer group including one or more layers is identified; and outputting information about the shape of the second interface obtained based on the target signal region.

2. The control unit identifying a first peak position in the target signal region where the signal intensity is highest in a stacking direction in which the first layer group, the second layer group, and the third layer group are stacked; The signal processing method according to claim 1 , further comprising: outputting information relating to the shape of the second interface based on the first peak position.

3. The signal processing method according to claim 1 , wherein the control unit corrects distortion in the target signal region.

4. The control unit identifying a reference signal region in the optical coherence tomography signal that includes the first interface; identifying a second peak position in the reference signal region where the signal intensity is highest in a stacking direction in which the first layer group, the second layer group, and the third layer group are stacked; obtaining information about the shape of the first interface based on the second peak position; 4. The signal processing method of claim 3, wherein the distortion of the target signal region is corrected by subtracting the shape of the first interface from the shape of the second interface.

5. The signal processing method according to claim 1 , wherein the control unit outputs information relating to a thickness of the third layer group.

6. 6. The signal processing method according to claim 5, wherein the control unit acquires information about the thickness of the third layer group based on predetermined correspondence information between the shape of the second interface and the thickness of the third layer group.

7. 2. The signal processing method according to claim 1, wherein a laminated structure including the second layer group and the third layer group has a transmittance of 20% or less for light having a wavelength of 960 nm or more and 2000 nm or less.

8. 8. The signal processing method according to claim 7, wherein the laminated structure includes a layer made of at least one of resin, metal oxide, metal, carbon, glass, ceramics, and cement.

9. The signal processing method of claim 1 , wherein the third group of layers includes a layer of rust.

10. The signal processing method of claim 1 , wherein the second group of layers includes a layer made of paint.

11. The signal processing method of claim 1 , wherein the first group of layers includes a layer of gas or liquid.

12. An information processing device having a control unit, The control unit An optical coherence tomography signal obtained by optical coherence tomography is input, In the optical coherence tomography signal, a target signal region corresponding only to a first interface between a first layer group including one or more layers and a second layer group including one or more layers, and a second interface between the second layer group and a third layer group including one or more layers is identified; an information processing device that outputs information about the shape of the second interface obtained based on the target signal region;

13. The information processing device according to claim 12; and a signal acquisition device that acquires the optical coherence tomography signal of the laminated structure by optical coherence tomography.

14. The optical coherence tomography apparatus according to claim 13 , wherein the signal acquisition device emits light having a wavelength of 960 nm or more and 2000 nm or less.

15. The optical coherence tomography apparatus according to claim 13 or 14, wherein the signal acquisition device emits linearly polarized light, circularly polarized light, or elliptically polarized light.

16. A control unit of the information processing device includes: An optical coherence tomography signal obtained by optical coherence tomography is input, identifying a signal region of interest corresponding only to a first interface between a first layer group including one or more layers and a second layer group including one or more layers, and a second interface between the second layer group and a third layer group including one or more layers; and a program for executing a process of outputting information about the shape of the second interface obtained based on the target signal region.

Images