Image generating device, program, and image generating method

Abstract

An image generating device according to the present invention includes: a tomographic-image acquisition unit that acquires an OCTA tomographic image in which the distribution of the blood flow of a subject is captured; an optical attenuation acquisition unit that acquires the optical attenuation of measurement light radiated on the subject in the layer direction of the tomographic image; and an image generating unit that generates an optical attenuation / blood-flow distribution image, which shows the distribution of the optical attenuation, on the basis of the acquired OCTA tomographic image and the optical attenuation.

Description

[Technical field]

[0001] The present invention relates to an image generating device, a program, and an image generating method. [Background technology]

[0002] Conventionally, there has been a technique for generating a tomographic image of a subject using an optical coherence tomography device (hereinafter, referred to as an OCT device) that scans a subject such as the fundus. There has also been a technique (OCT angiography) for extracting the blood flow of a subject using a tomographic image of the subject generated by an OCT device (see, for example, Patent Document 1). According to the conventional technique, it is possible to obtain an OCTA image, which is an image similar to an image obtained by a contrast test, without using a contrast agent, by imaging the time change of an OCT signal acquired by an OCT device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6371762 Summary of the Invention [Problem to be solved by the invention]

[0004] When the above-mentioned technology is used, the three-dimensional spatial information of the subject is examined using the OCT image showing the tissue structure and the OCTA image showing the blood flow. In other words, in order to examine the three-dimensional spatial information of the subject using the conventional technology, it was necessary to examine a plurality of tomographic images one by one. In order to investigate abnormal characteristics of a subject, there is a need to display three-dimensional spatial information of the subject in an easily surveyable manner.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a technology for generating two-dimensional images that makes it possible to easily determine whether or not a subject has an abnormality by observing a single two-dimensional image, without having to observe multiple tomographic images showing the subject's three-dimensional structure one by one. [Means for solving the problem]

[0006] An image generating device according to one aspect of the present invention includes: a tomographic image acquiring unit that acquires an OCTA tomographic image in which a blood flow distribution of a subject is imaged; an optical attenuation acquiring unit that acquires optical attenuation of measurement light irradiated on the subject in a stacking direction of the OCTA tomographic image; and an image generating unit that generates an optical attenuation-blood flow distribution map showing the distribution of the optical attenuation based on the acquired OCTA tomographic image and the optical attenuation. The optical attenuation is a value based on a position in the stacking direction, and the image generating unit generates the optical attenuation-blood flow distribution map by integrating a value based on a power of the optical attenuation in the stacking direction of the OCTA tomographic image. .

[0007] In the image generating device according to one aspect of the present invention, the light attenuation-blood flow distribution map is a two-dimensional image. 。

[0008] In the image generating device according to an aspect of the present invention, the two-dimensional image is an image colored according to the degree of the light attenuation.

[0009] Moreover, the image generating device according to one aspect of the present invention further includes an output section that outputs the generated light attenuation-blood flow distribution map.

[0010] In addition, in an image generating device according to one aspect of the present invention, the light attenuation acquisition unit includes an OCT image acquisition unit that acquires an OCT image of the subject, an OCT intensity signal calculation unit that calculates an OCT intensity signal based on the acquired OCT image, and a light attenuation calculation unit that calculates the light attenuation based on the calculated OCT intensity signal.

[0014] Furthermore, a program according to one aspect of the present invention causes a computer to execute a tomographic image acquisition step of acquiring an OCTA tomographic image in which a blood flow distribution of a subject is imaged, an optical attenuation acquisition step of acquiring optical attenuation of measurement light irradiated to the subject in a stacking direction of the OCTA tomographic image, and an image generation step of generating an optical attenuation-blood flow distribution map showing the distribution of the optical attenuation based on the acquired OCTA tomographic image and the optical attenuation. the optical attenuation is a value based on a position in the stacking direction, and the image generating step generates the optical attenuation-blood flow distribution map by integrating a value based on a power of the optical attenuation in the stacking direction of the OCTA tomographic image. .

[0015] An image generating method according to one aspect of the present invention includes a tomographic image acquiring step of acquiring an OCTA tomographic image showing a blood flow distribution in a subject, an optical attenuation acquiring step of acquiring optical attenuation of measurement light irradiated to the subject in a stacking direction of the OCTA tomographic image, and an image generating step of generating an optical attenuation-blood flow distribution map showing the distribution of the optical attenuation based on the acquired OCTA tomographic image and the optical attenuation. The optical attenuation is a value based on a position in the stacking direction, and the image generating step generates the optical attenuation-blood flow distribution map by integrating a value based on a power of the optical attenuation in the stacking direction of the OCTA tomographic image. . Effect of the Invention

[0016] According to the present invention, it is possible to easily generate an image that makes it possible to obtain information about the three-dimensional space of a subject. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating an example of a system configuration of an image generating system according to a first embodiment. [Diagram 2] 1 is a diagram illustrating an example of a functional configuration of an image generating apparatus according to a first embodiment. [Diagram 3] FIG. 2 is a diagram showing an example of a colored image output by the image generating device according to the first embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of a series of operations of the image generating apparatus according to the first embodiment. [Diagram 5] 13 is a diagram illustrating an example of a functional configuration of a light attenuation acquisition unit according to the second embodiment. FIG. [Figure 6] FIG. 13 is a diagram illustrating an example of a functional configuration of an image generating apparatus according to a third embodiment. [Figure 7]13A to 13C are diagrams illustrating an example of an image acquired by an image generating device according to a fourth embodiment, an image to be calculated, and an image to be output. [Figure 8] 1A and 1B are diagrams showing examples of an OCT image and an OCTA image according to the prior art. [Figure 9] FIG. 1 is a diagram showing an example of an image segmented in the depth direction according to the prior art. [Figure 10] FIG. 13 is a diagram showing an example of a colored image output by an image generating device according to a fourth embodiment. [Figure 11] FIG. 13 is a diagram showing a first cross section in a colored image output by an image generating device according to a fourth embodiment. [Figure 12] 13A to 13C are diagrams showing an OCT image and an OCTA image of a first cross section in a colored image output by an image generating device according to a fourth embodiment. [Figure 13] FIG. 13 is a diagram showing a second cross section in a colored image output by an image generating device according to a fourth embodiment. [Figure 14] 13A to 13C are diagrams showing an OCT image and an OCTA image of a second cross section in a colored image output by an image generating device according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] [First embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of a system configuration of an image generating system 1 according to this embodiment. With reference to the same figure, an example of the system configuration of the image generating system 1 will be described. The image generating system 1 generates an image that allows easy acquisition of three-dimensional spatial information of a subject based on an OCT image of the subject obtained by OCT (Optical Coherence Tomography). In this embodiment, an example of a subject in which the subject is an eyeball will be described as an example of the subject. This embodiment is not limited to this example, and can be used for various subjects. The image generating system 1 includes an OCT device 81 , an image generating device 10 , and a display device 86 .

[0019] The OCT device 81 irradiates a test object with measurement light and generates an OCT signal S based on the interference state between the light reflected from the test object and a reference light corresponding to the measurement light. OCT The OCT device 81 acquires the acquired OCT signal S OCT Based on the OCT image P OCT Generate an OCT image P OCT is a tomographic image showing the three-dimensional structure of a subject. The OCT device 81 receives the OCT signal S OCT Or OCT image P OCT to the image generating device 10. In this example, for example, the OCT device 81 provides the OCT image P OCT An example of the case where the above is provided to the image generating device 10 will be described.

[0020] In addition, the OCT device 81 outputs the acquired OCT signal S OCT By imaging the time-dependent changes in the OCTA That is, the OCTA image P OCTA is a tomographic image showing a three-dimensional blood flow distribution in a subject. The OCT device 81 receives the OCTA signal S OCTA or OCTA image P OCTA At least one of the OCTA signals S OCTA What is OCTA Image P OCTA In this example, for example, the OCT device 81 generates an OCTA image P OCTA An example of the case where the above is provided to the image generating device 10 will be described.

[0021] The image generating device 10 receives an OCT signal S representing the three-dimensional structure of the object from the OCT device 81. OCT Or OCT image P OCT and the OCTA signal S representing the blood flow in the subject.OCTA or OCTA image P OCTA The image generating device 10 obtains the obtained OCT signal S OCT Or OCT image P OCT and OCTA signal S OCTA or OCTA image P OCTA Based on the above, an output image P representing the three-dimensional structure and blood flow of the object is generated. OUT The output image P OUT is an image displayed so that the three-dimensional spatial information of the subject can be easily examined. For example, the output image P OUT is a two-dimensional image. Specifically, the output image P OUT The image may be a two-dimensional image that uses colors or the like to represent the distribution of blood flow and the optical attenuation at the depth of the blood flow.

[0022] The display device 86 displays the output image P output by the image generating device 10. OUT For example, the display device 86 is a liquid crystal display or the like. The image generating system 1 includes a storage device (not shown) instead of the display device 86, and stores the output image P OUT The storage device may be connected via a network (not shown). In this embodiment, the image generating device 10 outputs the output image P OUT An example of outputting the above will be described.

[0023] 2 is a diagram showing an example of a functional configuration of the image generating device 10 according to the first embodiment. With reference to the diagram, an example of the functional configuration of the image generating device 10 will be described. The image generating device 10 includes an optical attenuation acquiring section 110, an OCTA image acquiring section (tomographic image acquiring section) 120, an image generating section 130, and an output section 140.

[0024] The light attenuation acquisition unit 110 receives the OCT signal S OCTThe optical attenuation acquisition unit 110 acquires the optical attenuation A(z) of the measurement light irradiated when acquiring the OCTA tomographic image. The OCT device 81 irradiates the measurement light at least in the stacking direction of the OCTA tomographic image (depth direction of the subject). That is, the optical attenuation acquisition unit 110 acquires the optical attenuation A(z) of the measurement light irradiated to the subject in the stacking direction of the OCTA tomographic image. The optical attenuation A(z) is a value based on the position z in the stacking direction of the tomographic image (depth in the depth direction of the subject).

[0025] The OCTA image acquisition unit 120 receives an OCTA signal S obtained from the subject by the OCT device 81. OCTA or OCTA image P OCTA Obtain an OCTA image P OCTA The OCTA tomographic image is an OCTA tomographic image in which the distribution of blood flow in the subject is imaged. That is, the OCTA image acquisition unit 120 acquires an OCTA tomographic image in which the distribution of blood flow in the subject is imaged.

[0026] The image generator 130 combines the acquired optical attenuation A(z) and the OCTA signal S OCTA or OCTA image P OCTA Based on and, the output image P OUT The output image P OUT OCTA signal S OCTA or OCTA image P OCTA The output image P is a light attenuation-blood flow distribution map based on the blood flow contained in the image P and the light attenuation at that depth. OUT is, for example, a two-dimensional image. OUT is converted into a pattern image by optical attenuation according to the depth z in the stacking direction of the tomographic image based on a predetermined function. OCTA or OCTA image P OCTA Based on the OCTA tomographic image and the optical attenuation A(z), the OCTA signal S OCTA or OCTA image P OCTA A two-dimensional image is generated that is patterned based on the blood flow contained in the blood vessel and the optical attenuation at that depth. In order to make the image easier to recognize, the two-dimensional image may be colored based on the optical attenuation. Hereinafter, the two-dimensional image generated by the image generating unit 130 will be referred to as a colored image E. The colored image E is aOUT The colored image E is calculated by the following formula (1).

[0027]

number

[0028] The function T in equation (1) is an operation that converts the passed argument, for example, an operation that selects one from a color table that is a one-dimensional array of three-dimensional vectors in RGB (Red Green Blue).

[0029] When coloring, the color is selected based on the power of the optical attenuation A(z). As shown in formula (1), the colored image E may be calculated, for example, by multiplying the OCTA signal, which is a three-dimensional blood flow signal, by a color vector based on the power of the optical attenuation A(z). When a color table is used for the function T, the optical attenuation A(z) is converted into an index ([0, 1, 2, . . .]) indicating the position of an element in the array, and a specific color is selected. That is, the colored image E can be calculated by determining the color based on the optical attenuation A(z) and integrating the three-dimensional data weighted by the blood flow signal OCTA(z) in the depth z direction.

[0030] In the example shown in formula (1), an example will be described in which the color table T is a value based on the tenth power of the light attenuation A(z), but the exponent of the light attenuation A(z) is not limited to this example. The larger the exponent of the light attenuation A(z), the larger the change in the colored image E will be even if the change in the blood flow of the subject is small. Also, the smaller the exponent of the light attenuation A(z), the smaller the change in the colored image E will be even if the change in the blood flow of the subject is large. Also, the change in the blood flow signal OCTA changes the brightness of the colored image E. That is, the visibility of the colored image E is adjusted by the exponent of the light attenuation A(z). For example, the exponent of the light attenuation A(z) may be set to a predetermined value for each type of subject.

[0031] As shown in equation (1), the image generating unit 130 calculates a colored image E, which is a light attenuation-blood flow distribution map, based on a predetermined function T, light attenuation A(z), position z in the stacking direction of the OCTA tomographic image, and the OCTA signal OCTA(z).

[0032] The output unit 140 outputs the two-dimensional image (for example, the colored image E) generated by the image generation unit 130. In this embodiment, the output unit 140 outputs the colored image E to the display device 86, and causes the display device 86 to display the colored image E.

[0033] Fig. 3 is a diagram showing an example of a colored image E output by the image generating device 10 according to the first embodiment. With reference to the diagram, an example of the colored image E output by the image generating device 10 will be described. Fig. 3(A) to Fig. 3(C) are each a diagram showing the result of capturing an image of a part of an eyeball, which is a subject.

[0034] 3A is a diagram showing an example of a colored image E in this embodiment. As shown in the figure, in the colored image E, the three-dimensional structure of the subject and the blood flow can be recognized simultaneously by color. In addition, the colored image E is not a tomographic image composed of multiple two-dimensional images, but a single two-dimensional image.

[0035] FIG. 3B is an example of a projection of an OCT tomographic image in the prior art. In this figure, the two-dimensional structure of the subject is shown. In the OCT projection image in the prior art, the three-dimensional structure of the subject cannot be recognized. In addition, blood flow cannot be recognized.

[0036] FIG. 3(C) is an example of an OCTA image in the prior art. This figure shows blood flow. Since OCTA images in the prior art are generally projections in the depth direction, it is not possible to recognize the depth of blood flow within the integration range. In addition, it is not possible to recognize distributions other than blood flow in the subject.

[0037] 4 is a diagram showing an example of a series of operations of the image generating device 10 according to the first embodiment. The series of operations of the image generating device 10 will be described with reference to the diagram. (Step S100) The light attenuation acquisition unit 110 acquires the light attenuation A(z). For example, the light attenuation acquisition unit 110 acquires the light attenuation A(z) from the OCT device 81. (Step S110) The OCTA image acquisition unit 120 receives the OCTA signal S OCTA or OCTA image P OCTA For example, the OCTA image acquisition unit 120 acquires an OCTA signal S from the OCT device 81. OCTA or OCTA image P OCTA Get the. (Step S120) The image generating unit 130 calculates the obtained optical attenuation A(z) and the OCTA signal S OCTA or OCTA image P OCTA For example, the image generating unit 130 generates the colored image E based on the formula (1). (Step S130) The output unit 140 outputs the colored image E generated by the image generation unit 130. For example, the output unit 140 outputs the colored image E to the display device 86, and causes the display device 86 to display the colored image E.

[0038] [Summary of the first embodiment] According to the embodiment described above, the image generating device 10 includes the light attenuation acquisition unit 110 and the OCTA image acquisition unit 120, and thereby obtains the light attenuation A(z) and the OCTA signal S OCTA or OCTA image P OCTA The image generating device 10 includes an image generating unit 130, and thereby obtains the obtained optical attenuation A(z) and the OCTA signal S OCTA or OCTA image P OCTA The image generating device 10 converts the colored image E into an output image P OUT The colored image E is a two-dimensional image showing the three-dimensional structure and blood flow of the subject. That is, according to this embodiment, the image generating device 10 calculates the optical attenuation A(z) obtained from the OCT device 81 and the OCTA signal S OCTAor OCTA image P OCTA This makes it possible to generate a two-dimensional image showing the three-dimensional structure and blood flow of the subject.

[0039] Moreover, according to the embodiment described above, the image generating device 10 can generate a two-dimensional image showing the three-dimensional structure and blood flow of the subject, so that highly accurate image diagnosis of the subject can be easily performed. Moreover, according to the present embodiment, highly accurate image diagnosis of the subject can be easily performed, so that diagnostic accuracy can be improved. Moreover, according to the present embodiment, highly accurate image diagnosis of the subject can be easily performed, so that abnormalities present in the subject can be easily found, and overlooking abnormalities present in the subject can be suppressed.

[0040] Furthermore, according to the embodiment described above, the image generating device 10 generates a colored image E based on information acquired from the OCT device 81. That is, according to the present embodiment, the image generating device 10 can be added to the OCT device 81, so that the image generating device 10 can be easily applied to a conventionally used device. Therefore, according to the present embodiment, the image generating device 10 can be easily added to a conventional device without introducing a new device. Furthermore, according to this embodiment, the image generating device 10 can be applied as an optional component of a conventionally used device.

[0041] According to the embodiment described above, the subject is an eyeball, and the two-dimensional image output by the image generating device 10 is an image that represents the blood flow distribution in the subject's eyeball by brightness and the optical attenuation at depth in the layering direction of the tomographic images of the blood flow by color. Therefore, according to this embodiment, when diagnosing the three-dimensional structure and blood flow of the eyeball, it is possible to quickly recognize the three-dimensional structure and blood flow of the eyeball by checking one two-dimensional image, without having to check multiple stacked images in full as in the past, and it is necessary to check the tomographic image only when it is determined that it is necessary to accurately examine the details. In other words, according to this embodiment, when diagnosing the three-dimensional structure and blood flow of the eyeball, it is possible to omit the troublesome work of checking multiple tomographic images in full.

[0042] [Second embodiment] A second embodiment of the present invention will now be described with reference to the drawings. 5 is a diagram showing an example of a functional configuration of the light attenuation acquisition unit 110A according to the second embodiment. With reference to the same figure, an example of the functional configuration of the light attenuation acquisition unit 110A will be described. The light attenuation acquisition unit 110A is a modified example of the light attenuation acquisition unit 110. Configurations similar to those of the light attenuation acquisition unit 110 are given the same reference numerals, and descriptions thereof may be omitted.

[0043] The light attenuation acquisition unit 110A includes an OCT image acquisition unit 111, an OCT intensity signal calculation unit 112, and a light attenuation calculation unit 113. The light attenuation acquisition unit 110A acquires an OCT image P OCT The optical attenuation acquisition unit 110 differs from the optical attenuation acquisition unit 110 in that it calculates the optical attenuation A(z) based on

[0044] The OCT image acquisition unit 111 receives the OCT image P from the OCT device 81. OCT Obtain an OCT image. OCT That is, the OCT image acquisition unit 111 acquires an OCT image P OCT Get the.

[0045] The OCT intensity signal calculation section 112 processes the collected optical signal and calculates an OCT signal. Here, a method for calculating the OCT intensity signal I will be described. First, there is the Beer-Lambert law, a physical model for calculating the attenuation of light. The illumination intensity of light at a given depth is expressed by the following equation (2) based on the Beer-Lambert law.

[0046]

number

[0047] In formula (2), L0 represents the irradiation intensity of light on the surface of the object. μ(z) represents the attenuation coefficient at depth z. Based on formula (2), the light attenuation A(z) at depth z is expressed by the following formula (3).

[0048]

number

[0049] Generally, the OCT intensity signal I(z) at depth z is expressed by the following equation (4) as a model equation for the intensity at depth z. Here, the OCT intensity signal I(z) is generally calibrated for depth-dependent signal attenuation, noise offset, and confocal effect so that it is proportional to the detected light intensity.

[0050]

number

[0051] The OCT intensity signal calculation section 112 calculates the OCT intensity signal I based on equation (4).

[0052] The light attenuation calculation section 113 calculates the light attenuation A(z) based on the calculated OCT intensity signal I. Here, a method for calculating the light attenuation A(z) will be described. First, the optical attenuation A(z) is calculated from equations (3) and (4) and is expressed by the following equation (5).

[0053]

number

[0054] Now, by substituting A(0)=1 into equation (5), we obtain equation (6). A(0)=1 is the assumption that the light illumination intensity is constant at the minimum depth at the top of the image.

[0055]

number

[0056] Using equation (6), the optical attenuation A(z) can be expressed as equation (7) below.

[0057]

number

[0058] Equation (7) is a function for the OCT intensity signal I(z). That is, the light attenuation calculation unit 113 can calculate the light attenuation A(z) from the OCT intensity signal I(z) by applying equation (7). When calculating equation (7), the condition that the measurement light is entirely attenuated within the imaging depth range may be used. max ) = 0, and the integral over infinity can be replaced by an integral over a finite range. max indicates the maximum depth that can be imaged by OCT.

[0059] [Summary of the second embodiment] According to the embodiment described above, the light attenuation acquisition unit 110A includes the OCT image acquisition unit 111, the OCT intensity signal calculation unit 112, and the light attenuation calculation unit 113, and thereby the OCT signal S OCT Or OCT image P OCT That is, the optical attenuation acquisition unit 110A calculates the optical attenuation A(z) based on the OCT signal S acquired from the OCT device 81. OCT Or OCT image P OCT Based on this, the optical attenuation A(z) can be calculated. Therefore, according to this embodiment, the OCT signal S obtained from the OCT device 81 can be obtained without using other complicated devices. OCT Or OCT image P OCT Based on this, the optical attenuation A(z) can be easily calculated.

[0060] According to the embodiment described above, the light attenuation acquisition unit 110A obtains the formula (6) based on the assumption that A(0)=1. The light attenuation acquisition unit 110A obtains the formula (7), i.e., the light attenuation A(z), by applying the formula (6) to the formula (5). That is, the light attenuation acquisition unit 110A obtains the OCT signal S OCT Or OCT image P OCT However, at the depth z' (z' <z max ) are calculated based on the assumption that the tomographic images are captured in the stacking direction. Therefore, according to this embodiment, by performing calculations based on the assumption that A(0)=1, it is possible to calculate the light attenuation A(z) using a simple formula without using a complex formula.

[0061] [Third embodiment] Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. 6 is a diagram showing an example of a functional configuration of an image generating device 10B according to the third embodiment. Image generating device 10B differs from image generating device 10 in that it further includes an operation receiving unit 310 and in that it includes an image generating unit 130B instead of the image generating unit 130. Configurations similar to those of image generating device 10 are denoted by similar reference numerals, and descriptions thereof may be omitted.

[0062] The operation reception unit 310 receives an operation I from a user. O The user is a person who uses the image generating device 10. For example, when the image generating device 10 is used in a medical facility such as an ophthalmology clinic, the user is a doctor. OFor example, this refers to an operation of inputting data into a character input device such as a keyboard, pressing a button, rotating a dial, and the like.

[0063] The operation reception unit 310 receives an operation I from a user. O By accepting the input of the user instruction I, a value indicating the degree of coloring in the colored image E is obtained. The value indicating the degree of coloring in the colored image E is specifically the exponent of light attenuation A(z) in equation (1) used when calculating the colored image E. That is, according to this embodiment, the exponent of light attenuation A(z) used when calculating the colored image E is set in response to the user instruction I. O The degree of coloring in the colored image E is adjusted by obtaining the colored image E using the above method.

[0064] The image generating unit 130B receives an operation I from the user through the operation receiving unit 310. O as the exponent of light attenuation A(z) to generate colored image E. Specifically, image generating unit 130B generates colored image E by applying the value acquired by operation receiving unit 310 as the exponent of light attenuation A(z) in equation (1). That is, in this embodiment, the image generating unit 130B uses the light attenuation A(z) acquired by the light attenuation acquiring unit 110 and the OCTA signal S acquired by the OCTA image acquiring unit 120. OCTA or OCTA image P OCTA and an operation I from the user acquired by the operation receiving unit 310. O Based on this, a colored image E is generated. The output unit 140 outputs the colored image E generated by the image generation unit 130B to the display device 86.

[0065] In addition, when the user judges that the visibility of the colored image E is poor as a result of checking the colored image E displayed on the display device 86, the user may adjust the visibility of the colored image E again. In such a case, the operation detection unit 310 again detects the operation I from the user. O By acquiring the operation I from the new user, the image generating unit 130B OThe output unit 140 outputs the colored image E newly generated by the image generation unit 130B to the display device 86.

[0066] [Summary of the third embodiment] According to the embodiment described above, the image generating device 10B includes the image generating unit 130B, and thereby the value based on the power of the optical attenuation A(z) is converted into the OCT image P OCT A colored image E is generated by integrating the light attenuation A(z) in the layering direction of the tomographic images. In the calculation of the colored image E, the strength of blood flow can be expressed by varying the exponent of the light attenuation A(z). Therefore, according to this embodiment, the strength of blood flow can be easily expressed.

[0067] According to the embodiment described above, the image generating device 10B further includes an operation receiving unit 310, so that the image generating device 10B can receive an operation I from a user. O The image generating unit 130B acquires the operation I from the user. O and further generates a colored image E based on the result. Therefore, according to this embodiment, even if the user has difficulty recognizing the structure or blood flow of the subject from the colored image E output by image generating device 10B, the user can adjust the degree of colored image E. That is, according to this embodiment, image generating device 10B can provide the user with a colored image E with good visibility. According to this embodiment, image generating device 10B allows the user to adjust the visibility of colored image E.

[0068] Furthermore, when the image generating device 10 is applied to various subjects, the optimal exponent of the optical attenuation A(z) may differ depending on the application. According to the present embodiment, by providing the operation receiving unit 310, it is possible to output a suitable colored image E corresponding to various applications.

[0069] [Fourth embodiment] The above-mentioned first to third embodiments will be described in more detail as a fourth embodiment.

[0070] First, the image generating device 10 according to this embodiment receives an OCT signal S OCT Or OCT image P OCT The purpose of the present invention is to generate and output a two-dimensional image that can easily find out areas requiring attention that may be a cause of disease based on the above. The two-dimensional image output by the image generating device 10 allows tissue abnormalities (changes in optical attenuation) and vascular networks (distribution of blood flow signals) to be distinguished simultaneously.

[0071] Here, when the subject is an eyeball, in addition to subject abnormalities in the vascular network, subject abnormalities such as morphological changes in the retina (thickening, edema, etc.) and reduced scattering intensity are known to occur. In particular, the pigment epithelium plays an important role in retinal metabolism and is a tissue that scatters light very strongly. Therefore, abnormalities in the pigment epithelium cause reduced scattering intensity, etc. Therefore, there is a demand for easily detecting abnormalities in the pigment epithelium.

[0072] Conventionally, doctors identify the three-dimensional location of a disease by observing multiple cross-sectional images that show the three-dimensional structure of the subject one by one. However, the task of checking multiple images one by one is time-consuming and laborious. A doctor can check a single two-dimensional image output by the image generating device 10 to perform screening to determine the presence or absence of a disease.

[0073] 7 is a diagram showing an example of an image acquired, an image calculated, and an image output by the image generating device according to the fourth embodiment. The process of the image generating device 10 according to the fourth embodiment will be described with reference to the images shown in the diagram.

[0074] FIG. 7A shows an OCT signal S acquired by an OCT device 81. OCT The OCT image P OCT FIG. 7B shows an example of an OCTA image P acquired by the OCTA image acquisition unit 120. OCTAFIG. 7C shows an example of the OCT signal S OCT FIG. 7D shows an example of the optical attenuation A(z) calculated based on the above-mentioned equation (7). OCTA 7(E) shows an image colored by image generation device 10 by determining the lightness (i.e., weighting) based on , and determining the color based on the light attenuation A(z). Figure 7(E) shows an image generated by image generation device 10 by integrating the colored image in the z direction.

[0075] By performing the above-mentioned processing, the image generating device 10 can represent the accumulated light attenuation by color. Furthermore, the image generating device 10 can represent the blood flow signal by brightness. Therefore, the image generating device 10 can easily determine the decrease in light attenuation of the pigment epithelium. Furthermore, the image generating device 10 can easily determine the neovascularization above the pigment epithelium. Furthermore, the image generating device 10 can easily determine the generation of high light attenuating tissue in the retina.

[0076] According to this embodiment, the image generating device 10 expresses the relative depth of high light attenuation tissues based on the cumulative attenuation of light, not on the polarization uniformity of light. Here, the change in polarization uniformity is specific to melanin pigments and fibrotic tissues. However, light attenuation occurs in various tissues. Therefore, according to this embodiment, the image generating device 10 has low tissue specificity because it is based on the cumulative attenuation of light, not on the polarization uniformity of light. Furthermore, according to this embodiment, the image generating device 10 can generate a two-dimensional image based on information acquired by a commercially available OCTA device.

[0077] [Effects of the embodiment] The effects of the embodiment will be described with reference to Fig. 8 to Fig. 14. An example of an image according to the conventional technology and problems with the conventional technology will be described with reference to Fig. 8 and Fig. 9, and an example of an image according to the present embodiment and the effects of the present embodiment will be described with reference to Fig. 10 to Fig. 14.

[0078] FIG. 8 is a diagram showing an example of an OCT image and an OCTA image according to the conventional technology. FIG. 8(A) shows an example of an OCT image of an eyeball, and FIG. 8(B) shows an example of an OCTA image of an eyeball. As shown in the figure, according to the conventional technology, it is difficult to identify the location of a disease from a single two-dimensional image. Furthermore, according to the conventional technology, it is possible to identify the location of a disease by checking multiple tomographic images one by one, but there is a problem that it takes a lot of time and effort.

[0079] Fig. 9 shows an example of an image obtained by depth segmentation using conventional technology. Fig. 9(A) is an OCTA image of only the retina of the fundus (Retinal OCTA), and Fig. 9(B) is an OCTA image of only the choroid (Choroidal OCTA). In this way, it is possible to identify tissues in which abnormalities exist by simply segmenting OCTA images in the depth direction. Also, by referring to Choroidal OCTA, i.e., Figure 9(B), it is possible to estimate that there is abnormal blood flow in a location deeper than the location segmented as the pigment epithelium. However, it is not possible to identify the state of the pigment epithelium (optical attenuation). Furthermore, a problem with simply segmenting OCTA images in the depth direction is the need for accurate tissue segmentation. In the case of abnormal tissue, the structure of the tissue collapses, making the tissue boundaries unclear or even disappearing. Therefore, simply segmenting OCTA images in the depth direction causes the meaning of the segmentation results to be unclear, and the reader must use their imagination to interpret the images.

[0080] FIG. 10 is a diagram showing an example of a colored image output by the image generating device according to the fourth embodiment. With reference to the figure, an example of a colored image output by the image generating device 10 will be described. FIG. 10(A) shows a colored image output by the image generating device 10. In the figure, the image is colored with a color corresponding to the depth. From the figure, it can be recognized that a disease exists in the area surrounded by a circle. FIG. 10(B), FIG. 10(C), and FIG. 10(D) are images in which red (R), green (G), and blue (B) components are extracted from the colored image of FIG. 10(A), respectively, to improve visibility.

[0081] Next, a cross section of a portion where a disease is believed to exist will be described with reference to Figs. Fig. 11 is a diagram showing a first cross section in a colored image output by an image generating device according to the fourth embodiment. Fig. 11(A) to Fig. 11(D) correspond to Fig. 10(A) to Fig. 10(D), respectively. The a-a' cross section shown in the figure is a cross section of a location identified as having a disease by the colored image output by the image generating device 10. The a-a' cross section shown in Fig. 11(A) to Fig. 11(D) is shown in Fig. 12.

[0082] FIG. 12 shows an OCT image and an OCTA image in the first cross section in the color image output by the image generating device according to the fourth embodiment. FIG. 12(A) shows an OCT image of the a-a' cross section shown in FIG. 11(A) to FIG. 11(D), and FIG. 12(B) shows an OCTA image. From FIG. 12(A) and FIG. 12(B), it can be seen that the abnormal blood flow signal is located above the choroid and below the pigment epithelium. Also, from FIG. 12(A), it can be seen that the optical attenuation of the pigment epithelium on the abnormal blood flow signal is reduced, resulting in a high signal of the choroid (see the ellipse in the figure). Therefore, it is considered that an abnormal finding occurs in the area identified as having a disease by the image generating device 10.

[0083] FIG. 13 is a diagram showing a second cross section in a colored image output by an image generating device according to a fourth embodiment. With reference to the figure, a b-b' cross section different from the a-a' cross section will be described. FIGS. 13(A) to 13(D) correspond to FIGS. 10(A) to 10(D), respectively. The b-b' cross section shown in the figure is a cross section of a location identified as having a disease by the colored image output by the image generating device 10. The b-b' cross section shown in FIGS. 13(A) to 13(D) is shown in FIG. 14.

[0084] Fig. 14 shows an OCT image and an OCTA image of the second cross section in the color image output by the image generating device according to the fourth embodiment. Fig. 14(A) shows an OCT image of the b-b' cross section shown in Fig. 13(A) to Fig. 13(D), and Fig. 14(B) shows an OCTA image. Fig. 14(A) shows that the optical attenuation of the pigment epithelium has decreased and the depth of invasion into the choroid has increased. Therefore, it is considered that abnormal findings have occurred in the area identified by the image generating device 10 as having a disease.

[0085] According to the above-described embodiment, the location of a disease can be identified using a single color image generated by the image generating device 10. Therefore, a doctor can easily identify the approximate location of a disease without having to screen multiple tomographic images showing the three-dimensional structure of the subject one by one. Therefore, the image generating device 10 generates an image that allows easy acquisition of three-dimensional spatial information of the subject.

[0086] All or part of the functions of the image generating device 10 described above may be recorded as a program in a computer-readable recording medium, and the program may be executed by a computer system. The computer system includes hardware such as an OS and peripheral devices. Examples of computer-readable recording media include portable media such as flexible disks, optical magnetic disks, ROMs (Read Only Memory), and CD-ROMs, storage devices such as hard disks built into computer systems, and volatile memory (Random Access Memory: RAM) provided in servers on networks such as the Internet. Volatile memory is an example of a recording medium that holds a program for a certain period of time.

[0087] Furthermore, the above-mentioned program may be transmitted to another computer system via a transmission medium, for example, a network such as the Internet, or a communication line such as a telephone line.

[0088] The program may be a program that realizes all or part of the above-mentioned functions. Note that the program that realizes part of the above-mentioned functions may be a so-called differential program, which is a program that can realize the above-mentioned functions in combination with a program pre-recorded in the computer system.

[0089] The above describes an embodiment of the present invention with reference to the drawings. However, the specific configuration is not limited to the above-described embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0090] 1...image generating system, 10...image generating device, 81...OCT device, 86...display device, 110...light attenuation acquisition, 120...OCTA image acquiring section, 130...image generating section, 140...output section, 111...OCT image acquiring section, 112...OCT intensity signal calculating section, 113...light attenuation calculating section, 310...operation accepting section, A(z)...light attenuation, P OCT …OCT image, P OCTA …OCTA image, SOCT …OCT signal, S OCTA …OCTA signal, E…color image, T…color table, I…OCT intensity signal

Claims

1. a tomographic image acquisition unit that acquires an OCTA tomographic image in which a blood flow distribution in a subject is imaged; an optical attenuation acquisition unit that acquires optical attenuation of measurement light irradiated onto the subject in a stacking direction of the OCTA tomographic image; an image generating unit that generates an optical attenuation-blood flow distribution map showing a distribution of the optical attenuation based on the acquired OCTA tomographic image and the optical attenuation; Equipped with the optical attenuation is a value based on a position in the stacking direction; The image generating unit generates the optical attenuation-blood flow distribution map by integrating the value based on the power of the optical attenuation in a stacking direction of the OCTA tomographic image. Image generating device.

2. The optical attenuation-blood flow distribution map is a two-dimensional image.

2. The image generating device of claim 1.

3. The two-dimensional image is an image colored according to the degree of light attenuation.

3. The image generating device of claim 2.

4. and an output unit for outputting the generated light attenuation-blood flow distribution map. The image generating device according to any one of claims 1 to 3.

5. The light attenuation acquisition unit an OCT image acquisition unit that acquires an OCT image of the subject; an OCT intensity signal calculation unit that calculates an OCT intensity signal based on the acquired OCT image; an optical attenuation calculation unit that calculates the optical attenuation based on the calculated OCT intensity signal; The image generating device according to claim 1 , further comprising:

6. On the computer, a tomographic image acquisition step of acquiring an OCTA tomographic image showing the distribution of blood flow in the subject; an optical attenuation acquiring step of acquiring an optical attenuation of a measurement light irradiated on the object in a stacking direction of the OCTA tomographic image; an image generating step of generating an optical attenuation-blood flow distribution map showing a distribution of the optical attenuation based on the acquired OCTA tomographic image and the optical attenuation; A program for executing the optical attenuation is a value based on a position in the stacking direction; The image generating step generates the optical attenuation-blood flow distribution map by integrating the value based on the power of the optical attenuation in the stacking direction of the OCTA tomographic image. program.

7. a tomographic image acquisition step of acquiring an OCTA tomographic image showing the distribution of blood flow in the subject; an optical attenuation acquiring step of acquiring optical attenuation of a measurement light irradiated on the subject in a stacking direction of the OCTA tomographic image; an image generating step of generating an optical attenuation-blood flow distribution map showing a distribution of the optical attenuation based on the acquired OCTA tomographic image and the optical attenuation; having the optical attenuation is a value based on a position in the stacking direction; The image generating step generates the optical attenuation-blood flow distribution map by integrating the value based on the power of the optical attenuation in the stacking direction of the OCTA tomographic image. Image generation method.

Images