Measuring surface deformations on glass surfaces
Patent Information
- Application Number
- EP2024724093
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-04-24
- Filing Date
- 2024-04-24
- Publication Date
- 2026-03-04
AI Technical Summary
Existing methods for measuring surface deformations on glass panes during manufacturing, such as those caused by tempering processes, struggle to accurately distinguish and evaluate distortions on multiple surfaces due to overlapping light pattern reflections, leading to unreliable measurement of optical distortions.
A measuring method using a light pattern composed of polygonal, trapezoidal, or triangular light features with varying feature distances and orientations, projected onto the glass pane, allowing for precise determination of geometric parameters as the pane moves relative to the camera and illumination device, enabling separate evaluation of distortions along the transport and transverse axes.
This approach allows for simple and precise measurement of glass pane distortions by differentiating between light pattern features and accurately determining surface deformations, even in cases of cyclical wave structures, enhancing measurement accuracy and resolving the issue of overlapping reflections.
Smart Images
Figure EP2024061228_31102024_PF_FP_ABST
Abstract
Description
[0001] Viprotron GmbH
[0002] Measurement of surface deformations on glass surfaces
[0003] The invention relates to a measuring method and a measuring device for determining the flatness of a transparent pane, wherein the pane is displaced relative to a lighting device and a camera or the lighting device and the camera relative to the pane in a transport direction by means of a transport device, wherein a light pattern consisting of several two-dimensional light pattern features is projected onto the pane with the lighting device, wherein the several light pattern features are projected onto the pane next to one another in a transverse axis oriented perpendicular to the transport direction, wherein the light pattern reflected by the pane is at least partially recorded by the camera, wherein a geometric parameter of the light pattern features recorded by the camera is determined,and by evaluating several images captured successively by the camera, a change in the geometric parameter of one or more light pattern features caused by the reflections on the pane is evaluated.
[0004] Optical distortions can be caused by the reflection of light rays off surface deformations on the surface of the pane. These surface deformations are often caused by the tempering process used in the finishing of the glass pane. When glass panes are toughened or annealed, they are transported by a conveyor system through a heated furnace where they are heated to a critical temperature at which internal stresses are relieved. Evenly reaching the critical temperature is a challenge, especially with large-area glass panes, without the glass pane softening. Typically, the glass pane reaches a local softening point at which the glass is in a malleable state. During the manufacturing process, the glass pane usually rests on a large number of heat-resistant ceramic rollers on the conveyor system and is transported through the furnace.The locally softened glass pane is deformed by the force of gravity acting on it. This causes warping or deformation of the glass pane due to sagging of the glass pane in the space between two transport rollers. At a high preheating temperature inside the furnace, the sag is more pronounced, which is noticeable in the surface profile of the glass pane and in the reflective properties. The sag on the glass pane along the transport direction is usually cyclical. The period of high points compared to trough points is influenced by, among other things, the distance between adjacent transport rollers and the concentricity of the transport rollers.
[0005] As the glass pane rolls on a non-circular transport roller, peaks and troughs are periodically imprinted on the glass pane. These peaks and troughs are clearly visible when a glass pane is used, for example, under prestress. The deformations caused by the sag between the rollers or by a non-circular roller tend to be cyclical in nature and create a wave effect in the glass pane.
[0006] In addition to the high points and low points embossed into the glass pane in the longitudinal direction, which are visible as a cyclic wave structure, a local distortion can also be seen in the glass pane along a transverse axis parallel to the longitudinal direction.
[0007] The patent specification US 7,345,698 B2 discloses a measuring method and a measuring device for detecting and measuring optical distortion in glass panes. In the measuring method, an optical magnification of a reflected circular light pattern feature is recorded by means of a camera. For this purpose, a large number of circular light pattern features are projected onto the glass and reflected as ellipses that image the local surface contours. Distortions in the glass surface are measured as local magnification or reduction along the elliptical axis. The angle and the size of the minor and major axes of the reflected ellipses provide data for imaging the surface profile of the glass.This method is not suitable for measuring several different surfaces of a glass pane because the images of light pattern features reflected from multiple surfaces overlap, making it impossible to reliably distinguish which part of the reflection originates from which surface. In particular, the reflected image does not contain a single shape from each individual surface, but rather a composite image from the combined multiple reflections from the surfaces. This makes it impossible to evaluate the distortion separately from the individual reflecting surfaces.
[0008] Patent specification US 10,161,879 B1 describes a further development of the above-described device and method from document US 7,345,698 B2. The method and device disclosed in patent specification US 10,161,879 B1 are used to measure the surface profile and the optical reflection strength of one or more surfaces of transparent glass panes. A plurality of circular light pattern features are projected onto the glass surface. The light pattern features are not projected onto the glass surface in a solid pattern, but rather consist of a border. This allows for separate evaluation of the distortion when the images reflected from the multiple glass surfaces overlap, so that the determined distortion of a light pattern feature can be assigned to the respective glass surface.
[0009] In the described and known measuring methods and measuring devices, the camera is positioned and aligned such that the light pattern features projected onto the pane are completely captured by the camera. Only in this way is the evaluation of the magnification or reduction of the major or minor axes of the reflected ellipses possible. This requires the use of area scan cameras to capture the area of the pane in which the light pattern features are projected. The object of the present invention is to provide a measuring method that enables simple and accurate measurement of the distortion of the glass pane during the manufacturing process.
[0010] This object is achieved according to the invention in that a circumferential line of the light pattern features is in each case formed by a polygon which has a plurality of rectilinear polygon sections, wherein mutually facing polygon sections of adjacent light pattern features are not aligned parallel to one another. By projecting such light pattern features with known dimensions, the geometric parameter(s) can be easily determined. Because the feature distances between two adjacent light pattern features differ from one another at least in sections over their entire extent in the transport direction, the geometric parameters can be reliably recorded from sections of the light pattern recorded by the camera, so that the entire light pattern does not have to be recorded or evaluated in the transport direction.
[0011] By displacing the pane relative to the illumination device and the camera, or displacing the illumination device and the camera relative to the pane in the transport direction by means of the transport device, the plurality of images successively captured by the camera are recorded according to the invention in different relative positions of the pane to the illumination device and the camera in order to determine the change in the geometric parameters. In this way, for example, a distortion of the light pattern feature in the transport direction can be determined.
[0012] Advantageously, the invention provides that light pattern features projected directly next to one another onto the pane are designed and arranged in such a way that all feature distances determined perpendicular to the transport direction between mutually facing outer contours of the light pattern features projected directly next to one another differ from one another. Because the feature distances between two adjacent light pattern features differ from one another over their entire extent in the transport direction, the geometric parameters can also be reliably recorded from sections of the light pattern recorded with the camera, so that the entire light pattern does not have to be recorded or evaluated in the transport direction. The light pattern can, for example, be formed from trapezoidal light pattern features.It is also possible and provided according to the invention that the light pattern is formed from parallelogram-shaped light pattern features, wherein an angle of inclination of light pattern features projected directly adjacent to one another onto the disc differs from one another.
[0013] Particularly advantageously, the light pattern is formed from triangular light pattern features. By projecting triangular light pattern features with known dimensions, the determination of a geometric parameter can be carried out particularly easily. For example, the length of a triangle side can be determined by a reference measurement and by evaluating an image recorded with the camera. The image position of the reflected light pattern feature striking an image sensor of the camera can also be evaluated.
[0014] Advantageously, it can be provided that the light pattern features are projected onto the pane in such a way that one side of each light pattern feature, such as the side of a triangle, lies completely within the recording area recorded by the camera and is thus completely recorded. During a relative movement of the pane to the camera and to the illumination device in the transport direction, the geometric parameter, here the length of a side of the light pattern feature recorded with the camera, such as the triangle, is changed due to the surface deformation of the pane. By determining the changed length and with a known positioning of the camera and the illumination device relative to the pane, the extent of the surface deformation of the pane can be determined.The surface deformation can be formed as a curvature of the disc or can be visible as a wave-like cyclical wave structure in the transport direction of the disc caused by the manufacturing process.
[0015] Advantageously, the invention provides that the light pattern features are formed from a plurality of trapezoidal light pattern feature parts arranged one behind the other in the transport direction and adjacent to one another.
[0016] By using trapezoidal light pattern features or trapezoidal light pattern feature parts, a minimum distance between opposing polygonal sections perpendicular to the transport direction can be easily specified. By specifying a minimum distance, the individual polygonal sections can be reliably differentiated from one another in the camera image. The minimum distance is advantageously adapted to a maximum thickness of the pane to be measured in order to be able to differentiate between the polygon sections in the camera image that are generated once by the reflection of the light pattern on the top side of the pane and once on the bottom side of the pane and recorded by the camera. By using several trapezoidal light pattern feature parts, the measuring range can be easily enlarged without impairing the spatial resolution.
[0017] Advantageously, the invention optionally provides for the illumination device and the camera to be aligned at the same angle to the pane, so that the light pattern features reflected on the pane enter the camera perpendicularly. This makes evaluation of the images recorded with the camera particularly easy, since complex correction of distorted images caused by oblique incidence of the light pattern features into the camera is unnecessary.
[0018] Advantageously, several cameras arranged next to one another or aligned to adjacent light pattern feature sections are used to capture particularly wide light pattern features.
[0019] Due to the change in the angle of incidence of the light rays on the pane or the change in the angle of emission of the reflected light rays on the pane, the light rays impinge on the image sensor of the camera used in different positions. When using a line scan camera or when evaluating only individual image lines from an area scan camera, the surface deformation means that different areas of the light pattern are viewed, so that recorded dimensions of adjacent light pattern features differ from one another and individual recorded dimensions also differ from reference dimensions. The surface deformation of the pane can be determined by evaluating the position of the reflected light pattern feature or the deviation of the dimensions of the light pattern features or the light pattern feature sections.
[0020] The invention also provides for the light pattern feature to be configured as an isosceles and acute-angled triangle. When using a light pattern feature in the shape of a triangle with known side lengths and interior angles, a section through the triangular light pattern feature can determine a distance between the sides of the triangle based on a displacement or rotation of the pane.
[0021] In addition, a distortion of the light pattern feature in the transport direction and along the transverse axis can be evaluated separately. The distortion of the light pattern feature caused in the transport direction by the surface deformation of the pane can be evaluated by a cyclical and wave-like change in the width of the triangular light pattern feature. In an advantageous embodiment of the invention, the geometric parameter describes a distance between two intersection points, wherein the intersection points are generated by an intersection line with two sides of the light pattern feature. Because the dimensions of the light pattern features can be determined in a reference measurement on a reference surface, a change in the distance can be used to determine the surface deformation of the pane. The intersection line corresponds to the strip-shaped recording area recorded by the camera.
[0022] To ensure that the geometric parameters described using the light pattern features can be determined particularly accurately, an advantageous embodiment of the inventive concept provides for the light pattern features to be filled. When using spaced-apart light pattern features, a particularly high-contrast and thus sharp transition can be recorded between the light pattern feature projected onto the pane and an area adjacent to the light pattern feature. This allows the local surface deformation to be determined particularly accurately.
[0023] By filling in triangular light pattern features, for example, a particularly high contrast can be created between a bright area of the pane illuminated by the light pattern feature and an unlit area of the pane, or between adjacent light pattern features and dimly lit dark areas. This allows transitions between the light pattern feature and the unlit area to be determined particularly accurately and reproducibly.
[0024] Advantageously, the invention provides for a light band to be projected onto the pane in front of and / or behind the light pattern in the transport direction. In this way, it can be automatically determined whether the camera and projector are aligned in such a way that the maximum measuring range has been exceeded.
[0025] According to the invention, it can be provided that the light band is directly adjacent to the light pattern, so that the light pattern features and the light band merge into one another.
[0026] Advantageously, the invention provides that dark areas between adjacent light pattern features of the light pattern are also illuminated by the illumination device, with the illumination intensity of the dark areas being lower than the illumination intensity of the bright areas of the light pattern. In this way, even in the dark areas, a distinction can still be made between the glass surface and the area without glass, for example, to identify glass edges or the positions of drill holes.
[0027] To project the light pattern, the lighting device advantageously comprises a projection lamp and a light pattern element arranged in a projection region of the projection lamp. The light pattern element can be, for example, a film having translucent and non-translucent or slightly translucent regions. The light pattern is generated by illuminating the film arranged between the projection lamp and the pane with the projection lamp. In order to also dimly illuminate the dark regions, the slightly translucent regions can have a low degree of transparency.
[0028] Advantageously, the invention provides that the illumination intensity of the dark areas is a maximum of 10%, advantageously a maximum of 5% and particularly advantageously a maximum of 2% of the illumination intensity of the light areas.
[0029] To further increase measurement accuracy when using multiple light pattern feature parts, the invention provides for the illumination intensities of the light pattern feature parts of a light pattern feature to differ from one another. In this way, even when using a line scan camera, for example, it is possible to determine which area of the light pattern is being viewed.
[0030] In order to be able to detect the flatness of the pane over the entire width of the pane, an advantageous implementation of the inventive concept provides that a strip-shaped recording area of the pane is detected in an image recorded with the camera, wherein the strip-shaped recording area is oriented parallel to the transverse axis and the pane is completely detected along the transverse axis.
[0031] In order to be able to carry out a particularly precise determination of the flatness along the transverse axis of the pane, an advantageous embodiment of the invention provides that the triangular light pattern features are oriented such that tips of the light pattern features point in or opposite to the transport direction. Furthermore, the invention can also provide that the base of a light pattern feature designed as an isosceles triangle is oriented parallel to the transverse axis. In this way, the illumination generated by the illumination device can be aligned along the transverse axis and the recording field of the camera can be aligned particularly easily along the base of the triangle projected onto the pane.
[0032] In order to be able to measure a particularly large number of triangular light pattern features, an advantageous embodiment of the invention provides that the light pattern features are oriented such that the tips of adjacent triangular light pattern features point alternately in or against the transport direction. The number of triangular light pattern features along the transverse axis determines the resolution of the measuring method along the transverse axis and thus across the pane width. The number of data points for determining geometric parameters is therefore particularly large in order to be able to determine local curvatures of the surface deformation in each strip-shaped recording area and thus per pixel line of the line scan camera.
[0033] To enable a particularly precise determination of the geometric features, an advantageous embodiment of the method according to the invention provides for adjacent light pattern features to be projected onto the pane with different light intensities. This allows a particularly high contrast to be generated between two adjacent light pattern features. This allows, for example, the intersection points used to determine the geometric parameters to be determined particularly precisely.
[0034] It is also possible and provided according to the invention that differently designed light patterns are projected one after the other onto the pane and captured by the camera, wherein the light pattern features of each light pattern projected onto the pane directly next to one another are designed and arranged such that all feature distances determined perpendicular to the transport direction between mutually facing outer contours of the light pattern features projected directly next to one another differ from one another.
[0035] According to the invention, for example, light patterns with triangular light pattern features can be used, wherein the triangles of the light patterns projected successively onto the pane each have, for example, base sides of different lengths. Different surface deformations have different effects on the light pattern features used. By using different light pattern features in successive projection steps, any surface deformations can be easily determined, since a weaker effect of a surface deformation on a first light pattern can be compensated for by a stronger effect of the surface deformation on a second light pattern.
[0036] In practice, it is usually not possible, or only possible with great effort, to align the camera, the projection device, and the pane orthogonally to one another. It is therefore expedient to calibrate the measuring device before carrying out a measurement. Advantageously, the invention provides that when evaluating the images captured by the camera, an alignment of a recording area of the camera with respect to the projected light pattern, determined in a calibration step prior to the capture of the images, is taken into account. With knowledge of the relative position of the light pattern on the pane with respect to the camera, the evaluation steps described above can be carried out very precisely.
[0037] The object stated at the outset is also achieved by a measuring device, the measuring device having a transport device for displacing the pane relative to the illumination device and the camera or for displacing the illumination device and the camera relative to the pane in the transport direction, the light pattern consisting of a plurality of two-dimensional light pattern features being able to be projected onto the pane by the illumination device, the camera being aligned such that the light pattern reflected by the pane can be at least partially recorded by the camera, the evaluation device being able to determine a geometric parameter of the light pattern features recorded by the camera, the camera being designed as a line scan camera.By designing the camera as a line-scan camera, the alignment of the camera relative to the pane is particularly simple and quick, since the strip-shaped recording area is simply aligned parallel to the transverse axis to align the strip-shaped recording area on the pane. The illumination of the pane generated by the illumination device can also be easily adjusted to the strip-shaped area.
[0038] Furthermore, the images captured by the line scan camera can be evaluated quickly and easily by evaluating the image information pixel by pixel. The evaluation of a pixel line of the camera can take place at a faster clock rate than the evaluation of two-dimensional image information recorded by an area scan camera. This means that the geometric parameters can be determined particularly quickly by evaluating the images. The use of a line scan camera or the advantageous evaluation of just individual lines of the captured camera image from an area scan camera according to the invention advantageously allows a high spatial resolution of the camera image in the transport direction.
[0039] In order to be able to implement a stationary measuring device particularly easily, an advantageous embodiment of the inventive concept provides for the transport device to be designed as a roller conveyor or belt conveyor, with which the pane is moved relative to the lighting device and the camera in the transport direction. Such roller conveyors and belt conveyors are known from glass pane manufacturing systems, so they can be used to position the pane in the transport direction. The lighting device and the camera can thus be attached particularly easily to easily implemented stationary profile structures. A complex and potentially expensive drive device for moving the lighting device and the camera is not necessary. Thus, the distance between the lighting device and / or the camera relative to the transport device can be preset and adjusted particularly easily.
[0040] For particularly good accessibility to the lighting device and / or the camera, an advantageous implementation of the inventive concept provides for the camera to be arranged on a side of the pane facing away from the roller conveyor or the belt conveyor. Thus, the lighting device and the camera can be aligned at the same angle to the pane.
[0041] Advantageously, the invention provides that the lighting device comprises a projection lamp and a light pattern element arranged in front of the projection lamp in a projection region of the projection lamp, wherein the light pattern element has a plurality of translucent regions, the light pattern being formed by the translucent regions. The light pattern element is arranged between the projection lamp and the pane. The light pattern element can, for example, be a film having translucent and non-translucent or slightly translucent regions, by which the light pattern is formed.
[0042] Further advantageous embodiments of the inventive concept are shown in the drawings
[0043] Explained by examples. Figure 1 shows a schematic representation of the measuring device in a side view,
[0044] Figure 2 is a schematic representation of the measuring device in a plan view,
[0045] Figure 3 is a schematic representation of a light pattern projected onto the disc,
[0046] Figure 4 is a schematic representation of a section of the light pattern shown in Figure 3,
[0047] Figure 5 is a schematic representation of individual images drawn and composed using the line scan camera and
[0048] Figure 6 is a schematic representation of a light pattern with light pattern features having a plurality of light pattern feature parts.
[0049] Figure 1 shows a schematic representation of the measuring device in a side view. By means of a transport device 1, a disk 2 is positioned relative to an illumination device 3 and to a camera 4 designed as a line scan camera. The disk 2 lies flat and horizontally on a plurality of transport rollers 5 of the transport device 1 designed as a roller conveyor 6 and is positioned in a transport direction 7. By means of the illumination device 3, a light pattern 9 shown in Figure 3 is projected onto the disk. The light pattern 8 consisting of a plurality of light pattern features 10 shown in Figure 3 is projected along a direction perpendicular to the
[0050] The light is projected onto the pane 2 along a transverse axis 11 oriented in the direction of transport 7, which is shown in Figure 2. The light pattern 9 reflected by the pane is at least partially recorded by the camera 4. In this case, a strip-shaped recording area 12 aligned along the transverse axis is recorded by the camera 4, which is designed as a line scan camera. Geometric parameters of the light pattern features 10 recorded by the camera 4 and shown in Figure 3 are determined by an evaluation device 9.
[0051] Figure 3 shows a schematic representation of the light pattern 8 projected onto the pane 2. The light pattern 8 is formed from a plurality of triangular light pattern features 10 arranged next to one another. The light pattern features 10 are oriented such that the tips of adjacent triangular light pattern features 10 point in the transport direction 7 shown in Figure 2.
[0052] Figure 4 shows a schematic representation of a section of the light pattern 8 shown in Figure 3. Side edges of the dirty light pattern features 10 each form a polygonal section 15. Together, the polygonal sections 15 form the polygonal section 16 enclosing the entire triangular light pattern 10. The geometric parameter used is a distance between two intersection points 13 which are generated by an intersection line 14 through two sides of the light pattern feature 10. The intersection line 14 is determined by the strip-shaped recording area 12 of the camera 4. Figure 5 shows a schematic representation of individual images recorded and combined using the camera 4 shown in Figure 1. The surface deformation of the pane 2 can be determined by changing the width of the light pattern features 10 recorded with the camera 4 within the recording area 12.The distortion of the light pattern feature 10 caused in the transport direction 7 by the surface deformation of the pane 2 can be seen in the form of a cyclical and long-wave-like change in the width of the triangular light pattern feature 10.
[0053] Figure 6 shows a section of a light pattern 8. The light pattern features 10 of this light pattern 8 each consist of three trapezoidal light feature parts 17. With respect to the illustration below the light pattern 8, the light band 18 is projected onto the pane immediately adjacent to the light pattern 8.
[0054] In the illustrations of Figures 1 to 6, only individual elements of several similar types are identified by way of example with a reference symbol.
[0055] LIST OF REFERENCE SYMBOLS
[0056] 1. Transport device
[0057] 2nd disc
[0058] 3. Lighting device
[0059] 4. Camera
[0060] 5. Transport roller
[0061] 6. Roller conveyor
[0062] 7. Transport direction
[0063] 8. Light pattern
[0064] 9. Evaluation device
[0065] 10. Light pattern feature
[0066] 11. Transverse axis
[0067] 12. Recording area
[0068] 13. Intersection
[0069] 14. Intersection line
[0070] 15. Polygon section
[0071] 16. Polygon
[0072] 17. Light feature parts
[0073] 18. Light strip
Claims
P A T E N T A N S P R Ü C H E 1. A measuring method for determining the flatness of a transparent pane (2), wherein the pane (2) is displaced relative to a lighting device (3) and a camera (4) or the lighting device (3) and the camera (4) are displaced relative to the pane (2) in a transport direction (7) by means of a transport device (1), wherein a light pattern (8) consisting of several two-dimensional light pattern features (10) is projected onto the pane (2) by means of the lighting device (3), wherein the several light pattern features (10) are projected onto the pane (2) next to one another in a transverse axis (11) oriented perpendicular to the transport direction (7), wherein the light pattern (8) reflected by the pane (2) is at least partially captured by the camera (4), wherein a geometric parameter of the light pattern features (10) recorded by the camera (4) is determined,and by evaluating several images captured one after the other by the camera (4), a change in the geometric parameter of one or more light pattern features (10) caused by the reflections on the pane (2) is evaluated, characterized in that a circumferential line of the light pattern features (10) is formed in each case by a polygonal line (16) which has several rectilinear polygonal line sections (17), wherein mutually facing polygonal line sections (17) of adjacent light pattern features (10) are not aligned parallel to one another.
2. Measuring method according to claim 1, characterized in that light pattern features (10) projected directly next to one another onto the pane are designed and arranged in such a way that all feature distances determined perpendicular to the transport direction (7) between mutually facing outer contours of the light pattern features (10) projected directly next to one another differ from one another.
3. Measuring method according to claim 1 or claim 2, characterized in that the light pattern (8) is formed from triangular light pattern features (10).
4. Measuring method according to claim 1 or claim 2, characterized in that the light pattern features (10) are formed from a plurality of trapezoidal light pattern feature parts (17) arranged one behind the other in the transport direction (7) and adjacent to one another.
5. Measuring method according to one of the preceding claims, characterized in that the geometric parameter describes a distance between two intersection points (13) which are generated by an intersection of an intersection line (14) with two sides of the light pattern feature (10).
6. Measuring method according to one of the preceding claims, characterized in that the light pattern features (10) are designed to be filled.
7. Measuring method according to one of the preceding claims, characterized in that in the transport direction (7) before and / or a light band (18) is projected onto the pane behind the light pattern (8).
8. Measuring method according to claim 7, characterized in that the light band (18) is directly adjacent to the light pattern (8), so that the light pattern features (10) and the light band (18) merge into one another.
9. Measuring method according to one of the preceding claims, characterized in that dark areas between adjacently arranged light pattern features (10) of the light pattern (8) are also illuminated by the illumination device (3), wherein an illumination intensity of the dark area is lower than the illumination intensity of bright areas of the light pattern (8).
10. Measuring method according to claim 9, characterized in that the illumination intensity of the dark areas is a maximum of 10%, advantageously a maximum of 5% and particularly advantageously a maximum of 2% of the illumination intensity of the bright areas.
11. Measuring method according to claim 4 or claim 4 and one of claims 5 to 10, characterized in that illumination intensities of the light pattern feature parts (17) of a light pattern feature (10) differ from one another.
12. Measuring method according to one of the preceding claims, characterized in that in an image recorded with the camera (4) a strip-shaped recording area (12) of the pane (2) is detected, wherein the strip-shaped receiving area (12) parallel to the transverse axis (11) and the disc (2) along the transverse axis (11) is completely captured.
13. Measuring method according to claim 3 or claim 3 and one of claims 5 to 12, characterized in that the triangular light pattern features (10) are oriented such that tips of the light pattern features (10) point in or against the transport direction.
14. Measuring method according to claim 3 or claim 3 and one of claims 5 to 12, characterized in that the light pattern features (10) are oriented such that the tips of adjacent triangular light pattern features (10) point alternately in or against the transport direction (7).
15. Measuring method according to one of the preceding claims, characterized in that adjacent light pattern features (10) are projected onto the pane (2) with mutually different light intensities.
16. Measuring method according to one of the preceding claims, characterized in that differently designed light patterns (8) are projected one after the other onto the pane (2) and recorded by the camera (4), wherein the light pattern features (10) of each light pattern (8) projected onto the pane directly next to one another are designed and arranged such that all feature distances determined perpendicular to the transport direction (7) between mutually facing outer contours of the light pattern features (10) projected directly next to one another differ from one another.
17. Measuring method according to one of the preceding claims, characterized in that in the evaluation of the images captured by the camera (4), an orientation of a recording area of the camera (4) with respect to the projected light pattern (8) determined in a calibration step preceding the capture of the images is taken into account.
18. Measuring device for carrying out the measuring method according to claims 1 to 17, wherein the measuring device has a transport device (1) for displacing the pane (2) relative to the illumination device (3) and the camera (4) or for displacing the illumination device (3) and the camera (4) relative to the pane (2) in the transport direction (7), wherein the light pattern (8) consisting of a plurality of two-dimensional light pattern features (10) can be projected onto the pane (2) by the illumination device (3), wherein the camera (4) is aligned such that the light pattern (8) reflected by the pane (2) can be at least partially captured by the camera (4), wherein a geometric parameter of the light pattern features (10) recorded by the camera (4) can be determined by the evaluation device (9), wherein the camera (4) is designed as a line scan camera.
19. Measuring device according to claim 18, characterized in that the transport device (1) is designed as a roller conveyor or as a belt conveyor, with which the disc (2) is moved relative to the lighting device (3) and the camera (4) in the transport direction (7).
20. Measuring device according to claim 18 or 19, characterized in that the camera (4) is arranged on a side of the disc (2) facing away from the roller conveyor or the belt conveyor.
21. Measuring device according to one of claims 18 to 20, characterized in that the illumination device (3) has a projection lamp and a light pattern element arranged in front of the projection lamp in a projection region of the projection lamp, wherein the light pattern element has a plurality of translucent regions, wherein the light pattern (8) is formed by the translucent regions.