JP4570238B2 - Fundus image capturing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fundus image photographing apparatus capable of displaying a fundus photographed image three-dimensionally by adding image depth information to each pixel of the fundus photographed image.
[0002]
[Prior art]
In the fundus camera, a color photographed image has a much larger amount of information than a monochrome photographed image obtained by the monochrome photography system. Therefore, a system for color photographing by illuminating the fundus with visible light is adopted.
[0003]
The fundus camera includes a mydriatic type that takes images by administering a mydriatic agent to the eye to be examined, taking into account degradation of image quality due to miosis due to visible light illumination, and near-infrared light illumination to cover the fundus. There is a non-mydriatic type that observes and shoots the fundus by emitting a light source such as a xenon lamp only at the moment of photographing.
[0004]
[Problems to be solved by the invention]
However, the mydriatic type fundus camera has a problem that the illumination light amount at the time of photographing is larger than the illumination light amount at the time of observation, and the eye of the subject is burdened.
[0005]
Therefore, imaging using a non-mydriatic type fundus camera is performed, but in any case, in the case of color imaging, the subject must be irradiated with visible light, and imaging of the fundus region If a so-called panoramic imaging method is used, in which shooting is performed multiple times while changing the location, the amount of illumination on the eye to be inspected is integrated even if the time for one imaging is divided into short intervals. And the burden on the subject remains the same. Although shooting with near-infrared light has also been attempted, since it is a black-and-white shot image, the amount of information obtained is reduced.
[0006]
As described above, when the conventional fundus image capturing apparatus attempts to capture an image without imposing a burden on the subject's eye, the obtained information decreases.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fundus that can increase the obtained imaging information without imposing an excessive burden on the subject's eyes. An object is to provide an image photographing apparatus.
[0008]
[Means for Solving the Problems]
The fundus image photographing apparatus according to claim 1, wherein the fundus camera body is provided with a photographing optical system for forming an image of photographing light from the fundus of the subject's eye illuminated by the illumination light source on the imaging means, and the imaging means. Image recording means for recording and holding the fundus photographic images with different imaging parts obtained by the above, and imaging part position information recording means for recording position information of each imaging part with respect to the optical axis of the imaging optical system for each imaging part; And calculating the parallax equivalent amount of at least two fundus images based on the position information, and calculating image depth information for each pixel based on the parallax equivalent amount and the image movement amount for each pixel. Computing processing means, image processing means for converting the depth information of the image obtained by the computing processing means into a color and adding a color to the image for each pixel, and a depth based on the processing result of the image processing means. Information given as color Characterized in that and a display means for displaying a colored fundus photographing image.
[0009]
The fundus image photographing apparatus according to claim 2 is characterized in that the colored fundus photographing image obtained for each photographing part is a moving image.
[0010]
The fundus image photographing apparatus according to claim 3 is characterized in that stereoscopic display is possible by displaying the two colored fundus photographing images side by side.
[0011]
The fundus oculi imaging device according to claim 4, wherein the arithmetic processing unit subtracts pixel data for each pixel of a pair of retinal photographic images which are fundus photographic images of the same fundus region and are different over time, The image processing means displays a change portion of the fundus tissue on the display means based on the subtraction result.
[0012]
The fundus image photographing apparatus according to claim 5, wherein the image processing unit causes the display unit to display a fundus photographed image with a wide field of view by pasting the plurality of colored fundus photographed images. .
[0013]
The fundus image photographing apparatus according to claim 6 is characterized in that the fundus of the eye to be examined is illuminated with near-infrared light, and the imaging means has sensitivity in the near-infrared region.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, reference numeral 1 denotes a photographing optical system of the fundus camera body. The photographing optical system 1 includes an objective lens 2, a perforated mirror 3, a focusing lens 4, a quick return mirror 5, a photographing film 6, a field lens 7, a total reflection mirror 8, a relay lens 9, a TV camera 10, and image display means. As a television monitor 11 and an internal fixation target optical system 12. A field stop 13 ′ is provided on the front surface of the field lens 7.
[0015]
The internal fixation target optical system 12 is roughly composed of internal fixation lamps 12a, 12a ′, 12b to 12i shown in FIG. 2 and a pinhole plate 13 shown in FIG. The pinhole plate 13 is provided at a position conjugate with the fundus EF, and pinholes 13a, 13a ′, 13b-13i are provided corresponding to the internal fixation lamps 12a, 12a ′, 12b-12i. The internal fixation target optical system 12 is used to guide the line of sight of the eye E. The fixation direction of the eye E is determined by switching the lighting of the internal fixation lamps 12a, 12a ′, 12b, to 12i. The internal fixation lamp 12a is used when photographing the fundus EF of the right eye, and the internal fixation lamp 12a ′ is used when photographing the fundus EF of the left eye.
[0016]
When observation is performed, an observation light source such as a near-infrared light emitting LED (not shown) emits light. When photographing, a photographing light source such as a xenon lamp is emitted. The fundus illumination light P for observation / photographing is reflected by the perforated mirror 3, passes through the cornea C and pupil EP of the eye E through the objective lens 2, and is guided to the inside of the eye E to illuminate the fundus EF. The The illumination light reflected from the fundus EF is guided to the objective lens 2 and is once imaged by the objective lens 2 to form an aerial fundus image. The illumination light that forms the aerial fundus image is guided to the quick return mirror 5 via the half mirror 13, the hole 3 a of the perforated mirror 3, and the focusing lens 4. The focusing lens 4 plays a role of adjusting the focus of the fundus image according to the refractive power of the eye E to be examined.
[0017]
When the quick return mirror 5 is inserted into the optical path of the photographing optical system 1, the illumination reflected light from the fundus EF is guided to the TV camera 11 via the field lens 7, the total reflection mirror 8, and the relay lens 9, A fundus image EF ′ is displayed on the screen 11 a of the television monitor 11. The fundus camera body has an alignment optical system (not shown), and alignment with respect to the eye E is performed while observing the screen 11a of the television monitor 11.
[0018]
When shooting, when a shooting switch (not shown) is operated, the shooting light source emits light and the quick return mirror 5 is retracted from the optical path of the shooting optical system 1.
[0019]
As a result, fundus illumination light P as visible light is irradiated onto the fundus oculi Ef, and the reflected light is guided to the photographing film 6 as photographing light, and a fundus image is photographed.
[0020]
When observation and photographing are shared, the quick return mirror 5 is kept inserted in the optical path of the photographing optical system 1. In addition, the observation light source is shared with the imaging light source, and the fundus EF is illuminated with near-infrared light. In this case, the photographing film 6 is not necessary. Furthermore, the TV camera 10 is assumed to have sensitivity in the near infrared region.
[0021]
A central processing unit 15 is connected to the TV camera 10. The central processing unit 15 is connected to an image recording unit 16, an image processing unit 17, an arithmetic processing unit 18, and an imaging part position information recording unit 19. For the image recording means 16, for example, an information recording medium such as an MO or a hard disk is used.
[0022]
The internal fixation lamps 12a, 12a ′, 12b to 12i are controlled to be turned on by the lighting switch S1, and this lighting switch S1 is provided corresponding to each of the internal fixation lamps 12a, 12a ′, and 12b to 12i, for example. ing. The central processing unit 15 plays a role of performing lighting control of the internal fixation lamps 12a, 12a ′, 12b to 12i based on the lighting switch S1, and also takes position information of the lit internal fixation lamps for the photographing optical system 1. It plays a role of recording in the imaging part position information recording means 19 for each imaging part as position information of the imaging part with respect to the optical axis O1.
[0023]
An image recording switch S2 is connected to the central processing unit 15, and when the image recording switch S2 is turned on, a fundus photographic image with a different photographic site being observed is recorded in the image recording means 16 every time the operation is performed. For each imaging part, position information of each imaging part with respect to the optical axis O1 of the imaging optical system 1 is stored in the imaging part position information recording means 19 in association with each imaging part.
[0024]
Since the mutual positional relationship and distance between the internal fixation lamps 12a, 12a ′, 12b to 12i are known and the magnification of the imaging optical system 1 is also known, the relative positional relationship of the imaging region with respect to the optical axis O1 is geometric. Can be specified.
[0025]
Also, when photographing the fundus of the right eye, the reference position of the fundus camera body is, for example, the direction in which the internal fixation lamp 12a is turned on and the internal fixation lamp 12a is fixed, and the fundus camera body is related to the optical axis O1. If photographing is performed while moving in the direction of the arrow A1, fundus photographing images having different photographing parts when the fundus camera body is photographed in parallel can be obtained.
[0026]
The parallel movement amount information of the fundus camera body is also recorded in the imaging part position information recording unit 17 in association with each imaging part for each imaging part. Therefore, based on the parallel movement amount of the fundus camera, the position information of the imaging part with respect to the optical axis O1 of the imaging optical system 1 can be obtained for each imaging part.
[0027]
In this way, it is assumed that a large number of fundus photographic images with different photographic sites are obtained.
The central processing unit 15 is provided with an image display changeover switch S3. When the image display changeover switch S3 is operated, the switch S4 is turned off, the switch S5 is turned on, and the image processing means 17 is connected to the television monitor 11, The fundus photographed image recorded in the image recording means 15 can be displayed.
[0028]
Here, attention is paid to two fundus photographic images Q1 and Q2 (see FIG. 4A and FIG. 4B) recorded in the image recording means 16. These two fundus images Q1 and Q2 are the fundus images obtained by fixing the fixation direction of the eye E and moving the fundus camera body in parallel, and the pixels obtained by the parallel movement It is assumed that the amount of movement is about several pixels.
[0029]
In the fundus photographic image Q1, the image of the pixel Xi corresponds to the image of the pixel Xi + 1 of the fundus photographic image Q2, and the image of the pixel Xj corresponds to the image of the pixel Xj + 2 of the fundus photographic image Q2.
[0030]
By using the image matching method of the image processing means 17, the image for each pixel can be made to correspond. Here, since the movement amount of each pixel of the two fundus photographic images Q1 and Q2 varies depending on the depth of the image, it is based on the parallax equivalent amount and the movement amount of the image for each pixel. The depth information of the image can be obtained for each pixel. For example, if the image of the pixel Xi is at a deeper position than the image of the pixel Xj, the amount of movement of the image at the deep position is smaller.
[0031]
Therefore, using this property, the parallax equivalent amounts of the two fundus photographic images Q1 and Q2 are calculated based on the position information of the two fundus photographic images Q1 and Q2 recorded in the imaging region position information recording unit 19. If the calculation means 18 is operated and the amount of movement of the image is calculated for each pixel of the fundus photographic image Q1 to obtain depth information for each pixel, each pixel of the fundus photographic image Q1 is calculated. Image depth information can be obtained.
[0032]
Here, only the case where the direction of the line of sight of the eye E to be examined is fixed in this direction by turning on the internal fixation lamp 12a has been described. However, the imaging optical system is turned on by turning on another internal fixation lamp. The same applies to the case of obtaining a fundus photographed image by translating 1.
[0033]
If this processing is sequentially performed for fundus photographic images with different photographic sites, image depth information can be acquired for each pixel of each fundus photographic image.
[0034]
When the depth information of the image for each pixel is given by the arithmetic processing means 18, the image processing means 17 converts the depth information of the image into a color for each fundus photographed image and for each pixel, and converts it into an image. Add color.
[0035]
These processes may be started by incorporating a program for performing these processes into the central processing unit 15 and operating the operation means 20 after photographing each fundus image.
[0036]
The television monitor 11 displays the colored fundus photographic image obtained by the image processing means on the screen 11a by the operation of the operation means 20, and FIG. 5 shows the colored fundus photographic image Q1 displayed on the screen 11a. 'Show an example.
[0037]
According to the present invention, since the color based on the depth information is added to the image of each pixel of the fundus photographed image, the fundus photographed image can be stereoscopically displayed even when photographing with a single eye.
[0038]
In addition, if only the image of the fundus tissue having a specific depth is displayed, it is easy to confirm a state change such as bleeding of the fundus tissue having a specific depth. Furthermore, a tomographic image can be displayed by using a known image display method.
[0039]
As mentioned above, although embodiment of invention was described, this invention is not restricted to this but includes the following.
(1) Although the near-infrared light emitting LED is used for observation, a halogen lamp and an IR filter that blocks visible light and transmits infrared light may be used in combination.
(2) A configuration may also be adopted in which photographing time is associated with each fundus image and recorded.
(3) The fundus photographic images (so-called panoramic images) Q with a wide field of view can be displayed on the screen 11a of the television monitor 11 by pasting the fundus photographic images together as shown in FIG. In FIG. 6, a panoramic image Q obtained by bonding fundus photographic images Q3 to Q11 obtained by sequentially turning on the internal fixation lamps 12a to 12i is shown.
(4) It is also possible to adopt a configuration in which stereoscopic observation is performed by displaying fundus images side by side on the television monitor 11.
(5) A colored fundus photographed image obtained for each photographing region can be displayed as a moving image.
(6) The arithmetic processing means is provided with a function of subtracting pixel data for each pixel of a pair of fundus photographic images of the same fundus site that are different over time, and the image processing means has a subtraction result. On the basis of the above, a function of causing the television monitor 11 to display the changed part of the fundus tissue may be provided. In this way, it is easy to check for bleeding during fluorescence imaging.
(7) In the embodiment of the present invention, the direction of the line of sight of the eye to be examined is specified by detecting the lighting position of the fixation target. However, the direction of the line of sight of the eye to be examined is determined by a known line-of-sight detection device. It is also possible to correct the direction of fixation of the eye to be detected and thereby improve the calculation accuracy of the parallax equivalent amount.
(8) In the embodiment of the present invention, parallax is obtained by translating the fundus camera body, but the fundus camera body may be translated.
[0040]
【The invention's effect】
Since the present invention is configured as described above, it is possible to increase the obtained imaging information without imposing an excessive burden on the subject's eyes.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a fundus image photographing apparatus according to the present invention.
FIG. 2 is a diagram showing an example of an internal fixation lamp.
FIG. 3 is a diagram showing an example of a pinhole plate.
FIG. 4 is a diagram for explaining the principle for obtaining image depth information for each pixel of a fundus photographic image; FIG. 4A is a diagram in which the fixation direction is made to coincide with the optical axis direction of the photographic optical system. A fundus photographed image at the time of photographing is shown, and (b) shows a fundus photographed image when the optical axis of the photographing optical system is moved in parallel.
FIG. 5 is a diagram illustrating an example of a colored fundus photographed image.
FIG. 6 is a diagram illustrating an example of a panoramic image.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Shooting optical system 10 ... TV camera (imaging means)
16 ... Image recording means 17 ... Image processing means 18 ... Calculation means 19 ... Imaging part position information recording means

Claims (6)

A fundus camera body provided with an imaging optical system for imaging imaging light from the fundus of the subject's eye illuminated by the illumination light source to the imaging means, and fundus imaging images obtained by the imaging means with different imaging sites. Image recording means for recording and holding, imaging part position information recording means for recording position information of each imaging part with respect to the optical axis of the imaging optical system for each imaging part, and at least two fundus imagings based on the position information An arithmetic processing unit that calculates the parallax equivalent amount of the image and calculates image depth information for each pixel based on the parallax equivalent amount and the image movement amount for each pixel, and obtained by the arithmetic processing unit Image processing means for converting the depth information of the obtained image into a color and adding a color to the image for each pixel, and colored fundus photography in which the depth information is given as a color based on the processing result of the image processing means Display to display the image Fundus image photographing apparatus characterized by comprising a stage. The fundus image photographing apparatus according to claim 1, wherein the colored fundus photographing image obtained for each photographing part is a moving image. The fundus image photographing apparatus according to claim 1, wherein three-dimensional display is possible by displaying the two colored fundus photographing images side by side. The arithmetic processing means subtracts pixel data for each pixel of a pair of fundus photographic images of the same fundus region that are different over time, and the image processing means performs fundus tissue based on the subtraction result. The fundus image photographing apparatus according to claim 1, wherein the changing unit is displayed on the display unit. The fundus image photographing apparatus according to claim 1, wherein the image processing unit pastes the plurality of colored fundus photographed images to display a fundus photographed image with a wide field of view on the display unit. The fundus image photographing apparatus according to claim 1, wherein the fundus of the eye to be examined is illuminated with near infrared light, and the imaging means has sensitivity in the near infrared region.

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