Device and method for determining centring parameters

Abstract

A device is provided, comprising: a spectacle frame (10), at least one eye tracker (11) arranged in the spectacle frame (10), at least one inertia measuring unit (12) arranged in the spectacle frame (10), and a computing unit (13) which is configured to determine at least one centring parameter on the basis of a pupil position, determined by the at least one eye tracker (11), of a user wearing the spectacle frame (10) and on the basis of data from the inertia measuring unit (12).

Description

[0001] Description

[0002] Device and method for determining centering parameters

[0003] The present application relates to devices and methods for determining centering parameters.

[0004] Centration parameters are parameters required to correctly position lenses in a frame, i.e., to center them so that the lenses are worn in the correct position relative to the wearer's eyes. For this purpose, lens blanks are ground based on the centration parameters so that they fit the respective frame and are positioned appropriately for the wearer. This process is also known as lens grinding.

[0005] Examples of such centration parameters include the interpupillary distance, the corneal vertex distance, the frame lens angle, the Y-coordinates of the left and right centration points, also known as the visual height or grinding height, the far visual point, the pantoscopic angle (sometimes referred to as the forward tilt angle), and other parameters defined in Section 5 of the DIN EN ISO 13666:2012 standard, as well as, among others, the inclination of the frame. The inclination indicates the angle between the plane of the temples and the plane of the frame. It is related to the pantoscopic angle, but unlike the pantoscopic angle, it is independent of the wearing position of the glasses on the head.

[0006] These centering parameters are now determined automatically or semi-automatically using appropriate systems. An example of such a system is the applicant's VISUFIT 1000 system. Other such systems and devices are known from EP 1 844 363 B2, US 2007 / 035697 A1, US 2006 / 0044509A1, or US 10,690,945 B2.

[0007] Some of the systems mentioned above are relatively large devices, typically available at an optician or ophthalmologist. However, the shortage of skilled workers, including in the medical field, makes it desirable to perform procedures such as determining such centering parameters without qualified personnel and correspondingly specialized equipment.

[0008] A device according to claim 1 and a method according to claim 8 are provided. The subclaims define further embodiments.

[0009] According to one embodiment, a device is provided, comprising: a spectacle frame, at least one eye tracker arranged in the spectacle frame, at least one inertial measurement unit (IMU) arranged in the spectacle frame, and a computing device which is configured to determine at least one centration parameter based on a pupil position of a user wearing the spectacle frame determined by the at least one eye tracker and data from the inertial measurement unit.

[0010] The term "user" refers to the person whose centering parameters are to be determined.

[0011] The computing device can be built into the eyeglass frame and send its data to another device, or it can be external to the eyeglass frame. In some embodiments, the computing device is a computing device such as a smartphone, a tablet, a computer, or the like, which receives signals from the eye trackers and the IMU and performs the corresponding calculations.

[0012] In some data glasses such as AR (Augmented Reality) and VR (Virtual Reality) glasses, such sensors are already present, so that existing hardware can be used.

[0013] In this way, the centration parameters can be calculated, especially for data glasses with individual lenses adapted to the user's visual acuity.

[0014] The device can therefore, in particular, comprise smart glasses including the spectacle frame, wherein the smart glasses are configured to generate a visual target for a user wearing the spectacle frame to determine the at least one centering parameter. Such smart glasses can thus display a visual target toward which the user is to look. This can ensure correct alignment of the eyes for determining the distance visual point.

[0015] The at least one centering parameter may include a distance visual point and / or a grinding height.

[0016] The computing device can be configured to verify a gaze direction for determining the at least one centering parameter based on data from the at least one eye tracker.

[0017] The computing device may also or alternatively be configured to use the data from the inertial measurement unit to verify a head posture of the user when determining the at least one centering parameter.

[0018] By verifying the head posture, at least a gross misalignment in determining the distance visual point can be avoided, and by verifying the direction of gaze, an incorrect direction of gaze can be avoided.

[0019] The computing device can also or alternatively be configured to verify the fit of the spectacle frame on the user's head based on the data from the inertial measurement unit. This can, for example, detect a crooked fit of the spectacle frame.

[0020] The at least one centering parameter may also comprise a pantoscopic angle, wherein the computing device is configured to determine the pantoscopic angle based on data from the inertial measuring unit.

[0021] According to a further embodiment, a method for determining at least one centration parameter is provided, the method using a spectacle frame with at least one eye tracker arranged in the spectacle frame and at least one inertial measuring unit arranged in the spectacle frame (10), the method comprising:

[0022] Determining, using the at least one eye tracker, a pupil position of a user wearing the spectacle frame, and determining the at least one centering parameter based on the pupil position and on data from the inertial measurement unit. The method can be configured according to the devices explained above.

[0023] Various embodiments are explained in more detail below with reference to the accompanying drawings. They show:

[0024] Fig. 1 shows a device according to an embodiment,

[0025] Fig. 2 is a diagram illustrating a measurement with the device of Fig. 1,

[0026] Fig. 3 is a further view illustrating a measurement with the device of Fig. 1, and

[0027] Fig. 4 is a flowchart illustrating a method according to an embodiment.

[0028] Fig. 1 shows a device according to an embodiment. The device of Fig. 1 has a spectacle frame 10 that can be worn by a user 15. The spectacle frame 10 can be a spectacle frame of data glasses such as augmented reality (AR) glasses or virtual reality (VR) glasses. AR glasses are glasses that can display data for viewing by the user 15, wherein the data is superimposed on the view of the surroundings through the glasses. VR glasses only serve to display data without allowing a view of the surroundings. The term data is to be understood here to mean that it can be any type of data, including symbols, characters, text, images, and the like.By displaying such data separately for the left and right eyes 16 of the user 15, a 3D impression can also be created, meaning that the data appears to the user to be located at a specific location in space, which can essentially be determined arbitrarily by appropriate control. Such AR glasses are known in their own right and are sold commercially; therefore, they will not be discussed in more detail.

[0029] The spectacle frame 10 further includes eye trackers 11. These can be implemented in any conventional manner and can determine the position of the pupils of the eyes 16. An example of the implementation of suitable eye trackers is explained in DE 102013 103 801 A1. Light beams, particularly infrared light, are sent from two or more transmitters to the eyes 16, and the reflected light is detected by corresponding detectors. Other implementations of eye trackers can also be used.

[0030] Furthermore, the spectacle frame 10 has one or more inertial measurement units (IMUs). Such IMUs typically contain at least one acceleration sensor and a gyroscope. Some IMUs can additionally contain a magnetometer. Since the installation location of a respective IMU in the spectacle frame 10 is known, the IMU can be used to determine the orientation of the spectacle frame at that particular location relative to the direction of gravity. With an IMU installed close to the frame edges as shown, the pantoscopic angle can be determined, for example, when the head is held upright. If installed in the temples, the orientation of the temples can be determined. Furthermore, the orientation of the head can essentially be determined when the spectacles are worn normally, i.e., whether the head is held upright or tilted.

[0031] The device of Fig. 1 further comprises a computing device 13, which communicates with the eye trackers 11 and the IMU 12, for example, wirelessly via Bluetooth or similar wireless connections. The computing device 13 can also be built into the spectacle frame 10 and communicate with the eye trackers 11 and the IMU 12 via a wired connection and then transmit the results of its calculations, for example, wirelessly to other devices. In some embodiments, the computing device 13 can be a smartphone, a tablet, or a computer. The computing device 13 controls the method described below for determining centering parameters and evaluates the corresponding signals from the eye trackers 11 and the IMU 12 to determine the centering parameters.

[0032] Such a method will now be described with reference to Fig. 4. For illustrative purposes, it is assumed that the method is carried out using the device of Fig. 1, and Figures 2 and 3 illustrate some method steps. It should be noted that not all of the steps of Fig. 4 are necessarily performed; optional steps are also included.

[0033] The determined centering parameters can include distance vision points. These are defined as the intersection of the gaze direction, starting from the pupils, with the lenses. The gaze must be directed into the distance with the head held upright. For this purpose, a visual target is displayed in step 40 of the figure if the device is data glasses. A visual target is generally understood to be a displayed element toward which the user should direct their gaze. This visual target can, for example, have the shape of a cross, a circle, or another shape. Such a visual target 21 is shown schematically in Fig. 2.However, the representation here is not to scale, and the visual target 21 is shown such that it is at a greater distance, for example, apparently at least 7 m away from the user, so that the user is actually looking into the distance and, in particular, the lines of sight of the eyes are parallel. At the same time, the head posture can be monitored using the IMU 12, and if, for example, the head is initially tilted too far, the visual target 21 can initially be displayed higher so that the user straightens their head, and then readjusted accordingly. The visual target 21 can thus be displayed in a variable position within a display area. If the device is not a pair of data glasses, it is also possible, for example, by the computing device 13 to simply issue an instruction to look into the distance and straighten the head, without displaying a visual target.A similar instruction can also be given in the case of data glasses with a visual target 21 displayed and can be supplemented by the fact that the gaze should be directed towards the visual target.

[0034] In this position, the position of the pupils 22 of the eyes 16 is determined using the eye tracker 11, as shown in Fig. 2 by light rays 20. This occurs in step 41 of Fig. 4.

[0035] Based on the determined pupil positions, the direction of gaze can first be verified in step 43. If the pupil position shows, for example, that the pupils 22 of both eyes 16 are directed inward toward the nose, it can be concluded that the gaze is not directed into the distance as required, but rather toward a closer target. If this shows that there is no distant gaze, a warning can be issued, for example.

[0036] In step 42, the IMU data is evaluated. Here, in particular, the head posture can be verified in step 44. This means that if the IMU data indicates a very strong head tilt, the measurement can also be discarded and a warning can be issued, as discussed above for the direction of gaze, to encourage the user to keep their head upright. In addition, the position of the glasses can be verified in step 45. For example, an IMU on the temple can be used to determine whether the glasses are sitting very crooked by determining the direction of the IMU relative to the direction of gravity. In this case, a warning can also be issued and the measurement can be repeated. Finally, in step 46, centering parameters are determined based on the pupil position determined in step 41 and the IMU data received in step 42.For example, the pre-tilt angle can be determined from the IMU data if an IMU is located on the frame edge.

[0037] In addition, as shown in Fig. 3, the distance visual points 30 can be determined by drawing the gaze horizontally into the distance (gaze directions 31) from the determined spectacle position and determining the intersection point with the lens planes. The pantoscopic angle determined using the IMU can also be used here, or it can be input from another source. Since the geometry of the spectacle frame is known, the grinding height 32 for the right and left lenses can then be determined from the position of the distance visual points.

[0038] If a visual target 21 is displayed, the lateral position of the visual target 21 can be adjusted by moving it within the display area, either alternatively or in addition to the aforementioned warnings. For example, the visual target 21 can be moved until a distance gaze is detected upon repeated determination of the pupil position.

Claims

Patent claims 1. Device comprising: a spectacle frame (10), at least one eye tracker (11) arranged in the spectacle frame (10), at least one inertial measuring unit (12) arranged in the spectacle frame (10), and a computing device (13) which is configured to determine at least one centering parameter on the basis of a pupil position of a user wearing the spectacle frame (10), determined by the at least one eye tracker (11), and data from the inertial measuring unit (12).

2. Device according to claim 1, wherein the device comprises data glasses including the spectacle frame (10), wherein the data glasses are configured to generate a visual target (21) for a user (15) wearing the spectacle frame (10) in order to determine the at least one centering parameter.

3. Device according to claim 1 or 2, wherein the at least one centering parameter comprises a distance visual point and / or a grinding height.

4. Device according to one of claims 1 to 3, wherein the computing device is configured to verify a viewing direction (31) for determining the at least one centering parameter on the basis of data from the at least one eye tracker (11).

5. Device according to one of claims 1 to 4, wherein the computing device (13) is configured to verify a head posture of the user (15) when determining the at least one centering parameter based on the data from the inertial measuring unit (12).

6. Device according to one of claims 1 to 5, wherein the computing device (13) is configured to verify a fit of the spectacle frame (10) on a head of the user (15) on the basis of the data from the inertial measuring unit (12).

7. Device according to one of claims 1 to 6, wherein the at least one centering parameter comprises a pantoscopic angle, wherein the computing device (13) is arranged to determine the pantoscopic angle on the basis of data from the inertial measuring unit (12).

8. A method for determining at least one centration parameter, the method using a spectacle frame (10) with at least one eye tracker (11) arranged in the spectacle frame (10) and at least one inertial measuring unit (12) arranged in the spectacle frame (10), the method comprising: Determining, by means of the at least one eye tracker (11), a pupil position of a user wearing the spectacle frame (10), and determining the at least one centration parameter based on the pupil position and on the basis of data from the inertial measuring unit (12).

9. The method according to claim 8, wherein the spectacle frame (10) is a spectacle frame (10) of data glasses.

10. The method according to claim 8 or 9, further comprising: Generating, by means of the data glasses, a visual target (21) for the user (15).

11. The method according to claim 8 or 9, wherein the at least one centering parameter comprises a distance visual point and / or a grinding height.

12. The method according to any one of claims 8 to 10, further comprising: verifying a viewing direction (31) for determining the at least one centering parameter based on data from the at least one eye tracker (11).

13. The method according to any one of claims 8 to 11, further comprising: Verifying, based on the data from the inertial measuring unit (12), a head posture of the user (15) when determining the at least one centering parameter.

14. The method according to any one of claims 8 to 12, further comprising: Verifying a fit of the spectacle frame (10) on a head of the user (15) based on the data from the inertial measuring unit (12).

5. The method according to any one of claims 8 to 13, wherein the at least one Centering parameter includes a pantoscopic angle, the method further comprising: Determining the pantoscopic angle based on data from the inertial measuring unit (12).

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