Method and device for setting and controlling parameters of an illumination field of an ophthalmic apparatus

Abstract

The invention relates to a solution for setting and controlling parameters of an illumination field of an ophthalmic device. Here, for example, brightness, color / color temperature, field shape, polarization state, etc. can be considered as parameters. The device according to the invention comprises an operating unit for setting a desired illumination parameter, an illumination unit for generating an illumination radiation with the desired illumination parameter, a coupling-out element for coupling out a portion of the illumination radiation, a sensor element for analyzing the coupled-out portion of the illumination radiation, and an evaluation unit for evaluating the sensor data and for determining the actual illumination parameter of the illumination radiation. According to the invention, the sensor element is a local resolution image sensor. While the proposed solution is particularly used for setting and controlling parameters of an illumination field of an ophthalmic device, it can also be used in other technical fields, i.e. for example in microscopy.

Description

Technical Field

[0001] This invention relates to a method and apparatus for setting and controlling parameters of an illumination field in ophthalmic equipment. Here, parameters may include, for example, luminance, color / color temperature, field shape, and polarization state. Background Technology

[0002] In laser-based applications, the parameters of the illumination field are typically controlled by analyzing a defined portion of the coupled radiation output.

[0003] Based on known existing techniques, the shape of the wavefront is monitored in an optical system in a similar manner. A limited portion of the radiation to be monitored is coupled into the output and recorded and evaluated using a dedicated sensor (e.g., a Shack-Hartmann sensor). The information obtained is then used to selectively influence the wavefront.

[0004] In contrast, the parameters of the illumination field of ophthalmic devices such as slit lamps and fundus cameras have not been set at all, not fully set, or only indirectly set via calibrated scales at the operating elements.

[0005] The light distribution that appears in a real lighting field is not controlled in terms of brightness, color, or the position, width, and height of the slit.

[0006] Because the position of operating elements is typically determined from an ergonomic perspective, they are usually placed close to the components to be affected. However, the path used to transmit operating settings can be error-prone, making it difficult to eliminate deviations in scale settings and the resulting light distribution characteristics, especially after prolonged use of the device.

[0007] To enable repeated setting of operating elements, some ophthalmic devices have unitless scales, allowing for the reproducible execution of approximately the same settings at least at different times. However, a disadvantage is that while settings are executed on the operating elements, it is not actually known which corresponding parameters of the illumination field are being set in this manner.

[0008] In modern ophthalmic devices, increasingly important information regarding the actual parameters used in the illumination field is also stored electronically for purposes such as recording and / or use in the control loop. Furthermore, storing this information electronically allows it to be presented to the user on the eyepiece or display. This significantly improves the user's workflow because it maintains the user's position relative to the device and provides all relevant information.

[0009] Furthermore, the electronic availability of this parameter information opens up the possibility of using it as (meta) information in automated, continuously guided processes, such as image processing, deep learning, or other methods of artificial intelligence.

[0010] The existence of real-world usage parameters in electronic form of the illumination field is particularly significant in the remote control use of ophthalmic diagnostic equipment (also known as telemedicine). Here, external operators are compelled to rely on reliable feedback from the current equipment configuration, and especially on the real-world parameters of the illumination field.

[0011] Therefore, WO 2013 / 081619 A1 describes a system for ophthalmic imaging. This solution is based on an ophthalmic device controlled via a network and recording stereoscopic or three-dimensional images. Here, the system can be used remotely by one or more physicians to dynamically control every aspect of the ophthalmic device in real time via the network and to verbally interact with the patient. The recorded three-dimensional images of the patient's eyes are transmitted to the physician in real time, enabling the physician to perform an eye examination on at least a portion of the eye. Because the control of the ophthalmic device is performed in real time via the network, the physician can modify and refine the images to optimize the examination. Using this system, a comprehensive ophthalmic examination can be performed remotely with the same detail and clarity as if the physician and patient were physically present.

[0012] The significance and expectations of using such device parameters can be derived from various existing technical literature sources, so as to generate advantages or added value for users.

[0013] Therefore, a solution is known that describes the use of various lighting parameters to provide the solution to the user as an aid for operating ophthalmic equipment.

[0014] Therefore, for example, by using a slit-lamp microscope to illuminate the eye with a slit aperture, magnified observation of the entire anterior segment of the eye, cornea, sclera, iris, lens, conjunctiva, ventricles, periphery, vitreous body, and peritoneum can be performed. Furthermore, various observation techniques exist using a slit-lamp microscope. These techniques include different illumination and image recording methods. For example, illumination can be diffuse, direct, and tangential, or it can be backlit. In image recording methods, fluorescence staining photography or photography using an anterior corner lens or fixed lens (Befestigungslinse) is widely used. It should be noted that in examinations using a slit-lamp microscope, the observed target and observation techniques can be arbitrarily combined and applied.

[0015] To perform examinations using a slit-lamp microscope, the optical system settings need to be adjusted accordingly based on the selected observation target and / or observation technique. These adjustments include irradiation angle, illumination intensity, magnification, slit width, filters, and image recording system settings such as ISO, shutter speed, and aperture. Only in this way can optimal image recording and examination be achieved with minimal stress on both the doctor and patient.

[0016] Of course, it is difficult to properly execute or modify the settings of the optical and image recording systems according to the various combinations of observation targets and / or observation techniques. This problem arises in particular when physicians lack experience in using slit-lamp microscopes for examinations.

[0017] For this purpose, US 2014 / 0139807 A1 describes a slit-lamp microscope in which the optical system settings can be easily matched to different conditions.

[0018] To this end, the slit-lamp microscope has a storage unit configured to store corresponding information that associates default settings of the illumination and / or observation system with each of multiple eye positions. Standard settings include, for example, the magnification value, slit width, light intensity, irradiation angle, presence or absence of background illumination, and presence or absence of diffusers, apertures, or filters in the optical path.

[0019] After determining the eye position to be checked, the standard setting conditions for that position are retrieved from the corresponding information, compared with the previously detected current setting state, and a setting state that differs from the retrieved standard setting conditions is identified. Then, the different setting state is output on the display unit so that the setting state can be corrected accordingly. Of course, the described solution relies more on the use of data presented in the form of standard setting conditions, as the acquisition of this data is only a very vague description.

[0020] According to existing technology, this data is acquired using various sensors. Here, potentiometers with axial coupling are typically used, especially for detecting rotational or translational movement. Other feasible sensors are based on the detection of changes in characteristics such as resonant circuits, capacitance, and the Hall effect.

[0021] The dynamic range and value range required for such sensors are particularly challenging. For example, therefore, in the case of slit-lamp microscopy, if the slit width should be set between 100 μm and 20 mm, the slit width must be determined with an accuracy of less than 25 μm.

[0022] To detect the presence of diffusers, apertures, or filters in the optical path, it is necessary to determine their mechanical positional changes, which is, of course, very difficult in confined spaces.

[0023] Due to space constraints, it is sometimes necessary to place sensors not directly on the components that affect the emission field parameters, but rather along the control chain at any location between the actuator (e.g., knob, sliding element, etc.) and the component. This introduces systematic and random biases, hysteresis, and other errors, which can only be partially compensated for through the calibration process.

[0024] A known drawback of the system is that it also requires different sensors, including signal and power lines, and evaluation electronics, to determine very different parameters of the illumination field.

[0025] In addition to addressing structural space issues, it is also essential to ensure that different detectors and / or sensors do not interfere with each other or that changes in the detectors are detected only by associated sensors.

[0026] The latter is particularly difficult to address when components, such as those in a slit-lamp microscope, with multiple parameters to be set, as well as multiple detectors, sensors, terminal lines, etc., must move relative to the housing. Summary of the Invention

[0027] The objective is achieved by means of a method for setting and controlling the parameters of the illumination field of an ophthalmic device, wherein desired illumination parameters are set, illumination radiation is generated using the desired illumination parameters, the illumination radiation is converted into a light distribution in the focal plane, a portion of the output illumination radiation is coupled out, this portion is guided to a sensor element for analysis, and the true illumination parameters of the illumination radiation are determined from the sensor data. This objective is achieved by using a local resolution image sensor as a sensor element for analyzing the coupled output portion of the illumination radiation.

[0028] For example, a possible local resolution image sensor could be based on complementary metal-oxide-semiconductor (CMOS) or charge-coupled device (CCD) technology, but other technologies could also be considered in the future.

[0029] According to the first preferred design, the coupled output portion of the radiation reflects the true light distribution and, as far as possible, does not alter the light distribution. The image sensor of the digital camera records image data continuously or sequentially, utilizing the dynamics of the image sensor.

[0030] According to the second preferred design, the validity of the image data recorded by the image sensor is checked in the first step.

[0031] Calibration values ​​are used to determine parameters from the recorded image data. Furthermore, the derived true illumination parameters are provided to the user or the software provided to them as a digital and / or graphical representation, and are displayed on a monitor or in the observation optical path.

[0032] Although the proposed solution is specifically designed for setting and checking the illumination field of ophthalmic devices, it can also be applied to other technical fields, such as microscopy. Attached Figure Description

[0033] The invention will now be described in more detail with reference to embodiments. For this purpose, the following is shown:

[0034] Figure 1 A schematic diagram illustrating the flow of the method according to the invention in the form of a program flowchart, and

[0035] Figure 2 A schematic diagram of the device of the present invention is shown using a slit lamp as an example. Detailed Implementation

[0036] In the proposed method for setting and controlling the parameters of the illumination field of ophthalmic equipment, desired illumination parameters are set, illumination radiation is generated using these parameters, converted into a light distribution in the focal plane, a portion of the output illumination radiation is coupled, guided to a sensor element for analysis, and the true illumination parameters of the illumination radiation are determined from the sensor data. According to the invention, a local resolution image sensor is used as the sensor element for analyzing the coupled output portion of the illumination radiation. Here, the geometric resolution of the sensor can be matched to the accuracy required for the application. Thus, very inexpensive sensors can also be used for smaller sensor resolutions, such as those similar to an optical mouse (computer input device).

[0037] A local resolution image sensor of the camera is particularly preferred.

[0038] Here, the lighting parameters are preset and set by the system or user in the form of information, so as to produce the desired light distribution in one / the focal plane.

[0039] According to current solutions, for example, the following lighting parameters are used to generate the desired light distribution: brightness, color, light field shape, polarization, etc.

[0040] Here, the brightness of the light distribution can be set by changing the current or voltage at one or more light sources and by using the light color or color temperature with the aid of filters, or by combining different colored light sources and their targeted enhancement or reduction, and can be corrected if necessary.

[0041] Although the field shape of light distribution can be changed by means of aperture, digital micromirror (DMD), ELCoS, etc., a polarizer is needed to change its polarization.

[0042] Important to this invention is that the coupled output portion of the radiation actually reflects the true light distribution, and that, where necessary, the light distribution is not altered by the coupled output as much as possible.

[0043] If the coupled output ray changes, this must be forcibly taken into account when determining the true illumination parameters of the illumination radiation. Of course, the effect of this change must be understood for this purpose. For example, it could be possible to determine such a change during the manufacturing process of a calibration model, storing the specific parameters in the module to prepare for further use.

[0044] According to an advantageous embodiment of the method according to the invention, image data is recorded continuously or sequentially by a local resolution image sensor. Here, the dynamics of the image sensor can be used particularly advantageously and it can be used as a light power detector. For this purpose, it is especially important to ensure that individual pixels are not over-adjusted or that the dynamics of the camera used are utilized. To this end, the pixel with the highest intensity is selected, and its camera parameters (e.g., exposure time or magnification) are set via an algorithm (e.g., binary search) such that the value of said pixel is slightly below the upper dynamic range. Thus, there should no longer be any over-adjusted or under-adjusted pixels in the entire image, and all data can be used for further analysis. Here, camera settings can also be used as parameters.

[0045] Image data recorded by a local resolution image sensor is analyzed, and parameters are determined from it using matching and / or optimized algorithms. In the first step, the validity of the recorded image data can be checked.

[0046] Therefore, an algorithm is used to check the image data for the presence of one or more emission fields in the camera image. Only unique emission fields are expected. If multiple emission fields are found, it indicates that the system is not optimally configured. Subsequent algorithmic steps may not be effective. Ideally, the user should be informed of this.

[0047] Then, the parameters are determined using the image data recorded by the local resolution image sensor with the aid of matching and / or optimized algorithms.

[0048] The calibration values ​​are used to determine parameters, such as adjusting the size, angle, and color representations of the image field in a single step relative to the image sensor analysis results.

[0049] To determine the width, length, and orientation of the slit, an algorithm is used to detect the emission field and its edges from image data recorded by an image sensor. Here, the distance between two parallel edges corresponds to the slit width, and the distance perpendicular to them corresponds to the slit height. The midline between the two detected edges serves as a reference for evaluating the rotation angle of the slit position.

[0050] The color of the emission field can be inferred from the intensity of sub-images of different colors in the image data recorded by the image sensor.

[0051] Since only a small number of selected filters are typically used in ophthalmic devices, associating the light distribution detected by the sensor with the filters in use is no longer a problem. Within the scope of the adjustment / calibration process, the corresponding filter-related histogram of the light distribution can be stored in the sensor.

[0052] After determining, with the aid of image processing algorithms, whether one or more of the desired parameters are set correctly, the resulting true illumination parameters of the illumination radiation are stored for recording and / or reproduction.

[0053] In particular, the parameters and their magnitudes determined from the recorded images can be stored as metadata of the recorded images or used as input variables for the adjustment loop of the lighting module.

[0054] According to another advantageous design of the method according to the invention, the actual lighting parameters are provided to the user as a digital and / or graphical representation. This is achieved, for example, on a display or directly in the observation optical path.

[0055] to this end, Figure 1 A possible flow of the method according to the invention is shown in the form of a program flowchart.

[0056] After setting the desired lighting parameters and generating lighting radiation with the corresponding lighting parameters, a portion of the generated light distribution is coupled out, analyzed, and the true lighting parameters of the lighting radiation are determined from it.

[0057] To this end, images are recorded by a locally resolved image sensor, their validity is checked, and the recording is repeated if validity is lacking. The image recording parameters can be adjusted as needed. Illumination fields are detected from valid image data, their validity is similarly checked, and the recording is repeated if they are absent. The user receives feedback on this process.

[0058] In the first step, the edges of the slit image are detected from the effective emission field, its size is determined, and preferably displayed to the user. For this purpose, calibration data can be additionally used.

[0059] In the second step, the rotation angle of the slit image is determined, and preferably also displayed to the user. Here, the midline between the two detected long edges serves as a reference for evaluating the rotation angle. Calibration data can also be used additionally here.

[0060] In the third step, the intensity is determined and the color of the illumination field is inferred from the intensity of the sub-images of different colors.

[0061] At the same time, after appropriate calibration, the intensity of the light source can be inferred from the intensity measured at a given exposure time of the camera.

[0062] The proposed apparatus for setting and controlling the parameters of the illumination field of an ophthalmic device comprises: an operating unit for setting desired illumination parameters, an illumination unit for generating illumination radiation with the desired illumination parameters, a coupling output element for coupling a portion of the illumination radiation, a sensor element for analyzing the coupled output portion of the illumination radiation, and an evaluation unit for evaluating the sensor data and determining the true illumination parameters of the illumination radiation. According to the invention, the sensor element for analyzing the coupled output portion of the illumination radiation is a local resolution image sensor, which is capable of recording intensity and information locally.

[0063] According to a first advantageous design of the device according to the invention, the sensor element is a local resolution image sensor of a camera.

[0064] In order to evaluate color information, image sensors must have a different response in terms of the spectrum. For example, the BAYER matrix filter, which is present in many cameras, is also suitable for this purpose.

[0065] According to an advantageous design of the device according to the invention, the illumination unit comprises multiple light sources with different spectra and each capable of being individually driven. The illumination unit also has a variable aperture to increase the dynamic range.

[0066] As already described, the following lighting parameters are used, for example, to generate the desired light distribution: brightness, color, light field shape, polarization, etc. Here, the brightness of the light distribution can be set by changing the current or voltage at one or more light sources and by using a filter to adjust the light color or color temperature, or by combining different colored light sources and selectively enhancing or weakening them, and can be corrected as necessary. Here, the field shape of the light distribution can be changed by using aperture, DMD, ELCoS, etc.

[0067] In order to determine the parameters of the true light distribution, the coupled output actually reflects the radiative portion of the true light distribution. A beam splitter is therefore configured to forward this radiative portion to a local resolution image sensor used as a sensor element for analysis.

[0068] However, the coupling output element used to couple a portion of the output illumination radiation can also be an existing element in the form of a mirror or prism, wherein the optical active surface is designed as a semi-transparent layer rather than a reflective optical layer.

[0069] As already described, the local resolution image sensor is designed to continuously or sequentially record image data and transmit it to the evaluation unit for its evaluation and for determining the true illumination parameters of the illumination radiation.

[0070] The evaluation unit has a microprocessor to analyze images recorded by an image sensor and to determine the true lighting parameters of the illumination radiation.

[0071] The microprocessor analyzes the recorded image data using a matched / optimized algorithm and determines the parameters and their magnitudes. For this purpose, calibration values ​​are preferably used, for example, to adjust the magnitude, angle, and color representations between the set desired illumination parameters and the image data recorded by the image sensor, which characterizes the true light distribution in the focal plane.

[0072] The apparatus according to the invention is capable of having a storage unit for recording and / or reproducing true lighting parameters of the lighting radiation. Here, the calculated true lighting parameters of the lighting radiation can be stored as input variables for the adjustment loop of the lighting unit, and as metadata of the recorded image.

[0073] Specifically, it enables users to understand the lighting parameters. To this end, the device can have elements for digital and / or graphical representation of the actual lighting parameters.

[0074] to this end, Figure 2 A schematic diagram of the device according to the invention is shown using a slit lamp as an example. For instance, a desired illumination parameter 2 is set at the operation unit 1 so that a corresponding illumination radiation distribution is generated in the focal plane 5 by means of the illumination unit 3 and the (simplified) slit generating unit 4.

[0075] A portion of the illumination radiation is coupled out by beam splitter 6 and mapped onto local resolution image sensor 7 for analysis of the illumination radiation. Microprocessor 8 evaluates the sensor data transmitted by local resolution image sensor 7, calculates the sensor data using possible existing calibration data, thereby determining the true illumination parameters of the illumination radiation and displaying them on display 9.

[0076] According to another advantageous design of the device according to the invention, the device has an additional sensor element for performing polarization correlation analysis on a portion of the coupled output of the illumination radiation. Only in this way can the polarization correlation characteristics be detected.

[0077] For this purpose, for example, it is possible to use a Stokes-Aufbau structure, in which at least four different polarization states (in parallel or serial) are generated and measured, and then the polarization state of the radiation is inversely calculated from them.

[0078] Other design options include cameras that incorporate local resolution image sensors.

[0079] One advantageous design proposal is that existing cameras that observe real image fields have specific algorithms for analyzing and evaluating lighting information from the entire image.

[0080] Another advantage is that existing cameras used to record image information have specific algorithms for analyzing and evaluating lighting information from the entire image.

[0081] The present invention provides a method and apparatus for setting and controlling parameters of the illumination field of ophthalmic equipment, thereby eliminating the disadvantages of known solutions in the prior art. The proposed solution enables the setting and control of a large number of parameters of the illumination and / or observation field of ophthalmic equipment, while minimizing sensor interference and error variability.

[0082] A particularly advantageous aspect is that this solution can simultaneously record and analyze multiple parameters using only a single sensor. The use of a camera's image sensor also offers the advantage of significantly miniaturizing the entire structure.

Claims

1. A method for setting and controlling parameters of an illumination field in an ophthalmic device, wherein the method comprises setting desired illumination parameters, generating illumination radiation using the desired illumination parameters, converting the illumination radiation into a light distribution in a focal plane, coupling out a portion of the illumination radiation, directing the portion of the illumination radiation to a sensor element for analysis, and determining the true illumination parameters of the illumination radiation from the sensor data, characterized in that, Using a local resolution image sensor as a sensor element for analyzing the coupled output portion of the illumination radiation, the luminous field and its edges are detected in the image data recorded by the image sensor, and the width, length, and orientation of the slit are determined from the luminous field and its edges.

2. The method according to claim 1, characterized in that, Use the camera's local resolution image sensor.

3. The method according to claim 1, characterized in that, It is possible to use lighting parameters to produce the desired light distribution.

4. The method according to claim 3, characterized in that, The lighting parameters are brightness, color, light field shape, and polarization.

5. The method according to claim 1, characterized in that, The desired lighting parameters are preset by the system or the user.

6. The method according to claim 1, characterized in that, The coupled output portion of the radiation reflects the true light distribution without altering it.

7. The method according to claim 1, characterized in that, Digital camera image sensors record image data continuously or sequentially.

8. The method according to claim 1, characterized in that, Utilizing the dynamics of the image sensor.

9. The method according to claim 7, characterized in that, The image sensor's dynamics are used as an optical power detector.

10. The method according to claim 1, characterized in that, The parameters are determined by analyzing the images recorded by the image sensor and by means of matching and / or optimized algorithms.

11. The method according to claim 10, characterized in that, In the first step, the validity of the image data recorded by the image sensor is checked.

12. The method according to claim 10, characterized in that, The calibration value is used to determine the parameter.

13. The method according to claim 10, characterized in that, The color of the luminous field is inferred from the intensity of sub-images of different colors in the image data recorded by the image sensor.

14. The method according to claim 10, characterized in that, In the image data recorded by the image sensor, an image processing algorithm is used to detect whether one or more of the desired parameters are set correctly.

15. The method according to claim 1, characterized in that, To record and / or reproduce, store the actual lighting parameters of the lighting radiation.

16. The method according to claim 1, characterized in that, The parameters and their magnitudes determined from the recorded images will be stored as metadata or used as input variables for the adjustment loop of the lighting module.

17. The method according to claim 1, characterized in that, The actual lighting parameters are provided to the user as a digital and / or graphical representation.

18. The method according to claim 17, characterized in that, The digital and / or graphical representation of the actual lighting parameters is displayed on a monitor or coupled into the observation optical path.

19. An apparatus for setting and controlling parameters of an illumination field of an ophthalmic device, the apparatus comprising: an operating unit for setting desired illumination parameters; and an illumination unit for generating illumination radiation using the desired illumination parameters; A coupling output element for coupling out a portion of the lighting radiation; Sensor elements used to analyze the coupled output portion of the illumination radiation; An evaluation unit for evaluating sensor data and for determining the true illumination parameters of the illumination radiation, characterized in that the sensor element for analyzing the coupled output portion of the illumination radiation is a local resolution image sensor, wherein in the evaluation unit, the luminous field and the edge of the luminous field are detected in the image data recorded by the image sensor, and the width, length and orientation of the slit are determined from the luminous field and the edge of the luminous field.

20. The apparatus according to claim 19, characterized in that, The sensor element is a local resolution image sensor for the camera.

21. The apparatus according to claim 19, characterized in that, The lighting unit has a variable aperture to increase the dynamic range of the lighting unit.

22. The apparatus according to claim 19, characterized in that, The lighting unit consists of multiple light sources with different spectra, each of which can be driven and controlled individually.

23. The apparatus according to claim 19, characterized in that, The coupling output element used to couple out a portion of the illumination radiation is a beam splitter.

24. The apparatus according to claim 19, characterized in that, The coupling output element used to couple out a portion of the illumination radiation is an existing element in the form of a mirror or prism, wherein the optically active surface is designed as a semi-transparent layer rather than a reflective optical layer.

25. The apparatus according to claim 19, characterized in that, The evaluation unit has a microprocessor to analyze the images recorded by the image sensor and determine the true illumination parameters of the illumination radiation.

26. The apparatus according to claim 19, characterized in that, There exists a storage unit for recording and / or reproducing the actual lighting parameters of the lighting radiation.

27. The apparatus according to claim 19, characterized in that, There are elements for representing the actual lighting parameters in numerical and / or graphical form.

28. The apparatus according to claim 27, characterized in that, There are elements for coupling the digital and / or graphical representation of the actual lighting parameters into the observation optical path.

29. The apparatus according to claim 19, characterized in that, Additionally, there are sensor elements for performing polarization correlation analysis on the coupled output portion of the illumination radiation.

30. The apparatus according to claim 19, characterized in that, Existing cameras that observe real image fields have specific algorithms for analyzing and evaluating lighting information from the entire image.

31. The apparatus according to claim 19, characterized in that, Existing cameras used to record image information have specific algorithms for analyzing and evaluating lighting information from the entire image.

Images