JP2008104628A - Conjunctiva and sclera imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conjunctiva and sclera imaging apparatus which can image the blood vessels, blood flow and/or blood corpuscles of the conjunctiva and/or the sclera by compensating for fixation movements of an eyeball such as small involuntary eye movements. <P>SOLUTION: The conjunctiva and sclera imaging apparatus is composed of a target 10 for a subject to gaze at, an imaging device 3, a light source 4, an adjustment mechanism 5, an image processing section 6, a compensation portion 7 for small involuntary eye movement, and a monitor 8. The imager is structured so as to image an imaging area with a resolution of 2 μm or lower as a resolution permitting the analysis of the blood vessels, blood flows, and/or blood corpuscles of the conjunctiva and/or the sclera at a rate of 200 frames per second or higher so as to compensate for the influence of fixation small involuntary movements. The image processing section processes images captured by an imaging means to permit the recognition and chase of a blood vessel pattern of the conjunctiva and/or sclera. The compensation section processes images so as to stop the vibration of the images processed by the image processing means. The monitor displays the images. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a conjunctival sclera imaging apparatus that images the conjunctiva and / or sclera of an eyeball, and in particular, compensates for movement of the eyeball, such as fixation eye movement, and the conjunctival and / or scleral blood vessels, blood flow and / or blood cells The present invention relates to a conjunctival sclera imaging apparatus capable of imaging the image.

  Measure blood flow velocity by Doppler method by observing blood vessels etc. by observing blood vessels under the fingernail as a method of measuring capillaries, blood flow and blood cells of living body Are known (Patent Document 1, Patent Document 2).

JP-A-10-276986 JP 2000-83916

  However, since the blood vessel and blood flow measuring device under the nail cannot obtain sufficient resolution, it has not been possible to confirm blood cells. Further, in the observation of the fundus retina, the visual cells are sensitive and easily damaged, and therefore a light source that emits strong light cannot be used, so that high-speed imaging with sufficient resolution is difficult. In these methods, the Doppler method is used to measure the blood flow velocity, and the blood flow velocity cannot be obtained from the captured image. In the Doppler method, the blood flow of each blood vessel cannot be measured because the blood vessel at the measurement site is thin, and it is difficult to identify the position of the blood vessel and the blood flow velocity. For this reason, the measurement accuracy was not high.

  The blood vessels present in the conjunctiva and / or sclera are the closest to the body surface, and the conjunctiva, which is a coating, is highly transparent, making it the ideal place for non-invasive measurement of blood and blood vessels in a living body . However, since there are microscopic fixations that constantly vibrate at a high frequency (up to 90 Hz) even while the target is fixed, the eyeball is shaken violently when trying to image capillaries and blood cells. , Could not image.

  In view of such circumstances, the present invention is intended to provide a conjunctival sclera imaging device capable of imaging conjunctival and / or scleral blood vessels, blood flow, and / or blood cells by compensating for movements such as eye movements. To do.

  In order to achieve the above-described object of the present invention, an eyeball conjunctival sclera imaging apparatus according to the present invention includes a visual target for a subject to gaze, blood vessels in the conjunctiva and / or sclera of the eyeball, blood flow, and blood flow. In order to compensate for the effects of fixation micromotion and / or resolution capable of analyzing blood cells, the imaging area capable of imaging the imaging area at a resolution of 2 μm or less and 200 frames / second or more, and the imaging area of the imaging means are illuminated An image processing unit that performs image processing on an image captured by the imaging unit so as to be able to recognize and track the conjunctival and / or scleral blood vessel pattern of the eyeball, and a light source, an adjustment unit that adjusts the position of the imaging area of the imaging unit And a fixation micromotion compensation unit that stops vibration of an image processed by the image processing unit, an image captured by the imaging unit, an image processed by the image processing unit, or a fixation micromotion compensation unit. Display means for displaying that image, and comprising a.

  Here, the imaging area of the imaging means may be at least 100 μm to 2000 μm square.

  Further, the adjusting means may adjust the position of the imaging area so as to follow fixation fine movement using a signal from the fixation fine movement compensation means.

  Furthermore, you may make it have a high-resolution imaging device interlock | cooperated with the eyes | visual_axis position of an imaging means.

  Still further, the high-resolution imaging device may be provided, and the adjustment unit may adjust the imaging position of the high-resolution imaging device so as to follow the fixation micromotion using a signal from the fixation micromotion compensation unit.

  Furthermore, you may have a lens means arrange | positioned between a visual target and an eyeball.

  Further, the visual target may be sequentially moved so that each part of the conjunctiva and / or sclera of the eyeball can be sequentially imaged, and the image processing means may connect the sequentially imaged images.

  Further, the fixation fine movement compensation means detects the movement amount of the vascular pattern by extracting the vascular pattern from one frame of the image to be captured and searching for the corresponding pattern in the subsequent frame, You may make it arrange | position the blood vessel pattern of each image in the same position.

  Furthermore, the imaging means may use the depth of focus in order to distinguish and image the conjunctival blood vessel or the scleral blood vessel.

  Furthermore, the image processing unit may perform image processing on an image captured by the imaging unit so that blood cells in the blood vessel can be traced.

  Here, the light source may illuminate light having a specific wavelength distribution, and the display unit may display an image that can identify the blood vessel or blood tissue using the reflectance or transmittance of the blood vessel or blood.

  Further, the light source may illuminate light having a specific wavelength, and the conjunctival sclera imaging device may further include a spectroscopic unit that analyzes reflected light from the eyeball.

  The light source may be a laser light source.

  Furthermore, a laser analysis sensor that detects the wavelength, phase, and / or intensity of the reflected light from the eyeball may be provided.

  The light source may be arranged so that the incident angle of the light source with respect to the eyeball and the angle of the line of sight of the imaging means are symmetrical with respect to the normal of the eyeball at the incident position of the light source.

  The light source is a point light source or a line light source and scans the imaging area, and the image processing means extracts images by scleral reflected light from the images sequentially picked up by the imaging means, and synthesizes them for scleral reflection An optical image may be generated.

  Furthermore, you may make it have a nozzle for providing a chemical | medical agent to an eyeball.

  The eyeball conjunctival sclera imaging apparatus of the present invention has an advantage that it can image blood vessels and / or blood cells of the conjunctiva and / or sclera in a non-invasive manner. As a result, a blood test or the like can be performed non-invasively.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view for explaining a first embodiment of the conjunctival sclera imaging apparatus of the present invention. As shown in FIG. 1, the conjunctival sclera imaging device of the present invention includes a visual target 10 for a subject to watch, an imaging device 3 including a camera 1 and a lens 2, a light source 4, an adjustment mechanism 5, and an image. The processing unit 6, a fixation fine movement compensation unit 7, and a monitor 8 are mainly configured.

  The camera 1 is a camera capable of high-speed photography, and is preferably a digital camera capable of high-speed photography. The lens 2 is a high magnification lens. The imaging device 3 has a resolution that can analyze the conjunctiva and / or scleral blood vessels, blood flow, and / or blood cells of the eyeball, and is configured to be able to compensate for the influence of fixation micromotion. The imaging area, resolution, frame speed, etc. are set as appropriate. Specifically, the camera 1 and the lens 2 are selected so that an imaging area of at least 100 μm to 2000 μm square can be imaged at a resolution of 2 μm or less at 200 frames / second or more. High-speed imaging of the imaging area under such conditions provides sufficient spatial resolution to measure at high resolution an imaging area that exceeds the flick or drift motion range. More specifically, the camera 1 can use, for example, FASTCAM (registered trademark) manufactured by Photoron Corporation. For example, when 1 million pixel FASTCAM (registered trademark) capable of imaging at 1000 frames / second is used, the pixel size is 7 μm. In addition, the lens 2 may be a single high-power lens, but if necessary, a wide-angle lens having an angle of view capable of capturing the entire eyeball may be provided separately or a zoom lens. As a premise for photographing, it is preferable that the imaging device 3 is oriented toward the center of the eyeball. That is, theoretically, it is most preferable that the optical axis (visual axis) of the camera overlaps with the normal line of the center point of the imaging area, and an area that is out of focus will come out as it deviates. Since the depth of field of the high-magnification lens is very shallow, if the line of sight of the camera deviates from the normal of the eyeball at the center of the imaging area, the distance from the eyeball surface to the imaging plane of the camera will be increased. This is because it will be out of focus and will be blurred. Therefore, in order to avoid this, it is preferable that the angle formed by the line of sight of the imaging unit incident on the eyeball and the normal of the eyeball at the center of the imaging area is about 3 ° or less.

  The light source 4 is configured to illuminate the imaging area of the eyeball. Specifically, it is composed of a halogen lamp, an optical fiber, a lens and the like, and may be anything that can irradiate light with a radius of about 3 mm, for example, so as to illuminate the entire imaging area. In addition, if it is configured to be able to irradiate with light having a constant wavelength distribution, an image capable of discriminating or measuring a blood vessel or blood tissue can be displayed using the reflectance or transmittance of the blood vessel or blood. Is also possible. Furthermore, by using a spectrometer to analyze the reflected light from the eyeball, it is possible to analyze components such as blood and the structure of the tissue.

  The adjusting mechanism 5 adjusts the position of the imaging area so that the center of the imaging area of the conjunctiva and / or sclera of the eyeball is located at the intersection of the optical axes of the imaging device 3 and the light source 4. This may be an adjustment base having at least two degrees of freedom in the front, rear, left, and right directions, but is preferably an adjustment base having three degrees of freedom in the up, down, front, back, left, and right directions. Further, if necessary, the adjustment mechanism may be configured to have six degrees of freedom so that a higher degree of adjustment is possible. Note that the adjusting mechanism is not physical, and may be adjusted by software. That is, a desired frame may be selected from a wide imaging area, and the position of this frame may be adjusted by software. Further, since the movement of the head itself must be stopped in order to compensate for the fixation fixation fine movement, a fixture for fixing the head of the measurement subject may be used as necessary. Specific examples of the fixture include a combination of a rod-like member that is bitten with teeth and a plate-like member that presses a forehead portion. By firmly fixing the head with the fixing tool, it is possible to eliminate the rotation of the head, and it is possible to reduce the compensation range (movement amount) of the eye movement.

  Further, the adjustment mechanism can be configured to automatically and freely set the position of the imaging device using an actuator or the like. It is also possible to take an image of an eye angle or the like at the same time and compensate for the movement of the head based on this position.

  The image processing unit 6 is composed of an electronic computer such as a personal computer, and performs various image processing. That is, the image processing unit 6 performs image processing on the image captured by the imaging device 3 so that the conjunctiva of the eyeball and the blood vessel pattern of the sclera can be recognized and tracked. Specifically, the image processing unit 6 first performs noise removal processing as preprocessing on the captured image. In normal high-speed camera shooting, the exposure time is very short, so illumination with a sufficient amount of light is necessary to achieve proper exposure. However, since it is difficult to pick up an image by applying strong light to the eyeball, an image is picked up with a low light quantity, and therefore random noise such as high-sensitivity noise gets on the image. Therefore, in order to remove such noise, noise removal processing, for example, median filter processing is performed. Further, due to the characteristics of the lens 2 or the like, there may be a case where a decrease in peripheral light amount called vignetting or vignetting appears in the captured image. In addition, there may be a deviation in brightness due to irradiation spots of the light source 4 that illuminate the eyeball. Therefore, vignetting correction and irradiation spot correction may be performed as necessary so as to correct such bias. Such correction can be performed by dividing an image obtained by capturing an eyeball by an image obtained by photographing a blank sheet in advance.

  Further, the image processing unit 6 may be configured not to use an image at a blinking moment if necessary. Specifically, when images that are sequentially picked up are largely different from each other, processing may be performed so as to omit the images between them. Further, if necessary, the process of removing the influence of wrinkles and wrinkles, the influence of shadows, and the like from the image may be performed.

  Further, the eyeball 10 is intentionally rotated by moving the target 10 so that the conjunctiva and / or sclera are sequentially imaged, and these images are connected by the image processing unit 6 to form an image of a large area. You may make it produce | generate.

  Next, the fixation micromotion compensation unit 7 compensates for the fixation micromotion of the eyeball on the image that has been subjected to the predetermined processing in the image processing unit 6 in this manner. That is, an image in which the vibration of fixation micromotion is stopped is generated so that the conjunctiva and / or scleral blood vessel can be observed in a stationary state. The fixation fine movement compensation unit 7 may be configured by an electronic computer such as a personal computer, or may be the same as the electronic computer of the image processing unit.

  First, the fixation fine movement compensation unit 7 performs matching between two consecutive frames on sequentially captured images. That is, a predetermined pattern is selected from the previous frame, and the same pattern is extracted from the subsequent frame. As the predetermined pattern, it is possible to use an eyeball conjunctiva and / or a scleral blood vessel pattern. In the conjunctival sclera imaging apparatus of the present invention, imaging is performed under conditions that can compensate for the effects of eye movements of the fixation, so that it is possible to capture even the conjunctival and / or scleral blood vessel pattern. Therefore, for example, a region where blood vessels are closely distributed may be used as a predetermined pattern when matching is performed. An area surrounding this predetermined pattern is taken out as a search window, and matching with subsequent frames is performed.

  Here, matching will be described. The matching method is well known as a method for judging what an observed pattern is by superimposing an ideal pattern and an observed pattern in pattern recognition. In the present invention, matching between two consecutive frames is performed, and the movement amount of the same pattern is compensated in pixel units. Here, the matching method mainly includes a template matching method and a structure matching method. In the template matching method, a pattern is directly superimposed on the next frame, and the similarity is determined by comparing each element (each pixel). In the structure matching method, feature points are extracted from the pattern of the previous frame (reference frame) and the next frame (frame of interest), and the degree of similarity is determined by comparing the positional relationship between the feature points. In the conjunctival sclera imaging apparatus of the present invention, any matching method may be used. However, when it is difficult to extract a clear feature amount with a small outline or the like in an image to be captured, a template matching method is adopted. preferable. As a template matching method, a method using a correlation coefficient, an SSDA (Sequential Similarity Detection Algorithm) method, a least square matching method, and the like are known. The eyeball has only approximately parallel / rotational motion, and the SSDA method is the most preferable among them from the results of actual trials.

Is given. That is, the search image is, for example, a frame of interest, and the reference image is a selected partial region in the standard frame. At this time, the search window and the reference frame in the frame of interest
The position of the search window given by the above equation is most similar to the reference image. That is,

  Note that the matching method based on the SSDA method can detect only when the reference image is translated within the frame of interest, and cannot detect when the region within the frame of interest is geometrically deformed. Basically, only two degrees of freedom can be calculated. Although there is no problem with this, if the least square matching method is used instead of the SSDA method, it is possible to calculate the three-degree-of-freedom rotation of the eyeball, and it is possible to deal with geometric deformation.

  In this way, the corresponding position of the search window in each successive image is detected, the movement amount of the blood vessel pattern is detected, and the position of each image is moved so that the positions of the search windows overlap. By doing so, eye movement fixation is compensated, and the blood vessel pattern appears to be stationary. It is possible to perform various analyzes on the conjunctiva of the eyeball and / or the blood vessels of the sclera, etc., using the continuous image compensated for this fixation micromotion.

  The monitor 8 displays the image compensated in this way. Note that the monitor 8 is connected to the camera 1 and the image processing unit 6 as necessary, and can be used for visual check of a captured image and an image processed image.

  Hereinafter, a method for photographing an eyeball using the conjunctival sclera imaging apparatus configured as described above will be specifically described. As a premise for photographing, it is preferable that the imaging device 3 is oriented toward the center of the eyeball, so that the imaging area is adjusted by the adjustment mechanism 5 so as to meet this condition. Further, in order to adjust the position of the imaging device 3, an image from the imaging device 3 may be displayed on the monitor 8 in real time. Real-time display may be performed at a normal rate (30 frames / second) instead of a high-speed rate.

  The camera 1 used in the conjunctival sclera imaging apparatus of the present invention can image at 1000 frames / second and has a pixel size of 7 μm. The enlargement ratio of the lens 2 is 5 to 60 times. An image picked up by the image pickup device 3 is taken in by an electronic computer such as a personal computer as needed. If necessary, a storage device may be provided in the imaging device 3 and temporarily stored therein, and the image may be taken into an electronic computer after imaging.

  The subject to be measured presses the forehead against the forehead fixture in order to fix the head, and tightens the rod-like fixture with teeth. And in order to suppress rotation of an eyeball, the target 10 for a to-be-measured person's gaze is shown. The imaging device 3 that is a high-magnification high-speed camera is first set to a normal frame rate (for example, 30 frames / second or less), and the illumination intensity of the light source 4 is lowered to irradiate the sclera and / or conjunctiva of the eyeball. . If necessary, the eyeball is imaged with a wide-angle lens, and the position of the imaging device 3 is adjusted by the adjusting mechanism 5 while the image is displayed on the monitor 8 and confirmed. Then, the focal position is adjusted while confirming the image switched to the high magnification lens. Note that by using the depth of focus, it is also possible to perform imaging while distinguishing between conjunctival blood vessels and scleral blood vessels. That is, since the depth of field is very shallow, it is possible to select whether to focus on the conjunctival blood vessel or focus on the scleral blood vessel by adjusting the focal position. Next, the illuminance of the light source is increased so that a good image can be obtained even at high-speed imaging. However, the illuminance of the light source is set so as not to damage the eyeball. In this state, high-speed imaging is started, and images captured by the personal computer are sequentially captured.

  Next, the image processing unit 6 extracts a predetermined frame from the captured image and sets it as a reference frame. The image is subjected to noise removal processing, vignetting correction, and irradiation spot correction as preprocessing. The fixation fine motion compensation unit 7 performs feature point extraction on the image that has undergone the preprocessing. In the feature point extraction, a region where the conjunctiva and / or sclera blood vessels of the eyeball are closely distributed is cut out, and a region surrounding the region is extracted as a reference image.

  Next, the above preprocessing is also performed on the image of the subsequent frame, and matching by the SSDA method is performed. Thereby, the position of the search window corresponding to the reference image of the standard frame is detected in each image. Then, the position of each image is moved so that the positions of the corresponding search windows overlap, and an image in which the movement of the eyeball is compensated is generated. An example of the image generated in this way is shown in FIG.

  The images of the conjunctival and / or scleral blood vessels generated as described above are very clear images compensated for eye movements, and if these images are used, blood vessels, blood flow, blood cells Various analyzes such as these are possible. For example, it is possible to designate a blood vessel from the image and measure the diameter of the blood vessel or measure the thickness of the blood vessel wall. It is of course possible to display the measurement result on the monitor 8. In addition, since it is possible to resolve up to one red blood cell, the amount of movement between each frame can be calculated, and the red blood cell can be traced from this and the moving speed can be detected. It is also possible to count the number of red blood cells in capillaries and determine the unit blood volume of red blood cells from the flow rate of the blood vessels. Since red blood cells can be recognized one by one, it is also possible to measure the oxygen saturation rate from a spectroscopic image. Further, since leukocytes can also be detected, it is possible to determine the ratio of the number of leukocytes and erythrocytes. Furthermore, platelets can also be recognized. Moreover, since the plasma part can also be imaged, it is possible to analyze the components of the plasma.

  Then, if necessary, a nozzle may be prepared to provide a medicine to the eyeball, and a change in blood or the like before and after the medicine is sprayed on the eyeball surface can be observed. Further, if necessary, a fluorescent substance or a staining substance may be introduced into the blood vessel by intravenous injection so that blood and blood vessels can be imaged more clearly.

  Furthermore, since it is possible to obtain information in the depth direction using the depth of focus, it is also possible to generate a three-dimensional image of the conjunctiva and / or sclera by combining these.

  Here, in the illustrated example described above, the imaging apparatus is directly directed to the eyeball that is the imaging target. However, the present invention is not limited to this, and the position of the imaging apparatus can be arbitrarily set as described below. It may be configured to be installed at a place and indirectly image the eyeball. In other words, it is possible to arrange the mirror between the imaging device and the eyeball so that the line of sight of the imaging device is refracted by the mirror so that the imaging device is installed at a position that does not block the line of sight of the eyeball, for example. When the imaging device is directly directed to the eyeball, the line of sight of the eyeball may be blocked or the field of view may be narrowed due to the size of the imaging device itself. However, by providing the mirror in between as described above, it is possible to avoid the problem of obstructing the field of view due to the imaging device itself.

  Further, instead of the mirror, for example, an optical fiber may be disposed between the eyeball and the imaging device so that the line of sight of the imaging device is guided from an arbitrary position to the eyeball. When an optical fiber is used, the distance from the imaging device to the eyeball can also be adjusted. In the case of a mirror, the installation position of the imaging device is determined by the position of the eyeball and the focal length of the lens. Therefore, even if a mirror is installed, the total distance from the eyeball to the imaging device is the same as when no mirror is provided. However, in the case of an optical fiber, the total distance can also be set arbitrarily, so that the imaging device can be installed at an arbitrary location.

  Further, a lens may be disposed between the target and the eyeball in order to change the distance to the position where the target is placed and the distance felt by the eyeball. Furthermore, a lens may be arranged between the visual target and the eyeball so that different visual targets are shown to both eyes. If the conjunctival sclera imaging device is desired to be small, the target cannot be placed far away. If the visual target is placed several centimeters ahead of the eyeball, the visual target is too close and the subject is very tired. In such a case, by disposing a lens between the visual target and the eyeball, it is possible to easily focus on a short-distance visual target. Further, in order to give an illusion of looking at a distant target, two lenses may be shown to both eyes, and a lens may be used to eliminate a contradiction in the focal length of the eye lens. With this configuration, it is possible to arbitrarily adjust the position of the visual target and direct the eyeball in any direction.

  Further, the fixation fine movement compensator 7 can measure the amount of movement of the eyeball. Therefore, by using this information, the position of the imaging area is controlled by the adjustment mechanism 5 so as to follow the eyeball movement. Is also possible. For example, the adjustment mechanism 5 using a piezoelectric element, a giant magnetostrictive element, or the like can move the position of the imaging element of the lens 2 or the camera 1 in accordance with the movement of the eyeball. As a result, the imaging area can also follow fixation fine movement within a small range, so that it is possible to make the imaging area smaller than 100 μm, which is the minimum imaging area when not following eye movement. In addition, a low-resolution high-speed imaging device for tracking eye movements and a high-speed imaging device with a normal speed that links the line-of-sight position can be used together to follow fixation tremor using a high-speed imaging device. On the other hand, it is possible to obtain a good image with high resolution and high saturation and contrast by the high-resolution imaging device. In addition, the high-speed imaging device and the high-resolution imaging device are not linked, and the imaging position of the high-resolution imaging device is adjusted by the adjustment mechanism so as to follow the fixation micro-motion using the signal from the fixation-motion micro-motion compensation unit. It may be configured.

  Next, a second embodiment of the conjunctival sclera imaging apparatus of the present invention will be described. FIG. 3 is a schematic side view for explaining a second embodiment of the conjunctival sclera imaging apparatus of the present invention. FIG. 4 is a schematic top view of the second embodiment. In the figure, the portions denoted by the same reference numerals as those in FIG. As shown in FIG. 3, the conjunctival sclera imaging device of the present invention is similar to the first embodiment in that the visual target 10 for the measurement subject to watch, the imaging device 3 including the camera 1 and the lens 2, and the light source 4 ′, an adjustment mechanism 5, an image processing unit 6, a fixation micromotion compensation unit 7, and a monitor 8.

  The second embodiment is different from the first embodiment in that the light source 4 'is a laser light source. The laser light source is a point light source or a line light source, and the irradiation pattern becomes a point or a line, and is configured to be able to scan the imaging region. In the case of a line light source, the length of the irradiation pattern is preferably longer than the imaging area. In addition, the width of the irradiation pattern of the point light source or the line light source is preferably narrow, but it is preferable that the width received by the image sensor of the image pickup apparatus is about two pixels or more. Further, as shown in FIG. 4, the light source 4 ′ is arranged so that the incident angle of the light source with respect to the eyeball and the line-of-sight angle of the imaging device 3 are symmetric with respect to the normal of the eyeball at the incident position of the light source. ing. That is, the imaging device is configured to capture an image from an angle equal to the incident angle of the incident light from the light source using specular reflection with respect to the normal of the eyeball.

  An imaging principle using specular reflection will be described with reference to FIG. FIG. 5 is a diagram for explaining the relationship among the eyeball, the light source, and the imaging device. The imaging device 3 is placed on the side opposite to the normal of the eyeball, and the angle of the line of sight of the imaging device 3 is configured to be the same as the incident angle of the light source 4 ′. In this way, the strongest reflected light can be imaged by the principle of specular reflection. As an example, the imaging device 3 and the light source 4 ′ are placed with their height aligned so that the line of sight of the imaging device and the optical axis of the laser light source (in the case of a linear light source) are on the same horizontal plane. , And the mirror reflection is placed symmetrically so that it can be imaged. And it adjusts so that the visual field of the imaging device 3 may face the center of an eyeball. For example, when a line light source laser light source is used as the light source 4 ′, when the conjunctiva and / or sclera surface of the eyeball is irradiated, a line light image appears.

  The relationship between the conjunctiva, sclera, and blood vessels and the image to be captured will be described with reference to FIG. As shown in the figure, the laser beam is reflected on the conjunctival surface and the sclera surface, respectively, and two lines are imaged. Here, when a conjunctival blood vessel exists, the laser beam is also reflected by the blood vessel. That is, part of the laser beam is also reflected on the blood vessel surface, and the other part is absorbed by the blood vessel and then transmitted and reflected on the sclera surface. Since the blood vessel is cylindrical, a part of the reflected light is imaged as specular reflected light, but most of the reflected light is imaged as scattered light, so that the reflected light of the part that is not specularly reflected is weak. The reflected light on the surface of the sclera is not changed in the specular reflection light in a portion where there is no blood vessel, but the reflected light is weakened because part of the light transmitted through the blood vessel is absorbed by the blood vessel. As shown in the image shown in FIG. 6, of the two straight lines in the image, the left line is reflected light on the conjunctival surface, and the right straight line is reflected light on the sclera surface and is between them. The line is the reflected light at the blood vessel surface. The reflected light on the conjunctival surface is picked up with uniform brightness, but the reflected light on the scleral surface is partially dark because the reflected light transmitted through the blood vessel is weakened. The reflected light from the blood vessel surface is weakly reflected because the blood vessel has a cylindrical shape. In this way, the reflected light on the surface of the sclera changes depending on the presence or absence of blood vessels, so the state of blood vessels and blood cells can be changed by synthesizing an image that compensates for involuntary eye movements by scanning at high speed while scanning the imaging area with a laser beam. It is possible to display. Note that if the scanning speed of the entire imaging area by the laser beam is, for example, 10 ms or less, it is possible to compensate for fixation fine movement. If scanning is simultaneously performed using a plurality of laser beams (interlaced scanning or the like), the scanning speed can be further increased. Further, in addition to the laser beam, a light source such as a halogen lamp as in the first embodiment may be used at the same time, and the fixation micromotion compensation may be performed in the same manner as in the first embodiment using an image captured by the light source.

  The principle of synthesizing an image in which high-speed imaging is performed while the imaging area is scanned with a laser beam to compensate for fixation fixation micromotion will be described with reference to FIG. Assume that the imaging area is scanned from the right to the left on the drawing in the order of FIG. 7A to FIG. Images captured at this time are shown in FIGS. 7 (a ') to 7 (d'), respectively, and a combination of the respective reflected images is shown in FIG. 7 (e). As can be seen from FIG. 7 (e), the reflected light of the conjunctiva is basically uniform, so that when combined, images are captured with uniform brightness. In addition, since most of the reflected light from the blood vessels is scattered light, the synthesized image is captured in a dark and unstable state. As for the reflected light of the sclera, the light that has been transmitted through the blood vessel and then incident on the sclera and reflected from the same blood vessel and the light that has been incident and reflected on the sclera are transmitted through the blood vessel. Exists. For this reason, the reflected light image of the blood vessel and the transmitted light image are obtained from the image of the reflected light of the sclera. That is, if the imaging area is scanned with a light source, images of scleral reflected light are extracted from each image sequentially captured by the imaging device, and these are combined to generate a scleral reflected light image, the reflected light and transmitted light An image of the blood vessel is obtained. Note that only one of the images of the blood vessels by reflected light and transmitted light may be extracted by image processing. Here, the reflected light image and the transmitted light image of the same blood vessel may overlap depending on the positional relationship between the distance between the blood vessel and the sclera and the incident angle of the laser light. In this case, it is possible to distinguish the two by image processing using the gray value of the image or the like, but it is of course possible to use other blood vessel sites for measurement.

  Using the blood vessel image obtained in this way, various analyzes of blood vessels, blood flow, blood cells, and the like can be performed as in the first embodiment. In the above-described example, the line light source is used. However, even in the case of a point light source, it is sufficient that the entire imaging area can be scanned. Also, with regard to the line light source, if a plurality of line light sources are scanned at a distance exceeding two images by the conjunctival reflected light and the sclera reflected light, a plurality of irradiation positions can be imaged in one frame, so that the image is efficiently captured. It is also possible to do.

  In addition, it is also possible to analyze each tissue and the like by further providing a laser analysis sensor that irradiates the eyeball with a laser light source and detects the wavelength, phase, intensity, and the like of the reflected light from the eyeball. That is, for example, by irradiating an eyeball with a light source capable of emitting light of a plurality of wavelengths with uniform intensity and measuring reflected light using a spectrometer, various reflection intensities can be obtained from each wavelength. Can be analyzed.

  The conjunctival sclera imaging device for the eyeball of the present invention is not limited to the above-described illustrated examples, and it is needless to say that various modifications can be made without departing from the scope of the present invention. For example, the conjunctival sclera imaging device of the present invention can be applied to a fundus retinal imaging device that images the fundus retina and is used for various measurements, or can be applied to a blood vessel and blood flow measurement device under the nail. .

FIG. 1 is a schematic side view for explaining a first embodiment of the conjunctival sclera imaging apparatus of the present invention. FIG. 2 is an example of an image in which the movement of the eyeball is compensated. FIG. 3 is a schematic side view for explaining a second embodiment of the conjunctival sclera imaging apparatus of the present invention. FIG. 4 is a schematic top view for explaining a second embodiment of the conjunctival sclera imaging apparatus of the present invention. FIG. 5 is a diagram for explaining the relationship among the eyeball, the light source, and the imaging device. FIG. 6 is a diagram for explaining the relationship between the conjunctiva, the sclera, and the blood vessels, and the captured image. FIG. 7 is a diagram for explaining the principle of synthesizing an image in which high-speed imaging is performed while scanning an imaging area with a laser beam to compensate for fixation fixation micromotion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera 2 Lens 3 Imaging device 4 Light source 5 Adjustment mechanism 6 Image processing part 7 Fixation fine movement compensation part 8 Monitor 10 Target

Claims (17)

A conjunctival sclera imaging device for imaging the conjunctiva and / or sclera of an eye, the device comprising:
A target for the subject to gaze at;
The imaging area is imaged at a resolution of 2 μm or less and 200 frames / second or more so that the conjunctiva and / or scleral blood vessels, blood flow and / or blood cells of the eyeball can be analyzed and the effect of fixation micromotion can be compensated. Possible imaging means;
A light source that illuminates an imaging area of the imaging means;
Adjusting means for adjusting the position of the imaging area of the imaging means;
Image processing means for image-processing an image picked up by the image pickup means so that a blood vessel pattern of the conjunctiva and / or sclera of the eyeball can be recognized and tracked;
Fixation / micromotion compensation means for stopping vibration of the image processed by the image processing means,
Display means for displaying an image picked up by the image pickup means, an image processed by the image processing means or an image compensated by the fixation fixation compensation means;
An apparatus for imaging a conjunctival sclera of an eyeball characterized by comprising:   The conjunctival sclera imaging device for an eyeball according to claim 1, wherein an imaging area of the imaging means is at least 100 μm to 2000 μm square.   3. The eyeball conjunctival sclera imaging apparatus according to claim 1, wherein the adjustment means adjusts the position of the imaging area so as to follow fixation micromotion using a signal from the fixation micromotion compensation means. An apparatus for imaging the conjunctival sclera of an eyeball.   4. The conjunctival sclera imaging device for an eyeball according to claim 3, further comprising a high-resolution imaging device interlocked with a line-of-sight position of the imaging means.   4. The conjunctival sclera imaging device for an eyeball according to claim 1, further comprising a high-resolution imaging device, wherein the adjustment means uses a signal from the fixation micromotion compensation means. A conjunctival sclera imaging device for an eyeball, wherein the imaging position of the high-resolution imaging device is adjusted so as to follow fixation fine movement.   6. The eyeball conjunctival sclera imaging device according to any one of claims 1 to 5, further comprising lens means arranged between the eye target and the eyeball. Sclera imaging device.   The eyeball conjunctival sclera imaging apparatus according to any one of claims 1 to 6, wherein the target is sequentially moved so that each of the conjunctiva and / or sclera of the eyeball can be sequentially imaged, and the image An eyeball conjunctival sclera imaging device characterized in that the processing means stitches the sequentially captured images.   The eyeball conjunctival sclera imaging device according to any one of claims 1 to 7, wherein the fixation microtremor compensation unit extracts a blood vessel pattern from one frame of the image to be captured, and the subsequent frame. A conjunctival sclera imaging device for an eyeball, wherein the movement amount of a blood vessel pattern is detected by searching for a corresponding pattern in step S1, and the blood vessel pattern of each image is arranged at the same position.   9. The conjunctival sclera imaging apparatus for an eyeball according to claim 1, wherein the imaging means uses a depth of focus to distinguish and image a conjunctival blood vessel or a scleral blood vessel. Conjunctival sclera imaging device for the eyeball.   10. The eyeball conjunctival sclera imaging apparatus according to claim 1, wherein the image processing unit performs image processing on an image captured by the imaging unit so that blood cells in a blood vessel can be traced. An apparatus for imaging the conjunctival sclera of an eyeball.   11. The conjunctival sclera imaging device for an eyeball according to claim 1, wherein the light source illuminates light having a specific wavelength, and the display means uses a reflectance or transmittance of blood vessels or blood. An apparatus for imaging a conjunctival sclera of an eyeball that displays an image capable of distinguishing a blood vessel or blood tissue.   12. The eyeball conjunctival sclera imaging device according to any one of claims 1 to 11, wherein the light source illuminates light having a specific wavelength distribution, and the conjunctival sclera imaging device further reflects reflected light from the eyeball. A conjunctival sclera imaging device for an eyeball, characterized by comprising spectroscopic means for analyzing the above.   13. The eyeball conjunctival sclera imaging device according to any one of claims 1 to 12, wherein the light source is a laser light source.   14. The conjunctival sclera imaging device for an eyeball according to claim 13, further comprising a laser analysis sensor for detecting the wavelength, phase and / or intensity of the reflected light from the eyeball. Imaging device.   The eyeball conjunctival sclera imaging device according to claim 13 or 14, wherein the light source has an incident angle of the light source with respect to the eyeball and a line-of-sight angle of the imaging means set to a normal of the eyeball at the incident position of the light source. An apparatus for conjunctival sclera imaging of an eyeball, characterized by being arranged symmetrically with respect to the eyeball.   16. The eyeball conjunctival sclera imaging apparatus according to claim 15, wherein the light source is a point light source or a line light source, scans the imaging area, and the image processing means is configured to generate strong images from images sequentially picked up by the imaging means. An apparatus for extracting conjunctival sclera of an eyeball, which extracts images of membrane reflected light and combines them to generate a sclera reflected light image.   The conjunctival sclera imaging device for an eyeball according to any one of claims 1 to 16, further comprising a nozzle for providing medicine to the eyeball.