Apparatus for optically examining an object and use of the apparatus in a corresponding method

Abstract

The invention relates to an apparatus for optically examining an object (2) moved in a movement direction (3) and to the use of the apparatus in a corresponding method. The apparatus comprises an illuminating device (4) for illuminating an examination region on the object (2) and a camera device (5) for capturing the illuminating device (4) in a reflection arrangement or transmission arrangement. The illuminating device (4) comprises a light source (8) which emits light of a predefined spectrum. The camera device (5) captures the light emitted by the light source (8). The illuminating device (4) comprises a filter assembly (9) which comprises a first filter region (F1) and a second filter region (F2), the first and second filter regions (F1, F2) being disposed next to one another along an edge (10) and the edge being able to be visibly arranged in the capturing region (7) of the camera device (5) on the object (2), and the first filter region (F1) transmitting only light of a first wavelength range (W1) of the spectrum and the second filter region (F2) transmitting light of a second wavelength range (W2) of the spectrum and light of the first wavelength range (W1) of the spectrum.

Description

[0001] Device for optical examination of an object and use of the device in a corresponding method

[0002] The invention relates to a device for the optical examination of an object and to the use of the device in a method for the optical examination of an object.

[0003] The device proposed according to the invention has, for the optical examination of an object moved in a direction of movement, an illumination device for illuminating an examination area on the object and a camera device for recording the illumination device in a reflection arrangement or transmission arrangement relative to the object, wherein a recording area of ​​the camera device is focused on the object.

[0004] In a reflection arrangement, the camera device and the illumination device are arranged on the same side of the object such that the illumination device illuminates the (more or less reflective) surface of the object (e.g., metal), and light reflected from the surface is recorded in the camera device. Defects on the surface lead to a change in the angle of reflection and thus the light beam path, so that different areas of the illumination device are imaged in the camera device than in a defect-free object.

[0005] In a transmission arrangement, the camera device and the illumination device are arranged on different sides of the transparent object (e.g., glass or float glass) such that the illumination device is captured by the camera device through the object. Defects in or on the transparent object lead to a change in the angle of refraction and / or a local absorption of the light and thus a change in the light beam path, so that here, too, different areas of the illumination device are imaged in the camera device than in a defect-free object.

[0006] Devices and methods are known for such a structure in which the lighting device has a filter on one side that selectively filters out one color of the light.

[0007] Illumination with this color creates a transition field (also called a "directed bright field" or "knife-edge field"), where the area around the filter of the illuminator is dark and the rest of the illuminator is bright. The camera is positioned so that, for a flawless object, its image capture field sees half the bright part of the illuminator and half the dark part. This produces an image of medium intensity.

[0008] The change in the light beam path causes the defect to move, causing the light beam to fall into the dark area of ​​the illumination device on one side of the defect and a bright area of ​​the illumination device on the other side (or vice versa). This results in a characteristic light-dark contrast in an image composed of the object's movement (scan) in an otherwise medium-intensity image, revealing the defect.

[0009] When illuminated with light of one color that is not filtered out by the filter, a so-called bright field of uniform brightness is created, in which the characteristic light-dark contrast does not occur and only a topological image of the defect appears, with which, for example, the size of the defect can be estimated.

[0010] This measurement principle described above is known, for example, from EP 2 253 948 B1, which proposes an illumination device that is alternately operated with light of a first wavelength, which is blocked by the filter and creates a transition field, and with light of a second wavelength, which is not blocked by the filter and creates a bright field. A time-division multiplexing method is therefore used, in which differently colored LEDs are switched on alternately. This allows the full camera frame rate to be utilized for temporal resolution. The achievable measurement rate is limited by the switching time of the differently colored LEDs and is therefore unsuitable, particularly for fast-moving production lines. Furthermore, two different light sources are required.

[0011] DE 198 13 072 A1 describes a similar device and a corresponding method, in which an illumination device has two filters, each filter selectively transmitting a different color, e.g., red and green. Each of the two colors is assigned its own voltage signal to the camera device. The illumination device contains a light source that emits both colors. If there is a defect in the object, the light beam path shifts, with the result that the voltage signal of one color becomes larger and the voltage signal of the other color becomes smaller. According to this solution, two different transition fields are created, one on each half of the illumination device. To create a bright field, e.g., to determine the defect size, it is proposed to add the two color-specific voltage signals.The problem here, however, is that a true bright field only arises when the transmission through the two different color filters is the same, i.e. the measured intensity is the same for both filters. This is hardly achievable in practice and leads to systematic errors in the analysis. A particular disadvantage is that the bright field and the transition field are not independent of one another and changes or errors affecting the transition field have a direct impact on the calculation of the bright field. By summing the two transition fields, overflows can occur in the individual color channels, which typically cover a value range from 0 to 255, and influence the results. The same applies to the difference calculation described in DE 198 13 072 A1, which is used as a measure of the deviation of the viewing spot of the camera device.

[0012] The object of the invention is therefore to enable an improvement in the examination of an object moving in a direction of movement, which enables a robust and reliable detection of defects, in which the bright field and the transition field are preferably determined by independent measurement variables.

[0013] This object is achieved by a device having the features of claim 1.

[0014] According to the invention, the illumination device comprises a light source that emits light of a predetermined spectrum, in particular visible white and / or infrared light, and the camera device records (i.e., detects) the light emitted by the light source in the predetermined spectrum. The illumination device comprises a filter arrangement that is arranged in front of the light source and has a first filter region and a second filter region, wherein the first and second filter regions are arranged next to one another along an edge, and the edge is oriented transversely to the direction of movement of the object in such a way that the edge can be visibly arranged on the object in the recording area of ​​the camera device or - in the case of a defect-free object - is actually arranged.

[0015] The first filter region (also referred to as the “first color filter”) transmits only light of a first wavelength range of the spectrum, and the second filter region (also referred to as the “second color filter”) transmits light of both a second wavelength range of the spectrum and light of the first wavelength range of the spectrum, wherein the first wavelength range and the second wavelength range are different and, in particular, do not overlap.

[0016] In a first recording channel of the camera device, which is sensitive to the first wavelength range, light is received from both the first filter range and the second filter range. The first recording channel therefore forms a bright field. In the second recording channel of the camera device, which is sensitive only to the second wavelength range, in contrast, only light from the second filter range is received and the first filter range appears dark. The second recording channel therefore forms a transition field. An advantage of this arrangement according to the invention is that the illumination device has only one light source with a predetermined spectrum that covers both the first and the second spectral range and can therefore be switched on permanently, unlike described in the prior art EP 2 253 948 B1.This allows the full camera frame rate to be utilized for the measurement, as switching between different light sources to generate a transition field and a bright field in different recording channels is not necessary. By providing a bicolor filter arrangement with a first filter or filter range that transmits only the first wavelength range from the light source's spectrum, and a second filter or filter range,In a filter region that transmits both the first wavelength range from the spectrum of the light source and a different second wavelength range from the spectrum of the light source, the intensity of the bright field is generated directly from measurement data of the first recording channel (sensitive only to the first and not the second wavelength range), without the individual intensities of the first wavelength range and the second wavelength range being added together to create a bright field that, however, depends on both recording channels. In the solution according to the invention, the intensities of the bright field and the transition field are therefore based on independent measured variables. This enables robust and reliable defect detection with a high scanning speed that is limited by the maximum image recording rate of the camera device and not by the slower switching rate of different light sources.

[0017] In principle, the recording channels of the camera device can be implemented by suitable wave-selective filters in front of the sensor elements of the camera device. The camera device preferably has color channels (particularly as standard), wherein a first color channel of at least two color channels selectively detects light from the first filter range and a second color channel of the at least two color channels selectively detects light from the second filter range. Conventional cameras in the visible light range have three color channels: red, green, and blue. Cameras with a supplementary infrared measuring range have an additional infrared color channel. The first and second wavelength ranges (or filter ranges) can therefore, in a particularly preferred embodiment, each correspond to a different one of the colors red, green, blue, or infrared, so that conventional camera technology can be used.

[0018] A preferred embodiment of the invention provides that the filter arrangement is adjustable along the direction of movement of the object. As a result, the course of the edge in the recording area of ​​the camera device can be adjusted so that the course of the edge lies in or outside the center of the recording area (particularly in the case of a defect-free object). In order to have a sufficiently large adjustment range, it can further preferably be provided that the filter arrangement is adjustable to such an extent that in the recording area of ​​the camera device only light from the first filter area or from the second filter area is visible when the light is reflected on a defect-free object or transmitted through a defect-free object, i.e. in the case of a defect-free object.

[0019] In a further development of this embodiment, it can be provided that in order to adjust the sensitivity of the camera device for the second wavelength range, which is only transmitted through the second filter area or not through the first filter area, the filter arrangement (in the case of a flawless object) is adjusted from a position of maximum sensitivity, in which the edge is arranged in the middle of the recording area of ​​the camera device, to a position in which the edge is arranged outside the middle of the recording area of ​​the camera device.

[0020] If the edge is arranged in the middle of the recording area, the proportion and thus the intensity of the change in light of the second wavelength range is greatest when the light beam path is deflected by a defect in the object, and the sensitivity to changes is therefore maximum (particularly in relation to a maximum intensity that can be recorded by the camera device for this wavelength range). If, on the other hand, the proportion of light in this wavelength range is larger or smaller, the changes in intensity for small defects (with smaller deviations in the light beam path) are smaller, and the sensitivity is therefore reduced. Changes in the ratio between light in the first wavelength range and light in the second wavelength range due to smaller deviations in the light beam path then result in smaller intensity changes in light in the second wavelength range (as an absolute value).Major changes in intensity only occur when the first or second filter area is no longer imaged in the recording area of ​​the camera device.

[0021] For this purpose, the filter arrangement can preferably be arranged such that (of the available first and second filter areas) the filter area that transmits a higher overall light intensity has the larger surface area in the recording area of ​​the camera device. This ensures that no light intensity is lost in the device.

[0022] Furthermore, according to the invention, the filter arrangement can be rotated about a transverse axis that is perpendicular to a filter plane and the edge direction. Thus, the edge can be aligned along a longitudinal direction of the camera device (e.g., a line-scan camera) so that the proportions of the first and second filter areas remain constant in the recording area of ​​the camera device transverse to the direction of movement of the object across the examination area, e.g., the entire width of the object transverse to its direction of movement.

[0023] It is particularly advantageous for error detection if the light intensity of the light of the first wavelength range transmitted through the first filter range and through the second filter range is comparable, i.e. preferably differs by less than 20%, particularly preferably by less than 10%, relative to the higher intensity value. This achieves uniform illumination of the bright field. For calibration of the camera device, the amplification factor of the camera device can be adjusted according to the invention such that for the filter range with the highest transmission (from a selection of the first or the second filter range) in the first wavelength range, a maximum value in the recording channel of the camera device for the first wavelength range is not exceeded when the object is illuminated to the maximum by the illumination device.A maximum value can result from an analog-to-digital conversion of the voltage values ​​measured by the sensor elements of the camera device. For example, a recording channel can cover the value range 0 to 255.

[0024] For further calibration of the camera device, a default value can be set in the camera device's recording channel (as the target intensity) for the second wavelength range. This is usually not the maximum value, but rather, for example, a value from the middle of the value range available for the recording channel, in order to be able to quantitatively determine both a larger and a smaller portion of the second filter range in the recording range in the event of errors. This further calibration can be carried out, as described, for example, by shifting the edge in the camera device's recording range and / or - if the adjustment option is available - by selectively adjusting the camera device's recording channel.

[0025] In order to be able to scan an object transversely to its direction of movement in one measurement and to examine it for defects, the invention can provide that the camera device has a line-like recording area whose extent in the longitudinal direction of the lines is at least an order of magnitude (i.e. approximately a factor of 10) greater than its extent in the transverse direction (perpendicular to the longitudinal direction). Preferably, the longitudinal direction can be larger than the transverse direction by a factor of more than 20, particularly preferably by a factor of more than 50 to 100. If necessary, the camera device can also be composed of several camera modules which are arranged directly adjacent to one another, in particular in the longitudinal direction. Preferably, the recording area of ​​the camera device covers the entire examination area on the object transversely to the direction of movement of the camera device.

[0026] To achieve a uniform surface distribution of the first and second filter areas in the recording area of ​​the camera device across the entire longitudinal direction of the camera device, the camera device can be arranged such that the longitudinal direction of the recording area of ​​the camera device coincides with the direction of the edge in the recording area of ​​the camera device, i.e., it is particularly parallel or congruent with it. This setting can be finely adjusted by rotating the filter arrangement about its transverse axis, as described above.

[0027] The invention also relates to a preferred use of the above-described device in a method for optically examining an object moving in a direction of movement, in which (in particular by scanning the surface of the object) a bright-field image for the topological representation of defects of the object and a transition-field image for the contrast representation of defects of the object are generated in one measurement.

[0028] Further advantages, features, and possible applications of the invention will become apparent from the following description of exemplary embodiments and the drawings. All described and / or illustrated features, together or in any combination deemed reasonable by a person skilled in the art, are part of the subject matter of the invention, regardless of their combination in the described or illustrated exemplary embodiments or in the claims.

[0029] They show:

[0030] Fig. 1 shows schematically an embodiment of the device according to the invention for examining a moving object for defects in a reflection arrangement in a sectional view from the side;

[0031] Fig. 2 schematically shows the lighting device according to Fig. 1 with the filter arrangement in a three-dimensional side view;

[0032] Fig. 3 shows wavelength spectra recorded by the camera device according to Fig. 1 for three recording channels or color channels of the camera device;

[0033] Fig. 4 shows schematically the course of the light beam path in the device when used to examine a beam path for defects;

[0034] Fig. 5a, b show images of a transition field and a bright field produced when used according to Fig. 4;

[0035] Fig. 6a, b schematically show the effect of a shift of the edge of the filter arrangement between the first and the second filter area.

[0036] The embodiment of the invention shown schematically in Fig. 1 shows a device 1 for optically examining an object 2 moved in a direction of movement 3, with an illumination device 4 for illuminating an examination area on the object 2 and with a camera device 5 for recording the illumination device 4 in a

[0037] REVISED SHEET (RULE 91) ISA / EP Reflection arrangement relative to the object. In a transmission arrangement also according to the invention, the illumination device 4 and the camera device 5 are arranged on different sides relative to the object 2, and the light beam path 6 of the light passes through (a then transparent) object 2. The recording area 7 of the camera device 5 is focused on the object 2.

[0038] The illumination device 4 has a light source 8 that emits light of a predetermined spectrum, in particular visible white and / or infrared light. The camera device 5 records the light emitted by the light source 8; in the exemplary embodiment shown here, it detects the light reflected from the surface of the object in the recording area 7.

[0039] The illumination device 4 further comprises a filter arrangement 9, which is arranged in front of the light source 8 and between the light source 8 and the object 2. The filter arrangement has a first filter region F1 and a second filter region F2, wherein the first and second filter regions F1, F2 are arranged adjacent to one another along an edge 10. For the sake of simplicity, the filter regions F1, F2 are referred to below as filters F1, F2.

[0040] The edge 10 is aligned transversely to the direction of movement 3 of the object 2 such that the edge 10 can be visibly arranged or runs on the object 2 in the recording area 7 of the camera device 5.

[0041] As can be seen from Fig. 2, the filter arrangement 9 is adjustable along the direction of movement 3 of the object 2. This means that a projection of the adjustment direction 11 onto the surface of the object 2 runs parallel to the direction of movement 3 of the object 2, and the image of the edge 10 on the object 2 is displaceable in the direction of movement 3 of the object. Furthermore, the filter arrangement is rotatable about a transverse axis 12, which is perpendicular to a filter plane and the edge direction, as indicated in Fig. 2 by a rotation arrow.

[0042] The first filter region F1 transmits only light from a first wavelength range W1 of the spectrum. The second filter region F2 transmits light from a second wavelength range W2 of the spectrum and light from the first wavelength range W1 of the spectrum. In the illustrated embodiment, the first wavelength range W1 lies in the blue spectral range, and the second wavelength range W2 lies in the red wavelength range. In a third wavelength range W3 in the green wavelength range, no light is emitted due to the filter arrangement 9.

[0043] This is evident from Fig. 3, which shows the wavelength spectra of the first, second and third wavelength ranges W1, W2, W3 recorded by the camera device 5 for three recording channels A1, A2, A3 or color channels B (blue), R (red), G (green) of the camera device 5. For a conventional RGB camera device in the visible light spectrum, the recording channels A1, A2, A3 of the camera device 5 correspond to the color channels B, R, G, which are typically represented by three sensor elements of an image pixel.

[0044] The first color filter F1 is designed such that the transmission is limited to the wavelength range W1 of one recording channel A1 or color channel B of the camera device 5 used. In contrast, the second color filter F2 is permeable to the wavelength ranges W1 and W2 detected in the two recording channels A1 and A2 or the two color channels F1 and F2 of the camera device 5.

[0045] The recording channel A1 or color channel B thus detects light from the wavelength range W1 (blue), which transmits through both the filter area F1 and the filter area F2 of the filter arrangement 9. The bright field described above is thus realized by the recording channel A1 / color channel B.

[0046] The recording channel A2 or color channel R, on the other hand, only detects light from the wavelength range W2 (red), which only transmits through the filter area F2 of the filter arrangement 9. The filter area F1 of the filter arrangement 9 appears as a dark field in the recording channel A2. The transition field described above is thus realized by the recording channel A2 / color channel R.

[0047] With reference to Fig. 4 and Fig. 5, the method for optically examining an object 2 moving in a direction of movement 3, which can be carried out according to the invention with the proposed device, is described below.

[0048] The following description assumes that the camera device 5 and the illumination device 4 are aligned with each other such that, if the object is flawless, the light passing through the two filter areas F1, F2 is reflected onto the camera device and detected there. The edge 10 between the filter areas F1 and F2 is located in the center of the recording area 7 (Fig. 4, left).

[0049] If the light from the illumination device 4 strikes a topological defect 13, such as a dent in the metal, it is reflected in the direction of travel of the object in one direction on one side of the defect 13 (Fig. 4, center) and in the opposite direction on the other side of the defect 13 (Fig. 4, right). As a result, the light passes through the filter area F2 on one side of the defect 13, deflected (Fig. 4, center) and through the filter area F1 on the other side of the defect 13 (Fig. 4, right). If one now only considers recording channel A1 (color channel B, here: blue) of the camera device 5, it can be seen that the first wavelength range relevant for this recording channel A1 / color channel B passes through both filters F1, F2 with approximately the same intensity. In this recording channel A1 / color channel B, a bright field is created in which topological material defects do not lead to a contrast in the image.An image generated by scanning the object in this recording channel is shown in Fig. 5b, where the dark spots represent defect 13.

[0050] Due to the nature of the filters F1 and F2, the recording channel A2 (color channel R, here: red) reacts differently to a topological error 13 than the recording channel A1 / color channel B.

[0051] If light passing through filter F1 hits camera device 5 on one side of the defect (Fig. 4, right), the spectrum relevant to recording channel A2 (color channel R) is almost completely absorbed. As a result, this side of defect 13 appears dark in the camera image (Fig. 5a, dark area 14). On the other side of the defect, the light is reflected in the other direction and thus passes through filter F2 (Fig. 4, center). This filter transmits the wavelength range W2 of recording channel A2 / color channel R almost completely and therefore appears bright in the image (Fig. 5a, bright area 15).

[0052] In the method described here, with the device 1 according to the invention, with only one non-switched illumination device 3 with a light source 8 and with a camera device 5, two different illumination fields, namely a bright field and a transition field, can be realized by detecting real measurement data, which leads to robust defect detection. For cameras with more recording or color channels A3 or G, there is also the option of integrating a further, third field by means of additional illumination in a third wavelength range W3 (here: green), for example, to display a side or grazing light for locating scratches on the surface of the object.

[0053] As already explained, the device according to the invention also offers the possibility of easily adjusting the intensity of the transition field. For example, if strong vibrations occur in the system or the object to be examined is highly reflective, a sensitive transition field can lead to excessive deflections in the recording channel A2. The sensitivity of the transition field can be adjusted by adjusting the filter arrangement 9 along the direction of travel of the object 2. This is described in more detail below with reference to Figs. 6a and 6b.

[0054] In Fig. 6a, the displacement of the filter arrangement 9 is adjusted such that the edge 10 between the first filter area F1 and the second filter area F2 lies in the center of the recording area 7 of the camera device 5. This corresponds to maximum sensitivity in the transition field.

[0055] If the edge between the filter areas F1, F2 is shifted so that filter area F2 predominates, less variation can be seen in the recording channel A2 or the color channel R when the light beam path 6 is deflected, since the light beam path 6 only hits the filter area F1 in the event of extreme deflections. With less severe errors or vibrations, the light beam remains on the filter area F2, and no differences in brightness are apparent in the image. One advantage is that the bright field is not affected by the edge shift, since both filter areas F1, F2 have almost identical transmission properties for the wavelength ranges W1 of recording channel A1 or color channel B.During adjustment, the filter arrangement 9 is always shifted from the center position of edge 10 in the recording area 7 so that the filter area F2, which has a higher overall light transmission, covers a larger area of ​​the illumination device 4. This ensures that the system as a whole does not lose any light intensity. Depending on the desired intensity of the transition field, target values ​​for the light intensity in recording channel A2 / color channel R are defined using a calibration standard.

[0056] List of reference symbols:

[0057] 1 device

[0058] 2 Item

[0059] 3 Direction of movement of the object

[0060] 4 Lighting device

[0061] 5 Camera setup

[0062] 6 Light beam path

[0063] 7 Recording area

[0064] 8 Light source

[0065] 9 Filter arrangement

[0066] 10 edge

[0067] 11 Adjustment direction

[0068] 12 Transverse axis

[0069] 13 errors

[0070] 14 Dark area

[0071] 15 Bright area

[0072] F1 first filter area or filter

[0073] W1 first wavelength range

[0074] F2 second filter range or filter \N2 second wavelength range

[0075] W3 third wavelength range

[0076] A1 , A2, A3 Recording channel of the camera device B, R, G Color channel of the camera device

Claims

Claims:

1. Device for the optical examination of an object (2) moved in a direction of movement (3), comprising an illumination device (4) for illuminating an examination area on the object (2) and a camera device (5) for recording the illumination device (4) in a reflection arrangement or transmission arrangement relative to the object (2), wherein a recording area (7) of the camera device (5) is focused on the object (2); wherein the illumination device (4) has a light source (8) which emits light of a predetermined spectrum, in particular visible white and / or infrared light, and the camera device (5) records the light emitted by the light source (8);wherein the illumination device (4) has a filter arrangement (9) which is arranged in front of the light source (8) and has a first filter region (F1) and a second filter region (F2), wherein the first and second filter regions (F1, F2) are arranged next to one another along an edge (10) and the edge (10) is oriented transversely to the direction of movement (3) of the object (2) in such a way that the edge (10) can be visibly arranged on the object (2) in the recording area (7) of the camera device (5); wherein the first filter region (F1) only transmits light of a first wavelength range (W1) of the spectrum; characterized in that; the second filter region (F2) transmits light of a second wavelength range (W2) of the spectrum and light of the first wavelength range (W1) of the spectrum.

2. Device according to claim 1, characterized in that the camera device (5) has at least two color channels (B, R, G), wherein the first color channel (B) selectively detects light of the first filter area (F1) and the second color channel (R) selectively detects light of the second filter area (F2).

3. Device according to claim 1 or 2, characterized in that the filter arrangement (9) is adjustable along the direction of movement (3) of the object (2).

4. Device according to claim 3, characterized in that the filter arrangement (9) is adjustable so that in the recording area (7) of the camera device (5) only light from the first filter area (F1) or from the second filter area (F2) is visible.

5. Device according to claim 4, characterized in that in order to adjust the sensitivity of the camera device (5) for the second wavelength range (W2), which is only transmitted through the second filter area (F2), the filter arrangement (9) is adjusted from a position of maximum sensitivity, in which the edge (10) is arranged in the middle of the recording area (7) of the camera device (5), to a position in which the edge (10) is arranged outside the middle of the recording area (7) of the camera device (5).

6. Device according to claim 5, characterized in that the filter arrangement (9) is arranged such that the filter area (F2) which transmits an overall higher light intensity has the larger area proportion in the recording area (7) of the camera device (5).

7. Device according to one of the preceding claims, characterized in that the filter arrangement (9) is rotatable about a transverse axis (12) which is perpendicular to a filter plane and the edge direction.

8. Device according to one of the preceding claims, characterized in that the light intensity of the light of the first wavelength range (W1) transmitted through the first filter region (F1) and through the second filter region (F2) is comparable.

9. Device according to one of the preceding claims, characterized in that the amplification factor of the camera device (5) is adapted such that for the filter area (F1, F2) with the highest transmission in the first wavelength range (W1) with maximum illumination of the object (2) by the illumination device (4) a maximum value in the recording channel (A1) of the camera device (5) for the first wavelength range (W1) is not exceeded.

10. Device according to claim 9, characterized in that a default value is set in the recording channel (A2) of the camera device (5) for the second wavelength range (W2).

11. Device according to one of the preceding claims, characterized in that the camera device (5) has a line-like recording area (7) whose extension in the longitudinal direction of the lines is at least one order of magnitude greater than its extension in the transverse direction.

12. Device according to claim 11, characterized in that the camera device (5) is arranged such that the longitudinal direction of the Recording area (7) of the camera device (5) coincides with the direction of the edge (10) in the recording area (7) of the camera device (5).

13. Use of the device (1) according to one of claims 1 to 12 in a method for the optical examination of a moving object (3) moving object (2), in which a bright-field image for the topological representation of defects (13) of the object (2) and a transition-field image for the contrast representation of defects (13) of the object (2) are generated in one measurement.

Images