Image processing method, image processing program, image processing apparatus, image display apparatus, and image display method

Abstract

Non-perfusion area is estimated. An emphasis image processing unit performs emphasis image processing for emphasizing a blood vessel portion on a fundus image of an eye to be examined (304). An estimation processing unit estimates a non-perfusion area on the basis of the fundus image on which the emphasis image processing has been performed (306 to 312). A creation unit creates a non-perfusion area candidate image (314).

Description

[0001] This invention application is a divisional application of the invention application filed on December 28, 2017, with international application number PCT / JP2017 / 047379, national application number 201780098008.8 which entered the Chinese national phase, and entitled "Image processing method, image processing program, image processing apparatus, image display apparatus, and image display method". Technical Field

[0002] This invention relates to image processing methods, image processing programs, image processing apparatus, image display apparatus, and image display methods. Background Technology

[0003] Patent document 1 discloses a method for detecting retinal vascular occlusion in subjects.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 5535905 Summary of the Invention

[0007] The first aspect of the image processing method of the present disclosure includes estimating a non-perfusion area based on a fundus image of the examined eye.

[0008] The image processing method of the second aspect of the present disclosure includes: performing a first image processing on a fundus image of the examined eye to select a first non-perfusion zone candidate; performing a second image processing on the fundus image to select a second non-perfusion zone candidate; and selecting a candidate that is both the first non-perfusion zone candidate and the second non-perfusion zone candidate as a presumed non-perfusion zone.

[0009] The third-mode image processing program of the present disclosure enables a computer to perform the first-mode or second-mode image processing method.

[0010] The image processing apparatus of the fourth aspect of the present disclosure includes: a storage device storing an image processing program for causing a processor to execute an image processing method; and a processing device executing the image processing method by executing the image processing program stored in the storage device, wherein the image processing method is an image processing method of the first aspect or the second aspect.

[0011] The fifth aspect of the image display device disclosed herein includes a display unit that displays a non-infusion area estimated by the image processing method of the first or second aspect.

[0012] The sixth aspect of the image display method of this disclosure includes: receiving fundus image data of a fundus image of an eye under examination and non-perfusion area candidate image data of a non-perfusion area candidate image obtained by image processing of the fundus image; generating a screen that displays the fundus image in a fundus image display area based on the fundus image data and displays the non-perfusion area candidate image in a non-perfusion area candidate image display area based on the non-perfusion area candidate image data.

[0013] The image display apparatus of the seventh aspect of the present disclosure includes a display unit that displays a fundus image of the examined eye and a candidate image of a non-perfusion area obtained by image processing of the fundus image on the same screen. Attached Figure Description

[0014] Figure 1 This is a block diagram of the ophthalmology system 100.

[0015] Figure 2 This is a schematic diagram illustrating an example of the overall configuration of the ophthalmic device 110.

[0016] Figure 3 This is a conceptual diagram illustrating an example of the general configuration of the wide-angle optical system 19 included in the ophthalmic device 110.

[0017] Figure 4 This is a block diagram of the electrical system configuration of the image viewer 150 and the management server 140.

[0018] Figure 5 This is a block diagram of the functions of managing server 140.

[0019] Figure 6 This is a flowchart of the image processing program executed by CPU 162 of management server 140.

[0020] Figure 7 It is a diagram representing a fundus image (SLO image (UWFSLO fundus image)).

[0021] Figure 8 This is a diagram of the fundus that emphasizes the capillaries.

[0022] Figure 9 This is a simplified representation of the processing result of step 306, and is a schematic diagram showing a magnified portion of the UWFSLO image.

[0023] Figure 10 It means from Figure 9 The figure shows the case where candidate 412 is excluded from the six primary candidates 402, 404, 406, 408, 410, and 412.

[0024] Figure 11 It means from Figure 9 The diagram shows the situation where candidates 402 and 404 are excluded from the six primary candidates 402, 404, 406, 408, 410, and 412.

[0025] Figure 12 This diagram represents the case of candidate 450B reduced to 400E1, 400E2, and 400E3 along the ends of the blood vessels.

[0026] Figure 13 It means from Figure 9 The diagram shows the situation where candidates 402, 404, and 412 are excluded from the six primary candidates 402, 404, 406, 408, 410, and 412.

[0027] Figure 14 This is a diagram representing the presumed non-perfusion regions of 406 NPA, 408 NPA, and 410 NPA.

[0028] Figure 15 This diagram shows the case where colored borders are marked around the presumed non-inflation zones 406 NPA, 408 NPA, and 410 NPA.

[0029] Figure 16 This diagram shows the case where the presumed non-injected areas 406NPA, 408NPA, and 410NPA are painted with a lighter color.

[0030] Figure 17 This diagram shows the situation where the presumed unfilled areas 406NPA, 408NPA, and 410NPA are painted with the same or different colors as the actual colors.

[0031] Figure 18 It is a picture representing the screen 500 of the display 156 of the image viewer 150.

[0032] Figure 19 This is a screenshot of screen 500 when the NPA process observation button 524 is clicked. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, for ease of explanation, the scanning laser ophthalmoscope will be referred to as "SLO" in the following text. Additionally, for ease of explanation, the optical coherence tomography scanner will be referred to as "OCT" in the following text.

[0034] Reference Figure 1 The composition of the ophthalmic system 100 will be explained. As an example, such as... Figure 1As shown, the ophthalmic system 100 includes: an ophthalmic device 110; a visual field analyzer 120; a laser coagulation device 130; a management server device (hereinafter referred to as the "management server") 140; and an image display device (hereinafter referred to as the "image viewer") 150.

[0035] Ophthalmic device 110 acquires fundus images and tomographic images. Visual field analyzer 120 detects the patient's visual field. Laser coagulation device 130 coagulates the lesions in the patient's fundus using a laser to inhibit disease progression. Management server 140 stores multiple fundus images acquired by ophthalmic device 110 from multiple patients, corresponding to the subject's ID, and estimates non-perfusion areas (NPA) based on specified fundus images. Image viewer 150 displays candidate NPA images estimated by management server 140.

[0036] Here, the non-perfusion area (NPA) is the area in the fundus where blood does not flow or flows almost no due to blockage of the retinal capillary bed, etc. It is also the avascular area (AVA) in the fundus where there are no blood vessels or large blood vessels.

[0037] The ophthalmic device 110, visual field analyzer 120, laser coagulation device 130, management server 140, and image viewer 150 are interconnected via network 160.

[0038] The management server 140 is an example of the "image processing apparatus" of the present disclosure. The image viewer 150 is an example of the "image display apparatus" of the present disclosure.

[0039] Next, refer to Figure 2 The structure of the ophthalmic device 110 will be described. For example... Figure 2 As shown, the ophthalmic device 110 includes an imaging device 14 and a control device 16. The imaging device 14 images the fundus of the examined eye. The control device 16 is implemented by a computer including a CPU (Central Processing Unit) 16A, RAM (Random Access Memory) 16B, ROM (Read-Only Memory) 16C, and input / output (I / O) ports 16D.

[0040] Input / output (I / O) port 16D is connected to storage device 17. Storage device 17 is, for example, non-volatile memory (NVM) or hard disk. Furthermore, input / output (I / O) port 16D is connected to network 160 via communication interface (I / F) 15.

[0041] Furthermore, the control device 16 includes an input / display device 16E connected to the CPU 16A via an I / O port 16D. The input / display device 16E has a graphical user interface that displays captured images and handles various instructions, including shooting instructions. Examples of graphical user interfaces include touch panels or displays. Additionally, for clarity, "shooting" in the following text refers to a user acquiring an image representing a subject using the ophthalmic device 110.

[0042] The imaging device 14 operates under the control of the control device 16. The imaging device 14 includes an SLO unit 18, a wide-angle optical system 19, and an OCT unit 20.

[0043] Furthermore, in the following description, the horizontal direction when the ophthalmic device 110 is set along a horizontal plane is referred to as the "X direction", the direction perpendicular to the horizontal plane is referred to as the "Y direction", and the direction connecting the center 27 of the pupil of the anterior part of the examined eye 12 and the center O of the eyeball is referred to as the "Z direction". Therefore, the X direction, Y direction and Z direction are perpendicular to each other.

[0044] As an example of the main functions that can be achieved by the ophthalmic device 110, the ophthalmic device 110 of this embodiment has two functions: a first function and a second function. The first function is to operate the ophthalmic device 110 as a scanning laser ophthalmoscope (hereinafter referred to as "SLO") and perform SLO-based imaging (hereinafter referred to as the SLO imaging system function). The second function is to operate the ophthalmic device 110 as an optical coherence tomography (hereinafter referred to as "OCT") and perform OCT-based imaging (hereinafter referred to as the OCT imaging system function). Furthermore, for ease of explanation, the function of performing SLO-based imaging will be referred to as the "SLO imaging system function" in the following text. Similarly, for ease of explanation, the function of performing OCT-based imaging will be referred to as the "OCT imaging system function" in the following text.

[0045] The SLO imaging system function is realized by the control device 16, the SLO unit 18, and the wide-angle optical system 19 in the ophthalmic device 110. The SLO unit 18 is configured to include a light source 18A, a detection element 18B, and a dichroic mirror 18C, etc., to image the fundus of the examined eye 12. In other words, the ophthalmic device 110 enables the SLO imaging system function to perform, thereby image the fundus of the examined eye 12 (e.g., the imageable area 12A) as the subject. Specifically, light from the SLO unit 18 (hereinafter referred to as "SLO light") passes through the pupil of the examined eye 12 using the wide-angle optical system 19, scans the imageable area 12A in the X direction (horizontal direction) using the first optical scanner 22, scans in the Y direction (vertical direction) using the third optical scanner 29, and acquires the fundus image (SLO image (UWFSLO fundus image described below) formed by the reflected light through the SLO unit 18. In addition, the SLO imaging system function is a well-known function, so detailed description is omitted. Furthermore, if converted to the internal illumination angle from the center O of the eyeball, the area that can be photographed 12A is within a range of approximately 200 degrees.

[0046] The OCT imaging system functions via a control unit 16, an OCT unit 20, and a wide-angle optical system 19. The OCT unit 20 includes a light source 20A, a sensor (beam splitter) 20B, a fiber optic coupler 20C, and a reference optical system 21E including a polarization adjuster 21D, to image multiple tomographic regions in the membrane thickness direction of the fundus. In other words, the ophthalmic device 110 operates as an OCT imaging system, imaging regions in the membrane thickness direction of the fundus (e.g., the imageable area 12A), i.e., tomographic regions. Specifically, the light from the light source 20A of the OCT unit 20 (hereinafter referred to as the signal light (LS)) branches at the fiber optic coupler 20C. One branch of the signal light passes through the pupil of the examined eye 12 using the wide-angle optical system 19, and is scanned in the X direction (horizontal direction) by a second optical scanner 24 and in the Y direction (vertical direction) by a third optical scanner 29. The signal light from one of the components is reflected by the fault region, and the reflected light travels along the path from the fiber optic coupler 20C to the sensor 20B.

[0047] Here, the optical path length of the signal light (LS) is determined by the distance from the light source 20A to the fault region and the distance from the fault region to the sensor 20B.

[0048] In addition, the reflected light from the fault region that is incident on the sensor 20B is specifically referred to as the return light.

[0049] Furthermore, the signal light branching off at the fiber coupler 20C travels along the path incident on the sensor 20B after its optical path length is adjusted by the polarization adjuster 21D.

[0050] In addition, the signal light of the other party, namely the signal light traveling through the light source 20A, fiber optic coupler 20C, polarization adjuster 21D, and sensor 20B, is called the reference light (LR).

[0051] The returned light and the reference light interfere to form interference light, which is then incident on sensor 20B. Sensor 20B detects the various spectral components of the interference light. Control device 16 uses the detection results obtained from sensor 20B to acquire a tomographic image (hereinafter referred to as "OCT image") representing the tomographic region.

[0052] The acquired SLO and / or OCT images are sent to the management server 140 along with the patient ID via communication interface (I / F) 15 and network 160.

[0053] Next, refer to Figure 3 The configuration of the wide-angle optical system 19 included in the ophthalmic device 110 will be described. For example... Figure 3 As shown, the common optical system 28 includes a slit mirror 30 and an elliptical mirror 32 in addition to the third optical scanner 29. Furthermore, the dichroic mirror 26, slit mirror 30, and elliptical mirror 32 are shown in a side end view. Alternatively, multiple lens groups can be used to construct the common optical system 28 instead of the slit mirror 30 and elliptical mirror 32.

[0054] The slit mirror 30 has an elliptical first reflecting surface 30A. The first reflecting surface 30A has a first focal point P1 and a second focal point P2. The elliptical mirror 32 also has an elliptical second reflecting surface 32A. The second reflecting surface 32A has a first focal point P3 and a second focal point P4.

[0055] The slit scope 30, elliptical mirror 32, and third optical scanner 29 are configured such that the first focal point P3 and the second focal point P2 are located at the same position on the third optical scanner 29. Furthermore, the slit scope 30, elliptical mirror 32, and third optical scanner 29 are configured such that the second focal point P4 is located at the center of the pupil of the examined eye 12. Further, the first optical scanner 22, second optical scanner 24, and slit scope 30 are configured such that the first focal point P1 is located on both the first optical scanner 22 and the second optical scanner 24.

[0056] In other words, the first optical scanner 22, the second optical scanner 24, and the third optical scanner 29 are positioned conjugate to the center of the pupil of the eye being examined 12.

[0057] In addition, the wide-angle optical system 19 can be used not only with a wide-angle optical system that utilizes an elliptical lens, but also with an optical system that utilizes a wide-angle lens or a wide-angle optical system composed of a combination of multiple lenses.

[0058] In this embodiment, it is possible to utilize Figure 3 The wide-angle optical system 19 shown sets the field of view (FOV) of the fundus to an angle capable of observing a large area of ​​the fundus from its center to its periphery. The size of this large area of ​​the fundus is defined by the internal illumination angle and the external illumination angle.

[0059] The external illumination angle is the light illumination angle from the side of the ophthalmic device 110, that is, from the outside of the eye being examined 12. In other words, for the fundus of the eye being examined 12, the scanning light is directed towards the center 27 of the pupil of the eye being examined 12 (i.e., the central point of direct vision of the pupil, also referred to as...). Figure 2 The angle of the external illumination is equal to the angle of light reflected from the fundus and emitted from the center 27 of the pupil toward the outside of the examined eye 12 and toward the ophthalmic device 110.

[0060] On the other hand, the internal illumination angle refers to the light illumination angle that can be actually captured when the center O of the eyeball of the examined eye 12 is used as a reference position and the fundus of the examined eye 12 is illuminated by scanning light. The external illumination angle A and the internal illumination angle B are corresponding, but in the following description, since it is an ophthalmic device, the external illumination angle is used as the illumination angle corresponding to the field of view of the fundus.

[0061] The ophthalmic device 110 can capture images of the fundus region of the examined eye 12, specifically region 12A (also refer to...). Figure 2 Within the area 12A, the cameraable area is the maximum area that the scanning light of the wide-angle optical system 19 can scan, with an external illumination angle A of approximately 160 degrees (and an internal illumination angle of approximately 200 degrees). The SLO image obtained by capturing the cameraable area 12A is called an UWFSLO image. Additionally, UWF stands for Ultra-Widefield.

[0062] Next, refer to Figure 4 The electrical system configuration of the image viewer 150 will be described. For example... Figure 4As shown, the image viewer 150 includes a computer body 152. The computer body 152 has a CPU 162, RAM 166, ROM 164, and input / output (I / O) ports 168. The I / O ports 168 are connected to a storage device 154, a display 156, a mouse 155M, a keyboard 155K, and a communication interface (I / F) 158. The storage device 154 is, for example, composed of non-volatile memory. The I / O ports 168 are connected to a network 160 via the communication interface (I / F) 158. Therefore, the image viewer 150 can communicate with the ophthalmic device 110 and the management server 140.

[0063] The display 156 of the image viewer 150 is an example of the "display unit" of the technology disclosed herein.

[0064] The electrical system of the management server 140 is configured in the same way as that of the image viewer 150, including a computer body 152, a storage device 154, a display 156, a mouse 155M, and a keyboard 155K. The computer body 152 has a CPU 162, RAM 166, ROM 164, and an input / output (I / O) port 168. The storage device 154 is connected to the input / output (I / O) port 168.

[0065] The CPU 162 of the management server 140 is an example of the "image processing apparatus" of the present disclosure.

[0066] The storage device 154 of the management server 140 stores the subject's fundus image data and / or image processing program 154P.

[0067] Here, the case where the image processing program 154P is stored in the storage device 154 has been described, but the technology disclosed herein is not limited thereto, and the image processing program 154P may also be stored in the ROM 164.

[0068] Image processing program 154P is an example of an image processing program based on the technology of this disclosure.

[0069] As part of the electrical system configuration of the management server 140, elements corresponding to the monitor 156, mouse 155M, and keyboard 155K in the image viewer 150 may be omitted.

[0070] Next, refer to Figure 5 The various functions implemented by the CPU 162 of the management server 140 executing the image processing program 154P are described. The image processing program 154P includes acceptance, acquisition, emphasis image processing, estimation processing, creation, and transmission functions. The CPU 162 executes the image processing program 154P, which has each of these functions, thereby enabling functions such as... Figure 5 As shown, the CPU 162 functions as the receiving unit 200, the acquiring unit 202, the image processing unit 204, the estimation processing unit 206, the creation unit 208, and the sending unit 210.

[0071] Alternatively, an image processing chip (IC, circuit, or other hardware configuration) can be used that integrates the image processing unit 204, the estimation processing unit 206, and the creation unit 208 into a single unit.

[0072] Next, for Figure 1 The overall operation of the ophthalmic system 100 shown will be explained.

[0073] First, in order to examine the patient's eye 12 (also refer to...) Figure 2 In the diagnosis of [a specific condition], the ophthalmology system 100 collects basic information about the patient's examined eye 12. Specifically, axial length is measured using an axial length measuring device (not shown). Then, the patient goes to a room equipped with a visual field analyzer 120 as instructed by the doctor. The visual field analyzer 120 measures the visible range (visual field map) by applying light stimulation to the retina and observing the patient's response. The visual field analyzer 120 sends the measured visual field map along with the patient ID to the management server 140. The management server 140 stores the visual field map in a storage device 154 corresponding to the patient ID (see also [reference]). Figure 4 In addition, the patient goes to a room equipped with an ophthalmic device 110 according to the doctor's instructions. The ophthalmic device 110 takes a picture of the patient's examined eye 12 to obtain fundus images (SLO images (UWFSLO fundus images) and / or OCT images). The ophthalmic device 110 sends the acquired fundus images along with the patient ID to the management server 140. The management server 140 stores the fundus images in the storage device 154 corresponding to the patient ID.

[0074] When examining a patient's eye 12, the doctor may use the fundus image of the examined eye 12 to determine if there are any non-perfusion areas in the fundus. First, after inputting the patient ID into the image viewer 150, the image viewer 150 retrieves the patient's fundus image from the management server 140 and displays the retrieved fundus image on the monitor 156. Then, an instruction to create candidate images of non-perfusion areas based on the displayed fundus image is sent from the image viewer 150 to the management server 140.

[0075] The management server 140 sends image data of candidate images of non-perfusion areas, created based on specified fundus images, to the image viewer 150.

[0076] Candidate images of non-perfusion areas are fundus images that are overlaid with the presumed non-perfusion areas.

[0077] The management server 140 reads the specified fundus image from the storage device 154, infers the non-perfusion area based on the read fundus image, creates the final image (candidate image of non-perfusion area or candidate group image) of the candidate area of ​​the non-perfusion area, and sends the image data of the created final image to the image viewer 150, as detailed below.

[0078] Image viewer 150 uses communication I / F 158 to receive image data of candidate images of non-perfusion areas and causes display 156 to display candidate images of non-perfusion areas.

[0079] Here, the fundus image is a UWFSLO fundus image taken by the ophthalmic device 110, which can be used to infer the presence of NPA by examining a large area of ​​the fundus. Of course, it is not limited to using UWFSLO images; NPA can also be inferred from fundus images of the same patient (such as UWFSLO fundus images taken in the past or fundus images taken by other instruments).

[0080] The doctor diagnoses the patient's examined eye 12 based on candidate images of the non-perfusion area displayed on the monitor 156. If the examined eye 12 is normal, the diagnosis ends. However, if the doctor diagnoses a problem with the examined eye 12 and OCT images are required, instructions for OCT-based imaging can be output to the ophthalmic device 110 via the image viewer 150 in order to obtain tomographic images of the fundus using the ophthalmic device 110.

[0081] When an instruction is given to perform an OCT-based imaging, the ophthalmic device 110 sends the OCT image acquired by the ophthalmic device 110 along with the patient ID to the management server 140. The management server 140 stores the OCT image corresponding to the patient ID in the storage device 154 and sends it to the image viewer 150.

[0082] like Figure 18 As shown, the image viewer 150 displays images in various display modes on the screen 500 of the display 156 of the image viewer 150, as detailed below.

[0083] Next, refer to Figure 6 The image processing program executed by CPU 162 of management server 140 is described below. CPU 162 of management server 140 executes image processing program 154P, thereby achieving... Figure 6 The image processing shown.

[0084] Figure 6 The image processing shown is an example of the "image processing method" of the present disclosure.

[0085] Acceptance Department 200 (also refer to) Figure 5When instruction data is received from image viewer 150, image processing program 154P is started. Instruction data is an instruction issued from image viewer 150 to create a non-perfusion area (NPA) candidate image based on a specified UWFSLO image and to send the image data of the non-perfusion area (NPA) candidate image to image viewer 150.

[0086] After the image processing program 154P is started, in step 302, the acquisition unit 202 acquires a specified UWFSLO image from multiple UWFSLO images stored in the storage device 154, each corresponding to a multiple patient ID. For example... Figure 7 As shown, UWFSLO images contain retinal vascular structures and structures such as the optic nerve head.

[0087] Next, in step 304, the image processing unit 204 performs image processing on the acquired UWFSLO image to emphasize the blood vessels. This process makes the blood vessels, including capillaries, more visible, in order to accurately estimate non-perfusion areas (NPA).

[0088] Besides image histogram enhancement using methods like histogram averaging or adaptive histogram equalization (CLAHE), image enhancement can also employ various methods such as contrast conversion based on grayscale conversion, frequency enhancement for specific frequency bands such as unsharp masking, deconvolution processing such as Wiener filtering, and morphological processing to emphasize the shape of blood vessels. However, histogram averaging or adaptive histogram equalization is preferred. Through image enhancement processing, blood vessels are emphasized, and... Figure 8 As shown, capillaries are also emphasized.

[0089] Therefore, when using UWFSLO images that emphasize blood vessels, non-perfusion areas (NPAs) can be estimated with high accuracy. Thus, in the technology disclosed herein, through the following steps 306 to 312, the estimation processing unit 206 estimates multiple non-perfusion areas (NPAs) based on UWFSLO images that emphasize blood vessels.

[0090] Specifically, in step 306, the estimation processing unit 206 selects primary candidates for non-perfusion areas (NPA). More specifically, from UWFSLO images highlighting blood vessels (refer to...) Figure 8 Multiple pixels below the first level of darkness are selected from the sample, and one or more regions of continuous dark pixels below the first level of darkness with an area of ​​more than a specified area are selected as primary candidates for non-perfusion area (NPA).

[0091] Here, dark pixels below the first level of darkness refer to pixels whose pixel value is below the first specified value.

[0092] Alternatively, as a pixel value, a luminance value representing lightness can be used, but a value representing at least one of chroma and hue can be used instead of or together with the luminance value.

[0093] The primary candidate is an example of the "first non-infusion zone candidate" of the technology disclosed herein.

[0094] Figure 9 This is a simplified representation of the processing result of step 306, and a schematic diagram showing a magnified portion of the UWFSLO image. Figure 9 Along with vessel 400, six primary candidates for non-perfusion area (NPA) are shown: 402, 404, 406, 408, 410, and 412.

[0095] After step 306, image processing proceeds to steps 308 and 310.

[0096] In step 308, the estimation processing unit 206 selects darker candidates from the primary candidates based on the average pixel value within the region of each candidate, according to one or more primary candidates of the non-perfusion area (NPA). Specifically, it calculates the average pixel value within the region of each of the one or more primary candidates of the NPA and selects one or more candidates whose calculated average value is smaller than a second predetermined value as dark regions. The second predetermined value is a value that is a predetermined value smaller than the first predetermined value. In other words, only darker dark regions (candidates with a predetermined average pixel value) that are darker than the first darkness and below the second darkness are selected from the primary candidates of the first darkness as first secondary candidates.

[0097] The first secondary candidate is an example of the "second non-infusion zone candidate" of the technology disclosed herein.

[0098] When performing step 308 after the processing in step 306, such as Figure 10 As shown, the six primary candidates selected in step 306 are 402, 404, 406, 408, 410, and 412 (refer to...). Figure 9 For example, primary candidate 412 is excluded. Thus, the range is narrowed down to first-level candidates 402A, 404A, 406A, 408A, and 410A.

[0099] In step 310, the estimation processing unit 206 narrows down the multiple primary candidates for non-perfusion areas (NPAs) to only the region along the blood vessel. Specifically, first, the estimation processing unit 206 (1) extracts the blood vessel. The blood vessel is extracted using methods such as morphological processing or binarization based on pixel values. The extracted region is referred to as the blood vessel region. Next, the estimation processing unit 206 (2) calculates the distance between the blood vessel region and the periphery of the region group of one or more primary candidates or candidate groups of non-perfusion areas (NPAs) using distance transformation or the like, and selects the region where the distance is within a certain range.

[0100] Here, the first range is a certain range that is larger than the first specified distance and smaller than the second specified distance (which is larger than the first specified distance) (i.e., along the traveling blood vessel).

[0101] In step 310, the estimation processing unit 206 selects regions from the primary candidates whose distance from the blood vessel is less than or equal to a first distance as secondary candidates. Thus, for example, as... Figure 11 As shown, candidates 402 and 404 are excluded because they are not located along the blood vessel. Therefore, the range of secondary candidates 406B, 408B, 410B, and 412B is narrowed down as candidates along the traveling blood vessel.

[0102] Additionally, as a second-tier candidate, it can also be as follows: Figure 12 As shown, region 450B, which is within a certain range starting from the ends of the blood vessels 400E1, 400E2, and 400E3, is selected as the second-level candidate.

[0103] The second secondary candidate is an example of the "second non-infusion zone candidate" of the technology disclosed herein.

[0104] Steps 308 and 310 can be executed either first or simultaneously. After steps 308 and 310 are completed, image processing proceeds to step 312.

[0105] In step 312, the estimation processing unit 206 performs an integration process that merges the first secondary candidate and the second secondary candidate. Specifically, regions that are both first secondary candidates (multiple dark regions) and second secondary candidates (multiple regions along the blood vessel) are selected and determined as estimated non-perfusion areas.

[0106] exist Figure 9 In the example shown, in step 306, six primary candidates for the non-perfusion area (NPA) are obtained: 402, 404, 406, 408, 410, and 412. However, as... Figure 13 As shown, in step 308, candidate 412 is excluded, and in step 310, candidates 402 and 404 are excluded. Therefore, in step 312, as... Figure 14 As shown, candidates 406, 408, and 410 were identified as the presumed non-perfusion regions 406NPA, 408NPA, and 410NPA.

[0107] In the next step 314, the creation unit 208 marks the area around the presumed non-perfusion zone in the UWFSLO image with a colored border, creating a candidate image for the non-perfusion zone. To facilitate the identification of the location of the presumed non-perfusion zone on the UWFSLO image, the candidate image for the non-perfusion zone refers to a fundus image overlaid on the UWFSLO image, showing the presumed non-perfusion zone. To facilitate the identification of the location of the presumed non-perfusion zone on the UWFSLO image, the candidate image for the non-perfusion zone is an image that surrounds and displays the presumed non-perfusion zone with a border. As a display example, although only a portion of the UWFSLO image is shown, it is clear that... Figure 15 The image shows the colored borders around the presumed non-inflation zones 406 NPA, 408 NPA, and 410 NPA.

[0108] Furthermore, such as Figure 16 As shown, the creation unit 208 can also apply a lighter color (a color with a higher concentration than the first concentration of the UWFSLO image) to the estimated non-perfusion regions 406NPA, 408NPA, and 410NPA, thereby creating candidate images of non-perfusion regions. Additionally, in step 314, the creation unit 208 can also... Figure 17 As shown, the presumed unfilled areas 406NPA, 408NPA, and 410NPA are painted with the same or different colors as the actual colors. Additionally, the borders around the presumed unfilled areas 406NPA, 408NPA, and 410NPA can also be dashed borders.

[0109] These candidate images of the non-perfusion area serve as one of the pieces of information for doctors when diagnosing and assessing the progression of conditions such as diabetic retinopathy or retinal vein occlusion.

[0110] In the next step 316, the sending unit 210 sends the image data of the candidate image of the non-inflation area created in step 314 to the image viewer 150.

[0111] Image viewer 150 receives image data of candidates for non-inflation areas and displays the candidate images of non-inflation areas on display 156.

[0112] The following is for reference Figure 18 as well as Figure 19 The display 156 of the image viewer 150 shown provides a more detailed explanation of the method for displaying candidate images of non-inflation areas on screen 500.

[0113] Figure 18 as well as Figure 19The display method shown is an example of the "image display method" of the present disclosure.

[0114] Figure 18 In the image viewer 150, the NPA analysis mode display content of the monitor 156 is shown on screen 500. Screen 500 has a patient information display bar 502, a UWFSLO image display bar 504, an OCT image display bar 506, a candidate image display bar for non-perfusion areas 508, and two magnified image display bars 510 and 512. Furthermore, screen 500 has a menu button 522, an NPA process observation button 524, an NPA analysis button 526, an NPA laser coagulation button 528, an NPA field of view resolution button 530, and an OCT analysis button 540. Additionally, screen 500 has a tool button display bar 540.

[0115] Figure 18 The display screen for NPA analysis mode is therefore configured with the following modes: menu button 522, NPA process observation button 524, NPA analysis button 526, NPA laser coagulation button 528, NPA field of view resolution button 530, and OCT analysis button 540. The NPA analysis button 526 is displayed as the active state in the first mode, and the other buttons are displayed as inactive in the second mode. The first and second display modes can use different colors (e.g., green for the first mode, red for the second mode) or provide a three-dimensional display (e.g., a shadowed display for the first mode, or a display without shadows for the second mode).

[0116] The patient information display area 502 includes a patient ID display area 502A, a patient name display area 502B, a gender display area 502C, an age display area 502D, and a received information history display area 502E. The image viewer 150 retrieves the patient ID, patient name, gender, age, and received information history stored on the management server 140. The image viewer 150 displays the retrieved patient ID, patient name, gender, age, and received information history in the patient ID display area 502A, patient name display area 502B, gender display area 502C, age display area 502D, and received information history display area 502E, respectively.

[0117] The image viewer 150 displays the patient's UWFSLO image in the UWFSLO image display bar 504 of the screen 500, and displays candidate images of the non-perfusion area in the candidate image display bar 508.

[0118] To facilitate observation / diagnosis by physicians, candidate images of the non-perfusion area are displayed in the candidate image display area 508 at a different magnification than the UWFSLO image displayed in the UWFSLO image display area 504. For example, the candidate images of the non-perfusion area may be displayed at a predetermined magnification compared to the UWFSLO image displayed in the UWFSLO image display area 504. Alternatively, the candidate images of the non-perfusion area may be displayed at a predetermined magnification reduced compared to the UWFSLO image displayed in the UWFSLO image display area 504. Furthermore, the predetermined magnification can be varied.

[0119] There are also situations where doctors want to magnify a portion of a candidate image of a non-perfusion area. Thus, for example, as... Figure 18 As shown, the doctor uses an input unit such as a mouse to operate on the areas 508A and 508B that they want to magnify and observe, and specifies the area to be magnified within the candidate image display bar 508 for non-perfusion areas. When areas 508A and 508B are specified, the image viewer 150 magnifies and displays a portion of the specified areas 508A and 508B from the candidate images for non-perfusion areas in the magnified image display bars 510 and 512.

[0120] If a doctor observes a candidate image of a non-perfusion area and determines that an OCT image needs to be obtained, a specified region 508C for which an OCT image should be obtained is designated in the candidate image of the non-perfusion area displayed in the candidate image display bar 508. The designated region can also be a straight line or a rectangle. At this time, the designated region 504A can also be displayed on the UWFSLO image displayed in the UWFSLO image display bar 504 at the position corresponding to 508C designated on the candidate image of the non-perfusion area.

[0121] After specifying the region 508C for acquiring OCT images, the management server 140 issues an instruction to the operator of the ophthalmic device 110 to acquire OCT images of the specified region 508C. The patient then returns to the room equipped with the ophthalmic device 110. Based on the instruction, the ophthalmic device 110 acquires OCT images and sends them to the management server 140. The OCT image data is then sent from the management server 140 to the image viewer 150, which displays the OCT images in the OCT image display bar 506. The doctor thus reviews the OCT images of the areas identified as having problems in the examined eye 12 and examines the eye 12.

[0122] In addition, the tool button display bar 540 displays buttons for various input assistance tools, such as icons for displaying lines, icons for displaying rectangles, text input icons for inputting text on images, and pen input icons for overlaying hand-drawn drawings on images.

[0123] The patient information display area 502 includes a received information history display area 502E. Figure 18 In the example shown, received information history is displayed on June 20, 2017, September 22, 2017, and December 20, 2017. The doctor, determined to want to view the received information history, clicks the NPA process observation button 524. Upon clicking the NPA process observation button 524, the screen 500 on the display 156 of the image viewer 150 changes from... Figure 18 The display status of the NPA analysis mode has changed to Figure 19 The display status of the NPA process observation mode.

[0124] like Figure 19 As shown, in addition to the patient information display bar 502 and the tool button display bar 540, the NPA process observation mode screen 5001 also has a UWFSLO process image display bar 524A and a non-perfusion area candidate image display bar 524D. Furthermore, the patient information display bar 502, the tool button display bar 540, and the non-perfusion area candidate image display bar 524D are related to... Figure 18 The same display bar. Figure 19 The display screen is for the NPA process observation mode. Therefore, it is displayed in the first display mode, which indicates that the NPA process observation button 524 is active, and the second display mode, which indicates that the other buttons are inactive, among the menu button 522, NPA process observation button 524, NPA analysis button 526, NPA laser coagulation button 528, NPA field of view resolution button 530, and OCT analysis button 540.

[0125] The UWFSLO process image display bar 524A has process image display areas 524A1 to 524A3 for multiple past UWFSLO images (process images) (3 in the example above), and a slider 524B with a slider 524C.

[0126] If a patient has received more than four records, it is possible to display all four or more UWFSLO images simultaneously. However, displaying all of them would require shrinking the display area of ​​each image, making them difficult to observe. Therefore, three process image display areas 524A1 to 524A3 are set up as described above. Regarding the position of slider 524C, the right end corresponds to the present, and the further left corresponds to past time periods. The image viewer 150 displays three UWFSLO images for the time periods corresponding to the positions of slider 524C in the process image display areas 524A1 to 524A3.

[0127] The physician uses an input device such as a mouse to select the image to be performed on for NPA analysis from the three UWFSLO images displayed in the UWFSLO process image display panel 524A. For example, if process image 524A3 is selected, the border color of 524A3 is displayed in a different color than the border colors of 524A1 and 524A2. Alternatively, the thickness of the border line can be varied without changing the border color, or both the border color and thickness can be changed.

[0128] Next, the doctor uses a mouse or similar device to press (click) the NPA estimation button 525E. The image viewer 150 then sends a command to the management server 140, thereby creating a candidate image for the non-perfusion area from the selected process image 524A3. The management server 140 reads the image from process image 524A3 and performs... Figure 6 The image processing described above. Then, the candidate image of the non-perfusion area corresponding to the obtained process image 524A3 is saved in the storage device 154 of the management server, and the image data of the image-processed candidate image of the non-perfusion area is sent to the image viewer 150.

[0129] Image viewer 150 displays the processed candidate images of the non-perfusion area obtained by image processing the received process image 524A3 on the candidate image display bar 524D of screen 5001. Image viewer 150 can also display the display border of the candidate image display bar 524D of the non-perfusion area with the same color, line type, or thickness as the display border of the selected process image 524A3.

[0130] Alternatively, three candidate images of non-perfusion areas obtained by image processing of three UWFSLO images (process images) can be displayed in the candidate image display bar 524D.

[0131] Furthermore, if the physician presses the NPA estimation button 525E without selecting a process image from the three images in the UWFSLO process image display panel 524A, the image viewer 150 outputs an instruction to the management server 140 to create candidate images for the non-perfusion area for all UWFSLO images corresponding to the patient ID (in other words, images stored in the patient ID's image folders 524A1, 524A2, and 524A3). If a UWFSLO image with a candidate image for the non-perfusion area already exists in the UWFSLO image folder stored in the patient ID, an instruction to create a candidate image for the non-perfusion area can also be output for UWFSLO images for which no candidate image for the non-perfusion area has yet been created.

[0132] Management server 140 sequentially reads process images 524A1, 524A2, and 524A3 and performs them in sequence. Figure 6 The image processing described above. Then, the obtained process image 524A3 is saved in the storage device 154 of the management server, and the image data of the image-processed no-infusion candidate image is sent to the image viewer 150. Then, the no-infusion candidate images for the obtained process images 524A1, 524A2, and 524A3 are kept in the storage device 154 of the management server, and the image data of the three new no-infusion candidate images after image processing are sent to the image viewer 150.

[0133] Image viewer 150, having received image data from three new candidate images of non-inflation areas, displays the three candidate images of non-inflation areas in the process image display area of ​​the UWF image on screen 5001 based on the received information history. Next, if one of the three candidate images of non-inflation areas displayed in the process image display area is selected, the selected candidate image is enlarged and displayed in the candidate image of non-inflation area display bar 524D. For example, if candidate image of non-inflation area 524A3 with the latest received information history is selected, the display border of candidate image of non-inflation area display bar 524D can also be displayed with the same color, linearity, or thickness as the display border of candidate image of non-inflation area 524A3.

[0134] Furthermore, image processing can be performed by comparing candidate images of non-perfusion areas from different days of visit, and displaying multiple candidate images of non-perfusion areas in a way that changes the color of the newly generated presumed non-perfusion areas, thus displaying them in the process observation image display area. For example, using blue to display the candidate images shown in the process observation image display area. Figure 19 The presumed non-perfusion area was obtained by processing a UWFSLO image taken on June 20, 2017, using the 524A1. The following processing can be performed: [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Figure 19 In the presumed no-perfusion areas obtained by processing UWFSLO images taken on September 22, 2017 (e.g., 524A2), areas presumed to be the same as those from June 20, 2017 are shown in blue, while areas first appearing in the September 22, 2017 image processing are shown in red. This image processing provides physicians with useful information for diagnosing the development of a patient's symptoms, thus aiding in diagnosis.

[0135] Next, for the display in Figure 18 The image 500 and Figure 19 The functions of the menu button 522, NPA laser coagulation button 528, NPA field of view resolution button 530, and OCT analysis button 540 in screen 5001 will be explained.

[0136] Menu button 522 is used to return to the menu screen of the ophthalmology electronic medical record. The menu screen displays tools for selecting initial settings, user login, fundus observation mode, and anterior eye diagnostic mode. Selecting "fundus observation mode" in the menu screen will navigate to... Figure 18 The image is 500.

[0137] The OCT analysis button 540 is used to jump to a screen that performs image analysis using tomographic images of the retina and / or thickness maps of the optic nerve layer obtained by the ophthalmic device 110, B-scan data obtained by taking pictures of the retina, and / or OCT volume data.

[0138] The NPA laser coagulation button 528 is used to jump to a screen for treatment-related analysis using the laser coagulation device 130. In cases where the doctor determines that a lesion exists in the patient's fundus and disease progression needs to be suppressed, laser coagulation treatment using the laser coagulation device 130 may be performed by irradiating the fundus with laser. In this case, the NPA laser coagulation button 528 is clicked. After clicking the NPA laser coagulation button 528, to determine the location for laser irradiation, a screen with simulation functionality is displayed, allowing candidate images of the non-perfusion area to suggest the appropriate laser irradiation location.

[0139] The NPA visual field analysis button is used to jump to a screen that performs visual field analysis using the visual field map (showing the visible range) obtained by the visual field detector 120 and candidate images of the non-perfusion area. Clicking the NPA visual field analysis button 530 switches to an NPA visual field analysis mode that combines the visual field map obtained by the visual field detector 120 and the candidate images of the non-perfusion area. Analysis processing is performed by combining the visual field map and the image emphasizing the non-perfusion area, thereby enabling the investigation of the correlation between the location of the NPA on the retina and the visual field.

[0140] (Effects of the implementation method)

[0141] As described above, in this embodiment, non-perfusion areas can be estimated by performing image processing on fundus images.

[0142] Furthermore, in this embodiment, multiple non-perfusion areas are estimated based on fundus images that have undergone image processing that emphasizes the vascular portion, thus enabling the estimation of multiple non-perfusion areas with high accuracy.

[0143] Furthermore, by using UWFSLO images to estimate non-perfusion areas, it is possible to detect NPA in the peripheral retinal region at an early stage, in addition to diabetic retinopathy, retinal vein occlusion and retinal vein branch occlusion at an early stage.

[0144] Furthermore, it is beneficial for specifying the laser irradiation position in laser coagulation surgery performed using the laser coagulation device 130. Moreover, by performing analytical processing of visual field examination data from the combined visual field analyzer 120, visual field examination data, and images emphasizing non-perfusion areas, the correlation between NPA and visual field can be investigated.

[0145] Furthermore, through process observation, continuous monitoring of the non-perfusion area can provide doctors with information to assist in confirming treatment effectiveness and symptom development.

[0146] (Modified Example)

[0147] <Example 1>

[0148] In the technology disclosed herein, one of steps 308 and 310 may be performed first, and the candidate group of non-perfusion areas thus inferred may be used as secondary candidates. Then, in another step, the range of secondary candidates may be narrowed down to tertiary candidates. For example, after performing the process of step 308, the candidates may be further narrowed down in step 310, or vice versa, after performing the process of step 310, the candidates may be further narrowed down in step 308. Thus, step 312 can be omitted.

[0149] Alternatively, the results of narrowing the range in steps 306 and 308 can be used as a presumed non-perfusion zone. The results of narrowing the range in steps 306 and 310 can also be used as a presumed non-perfusion zone.

[0150] <Second Variation>

[0151] In the present disclosure, the processing of step 312 can also be modified as described above. It is assumed that the processing unit 206 selects at least a number of dark areas or areas along blood vessels as candidate groups of non-perfusion areas for the integration of step 312.

[0152] <Example 3>

[0153] In the above embodiment, in step 314, the presumed multiple non-perfusion areas in the UWFSLO image are marked with colored borders and painted with a lighter color. However, the technology disclosed herein is not limited to this; it is also possible to create an image that omits vascular portions and only shows multiple non-perfusion areas, or to create an image that omits vascular portions and only emphasizes multiple non-perfusion areas as described above.

[0154] <4th Variation>

[0155] In the technology disclosed herein, the information to be displayed may further include left and right eye information, a graph showing the time-varying number of non-perfusion areas, a graph showing the time-varying average area of ​​non-perfusion areas, and a graph showing the time-varying total area of ​​non-perfusion areas. Furthermore, during laser coagulation surgery, candidate images of non-perfusion areas may be overlaid on UWFSLO fundus images.

[0156] <5th Variation>

[0157] In the above implementation, the management server 140 performs... Figure 6 Image processing programs are available, but the technology disclosed herein is not limited thereto. For example, the first method can... Figure 6 The image processing program is pre-stored in the storage device 17 of the ophthalmic device 110, and the ophthalmic device 110 executes it each time a UWFSLO image is acquired. Figure 6 The image processing program. Second: The image viewer 150 can execute steps 302 to 314. Furthermore, in step 302 of the second case, image data of a specified fundus image is obtained from the management server 140, and instead of the above-described steps in step 316, an image emphasizing multiple non-perfusion areas is displayed on the monitor 156. In the first case, the ophthalmic device 110 is an example of an image processing apparatus according to the technology of this disclosure. In the second case, the image viewer 150 is an example of an image processing apparatus according to the technology of this disclosure.

[0158] <6th Variation>

[0159] In the above embodiment, an image emphasizing multiple non-infused areas is displayed on the display 156 using an image viewer 150; however, the technology disclosed herein is not limited to this. For example, it is also possible to display... Figure 7 UWFSLO images, Figure 8 The image of blood vessels is highlighted in UWFSLO images. Figures 15-17 The image emphasizes multiple non-perfusion areas. In this case, it is also possible to use... Figure 7 , Figure 8 , Figures 15-17 Images can be displayed in a list view, sequentially on each click, or selectively.

[0160] <7th Variation>

[0161] In the technology disclosed herein, the images of the primary candidates without perfusion areas obtained in step 306 and the candidates excluded from the candidates in steps 308 and 310 can also be displayed in a list manner, displayed sequentially on each click, or displayed selectively.

[0162] <Example 8>

[0163] In the above embodiments, an image of the entire fundus is acquired as a UWFSLO image, but the technology disclosed herein is not limited to this. As a process observation, a UWFSLO image containing only a specified area of ​​the discovered lesion may also be acquired.

[0164] <9th Variation>

[0165] The example of image processing of UWFSLO images has been used, but it can also be applied to fundus images obtained from fundus cameras, or to fundus images taken by various ophthalmic devices such as SLO ophthalmic devices or fundus cameras with a small field of view (e.g., an internal illumination angle of less than 100°).

[0166] <10th Variation>

[0167] In the above embodiments, an ophthalmic system 100 including an ophthalmic device 110, a visual field analyzer 120, a laser coagulation device 130, a management server 140, and an image viewer 150 has been described as an example, but the technology disclosed herein is not limited thereto. For example, as a first example, the ophthalmic device 110 may also have the function of at least one of the visual field analyzer 120 and the laser coagulation device 130. Furthermore, as a second example, it includes the ophthalmic device 110, the visual field analyzer 120, and the laser coagulation device 130 as described in the above embodiments. Moreover, in both the first and second examples, the ophthalmic device 110 may also have the function of at least one of the management server 140 and the image viewer 150. Thus, at least one device corresponding to the functions of the management server 140 and the image viewer 150 can be omitted.

[0168] Alternatively, the management server 140 can be omitted, allowing the image viewer 150 to perform the functions of the management server 140.

[0169] Furthermore, the image processing described in the above embodiments is merely an example. Therefore, it is naturally possible to delete unnecessary steps, add new steps, or change the processing order without departing from the purpose.

[0170] Furthermore, while the above embodiments illustrate data processing implemented using computer software, the technology disclosed herein is not limited to this. For example, instead of using computer software, data processing can be performed solely using hardware such as an FPGA or ASIC. Alternatively, a portion of the data processing can be performed using software, while the remaining processing can be performed using hardware.

[0171] Explanation of reference numerals in the attached figures

[0172] 12 eyes examined

[0173] 100 Ophthalmology System

[0174] 110 Ophthalmic Device

[0175] 120 Field of View Analyzer

[0176] 130 Laser Solidification Device

[0177] 140 Management Server

[0178] 150 Image Viewer

[0179] 154 storage devices

[0180] 154P image processing program.

Claims

1. An image processing method, comprising: The fundus image of the examined eye is subjected to a first image processing to select a first non-perfusion area candidate. In the first image processing, a region with multiple consecutive pixels that are darker than the first darkness level and have an area of ​​more than a specified area is selected. The fundus image is subjected to a second image processing step to select a second candidate non-perfusion area. In the second image processing step, blood vessels on the fundus image are detected, and regions within a certain range starting from the end of the blood vessel are selected. as well as Candidates that are both the first and second no-perfusion zone candidates will be selected as presumed no-perfusion zones. The range mentioned is a range that is larger than the first specified distance and smaller than the second specified distance.

2. The image processing method as described in claim 1, characterized in that, The first image processing includes: extracting multiple pixels darker than a first darkness level from the fundus image, and detecting a region from the extracted multiple pixels where the dark pixels below the first darkness level are continuous and the area is greater than or equal to a predetermined area.

3. The image processing method as described in claim 2, characterized in that, The area extracted from the fundus image as the presumed non-perfusion zone includes: From multiple regions with an area greater than or equal to the specified area, darker regions with a darker level of less than or equal to the first darkness are selected based on the average pixel value of each region.

4. The image processing method as described in claim 1, characterized in that, The fundus image is subjected to image processing that emphasizes the blood vessels. The first non-perfusion candidate and the second non-perfusion candidate are extracted from the fundus image after emphasis image processing.

5. The image processing method as described in claim 1, characterized in that, Also includes: A candidate image of the non-perfusion area is created by overlaying the presumed non-perfusion area onto the fundus image.

6. The image processing method as described in claim 5, characterized in that, Also includes: Images are generated that display the fundus image and the candidate image of the non-perfusion area at different magnifications.

7. The image processing method as described in claim 5, characterized in that, It also includes: generating a screen displaying multiple fundus images obtained by taking the examined eye at different times, and a candidate image of the non-perfusion area obtained by image processing at least one of the multiple fundus images.

8. A storage medium storing a program for causing a computer to perform an image processing method, the image processing method comprising: The first image processing step of the fundus image of the examined eye to select the first non-perfusion area candidate is to select a region that is darker than the first darkness level and has a continuous area of ​​more than a specified area. The second image processing step involves extracting candidates for the second non-perfusion area from the fundus image. In the second image processing, blood vessels are detected, and regions within a certain range starting from the end of the blood vessel are extracted. and The step of selecting candidates that are both the first and second no-perfusion zone candidates as the presumed no-perfusion zone is... The range mentioned is a range that is larger than the first specified distance and smaller than the second specified distance.

9. An image processing apparatus, comprising: A storage device that stores an image processing program for causing the processing device to execute an image processing method; and A processing device that executes the image processing method by executing an image processing program stored in the storage device. The image processing method is the image processing method according to any one of claims 1 to 7.

10. An image processing method, comprising: Obtain fundus images of the examined eye; and Image processing is performed on the fundus image, and regions along blood vessels that are consecutive pixels darker than the first darkness level and have an area greater than a specified area are presumed as non-perfusion areas. The presumption includes: The fundus image of the examined eye is subjected to the first image processing, and the region with multiple consecutive pixels darker than the first darkness and an area of ​​more than a specified area is selected as the first non-perfusion area candidate. and The fundus image is subjected to a second image processing step to detect blood vessels in the fundus image, and regions within a certain range starting from the ends of the blood vessels are selected as candidates for the second non-perfusion area. The range mentioned is a range that is larger than the first specified distance and smaller than the second specified distance.

Images