DETERMINATION METHOD FOR DETERMINATION OF THE ROLLING OR GUIDING GAPS OF THE ROLL STANDS OR GUIDE STANDS IN A MULTI-STAND ROLLING MILL

Abstract

In order to be able to determine the rolling or guiding gaps of the roll stands or guide stands in a multi-stand rolling mill, at a predetermined measurement precision, with the least possible effort, a master calibration and intermediate calibrations are carried out, wherein various calibration measures are refrained from, in a targeted manner. The targeted lack of recourse in the case of specific calibrations is also independently advantageous.

Claims

1. A determination method for determination of the rolling or guiding gaps of the roll stands (10) or guide stands (20) in a multi-stand rolling mill (1), having a pass line (30) that reaches through the roll stands (10) or guide stands (20) and serves as a reference for a gap offset, wherein first a camera (40) is arranged at one of the input (11) or output sides (12), and a background illumination (50) is arranged, correspondingly, on the other one of the input (11) or output sides (12), and subsequently the rolling or guiding gap of the stands (10, 20) is determined making use of an information technology device (60), wherein in a first step, the camera (40) and the information technology device (60) are calibrated offline and/or inline, with reference to the rolling mill (1), and wherein in a second step, the camera (40) determines the rolling or guiding gaps inline, making use of the information technology device (60), wherein (i) in the second step, exclusively the gap form is determined as a rolling or guiding gap is determined in the second step; and/or (ii) in the second step, exclusively the gap offset relative to a pass line (30) that reaches through at least two rolling machines (2) of a rolling mill (1) comprising at least two rolling machines (2) is determined as a rolling or guiding gap; and/or (iii) in the information technology device (60), the roll stands (10) or guide stands (20) are referred to successively as a function along the pass line (30), and the information technology device (60) comprises a measurement direction input possibility (61), by way of which the placement of the camera (40) on the input side (11) and of the background illumination (50) on the output side (12) or vice versa and thereby the measurement direction can be input, so that possible measurement results can be assigned to each of the stands (10, 20), independent of the measurement direction, by the information technology device (60); and/or (iv) in the first step, a first and a second reference sensor (43, 44; 71, 81) are arranged in the pass line (30), subsequently the position of the camera (40) and/or of a target (53) are changed in such a manner that the two reference sensors (43, 44; 71, 81) and, if applicable, also the target (53) are separately detected by the camera (40).

2. The determination method according to claim 1, wherein at least one of the two, preferably both reference sensors (43, 44; 71, 81) is/are one of the rolls (14), one of the guides (21), one of the roll stands (10) or guide stands (20), a reference stand (49) and/or a calibration ring (33, 34).

3. The determination method according to claim 2, wherein the first calibration ring (33) can serve as a first master reference (70) and the second calibration ring (34) can serve as a second master reference (80).

4. The determination method according to claim 2, wherein the first calibration ring (33) comprises at least two reference arms (75) and the second calibration ring (34) comprises at least two reference arms (85).

5. The determination method according to claim 1, wherein in the information technology device (60), the roll stands (10) or guide stands (20) are designated successively as a function of the rolling direction and/or wherein the measurement image is mirrored.

6. The determination method according to claim 1, wherein the calibration of the camera (40) and of the information technology device (60) takes place in the first step, by means of at least one reference (43) close to the camera and at least one reference (44) away from the camera, which are each arranged not between the rolls (14) or guides (21) of the first of the stands (10, 20) and the rolls (14) or guides (21) of the last of the stands (10, 20).

7. The determination method according to claim 1, wherein in a first step, the camera (40) and the information technology device (60) are calibrated offline and/or inline, with reference to the rolling mill (1), by means of at least one reference sensor (43) close to the camera and at least one reference sensor (44) away from the camera, which are each arranged not between the rolls (14) or guides (21) of the first of the stands (10, 20) and the rolls (14) or guides (21) of the last of the stands (10, 20), wherein in a second step, the camera (40) determines the rolling or guiding gaps inline, making use of the information technology device (60), wherein (i) before the calibration that corresponds to the first step, first the camera (40) is arranged on a reference holder (42) in a previously defined referenceposition (41), and the reference sensor (43) close to the camera and the reference sensor (44) away from the camera are arranged in previously defined reference positions (45), and then, for the calibration corresponding to the first step, the reference sensor close to the camera and the reference sensor away from the camera (43, 44) are measured by means of the camera (40) and the information technology device (60), and subsequently, the pass line (30) or the offset from the pass line (30) and/or a pixel factor are determined from the measurement result; and/or (ii) the reference sensor (43) close to the camera and the reference sensor (44) away from the camera are coordinated with one another and with reference to the camera (40), in such a manner that both of them can be detected simultaneously by means of the camera (40); (iii) before the calibration that corresponds to the first step, the camera (40) is arranged on a reference holder (42), in a previously defined reference position (41), and subsequently a lens (48) of the camera (40) is displaced, in terms of its focus, until the reference (43) close to the camera and the reference (44) away from the camera are imaged with an almost identical lack of focus.

8. The determination method according to claim 7, wherein the reference sensor (43) close to the camera and/or the reference sensor (44) away from the camera is/are one of the rolls (14), one of the guides (21), one of the roll stands (10) or guide stands (20), a reference stand (49) and/or some other reference sensor (71, 81).

9. The determination method according to claim 8, wherein the reference sensor (71, 81) or the reference stand (49) are brought into a reference position (45).

10. The determination method according to claim 8, wherein the rolls (14) or guides (21) of the first and of the last of the stands (10, 20) are brought into a reference position (41) and these or correspondingly moved modules of these stands are used as a reference (43) close to the camera or a reference (44) away from the camera (43, 44).

11. The determination method according to claim 7, wherein the lens (48) has a fixed focal width and/or that different lenses (48), in particular having different fixed focal widths, are used for different gap sets.

12. The determination method according to claim 7, wherein before the calibration that corresponds to the first step, a target (53), preferably together with the background illumination (50), is arranged on a reference holder (42) in a previously defined reference position (41) and/or wherein a target or the target (53) is coordinated, in terms of its size, with the reference (43) close to the camera and the reference (44) away from the camera, in such a manner that it, together with the references (43, 44), can be detected by the camera, at the same time, wherein the target (53), the reference (43) close to the camera and/or the reference (44) away from the camera is/are preferably configured in ring shape, in particular to be circular.

13. The determination method according to claim 1, wherein the roll or guide gaps are determined immediately after a rolling process, in particular between individual rolling processes.

14. The determination method according to claim 1, wherein the roll or guide gaps are measured in the warm state of the roll stand (10) or of the guide stand (20).

15. The determination method according to claim 1, wherein for the calibration in the first step, first a master calibration is carried out, then the camera (40) and the background illumination (50) are removed, and afterward a rolling process is carried out, and afterward the camera (40) and the background illumination (50) are arranged on one of the input (11) or output sides (12) again, for an intermediate calibration, and calibrated in the first step, before, in the second step, the camera (40), making use of the information technology device (60), determines the rolling or guiding gaps inline once again.

16. The determination method according to claim 1, wherein in a first step, the camera (40) and the information technology device (60) are calibrated offline and/or inline, with reference to the rolling mill (1), and wherein in a second step, the camera (40), making use of the information technology device (60), determines the rolling or guiding gaps inline, wherein for the calibration in the first step, first a master calibration is carried out, then the camera (40) and the background illumination (50) are removed, and afterward a rolling process is carried out, and afterward the camera (40) and the background illumination (50) are arranged on one of the input (11) or output sides (12) again, for an intermediate calibration, and calibrated in the first step, before, in the second step, the camera (40), making use of the information technology device (60), determines the rolling or guiding gaps inline once again, (i) wherein for the master calibration, master references (70, 80) are installed on the pass line (30), and the camera (40), on the one hand, as well as the background illumination (50) and a target (53), on the other hand, are oriented with reference to the pass line (30) defined by means of the master references (70, 80) and/or the position of the pass line (30) is measured accordingly, with reference to the camera (40) and/or the target (53), and stored in memory in the information technology device (60), while for the intermediate calibration, no recourse is taken to the use of the master references (70, 80); and/or (ii) wherein for the master calibration, at least three reference scales (46) are recorded offline, at reference heights previously defined with reference to the pass line (30), or inline in the case of at least one stand (10, 20) removed from the rolling mill (1), and a pixel factor determined from the reference scales (46) is stored in memory in the information technology device (60); and/or (iii) wherein for the master calibration, reference positions (41) for the camera (40) and a target (53) are established with reference to the pass line (30), the position of the pass line (30) with reference to the camera (40) and the target (53) is stored in memory in the information technology device (60), and at least one reference scale (46), in each instance, of two references (43, 44) to be used for intermediate calibrations is measured, and a pixel factor determined from the reference scales is stored in memory in the information technology device (60); and/or (iv) wherein the intermediate calibration is used as a calibration in the first step of the determination method.

17. The determination method according to claim 16, wherein for the master calibration, reference positions (41) for the camera (40) and the target (53) together with the background illumination (50), with reference to the pass line (30), are established, the position of the pass line (30) with reference to the camera (40) and the target (53) together with the background illumination (50) is stored in memory in the information technology device (60), and at least one reference scale (46), in each instance, of two reference sensors (43, 44; 71, 81) to be used for the intermediate calibrations, and a pixel factor determined from the reference scale, are stored in memory in the information technology device (60).

18. The determination method according to claim 16, wherein for measuring the reference scales (46) one scale, in each instance, is set at a reference height (47) previously defined with reference to the pass line (30), and measured by the camera (40), making use of an information technology device (60), wherein the measurement result is stored in memory in the information technology device (60) as a pixel factor.

19. The determination method according to claim 16, wherein merely two reference sensors (71, 81) are used for the intermediate calibration.

20. The determination method according to claim 16, wherein for the master calibration, for recording at least one of the three reference scales (46), more than two, preferably all of the stands (10, 20) are removed.

21. The determination method according to claim 16, wherein for establishing the reference positions (41) of the camera (40) and of the target (53) with reference to the pass line (30), master references (70, 80) are installed in related reference positions (72, 82), for example on the first and the last roll or guide stand (10, 20), which references can be detected by the camera (40) and the information technology device (60).

22. The determination method according to claim 16, wherein for establishing the reference positions (41) of the camera (40) and or the target (53) with reference to the pass line (30), the position of the camera (40) and/or of the target (53) is varied and/or wherein the detected position of the master references (70, 80) is stored in memory in the information technology device (60) as a position of the pass line (30).

23. The determination method according to claim 15, wherein during the master calibration, at least one reference offset of a reference sensor (71, 81) to be used for intermediate calibrations is measured and stored in memory in the information technology device (60).

24. The determination method according to claim 15, wherein during the master calibration, at least two reference scales (46) that are oriented in a linearly independent manner, preferably orthogonal to one another, are measured for a reference sensor (71, 81) to be used for intermediate calibrations, preferably for all the reference sensors (71, 81) to be used for intermediate calibrations, and a pixel factor determined from the reference scales is stored in memory in the information technology device (60).

25. The determination method according to claim 1, wherein the camera (40) records multiple images during a measurement and compares them with one another.

26. The determination method according to claim 1, wherein filters used for the camera (40) are changed during the measurement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0150] Other objects and features of the invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.

[0151] In the drawings,

[0152] FIG. 1 shows a first rolling mill in a schematic view;

[0153] FIG. 2 shows a second rolling mill in a schematic view;

[0154] FIG. 3 shows the calibration with reference positions without roll stands, in a schematic view;

[0155] FIG. 4 shows storing of the reference positions in an information technology device, in a schematic view;

[0156] FIG. 5 shows application of the stored reference positions to a first roll stand arrangement, in a schematic view;

[0157] FIG. 6 shows application of the stored reference positions to a second roll stand arrangement, in a schematic view;

[0158] FIG. 7 shows a third rolling mill, in a schematic view;

[0159] FIG. 8 shows a first master reference, in a schematic view;

[0160] FIG. 9 shows a second master reference, in a schematic view;

[0161] FIG. 10 shows a third master reference, in a schematic view;

[0162] FIG. 11 shows a fourth master reference, in a schematic view;

[0163] FIG. 12 shows focusing up to the same gray range of the master references, in a schematic view;

[0164] FIG. 13 shows moving the center of the background illumination into the center of the target, in a schematic view;

[0165] FIG. 14 shows removing the reference sensor from the master references, in a schematic view;

[0166] FIG. 15 shows aligning a target on the background illumination, in a schematic view; and

[0167] FIG. 16 shows a fourth rolling mill having two rolling machines, in a schematic view.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0168] In a first exemplary embodiment according to FIG. 1, a rolling mill 1 comprises a rolling machine 2 having three roll stands 10, which are arranged between an input side 11 and an output side 12 of the rolling mill 1 or of the rolling machine 2 and each carry rolls 14. Furthermore, the rolling mill 1 comprises a pass line 30, which ultimately corresponds to the intended pass-through center workpiece to be rolled, such as, for example, a pipe, a billet or a rod.

[0169] For measurement of the rolling or guiding gap, a camera 40, comprising a lens 48 having its optical axis or also defined otherwise, alternatively, is placed approximately on the pass line 30.

[0170] Furthermore, in the case of the present exemplary embodiment, a background illumination 50 is provided on the output side, in other words on the side that lies opposite to the camera 40, which illumination emits a sufficiently uniform light to the camera 40, so that the contours of the rolls 14 to be measured, in each instance, are clearly distinguished against the background illumination 50.

[0171] In a concrete application, background illumination 50 that can be used is, for example, a light plate, preferably with filter films or with LEDs, if necessary collimated LEDs, which reduce the exit angle from the light plate, so as to minimize scattered light.

[0172] In a further exemplary embodiment according to FIG. 2, the rolling mill 1 shown there, in deviation from the rolling mill 1 of the first exemplary embodiment according to FIG. 1, which comprises multiple such roll stands 10, comprises a rolling machine 2 having only one roll stand 10, as well as two conical rolls 14, set at a slant, which are arranged on the roll stand 10, wherein in the case of this rolling mill 1, furthermore a plurality of guides 21 is provided, which are arranged, in each instance, on guide stands 20, and guide a mandrel bar 13. The guides 21 are opened radially, successively, with regard to each guide stand 20, when a workpiece, driven by way of the mandrel bar 13, reaches the corresponding guide stand 20. The guides 21 are configured as circular disks in the case of this exemplary embodiment, wherein it is not compulsory but practical, if applicable, if they can also roll, as rolls. In the case of such an arrangement, as well, a determination of the gaps, in other words, in particular of the rolling gap and of the guide gap, appears to be advantageous, accordingly.

[0173] It is understood that in the present exemplary embodiment, as well, a background illumination 50 can be arranged on the output side, similar to the first exemplary embodiment, but this is not shown in the present representation in FIG. 2.

[0174] The embodiments explained above, according to FIGS. 1 and 2, show arrangement of a rolling mill known from the state of the art, so as to measure rolling or guiding gaps by means of a camera 40.

[0175] In a further exemplary embodiment according to FIGS. 3 to 6, the individual steps of a determination method for determination of a rolling or guiding gap are shown.

[0176] In a first step, which is shown in FIG. 3, a camera 40 having a lens 48 is arranged along a pass line 30, wherein the camera 40 is arranged at a reference position 41 by way of a reference bracket 42. Parallel to the pass line 30, a reference height 47 is defined, by way of which the reference position 41 of the camera 40 along the pass line 30 is defined. The reference height 47 thereby describes the position of the reference position 41 with reference to the pass line 30.

[0177] In the viewing field of the camera 40, multiple reference positions 45 are arranged at different reference heights 47. At a first reference position 45, furthermore, a reference sensor 43 close to the camera is arranged, while at a second reference position 45, a reference sensor 44 away from the camera is arranged, wherein the reference sensor 43 close to the camera is situated closer to the camera 40 than the reference sensor 44 away from the camera.

[0178] In this step, the camera 40 and an information technology device 60 connected with the camera 40 are calibrated offline, with reference to the rolling mill 1, by means of the reference sensor 43 close to the camera and the reference sensor 44 away from the camera, which sensors are arranged, in each instance, not between rolls 14 or guides 21 of a first stand 10, 20 and rolls 14 or guides 21 of a last stand 10, 20. In the viewing field of the camera 40, the reference sensor 43, 44 as well as, if applicable, reference scales 46 arranged at the corresponding reference positions 45 (not shown separately in FIG. 1) form objects, in each instance, that can be measured and recognized by the camera 40.

[0179] In this regard, before this calibration, first the camera 40 is positioned on the reference bracket 42, in a previously defined reference position 41, and the reference sensor 43 close to the camera and the reference sensor 44 away from the camera are arranged in previously defined reference positions 45. Then, for the calibration corresponding to the first step, the reference close to the camera and the reference close to the camera, 43, 44 are measured by means of the camera 40 and the information technology device 60, and subsequently the pass line 30 is determined from the measurement result.

[0180] At the same time, a pixel factor is determined from the measurement result.

[0181] In a next step, as it is shown in FIG. 4, the reference positions 45, in particular the reference positions 45 of the reference sensors 43 and 44, as well as also the related pixel factors, are stored in memory in the information technology device 60 that is connected with the camera 40. In this regard, depending on the concrete requirements, if applicable the pixel factors for reference positions 45 between the reference sensors 43, 44 close to the camera and away from the camera, if applicable, can also be extrapolated by way of beam sets, so that if applicable, storing in memory and measuring is not necessary at these reference positions 45.

[0182] The actual reference sensors 43 and 44 are no longer arranged in the viewing field of the camera 40 in this step, in the case of this exemplary embodiment, because their reference positions 45 are stored in memory in the information technology device 60 in the present step, and therefore their placement is no longer necessary. However, storing in memory can also take place if these are not yet in position there.

[0183] In the first steps according to FIGS. 3 and 4, a calibration of the camera 40 and of the information technology device 60 therefore takes place offline, with reference to a rolling mill 1 having a rolling machine 2. This can also take place at a completely different location, if necessary, for example, in a separate equipment hall. In particular, the measurement can take place offline, directly at the rolling mill, for the measurements between the reference sensors 43, 44 close to the camera and away from the camera, by means of taking away the stands 10, 20. It is understood that a corresponding calibration of the camera 40 and the information technology device 60 can also take place inline, in particular if it is possible to do without the determination of the pixel factor at reference positions 45 between the reference sensors 43, 44 close to the camera and away from the camera.

[0184] In a next step, as it is shown in FIG. 5, roll stands 10 are also arranged in addition to the arrangement from the previous steps in the pass line 30. Thus this step is also preferably carried out inline, accordingly. If applicable, if the camera 40 or the background illumination 30 and, if applicable, a target 53 were moved, a new calibration of these modules with reference to the pass line 30 and with reference to a current pixel offset is carried out, at least at the reference positions of the reference sensors 43, 44 close to the camera and away from the camera.

[0185] The camera 40 then calls up the reference positions 45 stored in the memory of the information technology device 60, by way of this device 60, as well as the related data, such as a pixel factor and, if applicable, an offset, which were previously measured and stored in memory offline in the prior step. As virtual references, these reference positions 45 can now be called up again, and by way of triangulation, a conversion to the actual positions of the roll stands 10 or also any possible guide stands can be carried out. From this, the rolling or guiding gaps can then be determined.

[0186] A further exemplary embodiment according to FIG. 6 differs from the exemplary embodiment of FIG. 5 in that the previously measured and then called up reference positions 45 stored in memory lie precisely at the position of the roll stands 10 or of guide stands, so that the values can be taken over directly. If applicable, here too a calibration is first carried out, if the camera 40 or the background illumination 30 and, if applicable, a target 53 were moved.

[0187] In a further exemplary embodiment according to FIG. 7, which has the fundamental arrangement of the first exemplary embodiment according to FIG. 1, a first reference sensor 81, which is also used as a master reference 80, is additionally provided on the first roll stand 10, from the point of view of the camera 40, and a second reference sensor 71, which is also used as a master reference 70, is arranged on the corresponding last roll stand 10.

[0188] Furthermore, the reference sensors 71, 81 are configured as calibration rings 33, 34, wherein the calibration ring 33 can represent a reference sensor 43 close to the camera, and the calibration ring 34 can then represent a reference sensor 44 away from the camera, which can also be used, if applicable, for intermediate calibrations and, as already above, for master calibrations. In this regard, the master references 70, 80 are arranged, in each instance, on a reference stand 49, which is in the case of this exemplary embodiment, for its part, on the first or last roll stand 10, so that the master references 70, 80 can be installed at a specific position, in operationally reliable manner, in the simplest possible manner. In alternative embodiments, here an independent reference stand 49 can be provided, replacing the corresponding roll stand 10, but ultimately this only appears to be efficient for master calibrations, due to the effort and expense.

[0189] The camera 40 comprises a lens 48 and is furthermore connected with an information technology device 60, which comprises a measurement direction input possibility 61. The lens has a fixed focal length. Furthermore, it is conceivable that different lenses 48 are used for different gap sets, in particular having different fixed focal lengths, so that these can be adapted to the corresponding gap set.

[0190] Furthermore, a circular target 53 is arranged on a background illumination 50, which target lies in the viewing field of the camera 40 and can be displaced perpendicular to the pass line 30.

[0191] In addition, reference scales 46 can be arranged on the individual roll stands 10, at the corresponding reference positions 45 of the roll stands 10, in each instance. This is a separate reference scale 46 for the central roll stand 10, for example in the form of a ruler that is brought to the corresponding reference position 45 when the roll stand is removed. If applicable, a separate reference stand 49 can also be used for this purpose. For the remainder, the master references 70, 80 or the reference sensors 43, 44 or 71, 81, which are provided in any case, are used as reference scales 46, wherein it is assumed that the deviations along the pass line 30, between the position of the master references 70, 80 or the reference sensor 43, 44 or 71, 81, relative to the related reference positions 45 are insignificant, in light of the very great distance between camera 40 and rolling machine 2, within the scope of the desired measurement accuracy. Otherwise, if applicable, the master references 70, 80 or the reference sensor 43, 44 or 71, 81 can be arranged differently, or supplemental reference scales 46 can be provided at the desired positions.

[0192] Using the arrangement of the present exemplary embodiment according to FIG. 7, rolling or guiding gaps of the roll stands are determined in a master calibration. In this regard, the target 53 can ensure that possible fluctuations of the camera 40 in the images taken, in each instance, can be recognized and calculated back.

[0193] Furthermore, it is understood that using the method described here, in all steps, guide gaps of guide stands 20 can also be determined, as long as guide stands 20 are used in the rolling mill 1.

[0194] The camera 40 is first arranged on the input side 11, and the background illumination 50 is arranged on the output side 12, accordingly. Then the correspondingly selected calibration takes place. Subsequently, the rolling gap of the roll stands 10 is determined, making use of the information technology device 60. It is conceivable that in an alternative embodiment, the camera 40 is also first arranged on the output side 12, and the background illumination 50 is arranged on the input side 11, accordingly.

[0195] In a first step, the camera 40 and the information technology device 60 are calibrated with reference to the rolling mill 1, for example offline. However, it is also conceivable that the corresponding calibration can take place inline. In this regard, the first calibration ring 33 and the second calibration ring 34 are arranged in the pass line 30 as master references 70, 80. Subsequently, the position of the camera 40 and the position of the target 53 are changed in such a manner that the two calibration rings 33, 34, surrounding the target 53, can be detected separately by the camera 40.

[0196] For the calibration in the first step of the present exemplary embodiment, first a master calibration is carried out, then the camera 40 and the background illumination 50 are removed, so that subsequently, a rolling process is carried out or the roll stands 10 and, if applicable, also guide stands 20 are inserted into the actual rolling machine 2, when the master calibration takes place in an equipment hall or at another position. Afterward, the camera 40 and the background illumination 50 are arranged at one of the input 11 or output sides 12 again, for an intermediate calibration, and calibrated in this first step, before, in the second step, the camera 40, making use of the information technology device 60, determines the rolling gaps or, if applicable, also the guiding gaps are determined inline.

[0197] For the master calibration, the master references 70, 80 are installed on the pass line 30. The camera 40, on the one hand, as well as the background illumination 50 and the target 53, on the other hand, are oriented with reference to the pass line that is defined by the master references 70, 80. At the same time, the position of the pass line 30 is measured with reference to the camera 40 and to the target 53, and stored in memory in the information technology device 60. For the intermediate calibration, it is possible to do without the use of the master references 70, 80, if applicable.

[0198] For the master calibration, the three reference scales 46 are recorded offline, in each instance, at reference heights previously defined with reference to the pass line 30, wherein it is also conceivable that these can be recorded inline on at least one stand 10 away from the rolling mill 1. From the reference scales, a pixel factor is then determined and stored in memory in the information technology device. For intermediate calibrations, it can also be possible to use the reference sensors 43, 44 used as the master references 70, 80. If applicable, the rolls 14 or guides 24 or other modules, in particular of the first or last roll or guide stands 10, 20, can also be used for this purpose, because then it is possible to do without the installation and removal of separate reference sensors.

[0199] In addition, in the case of this exemplary embodiment, reference positions for the camera 40 and the target 53 with reference to the pass line 30 are established by means of the master calibration, and then the position of the pass line 30 with reference to the camera 40 and the target are stored in memory in the information technology device. At least one reference scale 46, in each instance, of two references 43, 44 to be used for intermediate calibrations is measured, and a pixel factor determined from the reference scales 46 is then stored in memory in the information technology device.

[0200] Before the calibration of the present exemplary embodiment that corresponds to the first step, the target 53, together with the background illumination, is positioned on the reference bracket 42 in a previously defined reference position. The target 53 is coordinated, in terms of its size, with the reference 43 close to the camera and the reference 44 away from the camera, in such a manner that it can be detected by the camera 40 at the same time together with the references 43, 44. The target 53, the reference 43 close to the camera and the reference 44 away from the camera are configured to be circular, in this regard.

[0201] If the diameter of the calibration rings 33, 34 is known, these can be used as a reference scale 46.

[0202] It is possible that the rolling or guiding gaps are determined directly after a rolling process, in particular between individual rolling processes.

[0203] Likewise, it is conceivable that the rolling or guiding gaps are measured in the warm state of the roll stand 10 or of the guide stand 20.

[0204] In a second step, the camera 40 determines the rolling gap inline, making use of the information technology device 60. In this step, it is conceivable that exclusively the gap shape is determined as the rolling gaps.

[0205] Furthermore, in an alternative embodiment, it is possible that in this second step, exclusively the gap offset from a pass line 30 reaching through at least two rolling machines 2 of a rolling mill 1 comprising at least two rolling machines 2, as it is shown in FIG. 16, is determined as a rolling or guiding gap. Here, it may be true that for a sufficient determination of the actual rolling gap, the depth of focus through such a long rolling mill 1 is not sufficient, but the relative position of the individual rolling gaps can still be determined with sufficient precision. In particular, in such cases the use of a target 53 appears to be indispensable.

[0206] In the present exemplary embodiment according to FIG. 7, furthermore the roll stands 10 are referred to successively as a function along the pass line 30 in the information technology device 60. By way of a measurement direction input possibility 61 of the information technology device 60, placement of the camera 40 on the input side 11 and of the background illumination 50 on the output side 12 or vice versa, and thereby the measurement direction can be entered. Thus, possible measurement results can be assigned to each of the stands 10, 20, independent of the measurement direction, by the information technology device 60, to the corresponding stands 10, 20, wherein in a preferred implementation, the recorded images are also mirrored in the case of a reversal of the measurement direction.

[0207] It is conceivable that the reference sensor 43 close to the camera or the reference sensor 44 away from the camera can be one of the rolls 14, one of the guides 21, one of the rolling 10 or guide stands 20, a reference stand 49 or a reference sensor 71, 81. This holds true, in particular, for intermediate calibrations.

[0208] As master references 70, 80, references such as those shown in FIGS. 8 to 11, for example, can be used. It is understood that the master references shown here can, however, also be used as other references, and cannot be used exclusively as master references 70, 80.

[0209] In the exemplary embodiment according to FIG. 8, a reference sensor 71 is configured as a calibration ring 33 that comprises two reference arms 75. The reference arms 75 are attached, in each instance, at two locations on the reference sensor 71, wherein the two reference arms 75 meet at a central reference point 74. Furthermore, the two reference arms 75 are arranged horizontally and vertically as well as at a right angle to one another. The reference arms 74 serve for being able to adjust the camera 40 for a first orientation quickly, but with sufficient precision.

[0210] A further reference sensor 81 configured as a master reference 80 can comprise, as shown in FIG. 9, a fundamental arrangement of the reference sensor 81 or calibration ring 34 and of the reference arms 85 according to FIG. 8, wherein, however, the reference sensor 81 of the present exemplary embodiment is arranged offset by an angle of 45, so that the two cruciform reference sensors 71, 81 are oriented differently.

[0211] In a further exemplary embodiment of a master reference 70 according to FIG. 10, the master reference 70 is once again configured as a circular calibration ring 33. However, the cruciform reference sensors 71 are arranged in such a manner that the central reference point 74 is not arranged centrally in the center point of the reference sensor 71, as was the case in the previous exemplary embodiments according to FIGS. 8 and 9.

[0212] In a further exemplary embodiment according to FIG. 11, a similar master reference 80 as the one from the previous exemplary embodiment according to FIG. 10 is provided, wherein the master reference 80 is arranged offset by an angle of 45 as compared with the master reference 70. In the exemplary embodiments according to FIGS. 10 and 11, as well, the reference arms 75, 85 are arranged at a right angle relative to one another.

[0213] It is understood that the master references 70, 80 can also be configured in a manner that deviates from this. It is merely advantageous if the master references 70, 80 form some kind of central reference point 74, 84 in terms of their configuration, so that the camera 40 can be placed in a correspondingly simple manner. Preferably, the pass-through of the pass line 30 is depicted by the reference point 74, 84, in each instance, so that operating personnel can obtain an optical impression of the position of the pass line 30.

[0214] Furthermore, the circular configuration of a calibration ring 33, 34 offers particularly great precision for the calibration of the camera 40 and of the information technology device 60, because a center point and diameter can be determined particularly well by means of circular shapes.

[0215] It would be conceivable, as well, for example, that a reference sensor 71, 81 comprises three or four reference arms 75, 85, which are all jointly oriented at a common central reference point, and thereby each reference arm 75, 85 is also connected with the frame of the dimensional difference at only one location, and specifically no continuous reference arms 75, 85 as on the exemplary embodiments described above are used. Also, the possibility could exist that not only rod-like, long and narrow reference arms 75, 85 are used, as they are used in the exemplary embodiments according to FIGS. 8 to 11, but rather are configured in the most varied manner, as long as they offer the possibility of arranging the camera 40 close to the pass line 30, in an accordingly simple manner.

[0216] Because the rolling mills 1 of the present exemplary embodiments are relatively long, the references 44 away from the camera might possibly appear so small for the camera 40 that it cannot detect the references with sufficient accuracy and determine the center point. In these cases, the calibration ring 34 can be enlarged, and thereby more points are available along the calibration ring 34 for determining the center point. The precision can be increased in this way. Because, however, the central reference point 74, 84 is not supposed to be as greatly offset with the enlargement of the calibration ring 34, the positions or orientations of the reference arms 75, 85 can be adapted accordingly, so that the central reference point 74, 84 remains on the pass line 30, if at all possible, or at least close to the pass line. In order for both calibration rings 33, 34 to remain well visible, the size of the other calibration ring 33 should then be adapted accordingly.

[0217] In order to set the focus of the camera 40 correctly, in the present exemplary embodiment, before the calibration that corresponds to the first step, the camera 40 is arranged on the reference bracket in a previously defined reference position 41. Subsequently, the lens 48 of the camera 40 is repositioned, in terms of its focus, until the reference sensor 43 close to the camera and the reference sensor 44 away from the camera are imaged with an almost identical blurriness. For this purpose, multiple individual steps take place, as they are shown, for example, in FIGS. 12 to 15.

[0218] At first, two master references 70, 80 or calibration (gap) rings 33, 34 are arranged one behind the other from the point of view of the camera 40, wherein a first master reference 80 or a first calibration (gap) ring 33 comprises a reference sensor 81, 43 arranged according to the exemplary embodiment from FIG. 11, and wherein a second master reference 70 or a second calibration (gap) ring 34 comprises a reference sensor 71, 44 configured according to the exemplary embodiment of FIG. 10, so that the first reference sensor 81 is oriented offset by an angle of 45 relative to the second reference sensor 71. In this regard, the master reference 80 represents a reference 43 close to the camera and the master reference 70 represents a reference 44 away from the camera.

[0219] The camera 40, with the view at the master references 70, 80, has a virtual cross-hair 90 having a round edging, which is only visible to the camera 40 itself. The virtual cross-hair 90 has a center point and serves for simple rough adjustment of the camera 40. The master references 70, 80 are oriented, in the preceding step, in such a manner that the central reference points 74, 84 lie in the center point of the virtual cross-hair 90. In this manner, the master references 70, 80 and the camera 40 are roughly oriented along a common pass line 30.

[0220] In the next step, the focus of the camera 40 and, in particular, the lens 48 are changed until the two master references 70, 80 have approximately the same blurriness for the camera 40. As soon as both master references 70, 80 are represented with equal blurriness to the camera 40, the focus of the camera 40 lies approximately in the center between the two master references 70, 80. Then the focal width of the camera 40 can be used in the best possible manner so as to be able to image the entire region of the rolling mill, in particular between the two master references 70, 80, in the best possible way. In this manner, sufficiently precise focusing of the camera 40 is undertaken.

[0221] In order to also orient the background illumination 50 with the target 53, in accordance with the common pass line 30, in the next step, as it is shown in FIG. 13, the target 53 of the background illumination 50, which target is configured to be circular, is moved at least roughly into the center point of the virtual cross-hair 90. The camera 40 should then image both the calibration rings 33, 34 and the target 53 separately, sufficiently, in each instance.

[0222] Now the reference sensors 43, 44 or the master references 70, 80 or the calibration rings 33, 34 can be removed, and the gap measurement can be carried out, making use of the pixel factors and the offset of the pass line with reference to the respective positions of the rolls 14 or guides 21. In this regard, the target 53 helps to calculate possible fluctuations of the camera 40.

[0223] Depending on the concrete calibration precision, it is possible to do without the target 53 or the calibration rings 33, 34, wherein for the calibration in the latter case, rolls 14, guides 21 or stand parts of the roll or guide stands 10, 20, for example, can then be used as a reference sensor 43, 44.

[0224] In a further exemplary embodiment according to FIG. 16, a rolling or guiding gap of roll stands 10 or of guide stands 20 can be determined in a multi-stand rolling mill 1 having a pass line that reaches through the roll stands 10 or guide stands 20 and serves as a reference for a gap offset. First, a camera 40 is arranged on an input side 11 and a background illumination 50 is arranged on the output side 12, accordingly, and subsequently the roll or guide gap of the stands 10, 20 is determined, making use of an information technology device 60.

[0225] In a first step, the camera 40 and the information technology device 60 are calibrated inline with reference to the rolling mill, and in the second step, the camera 40 determines the rolling or guiding gaps inline, making use of the information technology device 60.

[0226] In the present exemplary embodiment, the rolling mill 1 comprises two rolling machines 2, which are set directly one behind the other as an overall rolling mill 1. In the present case, for example, a PQF rolling machine is arranged as the first rolling machine 2, close to the camera, and a reduction rolling machine is arranged as the second rolling machine 2, behind the PQF rolling machine from the point of view of the camera 40, away from the camera. It is conceivable that all other known rolling machines 2 can also be combined to form an overall rolling mill 1, such as, for example, an extraction rolling mill.

[0227] The pass line 30 in the present exemplary embodiment reaches through both rolling machines 2 of the rolling mill. It is conceivable that the rolling mill 1 also comprises more than two rolling machines 2, wherein then the pass line 30 can also reach through all the rolling machines 2. It is understood that in this regard, partial measurements of individual rolling machines 2 can also be carried out.

[0228] In the second step of the present exemplary embodiments according to FIG. 16 as explained above, it is conceivable that subsequently the gap offset from a pass line 30 that correspondingly reaches through the multiple rolling machines 2 is determined as a rolling or guiding gap. By means of individual measurements of the individual rolling machines 2, a more precise measurement can then be carried out, if necessary.

[0229] Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

TABLE-US-00001 Reference Symbol List: 1 rolling mill 2 rolling machine 10 roll stand 11 input side 12 output side 13 mandrel bar 14 roll 20 guide stand 21 guide 30 pass line 33 calibration ring 34 calibration ring 40 camera 41 reference position of the camera 40 42 reference bracket 43 reference sensor close to the camera 44 reference sensor away from the camera 45 reference position 46 reference scale 47 reference height 48 lens 49 reference stand 50 background illumination 53 target 60 information technology device 61 measurement direction input possibility 70 master reference 71 reference sensor 74 central reference point 75 reference arm 80 master reference 81 reference sensor 84 central reference point 85 reference arm 90 virtual cross-hair