Method and device for measuring the lens mount angle of eyeglasses and computer program product

Abstract

The invention relates to a method for measuring the angle of spectacle lenses, comprising the steps of placing (100) spectacles, having a first lens and a second lens, in a spectacle receiving area. The surfaces of the two spectacle lenses are scanned (110) by a scanner to generate position data points for the first lens and position data points for the second lens. The position data points for the first lens are reflected (120) onto the position data points for the second lens with respect to a central plane (M) between the two lenses, such that the position data points for the first and second lenses are superimposed.An offset function (A) (121) is determined as a surface function using the overlapping surface position data points of the two glasses lenses, and the frame lens angle is determined (160) by the surface function using the overlapping surface position data points of the two glasses lenses.

Description

[0001] The invention relates to a method and device for measuring the lens angle of a pair of glasses and a computer program product.

[0002] To measure and verify the lens angle, it is known to inspect the surface of a finished pair of glasses using a laser scanning process. For this purpose, the Rodenstock Centering Analyzer (RCA) can be used, for example. The RCA comprises a laser scanner that uses laser beams reflected from the glasses to determine a height profile of the lens surface. The lens angle of the glasses can then be determined from this height profile.

[0003] The lens angle (abbreviation: FSW) is defined according to DIN EN ISO 8624 and DIN EN ISO 58208 as the angle between the frame plane and the right or left lens plane. The lens plane is defined as the plane through the horizontal and vertical center lines of the right or left lens box of the spectacle frame. The frame plane is defined as the plane through the parallel vertical center lines of the lens boxes that define the right and left lens planes of a spectacle frame. The lens box is also defined in the aforementioned standards. The lens angle, the frame plane, the lens plane, and the lens box are standardized terms familiar to those skilled in the art.

[0004] Document DE 10 2016 009810 A1 discloses a method for checking the centering of at least one spectacle lens, wherein the spectacle lens is positioned in a recording field of an image recording device. At least one image of the spectacle lens is recorded using the image recording device. Positions of functional engravings on the spectacle lens are determined in the recorded image. Furthermore, at least one lens contour of the at least one spectacle lens is determined in the recorded image, and the centering of the spectacle lens is checked taking into account the determined position of the functional engravings, the determined lens contour, and a previously known, user-dependent target geometry of the centering. Document DE 10 2014 005281 A1 discloses a device and a method for the non-contact detection of the position of at least one spectacle lens marked in three-dimensional space.The device comprises at least one lighting device designed to illuminate at least one spectacle lens, at least in the area of ​​the markings. Two or more image acquisition devices are designed to generate image data of the markings and at least partial areas of the at least one spectacle lens. An image data processing device is designed to determine the three-dimensional positions of the markings based on the generated image data. A position determination device is designed to determine the position of the at least one spectacle lens in space based on spectacle lens data provided for the at least one spectacle lens and the determined three-dimensional marking positions.

[0005] The frame disc angle can be considered a measure of the curvature of a spectacle frame and plays a role in the centration of spectacle lenses as well as in the calculation of individualized ophthalmic spectacle lenses.

[0006] The previously known method for measuring and verifying the lens angle works relatively well for diffusely reflective surfaces. A difficulty with spectacle lenses lies in their reduced diffuse reflection and their transparency. The challenge lies particularly in identifying and filtering out the reflection signals relevant for the measurement. Here, reflection signals from the front and back of the lens must be distinguished. Furthermore, noise and measurement artifacts, which are caused, for example, by parts of the spectacle frame itself, should be filtered out.

[0007] This means that the reflection signals measured by the laser are sometimes very widely scattered, e.g. due to interference reflections, back surface reflections, and / or weak reflections in plastic lenses with a refractive index of 1.5.

[0008] The method therefore only works satisfactorily for some of the lenses, while it does not produce usable results for approximately one-third. For these lenses, the FSW must be measured manually, for example.

[0009] The invention is therefore based on the objective of providing a way to determine the lens angle of a pair of glasses more reliably.

[0010] This problem is solved by the subject matter of the independent claims. Preferred embodiments are the subject matter of the dependent claims.

[0011] One aspect concerns a method for measuring the lens angle of a pair of spectacles, wherein the spectacles, comprising a first lens and a second lens, are positioned on a spectacle frame. The lens surfaces of both lenses are scanned to generate first surface position data points for the first lens and second surface position data points for the second lens. The first surface position data points of the first lens are reflected onto the second surface position data points of the second lens with respect to a median plane between the two lenses such that the first and second surface position data points of both lenses overlap. A regression function, in particular a regression polynomial, is determined as a surface function through the superimposed surface position data points of both lenses.The frame disc angle is determined using the surface function through the superimposed surface position data points of both spectacle lenses.

[0012] Besides a regression polynomial, other functions can also be used as the regression function, e.g., straight lines and / or parabolas from special regression polynomials, a function with at least one exponential function, with at least one Fourier series, with at least one Gaussian curve, and / or a similar numerical approximation. Regression polynomials have proven particularly suitable because they are mathematically manageable and usually achieve sufficient accuracy.

[0013] The procedure is performed on a finished pair of glasses and / or a complete pair of glasses, i.e., on glasses with lenses made of plastic or glass already fitted into the frame. The Rodenstock Centering Analyzer, abbreviated RCA, can be used, for example, to perform the procedure.

[0014] First, the glasses are positioned on a measuring station within the scanner's scan field. A special spectacle holder is used for this purpose, which may include a centering piece on which the glasses are positioned with a predetermined orientation relative to the scanner. The glasses can be positioned on the spectacle holder so that the lens surfaces face the scanner. This means that the side of the lenses furthest from the wearer's eyes, also known as the front surface, is facing the scanner. These surfaces of the lenses are referred to as the lens surfaces.

[0015] A laser scanner can be used, meaning a scanner that scans the lens surfaces using laser light. A line laser scanner is particularly suitable for this purpose, such as the ScanCONTROL 2900-100 / BL laser scanner from Micro-Epsilon. The scanner shines a scan light onto the lens surfaces, from which the scan light is reflected. The scanner registers this reflected scan light as scan signals. Position data points can be assigned to these registered light reflections, which can then be determined, for example, by triangulation. For this, the scanner can be positioned in a well-defined and / or calibrated position relative to the glasses and / or the lens mount. In In some designs, the scanner can independently create the position data points (e.g., using triangulation).

[0016] The position data points of the reflection signals from the lens surfaces are stored as surface position data points. Scan signals reflected from the first lens and / or scan signals reflected from the first half of the frame (the part containing the first lens) are captured and processed as first surface position data points. Scan signals reflected from the second lens and / or scan signals reflected from the second half of the frame (the part containing the second lens) are captured and processed as second surface position data points. The distinction between first and second surface position data points is based solely on whether the reflection point of the scan signals is located in the first or second half of the frame, i.e., the left or right half of the frame as depicted in the image.

[0017] The surface position data points obtained in this way do not initially contain exclusively position data points that are actually located on the lens surfaces. In fact, the first and / or second surface position data points may initially contain interference signals, for example, position data points generated by reflections from the frame and / or reflections from the back surface of the lens. The back surface of the lens is located on the rear side of the lens, which, when the glasses are in use, faces the wearer's eyes.

[0018] Using the scanner, the first and second surface position data points can be generated in such a way that they are arranged sequentially on at least one scan line. This scan line can, for example, run across at least one lens surface. The scan line can extend (at least in the glasses' wearing position) approximately horizontally across the lens and / or lenses. In other words, the scan line can, for example, run across both lenses. The scan line can extend along its length over a large portion of both the first and second lenses. This means that the surface position data points cover at least 50% of the lens surfaces of the first and second lenses along the scan line. The scan line can be interrupted and / or cut off in front of the nasal and / or temporal edges of both lenses to reduce interference caused by the frame.Surface position data points located at the nasal and / or temporal edges of both spectacle lenses can be automatically discarded, for example.

[0019] The first and second surface position data points can be stored as coordinates of a coordinate system. Each surface position data point obtained in this way is assigned either the first or the second lens, so that it is stored as either a first or a second surface position data point. Here, the first lens could, for example, be the left lens of the glasses, and the second lens the right lens. Alternatively, the assignment can be reversed.

[0020] These can be processed further as a single data set. The subsequent evaluation of the first and second surface position data points obtained in this way can be carried out using computer-aided methods.

[0021] By mirroring the first surface position data points onto the second surface position data points, the number of data points arranged in one measurement half is increased, e.g., approximately doubled. This can significantly increase the accuracy of the measurement, thereby increasing the reliability of the measurement method.

[0022] The reflection is performed with respect to the median plane, which can be, for example, fixed and / or which divides the glasses approximately symmetrically into two halves. In the wearing position of the glasses, the median plane can be, for example, arranged as an approximately vertical plane running perpendicularly through the bridge of the spectacle frame. The median plane can be predefined relative to the spectacle mount on which the glasses are positioned during the measurement.

[0023] Provided the glasses are perfectly aligned with the image, the first surface position data points are mirrored almost perfectly onto the second surface position data points. In any case, the number of position data points increases due to the mirroring, allowing for a more stable surface function to be created by superimposing the surface position data points.

[0024] This allows for the creation of a superimposed dataset of surface position data points, in which the first and second surface position data points overlap in the second half of the spectacle. In further processing of the surface position data points, all of these points can remain indexed as either first or second surface position data points.

[0025] The surface function used to determine the correction function is calculated from the superimposed surface position data points. A second-degree correction polynomial is preferably used, which typically fits the curvature of the front surface of the lenses well, especially if the lenses are designed to resemble a spherical surface and / or are approximately spherical. The angle at which the laser scanner is positioned relative to the glasses and / or the lens mount can be taken into account when determining the correction function. In particular, the angle at which an optical axis of the laser scanner intersects the lens surfaces of the glasses mounted in the lens mount can be considered.

[0026] Preferably, the optical axis of the laser scanner intersects the lens surfaces of the glasses arranged in the spectacle image at approximately a perpendicular angle, e.g. at an angle of approximately 80° to approximately 100°.

[0027] The adjustment function can be determined, for example, by linear regression. This adjustment function is used as the surface area function of the spectacle lens. The lens tilt angle can be calculated based on the surface area function of the spectacle lenses, since this function represents the shape of the lens surface.

[0028] Since the surface function can change during the processing steps of the surface position data points described below, it is also referred to as the "current" surface function. This indicates that the surface function ultimately does not necessarily have to be the compensation function created solely on the basis of the simply superimposed surface position data points. Rather, for example, after filtering the surface position data points, a modified compensation function can be calculated again, and this modified compensation function can be used as the current surface function, e.g., for calculating the lens angle and / or for further data processing.

[0029] The method can either calculate just one lens disc angle or calculate both the right and left lens disc angles. To calculate the lens disc angle of the first lens, for example, the compensation function with respect to the midplane can be reflected back onto the first half of the lens, from which the first surface position data points were measured.

[0030] Alternatively, the first surface position data points (e.g., remaining after filtering) can be reflected back into the first half of the spectacle, and a first compensation function is applied to the first surface position data points and taken into account when calculating the first frame disc angle.

[0031] Therefore, when calculating the lens disc angle, either a single compensation function can ultimately be used as a surface function (e.g., for both lenses), or a first and a second compensation function can be determined as the first and second surface functions for the first and second halves of the lens. Then, the first and second lens disc angles can be determined based on the first and second surface functions.

[0032] This method exploits the symmetry of the eyeglass to increase the number of surface position data points, thus making the calculation more stable. Since most manufactured eyeglasses—over 95%—have the same base curve for the left and right lenses, very similar measurements are expected for the right and left lenses. The measurements may differ, for example, only due to noise caused by measurement errors. By mirroring the initial surface position data points, the data set is enriched and therefore more robust for further processing.

[0033] In one embodiment, the first surface position data points in the superimposed surface position data points are tilted relative to the second surface position data points such that the first and second surface position data points are positioned closer to the determined surface function. Since the glasses are not always perfectly aligned on the lens mount in practice, it can happen that the first surface position data points are not perfectly superimposed on the second surface position data points when reflected. To compensate for this, the first surface position data points are tilted relative to the second surface position data points. The aim of this tilting can be to ensure that the first and second surface position data points overlap as closely as possible.A tilt of up to approximately 2° may be sufficient to significantly increase the overlap of the superimposed surface position data points. The degree of tilt, i.e., the precise tilt angle, can depend on the degree of overlap of the surface position data points. The more accurately the surface position data points overlap after tilting, the better suited the tilt angle used for further data processing.

[0034] In a further training course, the tilt of the first surface position data points relative to the second surface position data points is optimized so that the superimposed first and second surface position data points are arranged as close as possible to an optimized compensation function as the surface function defined by the superimposed and optimally tilted surface position data points of both lenses. For this purpose, a best-fit approach can be chosen, for example, to optimize the degree of tilt, i.e., the tilt angle. This optimized tilt of the surface position data points can almost completely compensate for any asymmetrical contact of the glasses with the lens mount. After optimization of the tilt, the first and second surface position data points can be arranged almost congruently and / or identically on top of each other.An exception to this are the measurement errors and / or noise signals contained in the surface position data points. Based on the superimposed and thus optimally tilted surface position data points, the optimized adjustment function is calculated. Again, a second-degree adjustment polynomial is preferably used for this purpose. The optimized adjustment function is used as the surface function, e.g., in the calculation of the mounting disc angle(s). This optimized tilting improves the superimposed data set, making it an optimized data set, and can therefore lead to a more accurate and reliable measurement result.

[0035] According to one embodiment, in a reduction step, individual surface position data points whose distance from the surface function is greater than a predetermined first maximum distance are removed from the superimposed and, if necessary (e.g., optimized), tilted surface position data points, in order to obtain superimposed and reduced surface position data points. For the reduction step, either the superimposed surface position data points are used, or the already superimposed and tilted surface position data points are used, or preferably the superimposed and optimized tilted surface position data points are used. In the latter case, the tilt is already optimized as described above. To eliminate "outliers" in the dataset, those surface position data points from the (e.g.,The optimized data set is removed if it is further away than the predetermined maximum distance from the current surface function. One of the adjustment functions can be used as the surface function for this purpose. For example, the (simple) adjustment function created based on the superimposed surface position data points, the optimized adjustment function, or a reduced adjustment function during an iteration (see the processing steps described below) can be used. A first predetermined maximum distance of approximately 0.1 mm to approximately 0.5 mm can be used, preferably 0.2 mm to approximately 0.4 mm. An initial maximum distance of approximately 0.3 mm has empirically proven particularly suitable for achieving a meaningful reduction and thus filtering of the surface position data points. Therefore, all surface position data points that are further away than, for example, 0.3 mm are removed.Surface features that are 0.3 mm away from the current surface function are eliminated from the current data set and not considered for further calculation.

[0036] In a further training course, a reduced regression function, specifically a reduced regression polynomial, is determined as a surface function through the superimposed and reduced surface position data points of both spectacle lenses. After cleaning the dataset, i.e., after removing the surface position data points that were too far apart during the reduction step, a regression function is again fitted to the remaining surface position data points. This regression function can be a second-degree polynomial and can be called a reduced regression polynomial, since it is based on a reduced dataset of surface position data points.

[0037] The reduced compensation function is subsequently used as the actual surface function. For example, the mounting disc angle can be determined based on the surface function obtained in this way.

[0038] In a further training, at least the reduction step is iterated based on the reduced regression function as the surface function and on the superimposed and reduced surface position data points. During the iteration, individual surface position data points are removed whose distance from the current surface function (i.e., the reduced regression function) is greater than the predetermined first maximum distance. This further reduces the reduced dataset of surface position data points, thereby improving the quality of the remaining surface position data points. Based on these further reduced surface position data points, a new reduced regression function is determined.The reduction step can be iterated based on each newly calculated reduced regression function until no surface position data point is further away from the (current) reduced regression function than the first maximum distance determined by the remaining superimposed and reduced surface position data points. The iteration can then be terminated. This iteration achieves effective filtering of the surface position data points.

[0039] The iteration can also include further process steps. For example, in addition to the reduction step, the optimization of the tilt of the surface position data points relative to each other can also be iterated. For instance, the optimization of the tilt can be iterated first, then an optimized adjustment function can be determined again, and finally the reduction step is iterated.

[0040] The reduction step, based on the current surface function (e.g., the newly determined reduced or optimized regression function), can be iterated until a predetermined level of filtering of the surface position data points is achieved. This iteration can be performed, for example, using the Newton method. Iterations can be terminated, for example, when no further surface position data points are determined during the reduction step that are further away from the current surface function (e.g., the reduced or optimized regression function) than the first maximum distance.

[0041] In a further development of the embodiment with the reduction step, individual surface position data points are removed from the superimposed and reduced surface position data points. These points are located at a distance from the surface function greater than a predetermined second maximum distance, which is smaller than the first maximum distance, in order to obtain minimized surface position data points. This process step can be referred to as the minimization step. The second maximum distance can, for example, be approximately half the size of the first maximum distance. In the example, the second maximum distance can thus be approximately 0.15 mm. This minimization of the reduced and superimposed surface position data points achieves a further filtering of the data set, resulting in a minimized data set that comprises only the minimized (and still superimposed) surface position data points.

[0042] In a training course, a minimized adjustment function, specifically a minimized adjustment polynomial, is determined as the surface function through the minimized surface position data points of both lenses. The minimized adjustment function can then be used as the final surface function for calculating the lens tilt angle. Alternatively, the reduction and / or minimization step described above can be iterated again based on the minimized adjustment function and the minimized surface position data points. In practice, it has been shown that further iteration based on the smaller second maximum distance yields little improvement to the minimized data set. Therefore, it is usually sufficient to perform the minimization only once and use the calculated minimized adjustment function as the final surface function.

[0043] According to one embodiment, the mounting disc angle is determined based on the surface function, which corresponds to one of the following compensation functions: a) the optimized adjustment function, b) the reduced adjustment function, or c) the minimized adjustment function.

[0044] The more of the previously described procedural steps are performed, the more accurate the measurement result becomes. Ideally, the superimposed surface position data points are tilted relative to each other, this tilt is optimized, an iterative reduction is performed based on the first maximum value, and a minimization is carried out based on the second maximum value, with the minimized compensation function being used as the surface function. Using this approach, the lens angle of at least 97% of the measured eyeglasses could be correctly determined in practice. Only for less than 3% of the measured eyeglasses could a satisfactory measurement result not be achieved. This significantly increases the reliability compared to the previously known method, according to which the lens angle could not be determined with sufficient accuracy for approximately one in three eyeglasses.

[0045] According to one embodiment, a regression polynomial is determined as the regression function. Depending on the embodiment, the following may be determined and / or used: a) as an optimized regression function, an optimized regression polynomial, and / or b) as a reduced regression function, a reduced regression polynomial, and / or c) as a minimized regression function, a minimized regression polynomial.

[0046] Reduction polynomials are mathematically the easiest to handle and are therefore particularly suitable for creating technically useful approximation curves around measurement points. It has been shown that reduction polynomials are precisely the right approximation for the problem underlying the invention.

[0047] According to one embodiment, before determining the lens angle for the first lens, the remaining first surface position data points are reflected back onto the corresponding side of the spectacle. These are the remaining first surface position data points of the current data set, i.e., the optimized, reduced, or minimized data set. A first compensation function can be determined from these reflected first surface position data points, e.g., a first minimized compensation function from the reflected first minimized surface position data points. The first compensation function can be used as the first surface function to calculate the first lens angle of the first lens. The second surface position data points remaining in the second half of the spectacle after reflection, i.e.,The mined second surface position data points can be used to determine a second adjustment function, for example, a second minimized adjustment function. This second adjustment function can be used as a second surface function to calculate the second frame disc angle of the second spectacle lens.

[0048] Alternatively, only the current compensation function can be reflected back, for example, the optimized compensation function, the reduced compensation function, or the minimized compensation function. This allows the current compensation function to be used as the first and second surface functions in both halves of the lens to calculate the first and second lens angles. However, reflecting back the remaining first surface position data points into the first half of the lens generally yields more reliable results when calculating the lens angles.

[0049] According to one embodiment, the surface position data points are determined in two dimensions. Further evaluation, filtering, and calculation can also be performed in two dimensions. This is sufficient for a reliable measurement of the mounting disc angle and reduces the workload compared to three-dimensional calculations.

[0050] One aspect concerns a device for measuring the lens angle of a pair of spectacles, which includes a spectacle holder with a first lens and a second lens. A scanner is configured to scan the lens surfaces of both lenses of the spectacles mounted on the holder and to generate first surface position data points for the first lens and second surface position data points for the second lens. A mirror module is configured to reflect the first surface position data points of the first lens onto the second surface position data points of the second lens with respect to a median plane between the two lenses, such that the first and second surface position data points of both lenses overlap.A compensation function determination module is configured to determine a compensation function as a surface function using the superimposed surface position data points of both lenses. A frame disc angle determination module is configured to determine the frame disc angle using the surface function based on the superimposed surface position data points of both lenses.

[0051] The device can be configured to perform the procedure as described above. Therefore, the descriptions of the device also apply to the procedure, and vice versa. For example, an RCA (Rodenstock Centering Analyzer) can be used as the device. The RCA can include a computer and / or be connected to a computer on which the evaluation of the surface position data points can be performed.

[0052] The compensation function determination module can be used to determine the compensation function through the superimposed surface position data points, the optimized compensation function through the superimposed and optimized tilted surface position data points, the reduced compensation function through the superimposed and reduced surface position data points, and / or the minimized compensation function through the minimized surface position data points.

[0053] In one embodiment, the device has at least one of the following modules: a tilting module configured to tilt the first surface position data points relative to the second surface position data points in the superimposed surface position data points such that the first and second surface position data points are arranged closer to the determined surface function; and / or an optimization module configured to optimize the tilting of the first surface position data points relative to the second surface position data points such that the superimposed first and second surface position data points are arranged as close as possible to an optimized compensation function than the surface function defined by the superimposed and optimized tilted surface position data points of both lenses;and / or a reduction module configured to remove, in a reduction step, individual surface position data points from the superimposed surface position data points whose distance from the surface function is greater than a predetermined first and / or second maximum distance; and / or an iteration module configured to iterate at least the reduction step based on a reduced regression function through surface position data points superimposed and reduced by the reduction module as the surface function and on the basis of the superimposed and reduced surface position data points.

[0054] The modules are configured to execute the individual process steps described in connection with the procedure. The modules can be implemented as software modules.

[0055] One aspect concerns a computer program product comprising computer-readable program parts which, when loaded and executed, cause a device according to the aspect described above to perform a method according to the aspect described at the outset, wherein the computer program product at least partially controls and / or regulates the following units: the scanner; and the mirror module; and the compensation function determination module; and the mounting disc angle determination module; wherein the computer program product furthermore, in particular, at least partially controls and / or regulates at least one of the following units: the tilting module; and / or the optimization module; and / or the reduction module; and / or the iteration module.

[0056] The computer program product can be designed as control software. At a minimum, the computer program product can be designed to control the software modules used for evaluation. Additionally, it can be designed to send a start signal to the scanner and to receive measurement data from the scanner, from which the computer program product can obtain and / or calculate the first and second surface position data points.

[0057] Within the scope of this invention, the terms "essentially" and / or "approximately" may be used to include a deviation of up to 5% from a numerical value following the term, a deviation of up to 5° from a direction following the term and / or from an angle following the term.

[0058] Terms such as above, below, over, under, lateral, etc. refer - unless otherwise specified - to the Earth's reference system in an operating position of the subject matter of the invention.

[0059] The invention is described below with reference to the figures shown.

[0060] Exemplary embodiments are described in more detail. Here, identical or similar reference numerals can denote identical or similar features of the embodiments. Individual features shown in the figures may be implemented in other exemplary embodiments. The figures show: Fig. 1: Scanned first and second surface position data points of a pair of glasses in a diagram; Fig. 2: Superimposed surface position data points in a diagram through which a reconciliation function is applied; Fig. 3: Superimposed and optimized tilted surface position data points in a diagram through which an optimized reconciliation function is applied; Fig. 4: Superimposed and reduced surface position data points in a diagram through which a reduced reconciliation function is applied; Fig. 5: First and second minimized surface position data points in a diagram, wherein the first minimized surface position data points are mirrored back onto their origin side, wherein a first minimized reconciliation function is applied through the first minimized surface position data points as the first surface function, and a second minimized reconciliation function is applied through the second minimized surface position data points as the second surface function; and Fig.6. In a flowchart, an embodiment of a method for determining a mounting disc angle is shown.

[0061] The figures show and visualize an embodiment of a method for measuring the lens angle of a pair of glasses. Fig. 6 a flowchart shows the individual steps of the process. Figures 1 to 5 Each diagram shows surface position data points of a data set, which are determined and / or used during the execution of the procedure.

[0062] The inventive method does not necessarily have to encompass all of the above. Fig. 6 shown process steps, since some of the in Fig. 6 The process steps shown are optional. Furthermore, the process may include additional process steps that are not shown. Fig. 6 shown.

[0063] In the Fig. 6In the illustrated process step 100, the glasses to be measured are positioned with a first and second lens in the measuring field of a scanner. For this purpose, the glasses can be placed on a spectacle mount in such a way that the front surfaces of both lenses face the scanner.

[0064] In process step 110, the glasses are then scanned, specifically the two front surfaces, also called lens surfaces, of the first and second lenses. The glasses can be positioned relative to the scanner so that the scanner's light rays strike the two front surfaces of the glasses at approximately a right angle. The glasses and / or the scanner can be calibrated so that the scanner can generate surface position data points of the lens surfaces, for example, using triangulation. These surface position data points can be generated as 2D coordinates.

[0065] The scanner can be a laser scanner, for example, a line laser scanner. The scanner generates at least one data set 1, which contains the surface position data points. These surface position data points contain coordinates where reflections of the scan light occurred during scanning in process step 110. In process step 110, the scanner registers reflection signals from these reflections, which are then converted back into the surface position data points.

[0066] Fig. 1 Figure 1 shows the data set 1 recorded by the scanner, with first surface position data points 10 and second surface position data points 20. The first and second surface position data points 10 and 20 of data set 1 are plotted in a diagram. Fig. 1The diagram shown is plotted. A median plane M runs through the origin along the x-axis of the diagram, with respect to which the glasses are essentially symmetrical. During scanning, the first lens is positioned in the negative x-axis region. Therefore, this negative x-region is also referred to as the first half of the glasses. During scanning, the second lens is positioned in the positive x-axis region. Therefore, this positive x-region is also referred to as the second half of the glasses.

[0067] During scanning, the scanner does not generate surface position data points located closer than approximately 10 mm to the midplane M. Similarly, it does not generate surface position data points in an area further than approximately 50 mm from the midplane M. Therefore, the scanner only generates surface position data points that are at least one nasal distance (approximately 10 mm in this example) from the midplane M and / or that are at most one temporal distance (approximately 50 mm in this example) from the midplane M.

[0068] On the x-axis of the in the Figures 1 to 5 In the diagrams shown, the corresponding distance from the midplane M is given in millimeters.

[0069] On the Y-axis of the in the Figures 1 to 5 The diagrams shown indicate the height profile of the spectacle lenses in, for example, millimeters. In some of the diagrams, the height profile is shown in the diagrams. Figures 1 to 5The diagrams shown have slightly shifted and / or differently scaled y-axes.

[0070] In the Fig. 1 The exemplary measurement data from dataset 1 shows, particularly at the first surface position data points 10, a plurality of interfering reflection signals are shown alongside reflection signals along the lens surface of the first lens, which are probably caused by the back surface of the first lens. In the Fig. 1The second set of surface position data points shows a majority of reflection signals that are likely caused by noise and / or interference and were probably not actually reflected from the lens surface of the second lens. However, a large proportion of surface position data points 10 and 20 contained in data set 1 are likely actually caused by the two lens surfaces of the glasses and therefore allow conclusions to be drawn about the frame disc angle.

[0071] In process step 120, the first surface position data points 10 with respect to the midplane M are reflected from the first half of the spectacle (i.e., from the negative x-range) to the second half of the spectacle (i.e., into the positive x-range). This can be done, for example, simply by changing the sign of the x-coordinate of each first surface position data point 10. Thus, during the reflection, all surface position data points are reflected into the second half of the spectacle, i.e., in this example, into the positive x-range.

[0072] Fig. 2 Figure 1A shows a superimposed data set 1A obtained in this process, which includes both superimposed first surface position data points 11 and superimposed second surface position data points 21. The superimposed second surface position data points 21 are indicated by filled boxes. They can essentially be described in Fig. 1The second surface position data points 20 shown correspond to the surface position data points 20 shown. The superimposed first surface position data points 11 are in Fig. 2 marked by empty boxes. You can essentially see the one in Fig. 1 The first surface position data points shown correspond to 10 with a changed sign of the x-coordinate.

[0073] In a subsequent process step 130, the superimposed first surface position data points 11 are tilted relative to the superimposed second surface position data points 21. This tilting compensates for errors that may arise due to the glasses being placed asymmetrically on the spectacle mount. The tilt angle can be a single-digit number of degrees or even just a fraction of a degree. Such a small tilt angle can be sufficient to superimpose the surface position data points 11 and 21 of the superimposed data set 1A in a substantially congruent and / or largely coincident manner.

[0074] In a subsequent process step 131, the tilt is optimized, e.g. by means of a best-fit approach, so that the superimposed first and second surface position data points 11 and 21 overlap as identically and / or congruently as possible.

[0075] Fig. 3 Figure 1 shows an optimized data set 1B, which results from the optimization of the tilt in process step 131. The optimized data set 1B comprises optimized tilted first surface position data points 12 (in Fig. 3 (marked by empty boxes) and optimized tilted second surface position data points 22 (in Fig. 3 (indicated by filled boxes), which in turn are each based on the originally generated first and second surface position data points 10 and 20.

[0076] In process step 132, an optimized regression function Ao is fitted through all of these superimposed and optimized tilted first and second surface position data points 12 and 22. In the exemplary embodiment, an optimized regression polynomial can be used for this purpose, which is why the optimized regression function Ao is subsequently also referred to as the optimized regression polynomial Ao.

[0077] The procedure can then be continued on the basis of the optimized adjustment polynomial Ao determined in this way and the optimized data set 1B.

[0078] In a subsequent process step 140, a reduction step is performed by reducing the surface position data points 12 and 22 of the optimized data set 1B. In this process, so-called "outliers" are eliminated and / or filtered out from the optimized data set 1B. In particular, surface position data points 12 and 22 that are located further than a predetermined first maximum distance from the optimized regression polynomial Ao can be removed from the optimized data set 1B. For example, a distance of approximately 0.3 mm can be used as the first maximum distance.

[0079] Fig. 4 shows in a diagram a reduced dataset 1C, which superimposed and reduced first surface position data points 13 (in Fig. 4 (marked by empty boxes) and superimposed and reduced second surface position data points 23 (in Fig. 4(indicated by filled boxes). The reduced data set 1C is cleaned of those "outliers" which, in the optimized data set 1B, were located further apart than the first maximum distance from the regression polynomial Ao. In a process step 141, a reduced regression function AR is calculated using the surface position data points 13 and 23 of the reduced data set 1C. In the exemplary embodiment, a reduced regression polynomial can be used for this purpose, which is why the reduced regression function AR is subsequently also referred to as the reduced Ao.

[0080] Following the determination of the reduced regression polynomial AR, the procedure can be continued, for example, with minimization in procedure step 150. This can be done in particular if query 142 shows that in reduction step 140 not a single surface position data point had to be filtered out from the optimized data set 1B to obtain the reduced data set 1C.

[0081] Alternatively, especially if query 142 reveals that at least one surface position data point was filtered out in reduction step 140, an iteration 143 or 144 can then be performed.

[0082] Depending on the embodiment, either an iteration of process steps 140, 141 and e.g. 142) can take place in process step 143, or an iteration of process steps 131, 132, 140, 141 and e.g. 142 can take place in process step 144.

[0083] Iterations 143 and 144 include at least reduction step 140, in which surface position data points located further away from the reduced regression polynomial AR than the first maximum distance are filtered out and removed. Based on the again reduced dataset 1C, the reduced regression polynomial AR is also iterated in process step 141. Reduction step 140 can be iterated until no further surface position data points need to be eliminated, which can be verified, for example, in query 142.

[0084] As an alternative to iteration step 143, iteration step 144 can not only involve an iteration of reduction step 140, but the iteration can also begin earlier with the optimization of the tilt in process step 131. In this case, only the surface position data points of the reduced data set 1C are considered, from which outliers have already been filtered out.

[0085] Subsequently, all subsequent process steps can be carried out, namely process step 132, in which an optimized regression polynomial Ao (generally: an optimized regression function) is determined again, and process steps 140 to 142. Iteration 144, incorporating the optimization of the tilt (process step 131) into the iteration, further improves the result obtained and thus leads even more reliably to the calculation of the actual mounting disc angle.

[0086] Following query 142, minimization can be performed in process step 150. Here, similar to reduction step 140, outliers are removed. However, instead of the first maximum distance, a smaller second maximum distance is considered. During minimization, all surface position data points from the reduced dataset 1C that are located further away from the reduced regression polynomial AR than the second maximum distance, which might be approximately half the size of the first maximum distance, are removed. The result is a minimized dataset containing minimized first and second surface position data points (not shown in the figures). Graphically, the minimized dataset looks similar to the one in Fig. 4 Reduced dataset 1C shown.

[0087] In the subsequent process step 151, the minimized first surface position data points can be reflected back around the midplane M onto the first half of the glasses, i.e. in the example into the negative x-range.

[0088] When reflecting back the minimized first surface position data points in process step 151, the tilt and / or tilt angle can be taken into account in order to reflect the surface position data points back to their correct position.

[0089] Fig. 5 The figure shows the data points after mirroring. This results in a minimized and mirrored 1D dataset. The minimized and mirrored 1D dataset comprises minimized and mirrored first surface position data points 14 and minimized second surface position data points 24, where in Fig. 5All minimized and reflected surface position data points 14 and 24 are marked by filled boxes.

[0090] Two adjustment functions are defined using the minimized and reflected 1D dataset: a first minimized adjustment function A M1, derived from the minimized and reflected first surface position data points 14, serves as the first surface function for the first lens, and a second minimized adjustment function A M2, derived from the minimized second surface position data points 24, serves as the second surface function for the first lens. Determining these minimized adjustment functions A M1 and A M2 can be performed in a single process step 160.

[0091] In the exemplary embodiment, minimized regression polynomials can be used for this purpose, which is why the minimized regression functions are subsequently also referred to as the first and second minimized regression polynomials A M1 and A M2.

[0092] As an alternative to determining the first and second minimized regression polynomials A M1 and A M2, a single minimized regression function AM (not shown in the figures, referred to below as the minimized regression polynomial AM) can be determined from the (still superimposed, not yet reflected back) minimized first surface position data points and the minimized second surface position data points. In this case, the minimized regression polynomial AM is determined only for the superimposed and minimized surface position data points in the second half of the spectacle lens. The minimized regression polynomial AM can then be used as the second surface function for the second lens.The minimized adjustment polynomial AM can be reflected back into the first half of the spectacle with respect to the midplane M (instead of the minimized first surface position data points) in order to form the first surface function for the first spectacle lens.

[0093] In process step 170, at least one frame disc angle is determined. Preferably, a first and second frame disc angle can be determined for the first and second spectacle lenses, e.g., based on the first and second surface functions. The frame disc angle is determined based on one of the regression polynomials. For this purpose, either the normal regression polynomial A, the optimized regression polynomial Ao, the reduced regression polynomial AR, or preferably at least the minimized regression polynomial(s), i.e., the minimized regression polynomial AM or the first minimized regression polynomial A M1 and the second minimized regression polynomial A M2, can be used. More generally, one of the corresponding regression functions can be used for this purpose.

[0094] The method reliably delivers good results for the geometric frame disc angle. Through the tilting step 130 and / or the optimization of the tilting step in process step 131, any tilting of the spectacle frame on the spectacle mount is almost eliminated. Here, the tilting is adjusted to the currently used adjustment polynomial.

[0095] The filtering of the measurement data by reduction step 140 is preferably performed iteratively. In an iteration loop, the optimization of the tilt (procedure step 131), the calculation of the adjustment polynomial (procedure step 132 and / or 141), and the reduction of the measured values ​​(procedure step 140) can be repeated and calculated until the maximum deviation of the remaining and filtered surface position data points no longer exceeds the first maximum distance and / or the second maximum distance.

[0096] In most cases, and in at least 97% of trials, the final calculation of the lens mount angle can be accepted as the actual lens mount angle without any further measurements by an operator. This eliminates the need for manual remeasurement of the lens mount angle, which was previously often required. Reference symbol list

[0097] 1Dataset 1AOverlaid dataset 1BOverlaid and optimized tilted dataset 1CReduced dataset 1DMinimized and mirrored dataset 10. First surface position data points 11. Superimposed first surface position data points 12. Optimized tilted first surface position data points 13. Reduced first surface position data points 14. Minimized and mirrored first surface position data points 20. Second surface position data points 21. Superimposed second surface position data points 22. Optimized tilted second surface position data points 23. Reduced second surface position data points 24. Minimized second surface position data points 100 Arrange glasses 110 Scan 120 Mirror and superimpose 121 Determine the equivalent polynomial 130 Tilt 131 Optimize tilt 132 Determine optimized least-squares polynomial 140 Reduce 141 Determine reduced least-squares polynomial 142 Query 143 Iterate the reduction step 144 Iterate the optimization and reduction step 150 Minimize 151 Reflect back 160 Determine minimized least-squares polynomial 161 Determine FSW A: Adjustment polynomial AO: Optimized adjustment polynomial AR: Reduced adjustment polynomial AM: Minimized adjustment polynomial A M1: First minimized adjustment polynomial A M2: Second minimized adjustment polynomial M: Middle plane

Claims

1. Method for measuring the frame angle of a pair of glasses, comprising the steps: - Placing (100) the eyeglasses, which have a first eyeglass lens and a second eyeglass lens, on an eyeglass holder; - scanning (110) the lens surfaces of both lenses of the eyeglasses using a scanner to generate first surface position data points of the first lens and second surface position data points of the second lens; - mirroring (120) the first surface position data points of the first lens onto the second surface position data points of the second lens with respect to a center plane (M) between the two lenses such that the first and second surface position data points of both lenses overlap; - determining (121) a compensation function (A) as a surface function by the superimposed surface position data points of both lenses; and - Determining (160) the frame disc angle by means of the surface function through the superimposed surface position data points of both lenses.

2. Method according to claim 1, wherein in the superimposed surface position data points, the first surface position data points are tilted (130) relative to the second surface position data points such that the first and second surface position data points are arranged closer to the determined surface function.

3. Method according to claim 2, wherein the tilting of the first surface position data points relative to the second surface position data points is optimized (131) such that the superimposed first and second surface position data points are arranged as close as possible to an optimized compensation function (AO ) as the surface function by the superimposed and optimally tilted surface position data points of both eyeglass lenses.

4. Method according to one of the preceding claims, wherein in a reduction step (140), individual surface position data points whose distance from the surface function is greater than a predetermined first maximum distance are removed from the superimposed and, if necessary, tilted surface position data points in order to obtain superimposed and reduced surface position data points.

5. Method according to claim 4, wherein a reduced compensation function (AR) is determined (141) as a surface function by the superimposed and reduced surface position data points of both lenses.

6. Method according to claim 5, wherein at least the reduction step is iterated (143; 144) based on the reduced compensation function as the surface function and based on the reduced superimposed surface position data points.

7. Method according to one of claims 4 to 6, wherein individual surface position data points are removed from the superimposed and reduced surface position data points (150) whose distance from the surface function is greater than a predetermined second maximum distance, wherein the second maximum distance is smaller than the first maximum distance, in order to obtain minimized surface position data points.

8. Method according to claim 7, wherein a minimized compensation function (AM ; AM1 , AM2 ) is determined as the surface function by the minimized surface position data points of both eyeglass lenses (160).

9. Method according to one of the preceding claims, wherein the frame disc angle is determined based on the surface function, which corresponds to one of the following compensation functions: a) the optimized compensation function (AO ), b) the reduced compensation function (AR ), or c) the minimized compensation function (AM ; AM1 , AM2 ).

10. Method according to one of the preceding claims, wherein a compensation polynomial is determined as the compensation function (A) and, if necessary: a) an optimized compensation polynomial is determined as the optimized compensation function (AO ), and / or b) a reduced compensation polynomial as a reduced compensation function (AR ), and / or c) a minimized compensation polynomial as a minimized compensation function (AM; AM1, AM2).

11. Method according to one of the preceding claims, wherein, before determining the frame disc angle for the first lens, the remaining first surface position data points are reflected back to the corresponding lens side.

12. Method according to one of the preceding claims, wherein the surface position data points are determined in two dimensions.

13. Device for measuring the frame angle of a pair of glasses, comprising: - a spectacle holder for holding the spectacles, which has a first spectacle lens and a second spectacle lens; - a scanner for scanning the lens surfaces of both lenses of the glasses arranged on the glasses holder and for generating first surface position data points of the first lens and second surface position data points of the second lens; - a mirror module configured to mirror the first surface position data points of the first lens onto the second surface position data points of the second lens with respect to a center plane between the two lenses in such a way that the first and second surface position data points of both lenses overlap; - a compensation function determination module configured to determine a compensation function (A; Ao ;AOR ; AM ) as a surface function through the superimposed surface position data points of both lenses; and - a frame disc angle determination module configured to determine the frame disc angle by means of the surface function through the superimposed surface position data points of both lenses.

14. Device according to claim 13 with at least one of the following modules: - a tilting module configured to tilt the first surface position data points relative to the second surface position data points in the superimposed surface position data points such that the first and second surface position data points are arranged closer to the determined surface function; and / or - an optimization module configured to optimize the tilting of the first surface position data points relative to the second surface position data points such that the superimposed first and second surface position data points are arranged as close as possible to an optimized compensation function (AO ) as the surface function by the superimposed and optimally tilted surface position data points of both eyeglass lenses; and / or - a reduction module configured to remove, in a reduction step, individual surface position data points from the superimposed surface position data points whose distance from the surface function is greater than a predetermined first and / or second maximum distance; and / or - an iteration module configured to iterate at least the reduction step based on a reduced compensation function (AR) by superimposing and reducing surface position data points from the reduction module as the surface function and based on the superimposed and reduced surface position data points.

15. Computer program product comprising computer-readable program parts which, when loaded and executed, cause a device according to claim 13 or 14 to perform a method according to one of claims 1 to 12, wherein the computer program product at least partially controls and / or regulates the following units: - the scanner; and - the mirror module; and - the compensation function determination module; and - the socket disc angle determination module; wherein the computer program product furthermore controls and / or regulates at least one of the following units at least in part - the tilt module; and / or - the optimization module; and / or - the reduction module; and / or - the iteration module.

Images