Ophthalmic imaging system and ophthalmic imaging program

Abstract

The system automatically calculates the position of the object to be exposed for exposure time calculation, making it easy to determine the appropriate exposure time. [Solution] The system includes a camera 22 that photographs the target area including the subject's eye observed by the ophthalmic device 20, and an exposure time calculation means for calculating the exposure time of the camera 22. The exposure time calculation means divides the target area into areas with different brightness levels and calculates an exposure time that matches the brightness level of the area specified by the operator.

Description

[Technical Field]

[0001] The present invention relates to an imaging system and an imaging program for photographing a subject's eye. [Background Art]

[0002] As an ophthalmic apparatus, a slit lamp microscope can be mentioned, for example. A slit lamp microscope is also called a slit lamp microscope, and is an apparatus that irradiates a subject's eye (such as the anterior segment of the eye) with slit light from an oblique direction to visualize and observe transparent or translucent tissues for observing the subject's eye in ophthalmology.

[0003] For example, Patent Document 1 (Japanese Patent No. 3118862) discloses a slit lamp microscope including a slit lamp illumination unit that emits slit light, a microscope unit having an eyepiece for observing a subject's eye, and a camera arranged by branching an optical path on a path from the subject's eye to the microscope unit.

[0004] In Patent Document 1, a method is adopted in which predetermined combinations of an imaging site and an imaging method of a subject's eye are presented to an photographer, an operation of selecting one of the combinations is received from the photographer, coefficients for the imaging site and the imaging method of the combination are stored in advance, and an exposure amount is calculated using the coefficients and a predetermined calculation formula. [Prior Art Literature] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent No. 3118862 [Summary of the Invention] [Problem to be Solved by the Invention]

[0006] Slit-lamp microscopes are used in dark environments with low ambient light levels, and only the slit area is bright, making it extremely difficult to capture clear images with a camera. In other words, because only the slit area is bright and the rest of the image is dark, the bright areas tend to be overexposed and the dark areas tend to be underexposed.

[0007] While the configuration disclosed in Patent Document 1 is designed to calculate the appropriate exposure amount, it requires pre-setting the combination of the shooting area and shooting method, which presents a challenge in that it cannot be used universally.

[0008] Therefore, the present invention has been made to solve the above problems, and its objective is to provide an ophthalmic equipment imaging system and an ophthalmic equipment imaging program that can automatically calculate the position of the object to be exposed for exposure time calculation and set an appropriate exposure time. [Means for solving the problem]

[0009] The ophthalmic imaging system according to the present invention comprises a camera that captures a target area including the subject's eye to be observed by the ophthalmic device, and an exposure time calculation means for calculating the exposure time of the camera, wherein the exposure time calculation means divides the target area into areas with different brightness levels and calculates an exposure time that matches the brightness level of the area specified by the operator. With this configuration, the shooting area is divided into areas based on brightness, and the exposure time is calculated based on the brightness of the specified area, making it easy to calculate an appropriate exposure time.

[0010] Furthermore, the exposure time calculation means is characterized by creating a luminance value conversion image by converting the live view image of the target area based on luminance values, setting a predetermined range of the luminance value conversion image as the exposure time calculation range, dividing the exposure time calculation range into an area having a luminance of a predetermined threshold or higher and an area having a luminance of less than the threshold, and calculating the exposure time for an area specified by the operator from among the area having a luminance of a predetermined threshold and the area having a luminance of less than the threshold, based on a predetermined exposure time measurement algorithm. This configuration makes it easy to calculate exposure times based on either high-luminance areas or low-luminance areas.

[0011] Furthermore, the system is characterized by comprising HDR processing means that acquires the target area for shooting as a brightness image and a darkness image, and creates an image of the target area for shooting with HDR processing. Images captured by a camera can be made to appear as clear and easy to view as they would to the human eye. [Effects of the Invention]

[0012] According to the present invention, the position of the object to be measured for exposure time can be automatically calculated, and an appropriate exposure time can be easily determined. [Brief explanation of the drawing]

[0013] [Figure 1] This is an explanatory diagram showing the schematic configuration of an ophthalmic imaging device. [Figure 2] This is a side view of a slit-lamp microscope. [Figure 3] This is a block diagram showing the internal structure of a computer. [Figure 4] This is a flowchart explaining the process of calculating exposure time. [Figure 5] This is an explanatory diagram showing an example of a live view image. [Figure 6] This is an explanatory diagram showing an example of a brightness value conversion image. [Figure 7]It is an explanatory diagram showing an example in which an exposure time calculation range is divided into an area having a luminance equal to or higher than a threshold and an area having a luminance lower than the threshold. [Figure 8] It is an explanatory diagram showing another example in which an exposure time calculation range is divided into an area having a luminance equal to or higher than a threshold and an area having a luminance lower than the threshold. MODE FOR CARRYING OUT THE INVENTION

[0014] A schematic configuration of the ophthalmic device imaging system according to the present embodiment is shown in FIG. 1 and FIG. 2. In the following description, a slit lamp microscope is taken as an example of the ophthalmic device.

[0015] The ophthalmic device imaging system 10 of the present embodiment includes a camera 22 that images a subject's eye and a computer 24, and the camera 22 is provided in the slit lamp microscope 20. Although the camera 22 and the computer 24 are connected to enable data communication, the connection may be a wired connection or a wireless connection.

[0016] The slit lamp microscope 20 is provided with a slit light unit 31 that emits slit light, a mirror unit 32 that reflects the emitted slit light toward the subject's eye, and a chin rest 34 on which the subject places their chin. A microscope 36 for observing the subject's eye of the subject who has placed their chin on the chin rest 34 is provided at a position facing the chin rest 34.

[0017] The microscope 36 is provided with a camera mounting portion 38 that has a beam splitter (not shown) therein and allows the camera 22 to be mounted thereon. The camera mounting portion 38 is provided closer to the subject's eye than an eyepiece 39, and splits light from the subject's eye to the eyepiece 39 side and the camera 22 side.

[0018] The microscope 36, the slit light unit 31, and the mirror unit 32 are attached to a fine movement base 40. The fine-adjustment base 40 is provided so as to be able to move slightly in the horizontal plane relative to the base 42. The fine adjustment of the fine-adjustment base 40 can be performed by operating the joystick 44.

[0019] Figure 3 also shows a block diagram illustrating the internal configuration of the computer 24 connected to the camera 22. A general-purpose personal computer can be used as the computer 24. The computer 24 comprises a control unit 50 consisting of a CPU and memory, a storage unit 51 consisting of a hard disk or SSD, a monitor 54, and an input unit 55 consisting of a mouse and keyboard. Computer 24 is operated by operators such as ophthalmologists.

[0020] The memory unit 51 stores an exposure time calculation program P1 that calculates an appropriate exposure time based on the live view image from the camera 22. The control unit 50 implements an exposure time calculation means that calculates an appropriate exposure time by reading and executing the exposure time calculation program P1.

[0021] Figure 4 below shows a flowchart of the exposure time calculation process. When the control unit 50 executes the exposure time calculation program P1, it acquires a live view image from the camera 22 (step S100). As shown in Figure 5, this live view image reveals two rays of light: a slightly wider slit of light reflecting off the surface of the subject's eye, and a slightly narrower slit of light reflecting off the back of the subject's eye. The narrower slit of light reflecting off the back of the subject's eye does not reflect off the pupil, but can be seen on both sides of the pupil.

[0022] The control unit 50 creates a brightness value converted image by converting the acquired live view image based on the brightness value (step S102). Figure 6 shows the luminance value conversion image. Areas with high luminance are the areas that appear white. These areas correspond to the areas with a slightly wider slit of light that reflects off the surface of the subject's eye and the areas with a slightly narrower slit of light that reflects off the back of the subject's eye.

[0023] The control unit 50 sets a predetermined area in the brightness value conversion image as the exposure time measurement range (step S104). For example, as shown in Figure 7, 50% of the area in the center of the target area can be set as the exposure time measurement range. In Figure 7, the square area A1 located in the center of the brightness value conversion image is set as the exposure time measurement range. However, the operator may arbitrarily change the area within the target area to be set as the exposure time measurement range, and what percentage of the target area it represents.

[0024] The control unit 50 divides the exposure time calculation range A1 into an area a1 having a brightness equal to or greater than a preset threshold and an area b1 having a brightness less than the threshold (step S106). In Figure 7, area a1, which has a brightness above the threshold, is the L-shaped area from the left to the bottom of the exposure time calculation range A1, while area b1, which has a brightness below the threshold, is the rectangular area on the right side of the exposure time calculation range A1. However, the brightness threshold can be changed at the operator's discretion.

[0025] Based on the operator's instructions, the control unit 50 calculates the exposure time for either area a1, which has a brightness above a threshold, or area b1, which has a brightness below a threshold, based on a preset exposure time measurement algorithm (step S108). Furthermore, a general calculation formula can be used for the exposure time measurement algorithm.

[0026] Furthermore, the operator may choose which area to calculate the exposure time for—area a1 with a brightness above the threshold, or area b1 with a brightness below the threshold—by operating the input unit 55 each time, or the operator may pre-set which area to calculate the exposure time for in the initial settings. In addition, the initial setting for which area to calculate the exposure time can be changed.

[0027] The control unit 50 displays the exposure time calculated based on the selected area on the monitor 54. The operator then operates the camera 22 accordingly, based on the exposure time displayed on the monitor 54.

[0028] In step S106, the areas with a brightness above the threshold and the areas with a brightness below the threshold may each consist of multiple locations. In the example shown in Figure 8, area a1 is defined as having a brightness above the threshold, including the area of ​​the slightly wider slit light reflected from the surface of the subject's eye and the area of ​​the slightly narrower slit light reflected from the back of the subject's eye. Areas b1 and b2, located on either side of a1, are defined as having a brightness below the threshold.

[0029] As described above, the exposure time calculation range is divided into areas with brightness above a threshold and areas with brightness below a threshold, and the exposure time is calculated based on whichever area the operator wants to observe, so that the operator can obtain a clear image of the area they want to observe.

[0030] Furthermore, the memory unit 51 may also store an HDR processing program P2 that acquires the target area for shooting as a brightness image and a darkness image, and creates an HDR processed image of the target area. The control unit 50 implements an HDR processing means that creates an HDR-processed image by reading and executing the HDR processing program P2.

[0031] HDR processing, or High Dynamic Range processing, is a known technique that combines bright and dark images to make an image easier to view, similar to how humans see it.

[0032] Furthermore, in the embodiments described above, the exposure time calculation means has been described as being performed by a computer provided separately from the camera 22, but the exposure time calculation means may also be provided in the camera 22 itself.

[0033] Furthermore, ophthalmic equipment is not limited to slit-lamp microscopes; it can also be used in any device for observing a subject's eye, such as surgical microscopes, contrast and glare testers, and fundus examination devices. [Explanation of Symbols]

[0034] 10. Ophthalmic Imaging Systems 20. Slit-lamp microscope 22 cameras 24 Computers 31 Slit Light Unit 32 Mirror Unit 34 Chin rest 36 Microscopes 38 Camera mounting section 39 Eyepiece 40 Fine-touch base 42 base 44 Joysticks 50 Control Unit 51 Storage section 54 monitors 55 Input section P1 Exposure Time Calculation Program P2 HDR Processing Program

Claims

1. The system comprises a camera that captures a target area including the subject's eye observed by ophthalmic equipment, and an exposure time calculation means for calculating the exposure time of the camera. The exposure time calculation means is An ophthalmic imaging system characterized by dividing the target area into areas with different brightness levels and calculating an exposure time that matches the brightness level of the area specified by the operator.

2. The exposure time calculation means is A luminance value converted image is created by converting the live view image of the target area based on the luminance value. A predetermined range of the brightness value conversion image is set as the exposure time calculation range, The exposure time calculation range is divided into an area having a brightness above a predetermined threshold and an area having a brightness below the threshold. The ophthalmic imaging system according to claim 1, characterized in that it calculates the exposure time based on a preset exposure time measurement algorithm for an area specified by the operator from among the areas having a brightness above the threshold and the areas having a brightness below the threshold.

3. The ophthalmic equipment imaging system according to claim 1 or 2, characterized by comprising HDR processing means for acquiring the target area for imaging as a bright-luminance image and a dark-luminance image, and for creating an HDR-processed image of the target area for imaging.

4. A computer-readable program connected to a camera that captures a target area including the subject's eye observed by ophthalmic equipment, The aforementioned shooting target range is divided into areas with different brightness levels, A function that allows the operator to input a specified area, An ophthalmic imaging program characterized by a function that allows a computer to calculate the exposure time according to the brightness of an area specified by the operator.

5. A function to create a brightness value converted image by converting the live view image of the shooting target area based on brightness values, A function to set a predetermined range of the brightness value conversion image as the exposure time calculation range, The function divides the exposure time calculation range into an area having a brightness above a predetermined threshold and an area having a brightness below the threshold. The ophthalmic equipment imaging program according to claim 4, characterized in that it enables a computer to implement a function that calculates the exposure time based on a preset exposure time measurement algorithm for an area specified by the operator from among areas having a brightness above a threshold and areas having a brightness below the threshold.

6. The ophthalmic equipment imaging program according to claim 4 or 5, characterized in that it enables a computer to implement an HDR processing function that acquires the target area for imaging as a bright-luminance image and a dark-luminance image, and creates an HDR-processed image of the target area for imaging.

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