JP5701494B2 - Fundus image processing apparatus and fundus image processing method - Google Patents

Description

  The present invention relates to a fundus image analysis method for performing detection analysis of an optic nerve head from a fundus image, and a fundus image processing apparatus.

Glaucoma is one of the visual impairments. As a test for glaucoma, it is said that observation of the optic nerve head (hereinafter simply referred to as the “nipple”) by fundus images is important. In recent years, with the advance of image analysis technology, it has become possible to measure the nipple quantitatively. In the measurement of the nipple, for example, it is a ratio of the diameter of the outer edge of the nipple recess called a cup and the diameter (or radius) of the outer edge of the nipple called a disk from a photographed image of the fundus by the fundus camera. A technique is known in which the C / D ratio and the area ratio between the cup and the disk are obtained, and the condition of the eye to be examined is known based on the obtained C / D ratio (or area ratio). (For example, see Patent Document 1)
Further, since it is known that the cup expands with the progress of glaucoma, it has been proposed to objectively evaluate the degree of progression of glaucoma by confirming the change with time of the C / D ratio (for example, , See Patent Document 2)

JP 2006-280411 A JP-A-6-1225876

  In order for the examiner to diagnose the state of the eye to be examined using such a C / D ratio, it is required to grasp the state of the eye to be examined more efficiently and accurately. In addition, when confirming a change with time in the eye to be examined, it is necessary to compare the fundus image serving as a reference with the fundus image serving as a comparison and the corresponding change in the C / D ratio. It is required that the change in the ratio can be confirmed more accurately.

  In view of the above-described problems of the prior art, the present invention provides a fundus image processing apparatus and a fundus image processing method capable of accurately and quickly confirming information such as a C / D ratio together with a corresponding fundus photographed image. Is a technical issue.

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

(1) A disk line and a cup line of the optic nerve head are determined from a first fundus image including the optic nerve head of the eye to be examined, and a first C / D is determined by the determined disk line and cup line. A first C / D ratio acquisition means for obtaining a ratio with respect to a required meridian direction, and a discline and a cup line of the optic nerve head are determined from a second fundus image including the optic nerve head of the eye to be examined. Then, a second C / D ratio, which is a change with time of the first C / D ratio, is obtained with respect to the same meridian direction as the first C / D ratio by the determined disc line and cup line. Second C / D ratio acquisition means for
Storage means for storing the disk line determined by the first C / D ratio acquisition means,
The second C / D ratio acquisition unit applies the second fundus photographed image so that the feature point set in the first fundus photographed image matches the feature point set in the second fundus photographed image. Rotation, distortion, and size are corrected, the display state of the second fundus photographed image is matched with the display state of the first fundus photographed image, and the disk line stored in the storage means is called up to the second fundus It is determined as a disc line of the optic papilla on the photographed image.
(2) A disk line and a cup line of the optic nerve head are determined from a first fundus image including the optic nerve head of the eye to be examined, and a first C / D is determined by the determined disk line and cup line. A first step of determining a ratio with respect to a required meridian direction; and determining a discline and a cupline of the optic papilla from a second fundus image including the optic papilla of the eye to be examined. A step of obtaining a second C / D ratio, which is a change with time of the first C / D ratio, with respect to the same meridian direction as the first C / D ratio by the disc line and the cup line; The rotation, distortion, and size of the second fundus image are corrected so that the feature points set in the first fundus image match the feature points set in the second fundus image. The second The display state of the fundus photographed image is matched with the display state of the first fundus photographed image, and the disk line determined in the step is copied in the same shape as the disk line determined in the first step. A fundus image processing method characterized by comprising:

  According to the present invention, it is possible to accurately and quickly confirm information such as the C / D ratio together with the corresponding fundus photographed image.

  The fundus image processing apparatus used in this embodiment will be described below. FIG. 1 is a block diagram showing the configuration of a fundus image processing apparatus and the like. The fundus image processing apparatus 20 is connected to the ophthalmologic photographing apparatus 10 for photographing the fundus of the subject's eye via the communication cable 30, and a fundus photographed image (hereinafter referred to as fundus oculi) photographed by the ophthalmic photographing apparatus 10. It serves to filing the received fundus image and calculating the C / D ratio and R / D ratio of the optic nerve head (hereinafter simply referred to as the “nipple”) in the fundus image.

  The C / D ratio in the present embodiment refers to the radius of the cup line constituting the outer edge of the nipple recess (cup) formed inside the nipple, and the radius of the disk line constituting the outer edge of the nipple (disk). It is obtained as a value (ratio) divided by. In the present embodiment, the center O of a rectangle (rectangle) circumscribing the nipple edge (disc line) is calculated as a nipple center by the calculation described later, and the line segment from the center O to the disc line is defined as the radius of the disc line. , The line segment from the center O to the cup line is defined as the radius of the cup line. The R / D ratio is determined as the ratio of the width of the rim region defined as the region between the outer edge of the nipple and the outer edge of the nipple recess and the nipple diameter passing through the nipple center. The R / D ratio here is calculated based on the line segment from the center O to the outer edge of the nipple and the line segment from the center O to the outer edge of the nipple recess.

  An ophthalmologic imaging apparatus 10 that images the fundus of the subject's eye includes an imaging unit 11 for imaging the fundus of the subject's eye, an imaging switch 12 that inputs a trigger signal for imaging using the imaging unit 11, A control unit 14 is provided for controlling the entire apparatus and communicating with other apparatuses. The imaging unit 11 has an imaging optical system that includes an imaging device for imaging the fundus. A photographed image from the ophthalmologic photographing apparatus 10 is input to the fundus image processing apparatus 20 via a communication cable 30 such as a USB cable. In this embodiment, the fundus image is sent to the fundus image processing apparatus 20 using a USB cable. However, the present invention is not limited to this, and data transmission via a communication means such as a LAN (local area network) or the Internet is not limited thereto. It may be delivery or delivery of data using a storage medium such as a USB memory.

  Further, as the ophthalmologic photographing apparatus 10 used in the present embodiment, an existing ophthalmic photographing apparatus such as a fundus camera can be used, and a subject's eye such as a slit lamp (slit lamp microscope) with a built-in photographing section. Any fundus image may be used as long as the fundus image is captured and the captured image can be transferred to the fundus image processing apparatus 20 as digital data. The ophthalmologic photographing apparatus 10 itself can have the function of the fundus image processing apparatus 20 described in the present embodiment.

  As the fundus image processing apparatus 20, an apparatus capable of processing an existing image such as a personal computer is used. The fundus image processing apparatus 20 is a hard disk in which a fundus image processing program for calculating the C / D ratio and R / D ratio of the subject's eye and a large number of image data photographed by the ophthalmologic photographing apparatus 10 are stored. A storage unit 21, a fundus image processing screen that is an input / output screen of a fundus image processing program, and a display unit for displaying a fundus image, a monitor 22 including a liquid crystal display, and fundus image processing displayed on the monitor 22 A mouse 23 which is an input means (pointing device) for performing various operations on the screen, and a control unit 24 including a CPU and a communication circuit for controlling the entire driving of the fundus image processing apparatus 20 Is done. The control unit 24 performs display control of the monitor 22, execution of a program, control of the apparatus based on an input signal from an input means such as a mouse 23, image processing, and the like. Although not shown, a keyboard is also provided as input means for performing various settings and inputs. In addition, a large number of image data such as fundus images stored in the storage unit 21 is attached with various photographing conditions such as photographing date and time, subject information, and the like. It can be managed. Note that the fundus image processing program of this embodiment includes a function as a filing program capable of managing these image data in a unified manner.

  The mouse 23 has left and right buttons for clicking and a mouse wheel. When a touch panel is installed on the monitor 22, a touch pen or the like can be used as a pointing device. A detailed description of the fundus image processing screen will be described later.

  Next, a fundus image processing method using the fundus image processing apparatus having the above-described configuration will be described with reference to the flowcharts of FIGS. FIG. 2 is a flowchart showing a procedure for calculating a change with time of the C / D ratio and R / D ratio of the eye to be examined. FIG. 3 is a setting of a fundus image (reference image) serving as a reference when obtaining the change with time. FIG. 4 shows a flowchart of the change with time.

  First, in step 100, the examiner activates the ophthalmologic photographing apparatus 10 and the fundus image processing apparatus 20. On the initial screen of the monitor 22 of the fundus image processing apparatus 20, an unillustrated icon for starting up the fundus image processing program and an unillustrated cursor for performing an input operation with the mouse 23 are displayed. When the icon is double-clicked by the cursor operation by the examiner, the control unit 24 activates the fundus image processing program and causes the fundus image processing screen to be displayed on the monitor 22. Since the patient list screen (not shown) is displayed as the initial screen of the fundus image processing screen, the examiner selects the corresponding patient ID. In this state, when an imaging icon (not shown) for capturing a captured image acquired by the ophthalmic imaging apparatus 10 is selected, an image capture screen 200 is displayed on the monitor 22.

  FIG. 5 shows an example of the image capture screen 200. A control bar 210 is provided at the top of the image capture screen 200, and a display area 220 is provided at the center for displaying a fundus image photographed by the ophthalmologic photographing apparatus 10. The control bar 210 has a save icon 202 for saving the fundus image, a delete icon 203 for deleting the fundus image, and a screen for switching to a follow-up screen for calculating a C / D ratio and an R / D ratio described later. A plurality of icons for setting various conditions such as a switching icon 204 are prepared.

  In step 110, the examiner performs fundus photography of the subject. The examiner aligns the imaging unit 11 of the ophthalmologic imaging apparatus 10 with the subject's eye, and presses the imaging switch 12 to image the fundus. Based on the input signal from the switch 12, the control unit 14 drives the imaging unit 11 to obtain image data of the fundus of the subject's eye.

  Next, in step 120, the control unit 24 stores the image data of the fundus image in the storage unit 21 of the image processing apparatus 20. The image data acquired by the ophthalmologic photographing apparatus 10 is automatically transmitted to the image processing apparatus 20 side via the communication cable 30. When image data is received by the image processing device 20, the control unit 24 displays the fundus image F in the display area 220. The examiner selects the save icon 202 when the fundus image F is confirmed and saved. When deleting, the delete icon 203 is selected when deleting. The control unit 24 stores the image data in the storage unit 21 based on the signal from the save icon 202. When the ophthalmologic photographing apparatus 10 has a memory, image data may be input to the storage unit 21 on the image processing apparatus 20 side via an external storage medium.

  As described above, by performing step 110 and step 120 as appropriate, a plurality of fundus images having different photographing dates and times for the same subject (subject's eyes) can be acquired. As the imaging date and time, for example, one month later, three months later, six months later, one year later, etc., with respect to the first photographed fundus image, it is an interval necessary for knowing the temporal changes in the fundus of the eye to be examined. I just need it. Further, the photographed fundus image is stored in the storage unit 21 together with the photographing date and time and the eye information (for example, ID information for identifying the subject, left and right eye information, etc.).

  Next, in step 130, the examiner performs setting of a fundus image (hereinafter referred to as a reference image) that serves as a reference when obtaining a change with time. In the reference image setting flowchart of FIG. 3, first, the examiner selects the screen switching icon 204. The control unit 24 switches the display on the monitor 22 from the image capture screen 200 to the follow-up screen 300 based on the input signal by the selection of the icon 204.

  FIG. 6 is an example of the follow-up screen 300. Here, the configuration of the screen 300 will be described. In the control bar 310 prepared in the upper part of the follow-up screen 300, a disk icon 311 for setting a boundary line (disk line) D of the disk area and a boundary line (cup line) C of the cup area are set. A cup icon 312 for copying, a copy icon 313 for copying the disc line D of the reference image as a reference line (baseline), a graph switching icon 314 for switching the type of follow-up graph display to be described later, a C / D ratio, etc. A plurality of icons for setting various conditions such as an analysis icon 315 for calculation are prepared.

  In the thumbnail list 320 prepared on the left side of the screen 300, a list of thumbnails extracted based on patient ID information among the fundus images stored in the storage unit 21 is displayed in time series. Note that the display state of the thumbnail list 320 can be switched between the binocular, left eye, and right eye by selecting the switching tab 320a. Here, a case where both eyes are selected by the switching tab 320a is shown.

  The fundus image selected in the thumbnail list 320 is displayed in the display area 330 at the center of the screen 300. The display area 330 includes a left display column 331 and a right display column 332, and the registered reference image is always displayed in the left display column 331. In the display column 332 on the right side, a fundus image (hereinafter referred to as a progress image) for performing temporal observation by comparison with a reference image is displayed. Note that a plurality of progress images may be displayed at a time by providing three or more display columns.

  When the display fields 331 and 332 are double-clicked with the mouse 23, a pan window 321 in which the entire fundus image is displayed appears below the thumbnail list 320. By adjusting the magnification adjustment bar 321a prepared under the pan window 321, the fundus image displayed in the display area 330 is enlarged or reduced. The display range of the fundus image in the display column 331 or 332 can be confirmed in the display range R of the pan window 321.

A graph display area 340 is prepared on the lower side of the screen 300. In the graph display area 340, calculation results of the C / D ratio, R / D ratio, distance from the center O to the disk line D, and distance from the center O to the cup line C calculated based on the setting of the display area 330 are displayed. The graph is displayed as a curve. Below the display area 340, a comment field 341 for indicating the correspondence between the thumbnail list 320 and the graph calculation result is prepared. Here, the curve displayed in a graph in the display area 340 is displayed in a different color for each calculation result. Therefore, the correspondence between the color of the graph and the image data is shown in the comment column 341, so that the correspondence between the graph and the fundus image can be easily understood visually.
When the graph switching icon 314 is selected, the display format of the graph display area 340 is switched.

  In this way, the fundus image in the display area 330 and the calculation result such as the C / D ratio in the graph display area 340 are displayed at the same time, so the examiner can compare the reference image with the elapsed image and the C / D ratio. Thus, the change in the ratio between the disc and the cup of the nipple can be confirmed more accurately.

  The reference image shown in step 130 is set using such a screen 300. Step 130 is further configured by steps 131 to 135 shown in FIG. First, in step 131, the examiner selects an image (reference image) as a reference for follow-up observation. When a thumbnail is selected from the thumbnail list 320, the control unit 24 calls the corresponding image data from the storage unit 21 and displays the fundus image in the display field 331 (see FIG. 8).

  Next, the examiner uses the pan window 321 to adjust the magnification and the display position so that the vicinity of the nipple of the fundus image is enlarged and displayed in the display field 331. The display position can also be adjusted by dragging the image displayed in the display field 331 with the mouse 23.

  Next, in step 132, the disc line D is set by operating the cursor by the examiner. FIG. 7 is an explanatory diagram for setting the disc line D and the cup line C. When the disk icon 311 is selected, it is possible to set a point p that designates a boundary line of the disk area. Note that the disc area (nipple) has a brighter shade of pink to yellow-orange than red on the fundus. Therefore, the examiner determines the position of the point p by reading the boundary of the hue from the fundus image.

  As shown in FIG. 7A, the examiner forms a plurality of points p on this edge while visually judging the edge of the disk. Point p is formed by left-clicking the mouse with the cursor positioned on the edge of the disk. In response to a click signal from the mouse, the control unit 24 displays a point p (here, “x mark” mark) on the edge of the disk where the cursor is located, and stores the position (coordinates) of the point p in the storage unit 21. . Similarly, a plurality of points p are designated so as to trace the edge of the disk by operating the mouse 23, and the coordinates of each point p are stored in the storage unit 21. Here, the point p designated first is green, while the other points p designated second and later are displayed in white. By displaying the start point and other points in different colors, the start point of the point p can be easily understood visually.

  When a plurality of points p are formed along the disk edge, and finally a green point p (start point) is selected again, the control unit 24 connects each designated point p with a smooth curve by a spline curve. Thus, the operation of the disk line D is performed. Further, the control unit 24 displays the calculated disc line D so as to overlap the fundus image on the monitor 22 instead of displaying each point p (see FIG. 7B). By connecting each point p with a spline curve, the disk line D can be made a shape that more closely approximates the actual boundary line even in a distorted disk area.

  Here, each point p is connected by a spline curve. However, the disk line D may be determined by a known smoothing calculation. In order to correctly calculate the disk line by the above calculation, at least four points are selected on the boundary line of the disk.

Further, when the monitor 22 having a touch panel is used, the disk line D may be directly drawn by operating a touch pen used as a pointing device (the same is true for the cup line C described later). You may be allowed to.)
Next, in step 133, the disk line D calculated as described above is registered in the storage unit 21 as a baseline. When the thumbnail of the reference image is selected in the thumbnail list 320 and the right mouse button 32 is clicked, a pop-up menu (not shown) is displayed. The pop-up menu provides commands for baseline registration. When the corresponding command is selected by the cursor, the control unit 24 stores the disk line D (shape) in the storage unit 21 as a baseline. Here, the disk line D is set and then registered as the reference image. However, the disk line D may be set after the reference image is registered.

  Next, in step 134, a cup line C which is a cup edge is set. When the cup icon 312 is selected, the point p indicating the position of the cup edge can be set by operating the cursor. In addition, the cup area is captured as a light pinkish white part (light white part) in the nipple (disc). That is, for setting the cup line C, the point p may be designated on the borderline of the white part.

  As shown in FIG. 7C, the examiner designates a plurality of points p on the boundary line of the cup area (white area) by the same method as the setting of the disc line D. Then, when the starting point p is selected again, as shown in FIG. 7D, the control unit 24 determines the cup line C by connecting the designated points p with a spline curve.

  Next, in step 135, the control unit 24 obtains the C / D ratio in the reference image. When the analysis icon 315 is selected by the cursor, the control unit 24 obtains the center O assuming a square (rectangular) figure circumscribing the disk line D in the vertical and horizontal directions. Further, the control unit 24 obtains a line segment a obtained from the coordinates of the center O and the coordinates of the disc line D and a line segment b obtained from the coordinates of the center O and the coordinates of the cup line C for each predetermined angle. By dividing b by the line segment a, the C / D ratio is obtained for each angle and stored in the storage unit 21. For example, the calculation of the C / D ratio is performed in 1 to 5 degree steps and in the 360 degree direction with the center O as the center. By obtaining the C / D ratio in the 360 degree direction, it is possible to confirm not only the time-dependent change in the C / D ratio of the entire nipple but also the change in the C / D ratio at a specific location on the nipple (disc). become. In addition, the control unit 24 displays a horizontal line (axis) AX1 passing through the center O and a vertical line (axis) AX2 on the display column 331. The disk area is divided into four by the horizontal and vertical axes AX1 and AX2. Here, the right end of the axis AX1 is set to the origin (0 °), and the right end of the axis AX1 is T = 0 ° and the axis AX2 is counterclockwise. Is defined as S = 90 °, the left end of the axis AX1 is defined as N = 180 °, and the lower end of the axis AX2 is defined as I = 270 ° (see FIG. 7D).

  As described above, when the C / D ratio in the meridian direction of 360 degrees is calculated, the control unit 24 displays the graph display area 340 with the C / D ratio (0 to 1 here) in the vertical axis and the horizontal axis. Shows a curve A representing the C / D ratio in the 360 ° direction on the graph of the C / D ratio in the angle (0 to 360 degrees) in the meridian direction. The graph display area 340 is divided into four areas in association with the display field 331, and each axis (T, S, N, I) is each axis (T, S, N, I) in the display field 331. It corresponds to. Thus, the examiner can easily grasp the correspondence between the graph display area 340 and the display field 331 only by confirming the (symbol) of the display field 331 and the graph display area 340.

  Similarly, the R / D ratio is calculated for each predetermined angle based on the coordinates of the meridian direction of the base line (disk) D and the cup line C, so that the graph display area 340 has a 360 degree direction. The calculation result is displayed as curve B. The vertical axis at this time is the R / D ratio (0 to 1). Similarly, a change amount C indicating a change in the distance from the center O to the cup line C or the disk line D is also displayed on the graph, and the vertical axis at the other end indicates the distance from the center O.

  After the setting and calculation of the reference image as described above, the change with time of the C / D ratio and the R / D ratio is obtained from the comparison between the reference image and the fundus image taken at a later date. In step 140 of FIG. 2, the examiner displays the follow-up screen 300 on the monitor 22 in the same procedure as described above. At this time, the control unit 24 automatically calls the image data registered as the reference image from the storage unit 21 and causes the display field 331 to display the image data together with the horizontal and vertical lines.

  When new fundus image data is stored in the storage unit 21 by repeating Step 100 to Step 120 described above, thumbnails of newly added fundus images are also displayed in the thumbnail list.

  When the thumbnail of the fundus image (the eye on the same side as the reference image) to be monitored is selected from the thumbnail list 320 in step 141 in FIG. 4, the control unit 24 calls the image data from the storage unit 21 to display the thumbnail. The selected progress image is displayed on the list 320. Next, as described above, the examiner operates the pan window 321 displayed on the screen 330 so that the progress image displayed on the display field 332 becomes a desired display state.

  Next, in order to ensure consistency between the fundus image (reference image) in the display column 331 and the fundus image (progression image) in the display column 332, the fundus image in the display column 332 is corrected. FIG. 8 is an explanatory diagram of image correction by disk copy.

  When the disc copy icon 313 is selected in step 142, it becomes possible to designate a plurality of feature points ch on the disc line D of the reference image in the display field 331. Here, it is assumed that four feature points ch are preset in the storage unit 21 so that four points are designated. As shown in FIG. 8A, when four feature points ch are designated by the cursor operation by the examiner, the control unit 24 causes the storage unit 21 to store the coordinates of each feature point ch. As the feature point ch, it is only necessary to select a feature point having a fixed position and shape regardless of changes over time, such as a blood vessel located on the disc line D. Each feature point ch is assigned a number indicating the designated order. It should be noted that at least three or more feature points ch may be input. By inputting at least three feature points ch, not only enlargement / reduction and rotation of the fundus image but also distortion correction can be performed.

  Next, in step 143, the feature point ch is designated so that it becomes the same position as the four feature points ch designated on the baseline in the progress image in the display field 332. At this time, the feature points ch are designated in the same order while referring to the feature point ch numbers of the reference image. As shown in FIG. 8A, when four feature points ch are designated, the control unit 24 displays a comment (not shown) for confirming the presence or absence of disk copy on the follow-up screen 300.

  It is empirically known that the nipple size (discline D) of the same subject does not change over time. The control unit 24 first correlates the mutual positional relationship information based on the four feature points ch set on the reference image side and the mutual positional relationship information based on the four feature points set on the progress image side. While correcting the rotation, distortion, etc. of the entire progress image with respect to the reference image, the shape of the disc line D set in the reference image is applied as the disc line D in the progress image.

  In step 144, when the disk copy is executed, the control unit 24 calls the baseline image data from the storage unit 21, and coordinates of the feature point ch of the baseline and the feature point ch designated on the progress image. Copying is performed on the progress image in the display field 332 so as to match each coordinate.

  In step 145, the control unit 24 automatically performs calculations for correcting the rotation, distortion, size, and the like of the progress image so that the display state of the progress image in the display field 332 matches the reference image in the display field 331. Do. Thus, the display state of the reference image in the display field 331 and the display state of the elapsed image in the display field 332 are automatically matched, and the disc line D is automatically set in the display field 332.

  Next, when the cup line C is set in step 146 by designating a plurality of points p on the boundary line of the cup area of the elapsed image in the same procedure as described above, as shown in FIG. Similarly to the display column 331, the display column 332 also displays horizontal and vertical axes passing through the center O. In step 147, the C / D ratio is obtained in the same manner as in step 135 described above based on the disk line D set in step 144 and the cup line C set in step 146.

  When the C / D ratio between the reference image and the progress image is calculated as described above, in step 150, the C / D ratio and the R / D ratio of each of the reference image and the progress image calculated for each predetermined angle step. Etc. are displayed in a graph on the same graph display area 340 (see FIG. 8B).

  At this time, since the divided area on the follow-up screen 330 and the divided area of the graph display area 340 correspond to each other, the examiner can easily confirm the correspondence between the fundus image and the graph area. Further, since the calculation result of the C / D ratio in the 360 degree direction with the center O as the center is displayed, it becomes possible to grasp in detail the change over time such as the C / D ratio with respect to a predetermined meridian direction.

  Note that, as described above, the graph display area 340 displays curves colored according to calculation results in a graph, so that changes with time can be easily and accurately grasped. For example, here, the C / D ratio of the reference image is displayed in red, and the C / D ratio of the progress image is displayed in green. At this time, the corresponding thumbnail frame color is displayed in the same color in association with each graph in the thumbnail display field 320, so that the correspondence between the fundus image and the graph can be further visually understood.

  By displaying the graphs in different colors in this way, even if three or more graphs (curves) are displayed in the graph display area 340, the examiner can easily understand the correspondence between the fundus image and the graph. Thus, it becomes possible to correctly recognize changes with time.

  The graph displayed for each fundus image in the graph display area 340 may be distinguished by changing the line type (line). In addition to this, the display state of the graph may be switched for each captured image by a display method that allows the examiner to visually distinguish the graph.

  When the graph switching icon 314 is selected while the graph is displayed in the graph display area 340, the screen is switched to a numerical value display screen 340b as shown in FIG. On the upper side of the screen 340b, there is a selection column 341 for switching the contents to be displayed on the screen 340b by the C / D ratio, R / D ratio, etc., and the center part is in the direction of each axis (T, S, N, I). A list 342 of calculation results is displayed. By the numerical display of the list 342, the examiner can check the change with time of the C / D ratio in each axis direction in more detail.

  Furthermore, it is convenient if a criterion for determining the C / D ratio (for example, C / D ratio = 0.7) is stored in the storage unit 21 in advance. Note that the C / D ratio determination criteria may be set empirically based on the glaucoma diagnosis result, etc., and by providing a C / D ratio determination criterion input field (not shown) based on the examiner's experience. It may be set.

  In this case, when the numerical value of the C / D ratio is larger than the determination criterion, the control unit 24 displays the corresponding numerical value column s by changing the color (for example, displaying it in red). In this way, the examiner can easily confirm in which direction the calculation result of the disc line D exceeds the reference value only by looking at the screen 340b. As a result, it is possible to easily grasp the dangerous place where glaucoma is progressing.

It is a block diagram which shows the structure of a fundus image processing apparatus. It is the flowchart which showed the calculation procedure of a time-dependent change. It is a flowchart about the setting of a reference image. It is a flowchart about the calculation of a time-dependent change. It is an example of an image capture screen. It is an example of a follow-up screen. It is explanatory drawing of the setting of a disk line and a cup line. It is explanatory drawing about the image correction by a disk copy. It is an example of a numerical display screen.

DESCRIPTION OF SYMBOLS 10 Ophthalmology imaging device 14, 24 Control part 20 Fundus image processing apparatus 21 Storage part 22 Monitor 23 Mouse

Claims (2)

A disk line and a cup line of the optic nerve head are determined from a first fundus image including the optic nerve head of the eye to be examined, and a first C / D ratio is required by the determined disk line and cup line. First C / D ratio acquisition means for obtaining the meridian direction of
A disk line and a cup line of the optic nerve head are determined from a second fundus image including the optic nerve head of the eye to be examined, and the first C / D ratio is determined by the determined disk line and cup line. Second C / D ratio acquisition means for obtaining a second C / D ratio that is a change over time in the same meridian direction as the first C / D ratio;
Storage means for storing the disk line determined by the first C / D ratio acquisition means;
Have
The second C / D ratio acquisition means displays the display state of the second fundus photographed image so that the feature point set in the first fundus photographed image matches the feature point set in the second fundus photographed image. And the display state of the second fundus photographed image is matched with the display state of the first fundus photographed image, and the disk line stored in the storage means is called to call the optic disc on the second fundus photographed image. A fundus image processing apparatus, wherein the fundus image processing apparatus is determined as a disc line of a portion. A disk line and a cup line of the optic nerve head are determined from a first fundus image including the optic nerve head of the eye to be examined, and a first C / D ratio is required by the determined disk line and cup line. A first step for obtaining a meridian direction of
A discline and a cupline of the optic disc are determined from a second fundus image including the optic disc of the eye to be examined, and the first C / D is determined by the discline and cupline determined. A step of obtaining a second C / D ratio, which is a change in the ratio with time, with respect to the same meridian direction as the first C / D ratio, and the feature points set in the first fundus image and the The display state of the second fundus photographed image is corrected so as to match the feature point set in the second fundus photographed image, and the display state of the second fundus photographed image is changed to the display state of the first fundus photographed image. A second step in which the disc lines determined in the step are determined by copying the disc lines determined in the first step in the same shape,
Fundus image processing method characterized by having a.

Images