EP3574369A1

EP3574369A1 - Computer-implemented method for determining centring parameters

Info

Publication number: EP3574369A1
Application number: EP18702189.4A
Authority: EP
Inventors: Claudia NIEUWENHUIS
Original assignee: Carl Zeiss AG
Current assignee: Carl Zeiss AG
Priority date: 2017-01-27
Filing date: 2018-01-24
Publication date: 2019-12-04
Also published as: US11397339B2; CN110446968A; EP3355103A1; WO2018138165A1; US20200057316A1

Abstract

The invention relates to a computer-implemented method for determining centring parameters, wherein: at least two calibrated images of the head which are captured simultaneously from different viewing directions are provided, and geometric parameters which describe the position of the eyes are determined by means of geometric position determination; a three-dimensional data set describing geometric parameters of the frame front is provided; the geometric parameters of the frame front and the geometric parameters describing the position of the eyes are brought into relation to each other by means of a rigid transformation; and the centring parameters are calculated from the geometric parameters describing the frame front and those describing the position of the eyes.

Description

Computer-implemented method for the determination of centering parameters

The invention relates to a computer-implemented method for determining centering parameters according to the preamble of claim 1 or according to the preamble of claim 3 or according to the preamble of claim 6.

Centering parameters are used to correctly position or center lenses in a spectacle frame so that the lenses are positioned in the correct position relative to the eyes of the person wearing the spectacles. These are in part anatomical parameters of the person concerned, such as the pupil distance, in part to purely barrel-specific parameters such as the lens width or the mounting disc height and in part to combinations of anatomical and barrel-specific

Parameters such as the corneal vertex distance and the

Viewing height. An overview of the common centering parameters is given in DIN EN ISO 13666 of October 2013.

With the help of centering devices for the centering of spectacle lenses, the measurement of distances and dimensions is made, which are relevant for the production and the Einschieifen of the lenses. For the optometrist, it is important to have a workflow that is as fast and error-free as possible in order to achieve a high quality of advice that focuses on the end customer and is not dominated by technical processes. In this context, as trouble-free as possible operation (robustness) with high precision of automatic procedures is necessary. This can be done with methods of digital image analysis, machine learning and involving Model knowledge can be achieved. The centering device is equipped with multiple cameras that simultaneously record multiple images of the end customer. In the previous centering the customer uses a socket. In the pictures are automatically features such as pupil centers and

Fassungsrand detected and determines their subpixel exact position. Based on these measured image positions, you can then use

Centering algorithms are determined the relevant parameters for the lens centering. Centering measurements with spectacle frames that are not available in the optician's shop are not possible.

US Pat. No. 6,792,401 B1 discloses a method for adjusting spectacle lenses and spectacles, in which image data of the head of a subject are related to views of spectacle frames by means of a test socket. From US 2015/0055085 A1 a method of the aforementioned type is known, in which a point cloud describing its eye parts is generated from a plurality of calibrated images of a subject. On the present in the form of a point cloud "head" is virtually a version "put on", which already exists in the form of provided by the socket manufacturer CAD data sets. However, this method is not feasible if the CAD record of the socket manufacturer is not present, which is usually treated by the socket manufacturer as a trade secret. In addition, reference objects are used to scale the model of the head to the correct size.

It is therefore an object of the invention to develop a method of the type mentioned in such a way that it gives the customer a better choice

Spectacle frames allows.

Starting from US 2015/0055085 A1, the method according to claim 1 solves the problem to provide a simpler method by a reference object such as a test version is not needed, which is regularly perceived by the customer as uncomfortable. Based on the US 2015/0055085 A1, the method according to claim 3 solves the problem of providing a method that allows a determination of Zentrierparametern even without the presence of data of the socket manufacturer.

Starting from US 2015/0055085 A1, the method according to claim 6 solves the problem of providing a simpler method. A point cloud comprises less data than a CAD data set, so that less computing power is required to perform the method.

The invention is based on the idea to make also Zentriermessungen the customer with eyeglass frames that are not available in the shop but only as an SD record. As a result, you can offer the customer a much larger amount of eyeglass frames to choose from, which would find no place in a store. Besides, also can be customized for the customer

individualized spectacle frames are measured before they are ever made. This allows the customer to try out a much wider range of eyeglass frames and have them measured immediately without having to put on the eyeglass frame at all. It is sufficient if the data set describing the geometrical parameters of the spectacle frame which describe the geometry of the spectacle frame is provided as at least one three-dimensional point cloud - no metadata such as tracer contour of the spectacle lenses, etc. are required. In this case, calibrated images are provided. Their calibration encompasses the extrinsic properties of the cameras that record the images or the camera that captures the images, such as the relative orientation of their optical axes and the relative position of each other in space, as well as their intrinsic properties

Properties of the cameras or the camera itself, which define how a point in the space, which is located in the internal coordinate system of the respective camera, is mapped onto the coordinates of the pixels of the recorded image. A detailed description of the calibration of cameras can be found in the textbook "Multiple View Geometry in Computer Vision" by Richard Hartley and Andrew Zisserman, 2nd edition, Cambridge University Press 2004, and especially page 8.

Geometric position determination is used to determine geometric parameters that describe the position of the eyes. A three-dimensional data record describing a geometrical parameter of the eyeglass frame is provided, and by means of a rigid transformation the geometrical parameters of the eyeglass frame and the geometrical parameters describing the position of the eyes are related to one another. From the the spectacle frame

The centering parameters are subsequently calculated and the geometric parameters describing the position of the eyes are calculated. A rigid transformation is understood to mean translation, rotation or reflection or combinations thereof.

The data set describing the geometrical parameters of the spectacle frame can be generated to simplify the method by segmenting the silhouettes of the spectacle frame in the individual images and / or by means of an SD reconstruction method and / or by means of a method for machine learning.

Machine learning is a generic term for "artificial" generation

Knowledge from experience: An artificial system learns from examples and can generalize these after completion of the learning phase. That is, the examples are not simply memorized, but "recognize" patterns and laws in the learning data, so the system can also evaluate unknown data attached to the application and to which reference is expressly made in this connection. The mentioned Wikipedia article also gives an overview of various approaches and algorithms that can be used here.

Segmentation is a branch of digital image processing and

machine vision. The generation of content-related Regions of a picture by abstract

neighboring pixels corresponding to a particular one

Homogeneity criterion is called segmentation. she will

normally used to find objects or edges in the image.

Segmentation is at a glance in the Wikipedia article "Segmentation

(Image Processing) "explains along with various algorithmic approaches. This article is attached to the application and it will be in this

Context expressly referred to him.

A 3D reconstruction method is to be understood as follows:

Ordinary cameras produce images by projecting a picture

three-dimensional scene on a two-dimensional plane (i.e., the image plane). In this figure one dimension is lost, this corresponds to the depth of the image, i. the distance between the camera and the imaged objects. The depth information can consist of two (or more) images, which consist of

recorded different views, are recovered by means of an SD reconstruction method. From the obtained image depth, a three-dimensional model (i.e., a 3D reconstruction) of the scene can be created immediately and then it can be textured with the camera images.

A 3D reconstruction method usually works as follows:

• Find corresponding points in both images.

• For all correspondences found, triangulate below

Consider the internal and external geometry of the cameras (calibration) to obtain the three-dimensional points.

The data record describing the geometrical parameters of the spectacle frame can be provided in the form of a plurality of point clouds, each point cloud describing a part of the spectacle frame. In addition, it is preferred that the dataset describing the geometrical parameters of the spectacle frame comprises the orientation of the point cloud in space. Alternatively, it is possible that the orientation of the point cloud is calculated in space by automatically recognizing the individual parts of the socket and then the straps are oriented in a preferred direction, eg to the rear.

The data set describing the geometrical parameters of the spectacle frame expediently includes prominent points, in particular a prominent point sequence, of the spectacle frame, which are predetermined or calculated. These may be the position and / or orientation of the axes for the hinges of the stirrups and / or the bridge center and / or the ear pads and / or the

Frame edge and / or the glass outer edge and / or the endpoints of the temple. A further simplification of the method is achieved if the data record describing the geometrical parameters of the spectacle frame is projected onto a two-dimensional plane. According to an advantageous development of the invention, the glass rims belonging to the spectacle frame are determined from the dataset describing the geometrical parameters of the spectacle frame. In this case, it is expedient to adapt a three-dimensional model for the glasses of the glasses approximately to the specific glass edges. This three-dimensional model for the spectacle lenses may comprise glass surfaces and / or glass planes or, in a simpler variant, consist of glass planes.

Furthermore, it is possible to adapt a three-dimensional model for the spectacle frame and / or parts of the spectacle frame and / or the glasses of the spectacles approximately to the three-dimensional data set.

The three-dimensional model may be a parametric model whose parameters are determined by means of optimization methods to the three-dimensional data set, e.g. contains the point cloud or the plurality of point clouds. However, the three-dimensional model can also be generated by machine learning from example data.

Various methods can be used for the geometric position determination. However, it is preferred that the geometric Position determination comprises a thangulation method. Also, the generation of the geometrical parameters of the eyeglass frame descriptive

Record can be done by means of a triangulation method.

Preferably, the computer-implemented method according to the invention is carried out with a device as described in principle in claim 22 and in detail in the following description of the figures.

The centering parameters determined according to the invention can advantageously be used for centering a spectacle lens in a spectacle frame and / or for grinding a spectacle lens into a spectacle frame. In this case, in a method step, the at least one spectacle lens is centered with the specific centering parameters in the spectacle frame, or the at least one spectacle lens is ground on the basis of the determined centering parameters for an arrangement in the spectacle frame. That way you can

Eyeglass lenses and glasses are made. In the following the invention will be explained in more detail with reference to an embodiment schematically illustrated in the drawing. It shows:

Figure 1 a, b is a device for determining Zentrierparametern in

perspective view and in a view from the front;

Figure 2a, b, the representation of a spectacle frame before and after orientation in space and

3 shows the representation of the spectacle frame according to FIG. 2b as

three-dimensional point cloud with adapted glass planes.

The device 10 shown in the drawing is used to determine Zentrierparametern for spectacle fitting. It has a column 12 which carries a rigid camera support 14 which is height adjustable and in turn carries a number of cameras 16a, 16b. The camera carrier 14 is in plan view

bent approximately circularly and extends between two free ones Ends 18, which are spaced from each other. To the front, so the column 12 out, and to the sides encloses an inner surface 20 of the

Camera Carrier 14 an interior space 22 in which the head of a subject is when taking pictures by the cameras 16a, 16b. The inner surface 20 is concavely bent in a direction extending between the free ends 18 and has, for example, the shape of a portion of a

Cylinder surface on which the cylinder is a circular or oval

Can have footprint. In order to position the camera support 14 with respect to the head of the subject at the right height, a not shown lifting device is arranged in the column 12, with the

Camera carrier 14 can be moved by motor driven up and down.

All cameras 16a, 16b are in one between the free ends 18th

extending camera assembly 26 is arranged. In the present

Embodiment is the camera assembly 26 as a camera series 26th

are formed, whose cameras 16a, 16b are all at the same height, with their optical axes are directed to the interior 22. In the present embodiment, the camera row 26 includes one in the middle of the

Camera carrier 14 arranged front camera 16a, whose optical axis is directed frontally on the face of the subject, and eight pairs symmetrically with respect to a running through the optical axis of the front camera 16a perpendicular plane of symmetry arranged side cameras 16b of which four from the left and right to the face of Subjects are addressed. The cameras 16a, 16b are also calibrated so that they can simultaneously take calibrated images of the subject. The calibration includes the extrinsic properties such as the relative orientation of their optical axes and the relative arrangement of each other in space, as well as their intrinsic properties, ie the properties of the cameras themselves, which define, like a point in space, the internal coordinate system of the respective camera is located on the coordinates of the pixels of the recorded image is mapped. The camera support 14 encloses the interior 22 only forward, towards the column 12, and to the sides, so left and right of the head of the subject. Upwards, downwards and toward a rear side 30, it is open, the free ends 18 being at a distance of at least 25 cm from one another, so that the test person can easily approach from the rear side. Im shown

Embodiment, the distance is 70 to 80cm.

To illuminate the interior 22, a lighting device is provided with an upper light bar 32 extending above the camera row 26 and a lower light bar 34 extending below the camera row 26, which each have a multiplicity of LEDs as lighting means. The upper light bar 32 and the lower light bar 34 each extend continuously or intermittently over a length which is at least as long as the length of the circumferentially between the free ends 18 measured length of the camera row 26. This corresponds to a circumferential angle of at least 160 degrees , Near the free ends 18, the upper light bar 32 and the lower light bar 34 are each connected to each other by means of a vertically extending further light bar 36. The camera row 26 is thus completely framed by at least one row of LEDs. The device 10 also has a control or regulating device, not shown in detail in the drawing, with which the light intensity emitted by the LEDs depends on the light emitted by the

Cameras 16a, 16b detected light intensity can be controlled or regulated. The LEDs of the light strips 32, 34, 36 are to sectors

summarized whose radiated light intensities can be controlled or regulated separately. In addition, it is provided that the light intensities emitted by the individual LEDs can also be controlled or regulated separately from one another by means of the control or regulating device.

In order to be able to position the subject correctly in the interior 22, the two side cameras 16b closest to the front camera 16a are arranged to adjust the distance of the subject's head from the center 38 of the patient

Camera carrier 14 to measure. By means of a not shown Display unit is displayed to the subject whether he is correct or not. The display unit has a plurality of differently colored light sources, which are arranged in a row. The middle light source glows green when the subject is correct. Starting from the middle light source, there are one yellow, one orange and one red in each direction in this order

Light source, which indicates the color when the subject a little, clear or far too far from the center 38 of the camera support 14 or a little, clear or too close to the center 38 stands. In order to ensure that the viewing direction of the subject is directed to infinity during the determination of the centering parameters, one is arranged on the camera carrier 14

Fixation device 42 is provided which generates a fixation pattern for the subject in the form of a speckle pattern. The fixation pattern is arranged slightly higher than the front camera 16a, so that the subject on this

away look. So that his face can be taken up to the maximum extent.

The device 10 is also particularly suitable for producing an avatar of the subject's head, which can be used to determine the centering parameters. For this purpose, images calibrated by the cameras 16a, 16b of the subject's head are taken without glasses or spectacle frame. By means of a suitable process for geometric

Position determination such as triangulation creates a depth profile of the head that approximates it very well. The head is represented by a multitude of points, which can be connected to each other by means of a net pattern or can be stored as a point cloud. In the subsequent determination of the centering parameters of the thus determined avatar can be used to determine Zentrierparameter that due to the geometric properties of the glasses or

Spectacle frame worn by the subject, can not or only approximately can be determined. For example, a wide frame strap can obscure the eye in a side view to such an extent that the corneal vertex distance can not or only very inaccurately be determined. In addition, can be dyed or strong mirrored lenses do not make the eyes or very poorly visible. In order to counteract this, the depth profile of the avatar is projected onto the images taken by the cameras 16a, 16b of the subjects wearing the spectacles or spectacle frame, and the centering parameters, which can only be determined insufficiently due to the view restricted by the spectacles or spectacle frame, become determined by the image data of the avatar. In this case, an adaptation of the avatar on the images of the glasses or spectacle frame

carrying subjects to minimize deviations.

Alternatively, or in addition to the manufacture of the avatar, the apparatus 10 may perform the following to perform a computer-implemented method

Determination of Zentrierparametern be used.

Firstly, the cameras 16a, 16b simultaneously provide calibrated images of the subject's head. From these images, by means of geometric position determination, in particular by means of

Triangulation, geometric parameters that describe the position of the eyes. In particular, the avatar described above can also be used for this purpose. Then, the geometric parameters of the

Eyeglass frame descriptive three-dimensional data record provided, as illustrated in Figure 2a based on a spectacle frame 50. For simplicity, in Figure 2a, the spectacle frame 50, which is a three-dimensional point cloud, simplified with solid lines and not shown in the form of points. By means of a rigid transformation or rigid body simulation, the three-dimensional point cloud describing the spectacle frame 50 becomes a

Figure 2b illustrates the rotation in the coordinate system of the camera 16a, 16b, the z-direction given by the viewing direction of the front camera 16a Based on the geometric position describing the position of the eyes

Parameters and the geometrical parameters describing the spectacle frame in the carrying position are calculated as centering parameters for example, the corneal vertex distance. To simplify the process, the glasses of the glasses are approximately represented by planes 52, as shown in Figure 3, in which the spectacle frame 50 is also shown as a point cloud. For this purpose, the geometric parameters of the

Determining the eyeglass frame descriptive record the glass frame belonging to the eyeglass frame and it is a three-dimensional model for the glasses of the glasses approximately adapted to the specific glass edges, this model consists of the glass planes 52.

The following clauses reproduce preferred embodiments of the invention:

1 . Computer-implemented method for the determination of

Zentrierparametern, wherein at least two of different

Viewing taken recorded to each other calibrated images of the head and where by means of geometric

Positioning geometric parameters are determined which describe the position of the eyes, wherein a geometrical parameter of the spectacle frame descriptive three-dimensional data set is provided, wherein by means of a rigid transformation, the geometric

Parameters of the eyeglass frame and the position of the eyes

descriptive geometric parameters are related to each other and wherein from the spectacle frame descriptive and the position of the eyes descriptive geometric parameters, the centering parameters are calculated.

2. Computer-implemented procedure according to clause 1, thereby

characterized in that the geometric parameters of

Eyeglass frame descriptive record as at least one

three-dimensional point cloud is provided. Computer-implemented procedure according to clause 2, by

characterized in that a plurality of point clouds are provided for different parts of the spectacle frame. Computer-implemented method according to clause 2 or 3, characterized in that the geometric parameters of

Spectacle frame descriptive record includes an orientation of at least one point cloud in space. Computer-implemented method according to one of the clauses 2 or 3, characterized in that an orientation of the at least one point cloud in space is calculated. Computer-implemented method according to one of the preceding

Clauses, characterized in that the geometric

Parameter of the spectacle frame descriptive record comprises one or more predetermined points of the spectacle frame. Computer-implemented method according to one of the preceding

Clauses, characterized in that from the geometrical parameters of the spectacle frame descriptive record for

Glasses frame belonging glass edges are determined. Computer-implemented method according to one of the preceding clauses, characterized in that a three-dimensional model for the spectacle frame and / or parts of the spectacle frame and / or the glasses of the spectacles is approximately adapted to the three-dimensional data set or to the specific glass edges. Computer-implemented procedure according to clause 8, thereby

in that the three-dimensional model for the spectacle lenses comprises or consists of glass surfaces and / or glass planes (52). I O.Computerimplementiertes method according to one of the clauses 8 or 9, characterized in that the three-dimensional model a

parametric model whose parameters are adjusted.

1 1.Computer-implemented method according to one of the preceding

Clauses, characterized in that the geometric

Positioning comprises a triangulation method.

12. Computer program with program code to carry out all

Method steps according to one of the preceding clauses, when the computer program is loaded into a computer and executed in a computer.

13. Use of a device (10) for carrying out a

Computer-implemented method according to one of the clauses 1 to 9, wherein the device (10) has a camera carrier (14) which partially encloses an interior (22) which is open towards the top, bottom and back (30) and at least three cameras ( 16a, 16b), which are arranged between two free ends (18) of the camera carrier (14) and directed towards the inner space (22), wherein the

Camera support (14) for illuminating the interior (22) a

Lighting device (32, 34, 36).

14. A computer comprising a memory, wherein in the memory

Computer program is stored according to clause 12, and a processor to execute the computer program stored in the memory.

15. Computer according to clause 14, characterized in that the processor is set up, at least two at the same time from different ones

Viewpoints recorded calibrated images of the head

to provide and by means of geometric positioning

geometric parameters to determine the position of the eyes

describe a geometric parameter of the spectacle frame descriptive three-dimensional data set to bring by means of a rigid transformation, the geometric parameters of the spectacle frame and the position of the eye descriptive geometric parameters related to each other and out of the spectacle frame

descriptive and the position of the eyes descriptive geometric parameters to calculate the centering parameters.

Claims

claims

1 . Computerimplennentiertes method for the determination of Zentrierparametern wherein at least two recorded from different directions directions calibrated images of the head are provided and wherein geometrical positioning determines geometric parameters that describe the position of the eyes, wherein a geometrical parameter of the spectacle frame descriptive three-dimensional data set is provided by means of a rigid transformation, the geometrical parameters of the spectacle frame and the geometrical parameters describing the position of the eyes are related to one another, and from which the

Spectacle frame descriptive and the position of the eyes descriptive geometric parameters are calculated, the Zentrierparameter, characterized in that the geometric parameters of the spectacle frame and the position of the eyes describing geometric parameters without

Using a reference object defining a position or orientation in space or a scale.

2. Computer-implemented method according to claim 1, characterized

in that the data record describing the geometrical parameters of the spectacle frame is generated from at least two calibrated images of the head carrying the spectacle frame or from at least two calibrated images of the spectacle frame.

3. Computer-implemented method for determining Zentrierparametern wherein at least two recorded from different directions calibrated images of the head are provided and wherein geometrical positioning determines geometric parameters that describe the position of the eyes, wherein a geometrical parameter of the spectacle frame descriptive three-dimensional data set is provided by means of a rigid transformation, the geometric parameters of the spectacle frame and the position the geometrical parameters describing the eyes are related to each other and from which the

Spectacle frame descriptive and the position of the eyes descriptive geometric parameters, the Zentrierparameter be calculated, characterized in that the geometrical parameters of the spectacle frame descriptive record from at least two calibrated images of the frame carrying the spectacle frame or at least two calibrated images of the spectacle frame is generated ,

4. Computer-implemented method according to one of claims 1 to 3, characterized in that the geometric parameters of

Spectacle frame descriptive record is generated by segmentation of the silhouettes of the spectacle frame in the individual images and / or by means of an SD reconstruction method and / or by means of a method for machine learning.

5. Computer-implemented method according to one of the preceding

Claims, characterized in that the data set describing the geometric parameters of the spectacle frame as at least one

three-dimensional point cloud is provided.

6. Computer-implemented method for determining centering parameters, wherein at least two images of the head are taken from different viewing directions and wherein geometrical position determination determines geometric parameters which describe the position of the eyes, wherein a geometrical parameter of the spectacle frame is provided descriptive three-dimensional data record becomes, wherein, by means of a rigid transformation, the geometrical parameters of the spectacle frame and the geometrical parameters describing the position of the eyes are related to one another, and wherein the

Spectacle frame descriptive and the position of the eyes descriptive geometric parameters are calculated the Zentrierparameter, characterized in that the geometrical parameters of the spectacle frame descriptive record is provided as at least one three-dimensional point cloud.

7. Computer-implemented method according to claim 5 or 6, characterized in that a plurality of point clouds are provided for different parts of the spectacle frame.

8. Computer-implemented method according to one of claims 5 to 7, characterized in that the geometric parameters of

Spectacle frame descriptive record includes an orientation of at least one point cloud in space.

9. Computer-implemented method according to one of claims 5 to 7, characterized in that an orientation of the at least one

Point cloud is calculated in space.

10. Computer-implemented method according to one of the preceding

Claims, characterized in that the dataset describing the geometrical parameters of the spectacle frame comprises one or more predetermined points of the spectacle frame or that these points are calculated.

1 1. Computer-implemented method according to one of the preceding

Claims, characterized in that from the geometric

Parameters of the eyeglass frame descriptive record are determined to the eyeglass frame belonging glass edges.

12. Computer-implemented method according to one of the preceding

Claims, characterized in that the data describing the geometric parameters of the spectacle frame data set is projected onto a two-dimensional plane.

13. Computer-implemented method according to one of the preceding claims, characterized in that a three-dimensional model for the spectacle frame and / or parts of the spectacle frame and / or the glasses of the glasses is approximately adapted to the three-dimensional data set or to the specific glass edges.

14. Computer-implemented method according to claim 13, characterized

characterized in that the three-dimensional model for the lenses

Glass surfaces and / or glass planes (52) comprises or consists of these.

Computer-implemented method according to one of claims 13 or 14, characterized in that the three-dimensional model is a parametric model whose parameters are adapted.

16. Computer-implemented method according to one of claims 13 or 14, characterized in that the three-dimensional model means

Machine learning is generated from sample data.

17. Computer-implemented method according to one of the preceding

Claims, characterized in that the geometric

Position determination and / or the generation of the geometrical parameters of the spectacle frame descriptive record comprises a triangulation method.

18. Computer program with program code to carry out all

Method steps according to one of the preceding claims, when the

Computer program is loaded into a computer and run in a computer.

19. Use of a device (10) for carrying out a

A computer-implemented method according to any one of claims 1 to 17, wherein the device (10) comprises a camera support (14) which partially encloses an interior (22) open towards the top, bottom and back (30) and at least three cameras ( 16a, 16b), which are arranged between two free ends (18) of the camera carrier (14) and directed towards the interior space (22), wherein the camera carrier (14) for illuminating the interior (22) has a lighting device (32, 34, 36).

20. A computer comprising a memory, wherein in the memory

A computer program according to claim 18 is stored, and a processor for executing the computer program stored in the memory.

21. Computer according to claim 20, characterized in that the processor is set up, at least two at the same time from different ones

Provide viewing directions recorded calibrated images of the head and determine by geometric positioning geometric parameters that describe the position of the eyes to provide a geometrical parameter of the spectacle frame descriptive three-dimensional data set, by means of a rigid transformation, the geometric parameters of the

Spectacle frame and the position of the eye descriptive geometric parameters related to each other and from the spectacle frame describing and the position of the eye descriptive geometric parameters to calculate the Zentrierparameter.

22. Apparatus for determining centering parameters with a first camera for recording a first image from a first viewing direction, with at least one second camera calibrated for the first camera for capturing a second image from a second viewing direction different from the first viewing direction and with a computer which includes a memory in which a

Computer program is stored, which has a program code for performing the following method steps: i. Providing at least two of different

View directions of recorded calibrated images of the head of a subject ii. Determination of geometric parameters that describe the position of the eyes using geometric positioning iii. Providing a three-dimensional data set describing a geometrical parameter of a spectacle frame iv. relating the geometrical parameters of the spectacle frame and the geometrical parameters v describing the position of the eyes. Calculation of the centering parameters from the spectacle frame

and the geometrical parameters describing the position of the eyes, wherein the geometrical parameters of the spectacle frame and the geometrical parameters describing the position of the eyes are related to each other without using a reference object defining a position or orientation in space or scale, and wherein Computer includes a processor to execute the computer program stored in the memory.

23. Device for determining centering parameters with a first camera for recording a first image from a first viewing direction, with at least one second camera calibrated for the first camera for capturing a second image from a second viewing direction different from the first viewing direction, and with a computer includes a memory in which a

descriptive and the position of the eyes descriptive geometric parameters, wherein the geometrical parameters of the spectacle frame descriptive record from at least two calibrated images of the spectacle frame supporting head or at least two calibrated images of the spectacle frame is generated, and wherein the computer comprises a processor to run the computer program stored in memory.

24. Apparatus for determining centering parameters with a first camera for recording a first image from a first viewing direction, with at least one second camera calibrated for the first camera for capturing a second image from a second viewing direction different from the first viewing direction, and with a computer includes a memory in which a

descriptive and the position of the eyes descriptive geometric parameters, wherein the geometrical parameters of the spectacle frame descriptive record is provided as at least one three-dimensional point cloud, and wherein the computer comprises a processor to the in the

Memory stored computer program to run.

25. A method for centering at least one spectacle lens in one

Spectacle frame, characterized in that centering parameters are determined by a method according to one of claims 1 to 17 in a first method step and that in a second method step, the at least one spectacle lens with those determined in the first method step

Centering in the spectacle frame is centered.

26. A method for wrapping at least one spectacle lens in one

Spectacle frame, characterized in that centering parameters in a first method step with a method according to one of claims 1 to 17 be determined and that in a second method step, the at least one spectacle lens is ground based on the determined in the first step centering parameters for an arrangement in the spectacle frame

27. A method for producing a spectacle lens, characterized by the method step grinding the spectacle lens into a spectacle frame according to the method according to claim 26.

28. A method for producing a pair of spectacles, characterized in that a method according to any one of claims 25 to 27 is used.