Method and device for determining the position and / or orientation of a spectacle lens on a holder

Abstract

The invention relates to a method and a device for determining the position and / or orientation of a spectacle lens (35) with a permanent marking on a holder (36), in particular a suction holder. For this purpose, the apparent position of the permanent marking on the spectacle lens is detected using a detection unit (31, 33), for example. In addition, the spectacle lens (35) is illuminated eccentrically to the optical axis (310) of the detection unit using an additional light source (34A to 34C). The reflections resulting therefrom are likewise detected. Based on the detected reflections and the apparent position of the permanent marking, the position and / or orientation is determined.

Description

Technical Field

[0001] This application relates to methods and apparatus for determining the position and / or orientation of an eyeglass lens on a holder. In particular, the invention relates to methods and apparatus in which the position and / or orientation of an eyeglass lens is determined so that a stamp pattern can be correctly applied to the lens. In this context, position should be understood as the location of an object in space. Orientation specifies the orientation of the object at this position. Sometimes, particularly in robotics, the combination of position and orientation is also referred to as pose (see DIN EN ISO 837:2012-03). Background Technology

[0002] During the process of grinding and fitting eyeglass lenses, opticians use reference points on the lenses. In this context, grinding and fitting refers to the process of making the lenses roughly fit the selected frame and centering them. Before grinding and fitting, eyeglass lenses typically have a round or oval shape. Therefore, grinding and fitting gives the lenses a shape suitable for the selected frame. In this case, centering correctly orients the lenses, thereby achieving the desired optical power for the person ultimately wearing the glasses.

[0003] In this case, for spherical or toric spectacle lenses, a reference point on the lens is determined using a focimeter and marked on the lens by a marking device (also known as a dotting unit) (see, for example, "Handbuch der Augenoptik" ["Handbook of Ophthalmic Optics"], published by Carl Zeiss 8082, Germany, revised by Dr. Helmut Goersch, 3rd edition, 1987, p. 220). Specifically, the optical center point is used here as the reference point, at which perpendicularly incident light rays pass through the spectacle lens without refraction.

[0004] In the case of progressive lenses, it is impossible, or directly impossible, to reconstruct such a simple reference point using a focimeter. The reference point for progressive lenses is not limited in the case of spherical or toric lenses, in which case the aforementioned optical center point can be used as a reference point; however, in the case of progressive lenses, it is a point whose position is defined by the design of the spectacle lens. Reference points are, for example, the near reference point (see DIN 58208:2013-10, Section 3), the distance reference point (see DIN EN ISO 13666:2012; Section 5.15), and the prism reference point (see DIN EN ISO 13666:2012, Section 14.2.12) for progressive spectacle lenses. These reference points cannot be determined by a focimeter.

[0005] Eyeglass lens designers have the freedom to define the positions of distance reference points, near reference points, and prism reference points. Various eyeglass lens manufacturers have developed conventions in this regard, which are not necessarily the same for all lenses in their product line, and may even vary depending on the product type. The manufacturer's technical documentation describes the positions of these reference points on the lens.

[0006] Typically, at the prism reference point, the prescription prism power superimposed on the thickness-reducing prism is measured. This is the same for both eyes and only works in the vertical direction. The thickness-reducing prism aims to reduce the thickness of the spectacle lens and is explained on page 118 of the "Handbuchfür Augenoptik" cited above. The prism measurement derived from this (e.g., expressed in cm / m as the prism and the base as the angle in the TABO (German abbreviation - Technischer Ausschuss für Brillengläser [Technical Committee for Spectacle Lenses]) and the prism measurement that the spectacle lens is intended to have are indicated on the packaging.

[0007] Unlike the case of the optical center point of spherical or toric spectacle lenses, there is no standard-defined zero ray deflection at any reference point for progressive lenses; moreover, there is no standard requiring the use of a focimeter to measure the minimum astigmatism at that point.

[0008] Therefore, according to Section 7.1 of standard DIN EN ISO 898-2 (2004), progressive lenses have two permanent markings (see also DIN EN ISO 13666:2012 14.2). Since these permanent markings were previously applied as engravings, they are commonly referred to as permanent engravings. Because lasers are frequently used to apply them today, the term "signature" or "signature mark" is also commonly used for the various markings on spectacle lenses. The midpoint between these permanent markings is called the ERP (representing the engraving reference point). In the case of Zeiss progressive lenses, the ERP is also the aforementioned prism reference point. The permanent markings are located, for example, 17 mm to the left and right of the ERP.

[0009] The positions of these permanent markers can be used to reconstruct a coordinate system on the eyeglass lens: when viewed perpendicularly from the front of the lens, the midpoint between them determines the origin; the direction from the left permanent marker to the right permanent marker determines the positive X direction. The eyeglass lens manufacturer then typically specifies the positions of these reference points within this coordinate system.

[0010] For example, near and far reference points are located at points defined by the manufacturer in this coordinate system. These near and far reference points will play a role if you intend to measure the power of the progressive lens again: the measurements that must occur at these two points are determined by the optical designer before the lens is manufactured and are typically indicated in documents associated with the lens, such as on the packaging.

[0011] Furthermore, Section 7.2 of DIN EN ISO 8980-2 (2004) recommends non-permanent markings (i.e., markings that can be removed so that they are no longer present in the finished eyeglasses), commonly referred to as stamps or stamp graphics, even if they are applied to the eyeglass lenses by other methods (e.g., inkjet printing) rather than by stamping. In the following text, the term "stamp" is used to refer to the non-permanent markings described in Section 7.2 of DIN EN ISO 8990-2 (2004).

[0012] The stamp includes:

[0013] 1. Markings used for the orientation of eyeglass lenses.

[0014] 2. Use distant reference points for marking.

[0015] 3. Mark the nearest reference point.

[0016] 4. Marking of assembly points, and

[0017] 5. Marking of the prism reference point.

[0018] In the stamping, the distant reference point, the near reference point, and / or the prism reference point can be marked with thick circles so that only the correct circular area around these points is effective when measurements are taken using a focimeter. As a result, precisely, the aperture defined by the circle is effective when re-measured using a focimeter, which facilitates re-measurement.

[0019] The stamp must be applied consistently relative to the permanent markings because the optician will rely on the accuracy of the stamp when fitting the spectacle lenses by grinding and centering them. In this case, consistent application means that the stamped markings must be in the correct position defined by the spectacle lens manufacturer in the coordinate system defined by the permanent markings as explained above. Incorrect application of the stamp with respect to position can lead to errors in the position or orientation of the spectacle lenses; that is, if the optician relies on the correct position of the stamp, the spectacle lenses will not fit correctly into the frames. Here, centering error is understood as displacement of the spectacle lens relative to the correct position (changes in lateral position and / or fitting height), and orientation error is understood as torsion relative to the correct orientation. However, these terms are not used in a standardized manner in publications, and sometimes the term "centering error" is used generally for both centering error and orientation error as defined above. Further explanation can also be found on page 140 and subsequent pages of the "Handbuch der Augenoptik" already cited above.

[0020] Centering and orientation errors negatively impact the usability of finished eyeglasses. The effects of such positional or orientation errors are particularly critical in the case of lenses with relatively large absolute powers, as centering errors in these lenses can lead to an undesirable prismatic effect. The magnitude of the prismatic effect caused by centering errors can be calculated using the Prentice formula.

[0021] In the case of spectacle lenses intended to correct relatively large astigmatism, orientation error has a more severe impact compared to spectacle lenses with little or no astigmatism correction. In the case of progressive lenses, the impact of orientation error is also more severe with relatively large under-correction than with lenses with small under-correction. Here, under-correction refers to the near-vision under-correction of the progressive lens. An additional factor in the case of progressive lenses is that, due to the horizontal eccentricity of the two lenses in different directions (i.e., the two lenses are displaced differently relative to their correct positions), the eyes no longer receive the so-called progressive channel during use. Thus, the user may only see objects in the transition zone between the near and far vision zones through the associated progressive channel with one eye, while for the other eye, the user sees a position next to where astigmatism and other aberrations are interfering. The progressive channel extends between the far and near reference points and is designed to provide optimal visual conditions for the associated viewing directions of both eyes. Vertical eccentricity (i.e., displacement) in different directions also adversely affects the visual impression of the eyeglass wearer: the spectacle lenses no longer function in the way they are calculated. The visual impression of both eyes is mainly affected by centering error.

[0022] Therefore, a high degree of accuracy is required when fitting spectacle lenses by grinding and mounting them, which in some cases is mandated by standards or limited by the manufacturer. For example, point 5.2.4 of DIN EN ISO 8980-2 specifies the maximum deviation for centering. Centering accuracy is typically required to be within ±0.5 mm in both the horizontal and vertical directions. For single-vision lenses, the permissible angular error depends on the cylinder power of the spectacle lens (according to DIN EN ISO 13666:2012). According to DIN EN ISO 8980-2, the maximum permissible error during centering depends on the optical power intensity of the spectacle lens, particularly on the refractive power along the higher principal meridian. In the case of progressive lenses, orientation errors approaching the above-mentioned standard limits are absolutely not permitted – even for small prescription cylinders, i.e., the small cylinder prescribed in the prescription. When there is no centering error and no orientation error, the user will experience the best visual impression; therefore, opticians should work as accurately as possible.

[0023] For the purpose of applying a stamp, accuracy is typically required regardless of diopter. What is required here is an accuracy of ±0.3 mm in centering (i.e., position in the horizontal and vertical directions) and ±1 degree in orientation (i.e., rotation about an axis that is substantially perpendicular to the lens, referred to below as the z-direction).

[0024] Nowadays, a surface responsible for the progressive power of progressive lenses (also known as a progressive surface) is typically applied to the back of the lens. Therefore, these lenses are also called "back-progressive" (BSP). In this case, the back of the lens is the side facing the eye. In the case of progressive lenses, permanent markings are usually applied to the side of the lens that produces the progressive power, that is, nowadays, usually on the back of the lens. This is because during the production of the progressive surface, the lens is sealed, i.e., applied to a holder, and the seal precisely defines the coordinate system on the lens and the progressive surface. In this case, the seal, typically 43 mm in diameter, is located on the unprocessed side of the lens: that is, nowadays usually on the front of the lens. Therefore, with the lens sealed, since the coordinate system is precisely defined and mechanically implemented in the sealed state, it is simple to apply permanent markings in the correct position (e.g., ±17 mm relative to ERP). In the case of BSP lenses, however, if it is desired to apply it to the front of the spectacle lens, the sealing element will obscure the position of the permanent mark due to its size. Therefore, the light rays that are applied at the ERP point parallel to the front of the spectacle lens and incident at the prescription position will again leave the spectacle lens's position. In the correct posture, this will later produce the correct "apparent position" of the permanent mark. Viewed from the correct direction, this position ensures that the permanent mark appears correctly in the prescription position on the front of the spectacle lens.

[0025] The back of a spectacle lens is typically concave, while the front is convex. Therefore, in the case of most progressive spectacle lenses, permanent markings are applied to the concave surface of the lens.

[0026] In the past, when standard spectacle lenses were produced using a "semi-finished method," a progressive function was created on the front of the lens. Therefore, these lenses were also called "Front Progressive" (FSP). Consequently, in the case of progressive spectacle lenses, the permanent markings were always located on the front of the lens. Therefore, when applying permanent markings to the concave surface of the lens, optician's guidelines stipulated that the permanent markings should appear on the front of the lens at the point where they would appear when viewed from infinity perpendicular to the front surface at the midpoint of the lens. (The midpoint here is the midpoint between the two permanent markings, i.e., the ERP. In practice, maintaining a viewing distance of at least 400 mm is sufficient instead of viewing from infinity). In contrast, FSP spectacle lenses can be marked directly on the front of the lens.

[0027] When a stamp is applied in an automated device, the spectacle lens is held in place by suction on its concave surface; that is, in the case of progressive lenses, for example, by the back of the lens held in place by a suction holder. In this case, the lateral position of the holding point—that is, the intersection of the suction holder axis and the back surface of the lens—and the orientation of the lens are unknown. The position and orientation of the lens held in this way by suction are caused by a complex interaction between the suction holder and the lens. They depend on the holding point. TechOptics sells a device for applying a stamp and using a suction holder under the name "X-Cube," see www.techofrance.com / x-cube.html.

[0028] When the spectacle lens is precisely held in the center, the orientation of the suction holder still corresponds very well to the normal of the concave back surface of the spectacle lens held at the midpoint of the suction holder. If the spectacle lens is held eccentrically, the weight of the lens generates a torque on the suction holder, causing the suction holder to slightly yield. Therefore, the spectacle lens can then be tilted to sit on the suction holder.

[0029] In most cases, the back surface of eyeglass lenses is not spherical. If it is toric, the orientation of the lens held by suction is even more uncertain. Considering symmetry, it can be inferred that when holding a toric surface by suction, the orientation of the suction holder is still approximately normal at the midpoint of the suction holder. Gravity, particularly the torque generated by the weight of the lens, again causes this deviation. However, unlike the case of holding a spherical surface by suction, the suction holder yields differently to torque in the meridional and rotational sections.

[0030] Specifically, with the toric surface and the suction cup thereon oriented perpendicularly, the cross-sectional shape of the cylindrical surface with the cylindrical lens axis parallel to the suction holder direction is an approximate sine curve along the z-direction. (Refer to...) Figures 1A to 1D Here is a brief explanation.

[0031] Figure 1A An illustration shows a toric surface 10 as an example of a concave back surface of an eyeglass lens. Reference numeral 11 shows a cross-section of a cylinder having a toric surface. The cylinder represents a suction holder. Figure 1A In this case, the surface of the complex curved surface is perpendicular to the cylinder representing the suction holder. Along section 11, the height along the z-direction is as follows... Figure 1B As shown in curve 12. Figure 1C The cylinder is shown to be non-perpendicularly oriented on surface 10, which produces section line 13. Figure 1DIn the figure, curve 14 shows the height along the section line 13.

[0032] Compared to curve 12, curve 14 is clearly not a sine curve; that is, it deviates significantly from the shape of a sine.

[0033] exist Figure 2A and Figure 2B This effect is illustrated again in the figure, namely the change in height along the cross-sectional curve. Figure 2A A family of curves 15 is illustrated, where each curve in this family of curves 15 shows the height distribution in the z-direction along the section line (e.g., 12 or 13), which is offset by 2 mm between lines along the x-direction on surface 10. Similarly, in Figure 2B In the middle, a family of curves 16 shows curves with a step size of 1 mm in the y direction (in Figure 1A and Figure 1C The height distribution is shown in the figure for displacement in the x and y directions. Due to the elasticity of the suction holder used, the peaks and troughs of the curves shown compensate for each other during suction holding. This ultimately establishes... Figure 1A and Figure 1B It is held roughly vertically by suction.

[0034] In the case of free-form surfaces, such as progressive surfaces on the back of progressive spectacle lenses, the relationship becomes more complex. In this case, the cross-sectional curve of a cylinder with a free-form surface can indeed still be related to... Figures 1A to 1D and Figure 2A and Figure 2B The surface pattern resembles a tortuous surface, but it is no longer exactly this type of pattern. The widths of the "peaks" and "valleys" along the cross-section in the z-direction are no longer the same. Therefore, in the case of a progressive surface, the direction established by the suction hold is more difficult to predict and depends not only on the shape of the progressive surface but also to a large extent on the mechanical properties of the suction hold. Consequently, it is not easy to predict the exact spatial position of the spectacle lens on the suction hold.

[0035] As explained above, if a permanent mark is applied to the back of a spectacle lens, the mark will appear on the front of the lens to which the stamp is to be applied, depending on the position of light refraction. This position can vary depending on orientation. Ignoring the lens orientation during measurement makes accurate stamping more difficult or impossible.

[0036] EP 1 646 855 B1 and EP 2 597 451 A2 each disclose a method and illumination arrangement that makes a permanent mark visible and detectable by a camera. However, due to the aforementioned light refraction effects, the detected position of the permanent mark differs from its actual position and depends particularly on the orientation of the spectacle lens on the holder. In the context of this application, the position of the permanent mark in a camera image (primarily determined by such a device) is also referred to as the "apparent position".

[0037] DE 103 00 777 A1 describes centering of spectacle lenses based on permanent markings (referred to herein as engraved markings). In that case, also due to the effects of light refraction, it is possible that the apparent position of the detected engraved markings deviates from its actual position.

[0038] The present invention, derived from DE 10 2007 037 730 A1, solves this problem by applying markings to both the front and back of the spectacle lens. Then, with knowledge of the three-dimensional positional relationships, the spectacle lens can be correctly positioned.

[0039] The disadvantage in that case is that, for this purpose, markings must be applied to both the front and back of the spectacle lens, which can be complicated if precise positioning is required, and the process of DE 10 2007 037 730 A1 can only be used for spectacle lenses that are marked in that manner, and not for conventional spectacle lenses that are only marked permanently as described above. Summary of the Invention

[0040] Therefore, according to various aspects of the invention, the general object of the invention is to provide a method and apparatus for determining the position and / or orientation of an eyeglass lens on a holder (e.g., the suction holder described above), which is also applicable to eyeglass lenses that are only provided with permanent markings in a conventional manner. Additionally, the object of the invention is to allow the eyeglass lens to be stamped in the correct position even if the eyeglass lens is positioned on the holder in an tilted or rotated manner.

[0041] DE 10 2014 005 281 A1 describes an apparatus and method for non-contact detection of the position of at least one marked spectacle lens in three-dimensional space. According to the teachings of DE 10 2014 005 281 A1, the spectacle lens is illuminated and recorded by two cameras arranged differently in space. The true position of the marks is determined, wherein the marks can be illuminated through the spectacle lens, but the marks on the spectacle lens always face the cameras. Then, in a calculation step, the position of the spectacle lens is determined from the records of the different cameras.

[0042] DE 10 2013 219 838 A1 describes the coordination of three measuring stations for measuring an object, such as a spectacle lens having a first optically active surface and a second optically active surface, wherein the spectacle lens may have markings. A first measuring unit determines the positions of three points on the first and second optically active surfaces relative to a fixed coordinate system using a tactile measuring probe. In a second measuring station, the true position of the markings is detected by camera recording. For this purpose, the markings must be positioned on the side facing the camera. An alternative embodiment discloses an upper and lower device that allows the markings on the spectacle lens to be detected from both sides, wherein the respective devices detect the true position of the markings on the sides facing the sensors. In a third measuring station, the morphology of the first and second optically active surfaces is detected.

[0043] The teachings of both DE 10 2014 005 281 A1 and DE 10 2013 219 838 A1 require that the camera unit recording the marked image must observe the true position of the mark, meaning that light originating from the mark will not refract onto the first optically effective surface of the camera (e.g., the camera lens). Therefore, each spectacle lens must be oriented such that the side with the permanent mark is oriented towards the observation side. This can be disadvantageous – in a manner similar to the methods described in EP 1 646 855 B1 and EP 2597 451 A2 above – because it restricts the freedom of arrangement of lens elements and limits the possibilities for mounting spectacle lenses. This can be particularly problematic in the case of progressively backed spectacle lenses, as the latter typically have permanent marks only on the back. These limitations have, for example, the inability to use opaque materials for the holder, which can be detrimental to material properties, especially in the case of suction cup holders.

[0044] In this context, opaque material should be understood as a material that is opaque within the range of light wavelengths used, for example, because it greatly absorbs and / or reflects relevant light.

[0045] First, the methods of different aspects of the present invention are described below. Corresponding apparatus is also provided. Details and explanations then follow regarding the corresponding aspects or combinations thereof of the present invention.

[0046] Starting with DE 10 2014 005 281 A1, the first object of the present invention is to provide a method, apparatus and computer program that allows for determining the position and / or orientation of a back-mounted progressive spectacle lens with a permanent mark, even on an opaque holder.

[0047] According to a first aspect of the invention, the first objective is achieved by the method and apparatus according to the invention.

[0048] Starting with DE 10 2013 219 838 A1, a second object of the present invention is to provide a method and apparatus capable of robust position and / or orientation determination. According to the second aspect of the invention, this is achieved by a method and apparatus according to the invention.

[0049] Starting with DE 10 2014 005 281 A1, a third object of the present invention is to provide a method and apparatus capable of inferring the refractive properties of spectacle lenses. According to the third aspect of the invention, this is achieved by a method and apparatus according to the invention.

[0050] Starting with DE 10 2013 219 838 A1, a fourth object of the present invention is to provide a method and apparatus capable of inferring the refractive properties of spectacle lenses. According to the fourth aspect of the invention, this is achieved by a method and apparatus according to the invention.

[0051] Also starting from DE 10 2013 219 838 A1, a fifth object of the present invention is to provide a method and apparatus for simplifying the complexity of the apparatus and / or method of DE 102013 219 838 A1. According to the fifth aspect of the invention, this is achieved by a method and apparatus according to the invention.

[0052] Starting again from DE 10 2013 219 838 A1, the sixth object of the present invention is to enable the implementation of the method of DE 10 2013 219 838 A1 more quickly and to achieve higher accuracy of the method. According to the sixth aspect of the invention, this is achieved by the method and apparatus according to the invention.

[0053] Starting with DE 10 2014 005 281 A1, a seventh object of the present invention is to improve the accuracy of the method and apparatus of DE 10 2014 005 281A1 and to enable the use of different holders. According to the seventh aspect of the invention, this is achieved by the method and apparatus according to the invention.

[0054] According to all aspects of the present invention, a method is provided for determining the position and / or orientation of an eyeglass lens with a permanent mark on a holder, the method comprising:

[0055] Provides the detected apparent location of permanent markings on spectacle lenses.

[0056] The position and / or orientation of the spectacle lens are determined based on the detected apparent location of the permanent markers and additional information unrelated to the markers.

[0057] According to a first aspect of the invention, a method is provided for determining the position and / or orientation of an eyeglass lens with a permanent mark on a holder. The method includes providing a detected apparent position of the permanent mark on the eyeglass lens. Additionally, the method includes determining the position and / or orientation of the eyeglass lens based on the apparent position of the permanent mark and additional information unrelated to the mark.

[0058] The method of the first aspect of the invention is characterized in that the apparent location of these permanent marks is different from the actual location of these permanent marks.

[0059] Compared to DE 10 2014 005 281 A1, the first aspect of the present invention has the advantage that measurements do not need to be taken from the side with the permanent mark. This allows the use of opaque holders, such as suction cups in the case of progressive lenses with the mark applied to the back. As described above, the progressive lens can then be held in the same manner on the back.

[0060] According to a second aspect of the invention, a method is provided for determining the position and / or orientation of a spectacle lens with a permanent mark on a holder. The method includes: detecting the apparent position of the permanent mark on the spectacle lens, eccentrically illuminating the spectacle lens, and detecting the position of at least one reflection on the spectacle lens caused by the eccentric illumination process.

[0061] Additionally, the method of the second aspect of the invention includes determining the position and / or orientation of an eyeglass lens based on the apparent location of a permanent mark and additional information unrelated to the mark, wherein the additional information unrelated to the mark includes at least one apparent location of a reflection.

[0062] The method of the second aspect of the invention is characterized in that the position of the permanent mark is detected with a first light wavelength, and at least one position of reflection is detected by illumination with a second light wavelength, wherein the spectacle lens has a higher absorption rate for the second light wavelength than for the first light wavelength.

[0063] Compared to DE 10 2013 219 838 A1, one advantage of the second aspect of the invention is that it can reliably distinguish between reflections from the front of the spectacle lens and reflections from the back of the spectacle lens.

[0064] According to a third aspect of the invention, a method is provided for determining the position and / or orientation of an eyeglass lens with a permanent mark on a holder. The method includes: detecting the apparent position of the permanent mark on the eyeglass lens, and determining the position and / or orientation of the eyeglass lens based on the apparent position of the permanent mark and additional information unrelated to the mark.

[0065] The method of the third aspect of the present invention is characterized in that the apparent position of a permanent mark is detected from multiple viewing directions, wherein the apparent position of the permanent mark is different from the actual position of the permanent mark.

[0066] Compared to DE 10 2014 005 281 A1, one advantage of the third aspect of the invention is that observing the apparent location of the permanent marking from different directions allows for the inference of the refractive properties of the spectacle lens. This is not disclosed in D1 because the refractive properties of the spectacle lens are not important there.

[0067] According to a fourth aspect of the invention, a method is provided for determining the position and / or orientation of an eyeglass lens with a permanent mark on a holder. The method includes: detecting the apparent position of the permanent mark on the eyeglass lens, eccentrically illuminating the eyeglass lens, and detecting the position of at least one reflection caused by the eccentric illumination process on the eyeglass lens. Furthermore, the method of the fourth aspect of the invention includes determining the position and / or orientation of the eyeglass lens based on the apparent position of the permanent mark and additional information unrelated to the mark, wherein the additional information unrelated to the mark includes the position of at least one reflection.

[0068] The method of the fourth aspect of the invention is characterized in that the position of the at least one reflection is detected from multiple viewing directions, wherein the apparent position of the permanent marks is different from the actual position of the permanent marks.

[0069] Compared to DE 10 2013 219 838 A1, one advantage of the fourth aspect of the present invention is the improved accuracy and / or the fact that the method converges more rapidly. Thus, the quality and efficiency of the method can be improved compared to DE 10 2013 219 838 A1.

[0070] According to a fifth aspect of the invention, a method is provided for determining the position and / or orientation of an eyeglass lens with a permanent mark on a holder. The method includes: detecting the apparent position of the permanent mark on the eyeglass lens, eccentrically illuminating the eyeglass lens, and detecting the position of at least one reflection on the eyeglass lens caused by the eccentric illumination process. Furthermore, the method of the fifth aspect of the invention includes determining the position and / or orientation of the eyeglass lens based on the apparent position of the permanent mark and additional information unrelated to the mark, wherein the additional information unrelated to the mark includes the position of at least one reflection on the eyeglass lens.

[0071] The method of the fifth aspect of the invention is characterized in that detecting at least one apparent location of a reflection on the spectacle lens includes repeated detection during movement of the spectacle lens.

[0072] Compared to DE 10 2013 219 838 A1, one advantage of the fifth aspect of the present invention is that it is not necessary to arrange a large number of light sources on the polyhedral surface. Measurements can be performed using a single light source.

[0073] According to a sixth aspect of the invention, a method is provided for determining the position and / or orientation of an eyeglass lens with a permanent mark on a holder. The method of the sixth aspect of the invention includes: providing a detected apparent position of a permanent mark on the eyeglass lens; and determining the position and / or orientation of the eyeglass lens based on the apparent position of the permanent mark and additional information unrelated to the mark.

[0074] The method of the sixth aspect of the present invention is characterized in that determining the position and / or orientation of the spectacle lens includes iterative calculation of the position and / or orientation of the spectacle lens.

[0075] Compared to DE 10 2013 219 838 A1, one advantage of the sixth aspect of the present invention is that the method can be implemented more quickly through an iterative process and at the same time produce higher accuracy of results.

[0076] According to a seventh aspect of the present invention, a method is provided for determining the position and / or orientation of an eyeglass lens having a permanent mark on a holder. The method of the seventh aspect of the present invention includes: providing a detected apparent position of a permanent mark on the eyeglass lens; and determining the position and / or orientation of the eyeglass lens based on the apparent position of the permanent mark and additional information unrelated to the mark.

[0077] The method of the seventh aspect of the invention is characterized in that additional information unrelated to the markings includes calculated or experimentally determined positional characteristics of different shaped spectacle lenses on the holder, wherein these positional characteristics include the holding characteristics of the holder.

[0078] Compared to DE 10 2014 005 281 A1, one advantage of the seventh aspect of the present invention is that, while taking into account the holding characteristics, this improves the accuracy of the method compared to D1.

[0079] The various features of different aspects of the invention will now be explained and defined in more detail below.

[0080] As described above, the apparent position of the permanent mark is determined by the following method: if the permanent mark is applied to the back of the eyeglass lens, the eyeglass lens is observed through the camera unit, and observation is achieved from the front of the eyeglass lens.

[0081] For example, the apparent position can be detected as described in EP 1 646 855 B1 or EP 2 597 451 A2. This includes situations where the apparent position of a permanent engraving can be detected at a location different from the determined position and / or orientation, and where the detection can be initiated by a different person compared to a computer-implemented method. For instance, the calculations of the methods in this application can be performed on a remote computer, with communication with that remote computer via a network.

[0082] In this context, additional information unrelated to the marker should be understood as information that is unrelated to the detected apparent location of the permanent marker and also unrelated to other markers and their characteristics (such as the relative positions of the markers), for example, from which the location and / or position can be derived. Therefore, this additional information unrelated to the marker does not require the specific location of the marker, such as a permanent marker on a spectacle lens. This additional information unrelated to the marker can be based, for example, on measurements or on calculations based on the characteristics of the holder and the spectacle lens. Compared to implementing the method according to the invention, the measurements and / or optionally the calculations can then be initiated at different locations and by different people.

[0083] In this way, techniques known per se for detecting the apparent location of permanent markings using additional information unrelated to the marking can be extended to determine the position and / or location of spectacle lenses. The use of additional information unrelated to the marking means that a specific marking on the spectacle lens is not required, and the method is applicable to spectacle lenses with conventional permanent markings.

[0084] Position and / or orientation can be specified using a coordinate system, which will now be explained. These coordinate systems are also used in the subsequent explanations of this application. The spectacle lens is associated with a coordinate system (hereinafter referred to as the spectacle lens coordinate system) in which all indications about the spectacle lens are made. The origin (= zero point) of the spectacle lens coordinate system is formed by a point located exactly midway between the two (apparent) positions of the permanent mark. This point is also referred to as the ERP = engraving reference point. If the permanent mark is actually applied to a convex surface (which is quite rare nowadays for the reasons mentioned above, and actually still exists only in the case of FSP lenses), then the zero point is the actual center point of the shortest connecting curve between the two marks on the front surface (= convex surface). In the case of spectacle lenses where the mark is applied to the back surface (= concave surface), the apparent viewpoint on the front of the spectacle lens when viewed from the correct direction plays this role in defining the coordinate system. The XY plane of the spectacle lens coordinate system is the tangent plane of the spectacle lens at the ERP. The Z-direction of the spectacle lens coordinate system corresponds to the aforementioned prescription viewing direction of the lens with a permanent mark on the back of the spectacle lens, and is perpendicular to the XY plane. If the (apparent) position of the permanent mark is projected onto the XY plane, its connecting line determines the X-direction of the spectacle lens coordinate system. The permanent marks can be distinguished from each other by other indications in their vicinity. One is labeled the "left" permanent mark, and the other is labeled the "right" permanent mark. The sense of direction of the projected (apparent) permanent marks from left to right determines the counting direction of the X-axis. The Y-axis lies in the XY plane perpendicular to the X-axis, in the section of the front surface of the spectacle lens at the ERP, specifically rotated 90° counterclockwise when viewed from the front. The counting direction of the Z-axis is conveniently defined such that the X, Y, and Z axes form a right-handed system. The position of the spectacle lens relates to the "world coordinate system" of the device, that is, it relates to an externally fixed, predefined coordinate system. Orientation specifically includes a rotation angle about the Z-axis of the world coordinate system, which is necessary to transform the direction of the X-axis of the spectacle lens into the X-axis of the world coordinate system.

[0085] The holder also primarily defines the height of the spectacle lens within the device, which plays a role in image recognition. While saving the significant cost of a telecentric lens, the distance between the spectacle lens to be measured and the camera has some impact on the image size. Proper design, along with the necessary height displacement of the suction holder, ensures that the spectacle lens is held approximately at the correct height during measurement. As a result of the defined origin of the coordinates at the ERP, the method according to the invention is insensitive to small inaccuracies in height within the device, as it takes into account characteristics known from the spectacle lens itself. In contrast, simple coordinate determination, which determines the lateral position solely based on the deviation of the average coordinates of two permanent markers (measured in the camera image) (e.g., from their desired position in the camera image), yields erroneous results, which are avoided by the method according to the invention.

[0086] Preferably, some aspects of the method of the present invention further include:

[0087] Detect the apparent location of permanent markers.

[0088] Illuminating the eyeglass lens off-center.

[0089] Detect the location of at least one reflection on the spectacle lens caused by an eccentric illumination process.

[0090] The additional information, which is unrelated to the marker, includes at least one location of the reflection.

[0091] Eccentric illumination of a spectacle lens should be understood as illumination by an additional light source not located on the optical axis, through which the position of a permanent mark is detected, and then the position of the reflection, particularly the optical axis of the camera unit used to detect the apparent position of the permanent mark. In this case, the optical axis typically represents an imaginary line defining the propagation of light through the optical system. In the case of a rotationally symmetric optical system, the optical axis coincides with the axis of symmetry. For systems consisting of lens elements and mirrors, such as those used in a camera unit, the optical axis passes through the center of curvature of the lens elements and mirrors. See also the Wikipedia article "Optical Axis" (as of July 14, 2017) in the English version of Wikipedia.

[0092] In this way, additional information unrelated to the marker can be obtained by simply detecting the reflection using relatively simple means. If, for example, the BSP spectacle lens is mounted on the suction holder in a laterally shifted manner, this not only produces a translation that is essentially a translation during the detection of the permanent marker's position, but also a tilt of the spectacle lens. The tilt also has (though usually small) additional effects on the apparent position of the permanent marker. The tilt primarily causes a significant change in the detection position of at least one reflection. Therefore, in the case of tilt, the detected permanent marker and the position of at least one reflection "proceed" differently, and this provides additional, marker-independent information about the overall orientation of the spectacle lens.

[0093] To detect the location of at least one reflection, the same camera used for detecting the location of a permanent mark according to EP 1 646 855 B1 or EP 2597 451 A2 described above can be used. In these documents, as described, to detect the apparent location of a permanent mark, the spectacle lens is illuminated coaxially relative to the camera by specular reflection of light from a light source through a beam splitter onto the optical axis of the camera. This type of illumination is also called coaxial reflected light illumination. In the arrangement of EP 1646 855 B1, the light passing through the spectacle lens under coaxial reflected light illumination used in this document is additionally incident on a retroreflector and returns almost on its own to the camera from there. Light passing through the spectacle lens under eccentric illumination achieved by an additional light source, after being reflected at the retroreflector (if it completely strikes this), also returns on its own, but due to the eccentricity of the additional light source, it does not reach the camera in this path. This is done by reflections from up to two spectacle lens surfaces. Whether and where such reflections occur depends on the curvature of the spectacle lens surfaces and the lens orientation during the measurement. In the case of EP 2597 451 A2, a rotating wedge is used instead of a rear reflector.

[0094] In this way, compared with the construction in EP 1 646 855 B1 or EP 2 597 451 A2, the position and / or orientation of the spectacle lenses can be determined by a simple extension, i.e., setting one or more additional light sources for eccentric illumination.

[0095] The position and / or orientation can then be determined based on relatively simple optical considerations that take into account the light refraction of the spectacle lens.

[0096] In some exemplary embodiments, particularly according to the first aspect of the invention, but not limited thereto, the apparent position of a permanent mark may differ from the actual position of the permanent mark due to light refraction by the spectacle lens.

[0097] The advantage of this is that determining the apparent location of the permanent mark can also provide information about the refractive properties of the spectacle lens, compared to determining its actual location. Furthermore, the spectacle lens can therefore be measured from a side different from the side where the permanent mark was applied. This opens up more design options for the retainer.

[0098] In some exemplary embodiments, particularly according to the first aspect of the invention, but not limited thereto, the retainer may be made of an opaque material.

[0099] In some exemplary embodiments, particularly according to the first aspect of the invention, but not limited thereto, the holder may be a suction holder.

[0100] The advantage of this method is that it allows for quick and gentle installation and replacement of eyeglass lenses, resulting in a reduction in the time required to implement the method compared to other types of installation.

[0101] This also has the following advantages: more material can be used in the construction of the retainer, resulting in improved desired properties of the retainer, such as mechanical properties.

[0102] Preferably, the spectacle lens is irradiated off-center by multiple light sources, which produces multiple reflections (or multiple pairs of reflections in the case of reflections from the front and back of the spectacle lens). The accuracy of the determination can be improved by using multiple light sources.

[0103] To extend the measurable range of spectacle lenses (characterized by the curvature of the front and back surfaces of the lenses) and to further improve the accuracy of determining position and / or orientation, multiple light sources can be positioned at varying distances from the optical axis of the camera unit. According to differential geometry, curvature is defined as the reciprocal of the principal radius of curvature; see, for example, Bronstein-Semendjajew, *Taschenbuch der Mathematik* [Mathematical Handbook], 25th edition, 1991, Chapter 4.3. Therefore, an eccentric illumination process is implemented here using multiple light sources, which in particular induce multiple reflections on the front surface of the spectacle lenses, and the positions of these reflections are detected by measuring the reflections in the recorded image.

[0104] In this scenario, multiple light sources can be activated alternately, e.g., individually or in groups, and their corresponding reflections can be detected sequentially. In this way, each reflection can be assigned to a corresponding light source, which aids in the calculation because it eliminates errors caused by incorrect reflection assignment. The positions of the multiple light sources, as well as the positions of the camera units, are also known in the world coordinate system and influence the calculations for determining position and / or orientation.

[0105] If the groups are selected appropriately, alternating activation of groups can have the following effect: the number of times the location of at least one reflection (in this case, multiple reflections) is detected must be less than the number of existing light sources, so that each reflection can be explicitly assigned to its corresponding light source. An example of this process is presented in the table below:

[0106] sheet:

[0107] Light source detection #1 #2 #3 #4 #5 #6 #7 #1 1 0 1 0 1 0 1 #2 0 1 1 0 0 1 1 #3 0 0 0 1 1 1 1

[0108] Therefore, here, for the seven light sources #1-#7, the position of reflection is detected three times (detection #1-#3), where in each case, the light source identified by "1" is turned on, while the light source identified by "0" is turned off. Reflections or reflection pairs caused by the light sources have the same behavior as the light sources themselves, i.e., they exist when the light source is on and do not exist when the light source is off. If this behavior is written as a binary number, where 1 corresponds to the presence of reflection and 0 corresponds to the absence of reflection (i.e., 001 if there is no reflection in detection #1 but reflections exist in detections #2 and #3), the assigned light source is the one with the same binary number in the three detections in its column of the table above (light source #4 in the example).

[0109] In general, for each light source used, the eccentric illumination process produces two reflections on the spectacle lens: one on the front and one on the back. It is also possible that one or both of these reflections may not occur on the spectacle lens, for example, because the lens is too small or tilted too much. In the case of a back reflection, the refraction of light occurs at both the incident and exit points on the front of the spectacle lens. In the case of a back reflection, the reflection phenomenon is obviously located at the exit point behind the back reflection. The closeness of the front and back reflections depends on the radius of curvature of the spectacle lens: if they are very similar, the two reflections will be close to each other in every case; otherwise, they will be far apart, or one of the two reflections will not occur because it will be located outside the spectacle lens. However, if the front and back reflections are close together, and the spectacle lens also has a small power, then the difference between the two reflections becomes less important. For each assumed position and orientation of the spectacle lens, the position of the reflected image in the camera image (or, in the case of multiple cameras: in multiple camera images) can be calculated by ray tracing.

[0110] The calculation of position and / or orientation is preferably performed iteratively, and as already mentioned, can be implemented through additional steps, such as eccentric illumination and detection of the position of at least one reflection. An initial value for the orientation and position of the spectacle lens is taken as a starting point. For example, the initial value as the basis may not be tilted around the X and Y axes, but rather positioned exactly at the center of the spectacle lens, and without twisting around the Z axis, the twist being caused by the detected apparent position of the permanent mark. For each pose occurring in subsequent iterations, the expected apparent position of the permanent mark, as well as the expected position of at least one reflection, has been calculated. In this case, the expected position is the position derived by calculating a specific position and orientation value. The twist value of the spectacle lens, as well as the offset, can then be calculated by comparing the expected and detected apparent positions of the permanent mark and at least one reflection. For this purpose, small changes (variations) in the position and orientation of the spectacle lens can be assumed, and their effect on the expected apparent positions of the permanent mark and at least one reflection can be calculated. This is also known as the variational method, see, for example, the German Wikipedia article "Variationsrechnung" [variational method] as of July 14, 2017. The process then involves systematically altering the position and orientation in the calculation, such as displacements of the ERP in the three directions X, Y, and Z, and also three spatial rotations (e.g., expressed in Euler angles or coordinate axes around the world coordinate system), until the deviation between the calculated position and the detected position of the permanent marker and optional reflections is minimized. Mathematically, for this purpose, a minimization problem can be solved numerically, for example, where, for instance, the sum of the (weighted) squared deviations of the calculated position of the marker point image and the calculated position of the additional reflections from the corresponding positions determined by these measurements are minimized. Several possible processes exist for solving such minimization problems. Some possibilities are described in Press et al.'s *Numerical Recipes*, second edition (1992). The method terminates if the weighted sum of the squared deviations, as explained in the book "Numerical Recipes," or its variation between iterations, falls below a predetermined threshold, and the resulting information indicates the position and orientation of the spectacle lens with the accuracy determined by that threshold.

[0111] In some exemplary embodiments, particularly according to the sixth aspect of the invention, but not limited thereto, determining the position and / or orientation of the spectacle lens may include iterative calculation of the position and / or orientation of the spectacle lens.

[0112] Through such iterative calculations, the pose of the eyeglass lens can be determined efficiently, such as its position as the ERP and its tilt and twist around the axis of the world coordinate system.

[0113] In addition to using multiple light sources or as an alternative, the apparent location of at least one reflection and / or permanent marker can be detected using multiple viewing directions, for example, by setting up multiple camera units or successively changing the position of a single camera unit. Instead of a single camera unit with an associated beam splitter and a coaxially acting light source, as in EP 1 646 855 B1, multiple such arrangements including camera units and light sources can be set up to determine the apparent location of the permanent marker by stereophotometry using bundle adjustment (also known as bundle adjustment). Detailed information on this can be found in the German Wikipedia article "Blockbündelausgleichsrechnung [Bundle Adjustment]" as of July 15, 2017. To determine the relative positions of the camera units, the camera units can record objects with points easily identifiable in the recorded images in several known orientations; this then constitutes the calibration of the system. This calibration can then be used to determine the unknown orientation of the spectacle lens. In this case, the movable rear reflector according to EP 1 646855 B1 or the rotating prism according to another embodiment of EP 2 597 451 A2 can work together for a variety of arrangements, i.e., all camera units together require only one unit of this type.

[0114] Using multiple viewing directions can also improve accuracy or convergence rate. At least one light source can then be assigned to each viewing direction for the off-center illumination process, as explained above. These light sources can then be activated alternately to allow reflections to be assigned to them. However, the off-center illumination source can also be used collectively for all cameras whose reflected images can be identified on the spectacle lenses.

[0115] For the off-center illumination process, a different wavelength of light can be preferably used compared to the illumination used to detect the apparent location of a permanent mark. The wavelength of light for the off-center illumination process is then conveniently selected such that the spectacle lens absorbs its light significantly during transmission, so that refraction from the front of the spectacle lens and reflection from the back of the lens can be reliably distinguished. Outside the visible light wavelength range, some antireflective coatings have increased reflectivity relative to the visible light range, which is suitable for this method. However, for the off-center illumination process, the camera unit (or, in the case of multiple camera units: at least one) must be sensitive to the light wavelength, and its optical system must transmit the light.

[0116] In contrast, the apparent location of a permanent mark can be detected using a wavelength of light at which the spectacle lens has high transmittance (and therefore low reflectance, such as white light), so that the permanent mark is thus clearly visible, for example, in the method of EP 1 646 855 B1.

[0117] In some exemplary embodiments, particularly according to a second aspect of the invention, but not limited thereto, the location of a permanent mark is detected with a first light wavelength, and at least one location of reflection is detected by illumination with a second light wavelength, wherein the spectacle lens has a higher absorption rate for the second light wavelength than for the first light wavelength.

[0118] In some exemplary embodiments, the second wavelength may extend beyond the visible light wavelength range.

[0119] This can have the following advantages: the first and second wavelengths can be advantageously selected as described above in order to have the desired transmittance, absorption characteristics and / or reflection characteristics.

[0120] In a preferred embodiment, additional information unrelated to the markings includes, or alternatively, the holding characteristics of the holder. Given a known holder (e.g., a suction holder) and a known shape of the spectacle lens, the position and / or orientation of the spectacle lens can be estimated at least; that is, the holder has holding characteristics that produce the specific position and / or orientation of the spectacle lens. These holding characteristics can be calculated using the finite element method (e.g., see the German Wikipedia article "Finite-Elemente-Methode" [Finite Element Method], as of June 27, 2017) to calculate the holding orientation. For simplicity, a method can also be used where any holding orientation of a simple ruled surface (e.g., a spherical surface and a tortuous surface) is tabulated, where the holding orientation is the spatial angle between the surface normal at the center point of the holder (e.g., a suction holder) and the holding direction (the axis of symmetry of the holder, e.g., the suction holder). Furthermore, the way the suction characteristics of the surface change when an additional torque is applied to the spectacle lens is pre-calculated and tabulated. For tortuous surfaces, interpolation can be made between predicted or experimentally verified holding orientations, and if the spectacle lens is held in the position assumed in the corresponding calculation by suction, the additional torque due to the position of the center of mass of the spectacle lens can be taken into account.

[0121] Finite element method (FE) calculations can be used to calculate the holding characteristics of devices such as suction holders. These are contact problems with significant deformation and potentially nonlinear material properties, meaning they do not fall under the category of simple FE problems. In the case of suction holders, such calculations require the material constants of the suction holder, the suction pressure, the sliding behavior of the materials to be contacted (the spectacle lens and the suction holder), and the shape of the contact area. However, it is possible to predict the suction characteristics of a sufficiently large and closely spaced set of local alternative surfaces and tabulate them, including their compliance with external torques. Instead of the asymptotic surface itself, for each holding point, the most suitable closely predicted alternative surface is then sought—that is, the alternative surface that deviates least from the actual surface according to criteria (e.g., least sum of squares), such as the asymptotic surface, for example, in a ring-shaped region that roughly corresponds to the assumed contact area for many suction cases. The table shows, for each alternative surface, the position of the normal of the alternative surface held by suction relative to the holder axis, the point where the holder axis intersects the alternative surface when held by suction, and how this coordinate changes under the influence of an external torque, as well as how the angle between the holder axis and the surface normal changes under the influence of an external torque. All of this then allows the posture of the spectacle lens held at a given or calculated holding point to be determined by interpolation.

[0122] Interpolation predicting the holding orientation of a feature surface provides a good approximation of the shape of the surface of an eyeglass lens held by suction. This can also be done using other ruled surfaces instead of complex surfaces, such as two-dimensional polynomials, Zernyi polynomials, or Zernyi-Tatian polynomials. Information on these functions can be found in Chapters 4.3.1 and 4.3.2 of Bernd Dörband's "Analyseoptischer Systeme" (Dissertation, Stuttgart) (1986) and Chapter 47.8 of Volume 5 of B. Dörband, H. Müller, and H. Gross's Handbook of Optical Systems (2012).

[0123]

[0124] The chosen polynomial can also be, for example, a two-variable normal polynomial with an appropriate upper limit n. m and y m a represents the center point of the eyeglass lens. ij It is a coefficient, and n is an upper limit.

[0125] A preferred approach is to locally approximate the surface of the spectacle lens using a torus that contacts the lens tangentially to the equator at the point of contact with the holder and has the exact same principal curvature as the lens. The names of these torus surfaces are explained, for example, on page 24 and subsequent pages of the already cited *Handbuch der Augenoptik*. For a given base length (e.g., 20 mm or 30 mm), these toruses are conveniently identified by their "sagitta" along the principal meridian. This then produces a two-parameter interpolation table of the suction characteristics, which primarily yields the angle between the normal vector on the spectacle lens and the axis of the holder. Furthermore, it is preferable to determine the degree of yielding of the holder, particularly the suction holder, if gravity, such as an additional torque, acts on the spectacle lens arranged on, in particular, held by suction. Since the holding characteristics may depend on the surface shape, this is preferably implemented in multiple directions. Gravity and the additional torque also have little effect on the location of the intersection point between the considered holder axis and the torus surface.

[0126] The aforementioned normal vectors of the held lens can be tabulated to obtain appropriate graduation values ​​for interpolation. The graduation is conveniently chosen to cover all conventional spectacle lens surfaces within a small environment of all possible holder positions, allowing for sufficiently accurate determination of the holding orientation in a specific case via interpolation. The appropriate graduation can also depend on the type of alternative surface used, such as a torus. Here, the tabulation must be calculated only for one direction of orientation, not for all possible directions (e.g., a meridional section of the torus along the Y-axis), resulting in a small curvature in this section. The holding orientation pre-calculated in this way will produce the direction of the surface normals in the state of being held by suction. For surfaces that fit the pre-computed model only by rotating at the holding point (in this case, the holding point is the intersection between the holding axis and the spectacle lens), since their principal normal section (as defined in differential geometry, Bronstein-Semendjajew, Taschenbuch der Mathematik, 21st edition, Chapter 4.3) is not like the alternative surfaces in the list, the moment generated by gravity is first transformed into the local coordinate system, as with the alternative surfaces that table the holding features, then the direction between the surface normal vector and the position where the table is made is calculated, and the result is transformed back into the world coordinate system.

[0127] Therefore, in the case of aspherical and non-polygonal surfaces, during calculation, a polygonal surface is used to replace the surface that locally surrounds the suction point to be considered in each case during suction. This polygonal surface is optimally suited to the lens surface in the environment corresponding to the edge of the suction holder, for example, with the minimum distance from the pre-calculated polygonal replacement surface in terms of the root mean square of the contact area. In this case, local rotation may still be necessary so that, for example, the curvature along the Y-axis can still be assumed to be small for the local replacement surface.

[0128] If the spectacle lens is then held at such a point, in most cases its center of gravity will not be centrally located below or above the holding point. The combination of torques generated by the relative position of the center of gravity and the weight of the spectacle lens also plays a role due to gravity. By means of a table of the effects of experimentally determined additional torques or by finite element calculations, the additional tilt caused by gravity can then be determined as an interpolation. This determined holding orientation can, for example, be used as the starting value for the orientation in the iterative method described above, and this starting value converges rapidly because a relatively appropriate starting value has already been pre-defined for the method by the pre-calculated orientation. This calculation of the holding characteristics is also performed accordingly in each further iterative step.

[0129] These individual holding features of the suction holder, or their combination with the location of at least one reflection, can be used as additional information independent of the marker. If the accuracy of determining the apparent location based solely on the holding features and the permanent marker is sufficient, further marker-independent additional information can be omitted. In this case, iterative optimization can be performed based on the detected apparent location of the holding features and the permanent marker, in the same manner as with the aforementioned at least one reflection. The accuracy here depends on a precise understanding of the mechanical and material properties of the holder (e.g., the suction holder).

[0130] In some exemplary embodiments, particularly according to the sixth aspect of the invention, but not limited thereto, iterative calculations can be performed based on the detected apparent locations of the holding features and permanent markers.

[0131] The advantage of this is that the accuracy of the method can be further improved by understanding the retention characteristics.

[0132] Changes in material properties (e.g., due to aging) can reduce accuracy.

[0133] Therefore, it is preferable to combine the holding feature with at least one detected reflection, because in this combination, at least one reflection is highly sensitive to tilting, thus providing clear information about its size and orientation. Furthermore, this protects the method from errors caused by the changing characteristics of the holder over time.

[0134] Therefore, in some exemplary embodiments, particularly according to the sixth aspect of the invention, but not limited thereto, iterative calculations may also be performed based on at least one detected reflection.

[0135] In this case, for example, when held in place by suction, it is not necessary to statically determine the position of the reflection of the off-center illumination, but rather to determine the positional change during the introduction of the spectacle lens, for example, during the suction holding process. For this purpose, it is preferable to repeatedly detect the apparent position of the permanent marking and the reflection during the suction holding process. As a result, the suction holding process can also be characterized, or generally, the process of introducing the spectacle lens into or onto the holder can be characterized.

[0136] In some exemplary embodiments, particularly according to the fifth aspect of the invention, but not limited thereto, as described above, detecting the apparent location of at least one reflection on the spectacle lens may include repeated detection during movement of the spectacle lens.

[0137] In some preferred exemplary embodiments, the movement of the eyeglass lens can be generated by a process of attaching a suction holder with suction, and additional information unrelated to the marking can include a characterization of the process of attaching the lens with suction to the holder.

[0138] The advantage of this is that the movement of the spectacle lens during the attachment to the suction holder is used to determine the position of the spectacle lens. As mentioned above, this is particularly advantageous when detecting the apparent position of a permanent mark on the side away from the detection system, that is, when the apparent position is affected by refraction on the spectacle lens. In this case, the position of the spectacle lens can be determined more accurately using data obtained during the movement and known characteristics of the suction attachment process.

[0139] In some exemplary embodiments, particularly according to the sixth aspect of the invention, but not limited thereto, the iterative calculation may include, in the corresponding iterative step, a comparison between the expected position of the spectacle lens and the detected apparent position of the permanent mark and at least one reflection.

[0140] The advantage of this is that, as described above and below, it can further improve the accuracy of the method.

[0141] If multiple viewing directions exist, the positions of two permanent markers can be determined through a "predictive process," even without the holding features of a suction holder, though not with great precision. This method yields relatively good spatial positions of the two permanent markers. However, the lateral tilt of the line connecting the two (apparent) positions of the marker points can only be determined poorly, or even impossible to determine at all. At this point, additional reflections from the holder features, or additional information unrelated to the markers, come into play: as explained above, they primarily determine the tilt of the lens around the line connecting the two (apparent) markers.

[0142] This method can be used to correctly orient a stamp on a spectacle lens. In this case, determining the position and / or orientation of the spectacle lens allows for accurate positioning of the stamp.

[0143] In other words, the determination of position and / or orientation makes it possible to compensate for errors caused by the difference between apparent position and actual position.

[0144] - If the viewing direction when detecting apparent position is not in the normal manner but rather the optical center of the spectacle lens is tilted, this is due to the orientation of the spectacle lens on the holder. As explained, this occurs particularly when the spectacle lens is held by a suction holder.

[0145] - If the detection of apparent location (e.g., via camera) is performed within a limited distance, particularly a distance shorter than the aforementioned 400 mm, and / or

[0146] - Permanent markings are applied to the back of the eyeglass lens, where the apparent location is detected from the front of the lens.

[0147] Specifically, the apparent location of the permanent markings that appear on the front of the eyeglass lens depends on the viewing direction, and also on the position of the eyeglass lens if the lens is not viewed from infinity.

[0148] In addition, a device is provided for determining the position and / or orientation of an eyeglass lens on a holder.

[0149] The apparatus includes a providing unit for providing the detected apparent location of a permanent mark. The apparatus may also include a detection unit for detecting the apparent location of the permanent mark on a spectacle lens. It is characterized by a calculation unit for determining the position and / or orientation of the spectacle lens based on the provided detected apparent location of the permanent mark and additional information unrelated to the mark.

[0150] The device can determine position and / or orientation using additional information unrelated to the marker, based on the methods already discussed.

[0151] Preferably, the device includes one or more illumination units for eccentrically illuminating the spectacle lens, wherein a detection unit is further configured to detect the position of at least one reflection caused by the eccentric illumination process as additional information unrelated to the mark. Preferably, the device includes a plurality of such light sources, particularly preferably, these light sources are spatially arranged at different distances from the optical axis of the detection unit used to detect the permanent mark. This configuration of the device corresponds to the method explained above, wherein at least one reflection is used as additional information unrelated to the mark. In this case, a calculation unit for determining position and / or orientation is configured to determine the position and / or orientation of the spectacle lens based on the position of the permanent mark and the position of at least one reflection.

[0152] Alternatively or additionally, the device may use the holding characteristics of the holder as additional information unrelated to the marking, as explained in detail above for the method. These holding characteristics may be stored in the device's memory or retrieved from a server via a communication network such as the Internet.

[0153] Similar to the methods discussed above, the device can easily determine the position and / or orientation of the eyeglass lenses, upon which further steps, such as applying a stamp, can then be performed.

[0154] In this case, the computing unit may in particular be a correspondingly programmed computer. Accordingly, a computer program is also provided, which, when executed on a processor, controls and implements one of the methods described above. Attached Figure Description

[0155] The invention will now be explained in more detail based on exemplary embodiments. In the figures:

[0156] Figures 1A to 1D as well as Figure 2A and Figure 2B A diagram is shown to illustrate the process of holding eyeglass lenses to a suction holder.

[0157] Figure 3 An apparatus for determining the position and / or orientation of spectacle lenses, according to an exemplary embodiment, is shown.

[0158] Figure 4 It shows Figure 3 Examples of reflection in a device,

[0159] Figure 5 It shows Figure 3 A device in which the lenses of the eyeglasses are tilted.

[0160] Figure 6 It shows in Figure 5An example of reflection in an tilted position.

[0161] Figures 7A to 7F An illustration is shown illustrating the apparent location of the permanent marking.

[0162] Figure 8 and Figure 9 A flowchart illustrating a method according to an exemplary embodiment of the present invention is shown, and

[0163] Figure 10 A diagram is shown to illustrate, for example, the positions of the coordinate axes used to describe the present invention. Detailed Implementation

[0164] The following explains exemplary embodiments of this application.

[0165] Figure 3 An apparatus for determining the position and orientation of an eyeglass lens 35 on a suction holder 36, which holds the eyeglass lens 35 by suction on the concave surface of the lens. The apparatus includes an illumination and image recording unit 30, a retroreflector 37, and a computing unit 39.

[0166] The illumination and image recording unit 30 includes a camera 31 capable of recording an image of the spectacle lens 35 onto a suction holder 36. A light source 33 is used to illuminate the spectacle lens 35 to determine the apparent positions of permanent markings 312, 313 on the spectacle lens. The light source 33 is coaxially (sometimes referred to as concentrically) coupled to the optical axis 310 of the camera 31 via a beam splitter 32. The correlation between illumination and the determination of the apparent positions of the permanent markings is implemented as described in EP 1 646 855 B1. In this case, light from the generally point light source 32 illuminates the spectacle lens such that the light transmitted from the beam splitter 32 to the spectacle lens 35 appears to originate from the entrance pupil of the lens of the camera 31, i.e., concentric with respect to the optical axis 310. This illumination, also known as coaxial reflected light illumination, illuminates the spectacle lens 35 and is intended to determine the position of the spectacle lens. Light passes through spectacle lenses with permanent markings 312 and 313, which in the depicted example are applied to the back of the spectacle lenses, then strikes a movable rear reflector 37, and then returns to camera 31 via approximately the same path. The lens of camera 31 then images the permanent markings with high contrast to the light that was initially illuminated by coaxial reflected light and has passed through the spectacle lenses twice via the rear reflector 37.

[0167] As described in the introduction, when the permanent marks 312 and 313 are arranged on the back of the spectacle lens 35 (i.e., the side facing the holder 36), image recording is not always performed precisely from the prescription direction, as explained in the introduction. This causes the apparent position of the permanent marks to differ from their actual position due to the refraction of light at the front surface of the spectacle lens. When the spectacle lens 35 is tilted, the apparent position of the permanent marks on the front of the spectacle lens as seen through the camera 31 changes.

[0168] This will refer to Figures 7A to 7F Let me explain. Figures 7A to 7F Each figure shows an eyeglass lens with a front lens 72 and a back lens 71, and permanent markings P1 and P2 on the respective back lens 71. Depending on the tilt of the eyeglass lens on the holder (not depicted) and the shape of the front lens 72 and the back lens 71, the camera 31 identifies different apparent positions V1 and V2 on the respective front lens 72 to the permanent markings. The apparent positions V1 and V2 are generated in a simple manner by the actual positions of the permanent markings P1 and P2 using Snell's Law. In each case, these figures show the light from an external light source (not depicted because it is above the applied force shown) in dashed lines; this could be, for example, light source 34A. In each case, ERP is also depicted as a point on the front lens. This reveals the degree of eccentricity of the lens on the lens holder. These figures use the back lens 71 of a spherical eyeglass lens and assume that the torques acting on the eyeglass lens due to the displacement of the center of gravity are small enough that they do not affect the illustration. Additionally, it is assumed that the holding point on the back lens is always located at {0,0} in the figures. If the torques are due to weight distribution, then Figure 7A and Figure 7B as well as Figure 7E and Figure 7F The hold point in the diagram may shift slightly along the Z-axis, that is, towards {0, zh}, where zh is smaller. Moreover, the actual tilt may actually be greater than depicted.

[0169] exist Figures 7A to 7F In the figure, light rays are depicted as solid lines from permanent marks P1 and P2 on the back of the spectacle lens, through apparent positions V1 and V2 on the front, to the projection center of the camera; again, it is assumed that the projection center is located above and outside the figure on the Z-axis.

[0170] Figures 7A to 7FFurthermore, the light rays are depicted as dashed or dotted lines originating from an eccentric light source 34A that satisfies the reflection conditions. This eccentric light source is also located outside the upper left of the partial drawing and is therefore not shown: the dashed lines indicate that the corresponding reflection 76 is caused by reflection at the front 72 of the spectacle lens, while the dashed lines indicate that the corresponding reflection 75 is caused by reflection at the back 71 of the spectacle lens. Two light refractions appear on the gradient of the dashed line of reflection 75: the light beam on the front of the spectacle lens (at...) Figure 7B The position of light entering the spectacle lens (not further indicated by 73), and the position of light entering the spectacle lens at 74 on the back of the spectacle lens (only partially indicated by 74). Figure 7B The point at which the reflection is emitted again from the lens (indicated by 75) is marked separately on the back of the camera 31. The camera 31 marks the reflection at position 75 via the back. For example, the key point of this reflection can be calculated by applying the law of reflection or by solving Snell's law and the implicit equation twice. In practice, this is equivalent to an iterative method in each case.

[0171] Local Figure 7A and Figure 7B This shows the resulting eccentricity and leftward tilt, locally. Figure 7C and Figure 7D The "ideal" positioning is shown, and locally... Figure 7E and Figure 7F The corresponding eccentricity and rightward tilt are shown. Clearly, roughly speaking, the apparent position of the permanent mark is displaced in a manner similar to, but not exactly the same as, the ERP (which cannot be directly recognized by the camera), but the light reflection is displaced to a greater extent. Reflections primarily at surfaces with less curvature—that is, reflections at the back of the lens 71 in the local view where the lens has positive refractive power, and reflections at the front of the lens 72 in the view where the lens has negative refractive power—respond more strongly to the tilt caused by eccentricity. If only a tilt without eccentricity were effective, the situation would be as follows: reflections would be relatively sensitive to this, and points V1 and V2 would then be affected only by the cosine effect (i.e., the effect of the cosine depending on the tilt angle), that is, only by a relatively small effect. Therefore, reflection provides valid additional information, independent of the mark, that can be used to accurately determine the lens orientation, which is necessary for a properly fitting stamp.

[0172] In order to determine the position and orientation of the spectacle lens 35 Figure 3 The exemplary embodiment includes additional light sources 34A, 34B, and 34C, the reflections of which are determined in a camera image recorded by camera 31. The light path of this reflection on the lens surface of the eyeglasses, as seen through the camera in the accompanying drawings, is... Figure 3The light source 311 is used as a reference. Light passing through external light sources 34A to 34C passes through spectacle lens 35 and is reflected by rear reflector 37, essentially returning to the corresponding light source. For light from all light sources, including concentric reflection illumination 33, there is virtually no interference with image recording by camera 31. Furthermore, all these light sources can be configured to be turned on sequentially only for separate camera images in each case, making it easy to determine their spacing and the allocation of which reflection originates from which light source. In the case of spectacle lenses with anti-reflective coatings, only weak reflections occur on the front and back of the spectacle lens. However, since the light reaches the camera only through reflection, these light sources can be configured to be correspondingly bright.

[0173] In addition to reflections at the front of the spectacle lens, reflections may also occur at the back of the spectacle lens. These must be distinguished from the reflections at the front of the spectacle lens. This is particularly straightforward if the light sources 34A to 34C are provided with wavelengths that are greatly absorbed in the spectacle lens material. Therefore, reflections through the back of the spectacle lens appear much darker than reflections from the front. Ideally, their intensity is below a threshold, such as a detection threshold. The camera 31, along with its optical system, must then be sensitive to the light from the light sources 34A to 34C.

[0174] Figure 4 An example of the location of the front reflection point 314 (i.e., the reflection caused by reflection at the front of the eyeglass lens) is shown when using five light sources, wherein Figure 4 The diagram illustrates three light sources (34A to 34C). Reference numeral 315 indicates the field of view of camera 31. Furthermore, back reflection points can be generated due to reflections at the back of the spectacle lenses. For simplicity, these points are not shown... Figure 4 There are also the following further details Figure 6 The image is shown in the middle, but will be referenced later. Figures 7A to 7F To explain.

[0175] If the tilt is not so large that reflections no longer occur on the front of the eyeglass lens or fall outside the camera's field of view, then camera 31 can detect these reflection points. If the tilt is doubled... Figure 7E The imaging is evident in that the reflection 76 on the front 72 will fall off the lens. See also Figure 7A , Figure 7C and Figure 7EThe position of point 76. Coaxial reflected light illumination 33 also produces a reflection point. However, because the light from light source 33 prevents an unnecessarily large amount of light from being absorbed by the lens material, the contrast of this reflection point is relatively low. A larger portion of the light at this reflection point reaches the rear reflector and returns from there to camera 31. Its sensitivity is set so that the entire area of ​​the lens appears "bright". For example, the rear reflector 37 is only blocked by the suction holder 36 when the suction holder 36 is slightly positioned on the optical axis 310 of camera 31, and the reflection is visible and further used to determine position and / or orientation. However, the reflection can then be superimposed on or confused with the reflection from the back of the lens. The reflections from external light sources 34A to 34C can be better evaluated, especially if the light from the external light sources is absorbed so much by the lens material that the reflections from the front and back of the lens are clearly distinguishable.

[0176] In cases where it is impossible to distinguish them by their apparent brightness, and where the radii are significantly different, reflections from the front and back of the spectacle lens can also be considered defocused and distinguished by their size: the camera focuses such that a point at a distance from the permanent engraving is displayed with optimal sharpness. Due to reflections on surfaces curved towards the camera in each case from the camera's perspective, external light sources (e.g., 34A) appear even farther than they actually are. This primarily applies to reflections on more curved surfaces in each case. As a result, the luminous reflection point appears noticeably more blurred. However, this effect is not very pronounced, especially since the camera lens aperture of camera 31 is significantly reduced to achieve a large depth of field. A further distinguishing feature is the relative position: the shape and construction of the corresponding spectacle lens are known; only the orientation to be determined is unknown. Calculation unit 39 can calculate which of the two distinguishable reflections more appropriately matches the front of the spectacle lens, and which matches the back. Moreover, this situation will not apply to other external light sources if the two reflections converge very closely and are practically indistinguishable. Therefore, it is also advantageous to set light sources that are approximately opposite to each other relative to the optical axis of camera 31, i.e., for example, in... Figure 7A In the case shown, with approximately 7 / 12 of the eccentricity depicted, the external light source is relative to the optical axis. Figure 7A The light source is mirrored. Then, Figure 3 The 34C light source will produce clearly distinguishable front and back reflections.

[0177] exist Figure 3 In an exemplary embodiment, under the control of the computing unit 39, light sources 34A to 34C and 33 can be activated and deactivated individually or in groups, such that... Figure 4The reflections shown can be detected sequentially, and it can be determined which reflection should be assigned to which light source 34A to 34C, 33.

[0178] By appropriately setting the operating point of camera 31 (sensitivity or exposure time depends on the intensity of light sources 33, 34A to 34C and the transmittance of spectacle lens 35), it can be ensured that the brightest areas in the image do not completely exhaust the dynamic range of camera 31's sensitivity, but rather that the reflections from additional light sources 34A to 34C are clearly visible simultaneously in the image recorded by camera 31. However, as explained above, multiple images can also be recorded using optional activated light sources.

[0179] Therefore, measurement Figure 4 The position of the reflection 313 is determined in order to determine the position and orientation of the spectacle lens 35. This is because, for example, when the spectacle lens 35 is tilted, the position of the reflection 313 changes. Figure 4 The apparent location of the permanent markings was further revealed, and the permanent markings were once again identified by 312 and 313. Figure 5 and Figure 6 The position of the eyeglass lens is shown; the lens is attached to a suction holder by suction and thus held in a laterally displaced manner. Figure 5 In this configuration, the spectacle lens 35 on the suction holder 36 is therefore in an inclined position. Correspondingly, this is in contrast to the orientation that is straight. Figure 4 Compared to the previous case, the position of reflection 314 also changes. In contrast, the position changes of permanent marks 312 and 313 are relatively small. The position of the reflection and the apparent position of the permanent marks thus change in different ways, and as explained, this is used to determine the position and orientation of the spectacle lens. Assuming... Figure 3 and Figure 5 Multiple light sources are arranged on an imaginary circle around the optical axis 310. To enable measurement of even relatively large areas of spectacle lenses with varying curvatures, multiple imaginary circles of different diameters can be conveniently provided for these light sources, or they can be spirally arranged around them. Figure 3 The optical axis is arranged at 310.

[0180] In the case of spherical eyeglass lenses, reflections with a circular arrangement also lie on an imaginary circle, such as... Figure 4 As indicated. In the case of an aspherical shape, a deviation in roundness from the reflection position occurs.

[0181] In the case of spectacle lenses with a spherical front surface, the diameter of the imaginary circle depends primarily on the radius of curvature of the lens surface. If the spectacle lens to be measured is ideally centered and oriented on the suction holder 36, i.e., the center point of the lens (the center point between the permanent marks) lies on the optical axis 310, and the direction perpendicular to the center of the surface extends along the optical axis 310, then the reflection point lies on a circle around this center point in the image recorded by the camera 31, and the positions of the two permanent marks are symmetrical about this center point, such as... Figure 4 As shown.

[0182] like Figure 6 As shown, reflection shifts when there is lateral displacement or when the spectacle lens is tilted. (Image...) Figure 4 Same, Figure 6 Only the front surface reflection is shown. This displacement follows the imaging law on a curved mirror with the front surface shape of an eyeglass lens. The displacement of the rear surface reflection due to tilt follows a similar law, but in this case, both refractions at the eyeglass lens also take effect.

[0183] Figure 10 The axis names shown are used for further explanation below. Figure 10 A plan view of the spectacle lens 35 and the holder 36 along the optical axis 310 is shown. When the spectacle lens is positioned on the holder 36 without tilting, the z-axis is parallel to... Figure 3 The optical axis 310 extends, with the x and y axes perpendicular to it, essentially within the lens plane that roughly describes the spectacle lens. The fact that the apparent position of the permanent mark has shifted clearly indicates the offset of the spectacle lens 35 in the xy plane. Tilts around the x or y axis will, in principle, shift the position of the reflection point, while the apparent position of the permanent mark changes relatively little. Furthermore, the position of the permanent mark also depends on the twist around the z-axis. Therefore, in general, the offsets along the x and y axes, the tilts around the x and y axes, and the twists around the z-axis can be determined by evaluating the position of the reflection (314) detected by the camera 31, as well as the apparent position of the permanent mark. This evaluation can be performed by means of a computing unit 39 via a corresponding computer program. Important factors in the calculation are the position of the external light sources 30A…30F, the optical data of the image recording unit 30, and the known data of the spectacle lens (represented in its own coordinate system associated with the spectacle lens, whose position and orientation relative to the world coordinate system of the image recording unit are unknown, and this position and orientation are intended to be determined according to the invention). Important factors include, in particular, the location of the permanent mark, and, if the mark is located on the back of the spectacle lens, the refractive index of the spectacle lens. Once the location and orientation of the spectacle lens 35 are determined, a stamp can be applied to the spectacle lens using the stamping device 38. In this case, in the illustrated example, the stamping device 38 is configured as an inkjet printhead.

[0184] In the case of stamping using inkjet printing (inkjet method) via stamping device 38, tilt is less important because the print head is suspended above the spectacle lens during printing. To accurately determine the offset (position in the x and y directions), this is absolutely crucial when the permanent mark is located on the back of the spectacle lens (facing the suction holder 36), because if the spectacle lens is tilted differently, the apparent position of the permanent mark changes, as already referenced. Figures 7A to 7F This effect is particularly noticeable for spectacle lenses with high negative power, i.e., for lenses with, for example, -10 dpt spherical or cylindrical lenses, because the light path in the spectacle lens is relatively long there, which causes greater variations depending on the tilt position.

[0185] Now refer to Figure 8 and Figure 9 The determination of the position and / or orientation of the spectacle lens 35 on the suction holder 36 is explained in more detail. Figure 8 and Figure 9 This demonstrates that it can be controlled by the computing unit 39. Figure 3 A flowchart of the method implemented in the apparatus. In this case, Figure 8 The method diagram in the image illustrates the general order of methods, while Figure 9 The above references are shown. Figure 10 The iterative method for explaining the parameters (offset along the x and y directions, tilt around the x and y axes, and twist around the z axis).

[0186] In step 80, the spectacle lens 35 is secured to the holder 36. In step 81, the apparent location of the permanent mark is determined, wherein for this purpose, as explained, the light source 33 provides coaxial reflected light illumination. In step 82, the spectacle lens 36 is eccentrically illuminated by one or more light sources 34A to 34C, for example, sequentially or in groups, such that it can be definitively determined which reflection originates from which light source. If there is more than one external light source whose reflection is visible, reflections from which it cannot be determined whether they originate from the front or back are discarded. In step 83, the location of the reflection caused by the eccentric illumination is determined by accordingly evaluating one or more images recorded by the camera 31. Reflections can be identified from the fact that they are spatially small and bright. If such a reflection is incident on more than one camera pixel, there are many possible ways to evaluate such a reflection: this can be done, for example, by establishing the centroid of all nearby pixels exceeding a threshold, or the most suitable intensity distribution of the light source expected after reflection at a correspondingly curved reflector, which is located at a virtual distance from the virtual location of the light source.

[0187] Then, step 84 includes, for example, referenced later. Figure 9The position and / or orientation of the spectacle lens 35 on the holder 36 are calculated iteratively. Based on these results, for example, in step 85, a stamp pattern can then be applied to the spectacle lens by the stamping device 38. Since the spectacle lens is not held in the correct orientation in most cases, a rotating stamp pattern is printed due to the lens being misaligned on the holder. If necessary, distortion of the inkjet pattern due to the different flight times of the inkjet droplets, caused by the different distances of different points of the pattern to be printed from the front surface of the lens, should also be considered.

[0188] Figure 9 An iterative method for determining position and orientation is shown. Figure 8 An example of how step 84 is implemented.

[0189] Figure 9 The method in the middle uses sub-methods (in Figure 9 (Not explicitly illustrated in the diagram), this sub-method is in Figure 9 The method is reused repeatedly during the process. The sub-method is hereinafter referred to as SR and can be implemented as a corresponding subroutine in computation unit 39. For in Figure 9 The method determines the orientation of the spectacle lens during the process, and the sub-method calculates the expected apparent position of the permanent mark and the expected position of the reflection caused by eccentric illumination (separated based on reflections from the front and back of the spectacle lens). Therefore, SR affects the ray trajectory. (As from...) Figures 7A to 7F As is evident, these are based on simple geometric optics. SR further compares the calculated expected location of the permanent mark and the expected location of the reflection with the corresponding locations detected in steps 81 and 83. As a result, SR returns an error vector that identifies the deviation that caused this comparison process. Figure 9 In the method, the current pose is represented as... Figure 9 The pose corresponding to the instantaneous state calculated in the iterative calculation.

[0190] Figure 9 The method begins at step 90: initialization, which sets the initial values ​​for the current posture of the spectacle lens. For example, based on the apparent position of the permanent marker detected from step 81, initial values ​​for eccentricity (offset in the XY plane) and torsion around the Z-axis can be established. In this case, eccentricity is determined based on the center of the permanent marker projected onto the XY plane of the ideally positioned spectacle lens, compared to the position of the holder's axis in the XY plane. Torsion around the Z-axis of the world coordinate system is determined based on the direction of the permanent marker from left to right in the aforementioned plane. For example, it may be assumed that this tilt is caused, for example, by a feature of the holder at this holding point, or it may be set to 0 as the initial value.

[0191] In step 91, all parameters of the current pose (eccentricity, torsion, tilt) are changed by small values, and the effect of SR on the error vector is calculated. The result is a mutation matrix. The mutation matrix indicates how the error vector changes with small changes in the parameters.

[0192] In step 92, the pseudo-inverse of the mutation matrix is ​​calculated (see, for example, the German Wikipedia article "Pseudoinverse" [pseudo-inverse matrix], as of July 16, 2017); together with the error vector from step 91, the search direction is generated, i.e., the direction in which the parameters change in the next step.

[0193] In step 93, when the current parameters of the current pose change by w* search direction relative to the state directly prior to step 91, the minimum of the weighted sum of the squares of the elements of the error vector is determined for different time lengths w. Ideally, the minimum is at w = 1, but w can also yield different results. In this exemplary embodiment, w is determined by using the Brent method and repeatedly within this SR. (See, for example, Press et al., Numerical Analysis, 2nd ed. (1992), p. 394ff).

[0194] In step 94, the current pose is updated to the pose of the minimum value just found, that is, the pose changes the w* search direction from which the minimum value w is obtained.

[0195] Step 95 includes checking whether, for example, the weighted sum of squares regarding the deviation indicated by the error vector, has fallen below a predetermined threshold accuracy criterion. The accuracy criterion typically indicates how well the current pose matches the measured variable. If the accuracy criterion is met (e.g., the weighted sum of squares is below the threshold or even zero), the method terminates in step 97, and the final current pose is considered to have been determined sufficiently accurately. The final current pose then represents... Figure 9 The results of the method in [the document / method].

[0196] If the check in step 95 reveals that the accuracy criterion has not yet been met, then different error criteria are also checked in step 96: this includes checking whether the method still results in an improvement in posture (a reduction in the error criterion), or whether step 91 has been performed more frequently than the predefined maximum number. Furthermore, in other method steps, and also in SR, there may be error conditions that must be detected by the method, such as postures that should never occur.

[0197] If appropriate, the method is terminated with an error message in step 98. Otherwise, the method jumps back to step 91 to restart.

[0198] If the device has more than one camera, each image is evaluated individually, and the apparent locations of permanent markers and additional reflective points are identified within it. Then, as described above, all these optical configurations are evaluated together in a minimal search to arrive at the position and orientation of the spectacle lens in the device (besides measurement and truncation errors that always occur in this approximation method).

[0199] Using the data determined in this way, then in step 85, the stamp is applied at the correct location by calculating the corresponding coordinates on the lens surface to which the stamp is to be applied. (Based on reference...) Figures 7A to 7F The apparent location of the explained permanent marker, plus reflection, can determine the actual location.

[0200] The following specifies at least some possible exemplary embodiments:

[0201] Article 1. A method for determining the position and / or orientation of a spectacle lens (35) with a permanent mark on a retainer (36), comprising:

[0202] Provide the detected apparent location of these permanent markings on the spectacle lens (35),

[0203] Its characteristics are,

[0204] Based on the apparent location of these permanent markings and additional information unrelated to the markings, the position and / or orientation of the spectacle lens are determined.

[0205] Article 2. According to the method described in Article 1,

[0206] Its characteristics are,

[0207] The apparent location of these permanent markings on the spectacle lens (35) was determined.

[0208] The lens of the eyeglasses was irradiated eccentrically (35).

[0209] Detect the location of at least one reflection (40A to 40F; 60A to 60F) on the spectacle lens caused by the eccentric illumination process.

[0210] The additional information, which is unrelated to the marker, includes at least one apparent location of the reflection.

[0211] Article 3. The method according to Article 2 is characterized in that detecting the apparent position of the at least one reflection includes repeated detection during movement of the spectacle lens (35).

[0212] Article 4. The method according to Article 2 or 3 is characterized in that the eccentric illumination process includes an eccentric illumination process that uses multiple light sources to generate multiple reflections.

[0213] Article 5. The method according to Article 4 is characterized in that the plurality of light sources are activated alternately, individually or in groups.

[0214] Article 6. The method according to any one of Articles 2 to 5 is characterized in that the position of the permanent markings is detected with a first light wavelength and the position of the at least one reflection is detected by illumination with a second light wavelength, wherein the spectacle lens (35) has a higher absorption rate for the second light wavelength than for the first light wavelength.

[0215] Article 7. The method according to any one of Articles 1 to 6 is characterized in that the apparent position of the permanent mark is detected from multiple viewing directions and / or the position of the at least one reflection is detected.

[0216] Article 8. The method according to any one of Articles 1 to 7 is characterized in that the additional information unrelated to the marking includes the calculated or experimentally determined positional characteristics of different shaped spectacle lenses on the holder (36).

[0217] Article 9. The method according to any one of Articles 1 to 8 is characterized in that determining the position and / or orientation of the spectacle lens (35) includes iterative calculation of the position and / or orientation of the spectacle lens (35).

[0218] Article 10. A computer program having program code that, when executed on a processor, causes the implementation of the method described in any one of Articles 1 to 9.

[0219] Article 11. A device for determining the position and / or orientation of a spectacle lens with a permanent mark on a holder, the device comprising:

[0220] A providing unit is used to provide the detected apparent location of these permanent markings on the spectacle lens (35).

[0221] Its characteristics are,

[0222] The calculation unit (39) is used to determine the position and / or orientation of the spectacle lens based on the apparent position of these permanent markings and additional information unrelated to the markings.

[0223] Article 12. The apparatus according to Article 11 is characterized by a detection unit for detecting the apparent location of these permanent markings on the spectacle lens (35).

[0224] Article 13. The apparatus according to Article 12,

[0225] Its characteristics are,

[0226] Illumination unit (34A-34C) for eccentric illumination of the eyeglass lens.

[0227] The detection unit (31) is further configured to detect the location of at least one reflection caused by the eccentric illumination process performed by the illumination unit, wherein the additional information unrelated to the mark includes the location of the at least one reflection.

[0228] Article 14. The apparatus according to Article 13 is characterized in that the illumination unit (34A-34C) includes a plurality of light sources arranged eccentrically relative to the optical axis of the detection unit, wherein the computing unit (39) is preferably configured to alternately activate these light sources.

[0229] Article 15. The device according to any one of Articles 11 to 14 is characterized in that the additional information unrelated to the marking includes calculated or experimentally determined positional characteristics of different shaped spectacle lenses on the holder (36).

Claims

1. A method for determining a position and / or orientation of an eyeglass lens (35) with permanent markers on a holder (36), comprising: providing detected apparent positions of the permanent markers on the eyeglass lens (35), wherein the apparent positions of the permanent markers differ from the real positions of the permanent markers due to light refraction through the eyeglass lens, determining a position and / or orientation of the eyeglass lens based on the apparent positions of the permanent markers and additional information independent of the markers, characterized in that the additional information independent of the markers comprises calculated or experimentally determined position characteristics of eyeglass lenses of different shapes on the holder (36), wherein the position characteristics comprise holding characteristics of the holder.

2. The method according to claim 1, characterized in that detecting apparent positions of the permanent markers on the eyeglass lens (35), illuminating the eyeglass lens (35) eccentrically, detecting positions of at least one reflection on the eyeglass lens caused by the eccentric illumination, wherein the additional information independent of the markers comprises the positions of the at least one reflection.

3. The method of claim 2, wherein, Detecting the positions of the at least one reflection comprises repeated detection during movement of the eyeglass lens (35).

4. The method according to claim 2 or 3, characterized in that, The eccentric illumination comprises a plurality of reflections using a plurality of light sources for the eccentric illumination.

5. The method of claim 4, wherein, The plurality of light sources is activated individually or in groups alternately.

6. The method according to claim 2 or 3, characterized in that, The positions of the permanent markers are detected with a first light wavelength and the positions of the at least one reflection are detected by illumination with a second light wavelength, wherein the eyeglass lens (35) has a higher absorption for the second light wavelength than for the first light wavelength.

7. The method of claim 2 or 3, wherein, The apparent positions of permanent markers and / or the positions of the at least one reflection are detected from a plurality of viewing directions.

8. The method according to any one of claims 1 to 3, characterized in that, Determining the position and / or orientation of the eyeglass lens (35) comprises an iterative calculation of the position and / or orientation of the eyeglass lens (35).

9. An apparatus for determining a position and / or orientation of an eyeglass lens with permanent markers on a holder, the apparatus comprising: a providing unit for providing detected apparent positions of the permanent markers on the eyeglass lens (35), wherein the apparent positions of the permanent markers differ from the real positions of the permanent markers due to light refraction through the eyeglass lens, a calculation unit (39) for determining a position and / or orientation of the eyeglass lens based on the apparent positions of the permanent markers and additional information independent of the markers, characterized in that the additional information independent of the markers comprises calculated or experimentally determined position characteristics of eyeglass lenses of different shapes on the holder (36), wherein the position characteristics comprise holding characteristics of the holder.

10. The apparatus according to claim 9, characterized by a detection unit for detecting apparent positions of the permanent markers on the eyeglass lens (35).

11. The apparatus according to claim 10, characterized in that an illumination unit (34A-34C) for illuminating the eyeglass lens eccentrically, wherein The detection unit (31) is further configured to detect a position of at least one reflection caused by the off-center illumination by the illumination unit, wherein the additional information independent of the marker comprises the position of the at least one reflection.

12. The apparatus of claim 11, wherein, The illumination unit (34A-34C) comprises a plurality of light sources arranged off-center with respect to an optical axis of the detection unit, wherein the computation unit (39) is configured to activate the light sources alternately.

Images