EP0463566B1 - Method and device for estimating the shots on a target - Google Patents

Abstract

A scanner (22) is assigned a reflected-light line (32) above a target-disc transport path and a transmitted-light transmission line (28) below this transport path. When a shot hole comes into the detection range of the scanner (22), the disc band is sensed by this in lines and a plurality of hole edge points are determined, these being combined arithmetically to form a polygon from which the shot- hole centre is calculated. Simultaneously with the entry of the hole- edge points, the same scanner (22) detects a number of points of the target-disc ring adjacent to the shot hole. An arc segment of the disc ring is calculated arithmetically from these ring points and its centre point is determined. The shot result is calculated from the distance between the shot-hole centre and the disc centre. <IMAGE>

Description

The invention relates to a method and a device for evaluating hits from shooting targets, according to the preamble features of claims 1 and 10, and to the use of an optical system.

According to the process according to EP-PS 86 803, the shooting target or the target target belt is transported through a first stationary optical system in which a photocell detects the light-dark transitions of the mirror of the target target and from this the target center coordinate in the target transport direction is calculated. By means of transmitted light, the hole position is also determined in the direction of transport of the pane, in such a way that the shot hole is located exactly above a light transmission line, which is made possible by comparing the light reception values of two light receiver lines arranged on the other side of the window. In this way, the center coordinate of the shot hole in the target transport direction is determined. Then, in the same way, the center coordinates of the target and the shot hole must be determined transversely to the target transport direction. To do this, it is necessary to arrange the second optical system on a transversely movable carriage. The transport path of the target and that of the carriage, measured between the center of the hole and the center of the target, are then offset to form the shot result. The result is displayed and can also be printed on the pane.

The known evaluation method and the device operating according to it have proven themselves in practice, but some disadvantages are unmistakable. The optical scanning system works with an LED line and photo transistors. For an exact evaluation, these optical elements must have the same electrical, optical and mechanical values in the entire operating temperature range. Fringes at the edge of the shot hole can lead to evaluation errors. The mechanical guidance of the second optical system on the transversely movable carriage is complex. There are comparatively long transport routes that go into the measuring process. The percentage slip affects the measurement result. For large shooting targets, such as those required for small-caliber shooting, sufficient accuracy can only be achieved with very great technical effort.

The documents DE-A-30 27 775, DE-A-30 13 244, WO-A-86 04 676 and WO-A-89 01 147 describe scanner systems for the detection of defects in continuous textile webs and the like Shooting targets made, in which basically two different positions have to be detected, namely first the target rings to determine the center of the target as a reference and the other the edge points to determine the center of the hole. Only in this way is it possible to determine the relative position from the center of the hole to the center of the disc and to then evaluate the results in the form of a specific ring value. However, such an evaluation is completely absent, as is the determination of a center of the pane as a reference, as is essentially done in EP-A-86803 (= WO 83/00920) by two optical systems separated for the longitudinal and transverse movement. In addition, in this document, the center of the hole on the one hand and the center of the pane on the other hand are determined by two separate subsystems, namely a light transmission / reception line on the one hand and several button-shaped reflective light barriers on the other hand. As a result, this device for evaluating hits from shooting targets is extremely complex, as illustrated at the beginning.

From DE-A-26 25 500 a shooting range is also known in which a television camera is used to display the shot image. The ring value is not evaluated here either, as would be required for a ring reading machine for the exact evaluation of the rings shot.

Finally, from DE-A-23 64 386 a method for counting shot hits on a test disk is known, a television camera being used to count these hits on a test disk. Here, too, there is no assignment from the center of the hole to the center of the target, as would be necessary for an exact, quick and accurate evaluation of the target.

The object of the invention is to simplify the evaluation method and the evaluation device operating according to it, to accelerate the method of operation and, nevertheless, to increase the accuracy of the shooting target evaluation.

This object is achieved in a method for evaluating hits from shooting targets according to the preamble of claim 1 by means of its identification features.

A preferred embodiment forms the subject of claim 2.

The invention has significant advantages. The method is suitable for the evaluation of all common disc bands and individual discs. Inaccuracies in the transport of the disks due to slippage have little or no effect on the measurement result. The evaluation process is significantly accelerated since only the shot hole area needs to be recorded. A single scanner, for example in the form of a high-resolution scanner, significantly reduces manufacturing costs. In contrast to the prior art, the center of the shot hole is no longer on the center of the pane, but on the closest and preferably referring to the inner disc ring, as is also done manually with the usual "shot hole tester". Thanks to the invention, large-area shooting targets can also be evaluated. The shot holes do not have to be sharply contoured, but can be frayed to a certain extent and so-called double shots can also be evaluated, that is to say two overlapping shot holes.

The invention also relates to the use of a single optical system according to the features of claim 14. The use of an optical system for scanning a target is known from EP-A-86803.

The use of a scanner according to claim 14 represents a particularly advantageous hardware implementation of the method according to the invention. Such scanners are commercially available. For the invention, a scanner version with normal resolution is sufficient, e.g. at 200 DPI (dots per inch), which means that the sampling point spacing is about 0.12 mm. The width of the scan line is the same size. It is within the scope of the invention to first detect the edge points of the hole and then the points of the adjacent arc piece of the disk. In contrast, the subjects of claims 4 and 5 form a more advantageous alternative since they increase the evaluation speed and the accuracy. During a half line feed of approximately 0.06 mm e.g. two opposing edge points of the hole are detected due to the transmitted light hitting the scanner. During the next half-line feed, the transmitted light is switched off or covered, so that two points can now be detected by means of reflected incident light on the disk ring adjacent to the shot hole. In this way, image points of the edge of the hole and the disk ring are determined alternately. One or two comparatively short elbows of the corresponding disc ring are sufficient for the mathematical determination of the center of the disc. A circumferentially closed polygon is also not required for the hole edge; rather, e.g. the hole center can already be calculated from a half polygon. Therefore, double shots can also be evaluated with the method according to the invention. Any fringes do not affect the measurement result, since their signals fall out of the hole contour so strongly that they can be electronically eliminated.

In order to be able to alternately determine perforated edge signals and ring arch signals, the transmitted light for the perforated edge detection does not necessarily have to be switched off periodically, even if this is readily possible so as not to disturb the ring detection, rather a detection system can be used which reflects the transmitted light from the reflected light Incident light differs and only takes the transmitted light into account when determining the edge of the hole and only the reflected incident light is taken into account for ring detection. For this purpose, the light sources can be in different frequency bands, and it is also possible to design the light transmission line for the transmitted light with a light intensity that is substantially greater than that of the incident light.

An important further development of the invention forms the subject of claim 7. Here, when a defined deviation of the hole edge polygon from the reference polygon of the optical hole scanning is followed by a mechanical or ultrasonic auxiliary scanning method. If this detection unit determines that the edge of the hole has not been detected so reliably that a clear hole center determination is possible, this optical measurement result is used as a rough measurement, which is followed by a fine measurement. For this fine measurement, a secondary scanning system is used, which works mechanically or with ultrasound and is moved at a predetermined distance from the optical system transversely to the disk transport direction. The optical rough determination of the hole then serves to bring the secondary scanning system on the transversely movable carriage into the roughly scanned position so that the shot hole reaches the detection area of this secondary scanning system. This is now adjusted to the shot hole, in that the disk carries out a correction path relative to the secondary scanning system in the conveying direction and the secondary scanning system carries out its own correction path at right angles thereto, and by the transport path of the target between the two scanning systems and the transverse movement path of the secondary scanning system with the two correction paths Hole center determination can be offset. Such a secondary scanning system represents an increased construction outlay, but also enables an automatic evaluation of optically ambiguous shot holes and even of "closed" shot holes. The mechanical secondary scanning system uses a gimbal-mounted mandrel that has an axial play. The mandrel is held in a neutral position and, after the transversely movable carriage has moved into the rough position determined by the optical system, is lowered into the hole, where it is centered automatically with respect to the circumference of the hole, and undergoes a deflection, the components of which in the disk transport direction and transversely thereto recorded and offset with the coordinates of the rough hole determination. The detection of the mandrel deflection can easily be determined inductively or optically. A particularly precise and advantageous solution consists in that the centering mandrel is gimbally and axially movably suspended in a pendulum ball bearing in its central region and carries a light-emitting diode at its end opposite the mandrel tip, the light of which falls on a four-quadrant photodiode system. The sum of all four individual levels remains constant. In the neutral position of the centering mandrel, the four quadrants receive the same level. When the mandrel is deflected, there are level differences that lead to the determination determination of the deflection coordinates.

The ultrasound scanning system that can be used instead of in addition to the mechanical secondary scanning system uses an ultrasound barrier with a transmitter on one side of the pane and a receiver on the other side. Just like the mechanical variant described above, the ultrasound barrier is moved into the shot hole position roughly determined by the optical system in the transverse direction for the pane transport. Then the pane transport and the carriage transport carry out correction paths until the formwork performance measured by the receiver reaches its maximum. The two correction paths are in turn offset against the coordinates of the roughly determined hole position. The mechanical solution of the secondary scanning system has the advantage that double shots can be evaluated very precisely, while the secondary scanning system working on the basis of ultrasound is used advantageously when the shot holes are very frayed, because it has surprisingly been found that such fringes hardly have one when subjected to ultrasound Have an effect on the measurement result.

The invention further relates to a device for the evaluation of hits from shooting targets with a housing in which a motor-driven transport device for the shooting target or the -disc belt is arranged, with a light transmission line arranged on one side of the transport path for the target and aligned transversely to the direction of transport parallel light reception line on the other side of the transport path, the light transmission line and the light reception line being arranged in or symmetrically to a transverse plane crossing the disc transport path at right angles. Such a device is known from the aforementioned EP-PS 86 803. The novelty of the invention according to claim 10 consists in the fact that the light receiving line is designed as a scanner or surface image sensor equipped with a full-length incident light illumination unit as the only light receiving element for the penetrating transmitted light and the reflected light reflected from the target. A line-wise scanner is preferred for the invention, since it takes up little space in the housing and is inexpensive. For the shot hole edge detection and for the detection of the adjacent disk ring, the disk must be moved a small distance in the order of the shot hole diameter. In many cases, however, the scanning of a partial area of the shot hole is sufficient, so that a transport distance of the disk of half the diameter of the shot hole is sufficient for the scanning. If an area scan camera is used instead of the line scanner, which is basically composed of a large number of scanners placed one behind the other, then the edge of the shot hole and the ring arch can be evaluated at the moment. The disc remains at rest during the scanning. The evaluation speed increases, but the construction effort is greater.

The invention is explained in more detail by way of example with reference to the drawing.

• FIG. 1 eine schematische vertikale Schnittansicht durch eine Ausführungsform der Auswertevorrichtung,
• FIG. 2 eine Draufsicht auf die Auswertevorrichtung nach Wegnahme des Gehäuseoberteils, und
• FIG. 3 eine perspektivische Ansicht einer sekundären Abtasteinrichtung, die bei der Vorrichtung gemäß Figuren 1 und 2 Verwendung findet.

It shows

• FIG. 1 shows a schematic vertical sectional view through an embodiment of the evaluation device,
• FIG. 2 shows a plan view of the evaluation device after removal of the upper housing part, and
• FIG. 3 shows a perspective view of a secondary scanning device which is used in the device according to FIGS. 1 and 2.

Arranged in a housing 10 are two pairs of transport rollers 12, 14, which are synchronized with one another, for transporting a shooting disk belt 16 and which are driven by a motor 18 which can be driven in both directions. A fork light barrier 20 detects the presence of a shooting target 16 and puts the motor 18 into operation at high speed. Immediately behind the first pair of drive rollers 12, a scanner 22 is arranged above the disk transport path and extends over the usable width of the housing. In the exemplary embodiment, the shooting disk band 16 does not take up the full usable width of the housing 10. With one edge, the shooting disc band 16 rests against a fixed angle stop 24 and with the other edge against a manually movable stop bar 26, which can be adjusted to the dashed position 26 '.

In the vertical transverse plane of the scanner 22, a light transmission line 28 is arranged below the disk belt 16, which also extends over the entire useful width of the housing 10 and whose upward light strikes the underside of the shooting disk belt 16 almost perpendicularly via a cylindrical lens 30.

Once the scanner 22 receives light through a shot hole from the transmit line 28, the motor 18 is reduced to operating speed, which is synchronized with the scanning speed of the scanner 22.

A scanner of normal, ie not particularly high, resolution is able to capture eight pixels per millimeter. The pixel distance is thus 0.12 mm. This is also the line width. During the advancement of the disc band 16 by half a line width, the scanner 22 receives transmitted light from the light transmission line 28 and thus generally detects two opposite edge points of the hole which are fed to a computer memory. The light transmission line 28 is then switched off by the next half line width during the feed. The scanner now only receives the reflected incident light from one in the scanner 22 built-in incident light line 32. By means of this illumination, the scanner generally detects two points which lie on the ring of the shooting disk 16 adjacent to the shot hole. The two lighting lines 28, 32 can be switched on and off alternately. The incident light 32 can also be in continuous operation, since the electronics downstream of the scanner 22 can distinguish the two light sources.

The alternate reading of hole edge points and ring points takes place in a period of about 0.5 s and is fed to a computer which calculates a hole edge polygon from the plurality of hole edge points. Scanning half the circumference of a shot hole is generally sufficient for this. This actual polygon is compared with a regular reference polygon or reference circle, i.e. aligned with the polygon in such a way that the sum of all squares of deviation from the actual polygon is minimal. The center of the hole is then calculated from this reference polygon. In the same way, a ring arch piece or two ring arch pieces is calculated from the number of ring points detected and the center point of the ring and thus the disk is determined therefrom. Finally, the distance from the center of the hole to the center of the pane is calculated, which is proportional to the result of the shot, which is shown on a display (not shown) and printed on an edge area 36 of the disc band 16 by means of a printer 34. Depending on the computer used, the computing time is 0.2 s to 0.6 s, so that the overall evaluation is of the order of 1 second.

If the computer determines that the reference polygon superimposed on the actual polygon of the edge points of the shot hole has deviations that are too large, which e.g. indicates a very frayed shot hole, the optical scanning of the shot hole is only detected as a rough determination of its position and the shooting disk 16 is transported at high speed until the shot hole reaches a transverse plane 38, where a secondary scanning takes place. In this transverse plane 38, a carriage 40 is guided on guides over the entire usable housing width and is connected to a drive belt 42 which is driven by a reversible stepper motor 44. The carriage 40 carries a mechanical scanner 46, which is shown in detail in FIG. 3 is illustrated. A lifting platform 50 is guided in a vertically movable manner on the carriage 40 by means of guide pins 48. It is pressed by compression springs 52, which surround the guide pins 48, into an upper position, which is determined by the position of an eccentric disk 54 of a geared motor 56. In the lifting platform 50, a centering mandrel 58 is cardanic by means of a self-aligning ball bearing 60, i.e. Can be swung out sideways in all directions. The centering pin 58 is axially displaceably mounted in the inner ring of the bearing 60 without play. A helical spring that surrounds the centering mandrel 58 supports it. In the rest position of this secondary scanning device 46, the lifting platform 50 is in its upper position, in which the rear conical surface of the mandrel tip is locked in the receptacle of the carriage 40.

After the optical scanning of the shot hole has shown that a secondary scanning is necessary, the stepper motor 18 transports the disc belt 16 by the fixed distance between the optical system and the central transverse plane of the carriage 40. At the same time, the stepper motor 44 moves it into the optically roughly determined transverse position of the shot hole. The two movements are offset against the roughly determined shot hole position. The shot hole is then in the detection area of the centering mandrel 58. Now the gear motor 56 is actuated, which rotates the eccentric disk 54 by half a turn into the position shown in FIG. 3 position shown brings. The lifting platform 50 then has its lower working position and the centering mandrel 58 penetrates into the shot hole. It is pivoted in the self-aligning ball bearing 60. The swivel angle and the swivel direction are optically recorded. For this purpose, a light-emitting diode 62 is provided at the upper end of the centering mandrel 58, which illuminates a four-quadrant photodiode system 64, which is arranged on a mounting bracket of the lifting platform 50 such that the levels of all four quadrants of the diode system 64 are the same when the centering mandrel 58 is in its neutral position. Since the centering mandrel 58 pivots when it is placed on the edge of the hole, the level differences of the four quadrants of the photodiode system 64 change, and these level differences are a measure of two orthogonal correction paths, namely in the disk conveying direction and transversely thereto. The roughly determined hole position is refined around these correction paths.

The helical spring supporting the centering pin 58 ensures that the shot hole is only loaded by the weight of the centering pin 58, so that the permissible load on the shot hole is not exceeded. When the centering mandrel is lowered, an axial relative movement of the centering mandrel 58 begins at the moment when it is placed on the edge of the shot hole. Because of the greater proximity to the four-quadrant photodiode system 64, its level sum decreases. This reduction is a measure of the mechanical concentric hole loading.

The control of the correction values by the secondary scanning device 46 can also be carried out in such a way that, after the centering mandrel 58 has been put in place, the disk 16 in the transport direction or counter to the transport direction and the carriage 40 are adjusted transversely to the transport direction until all level differences of the four-quadrant photodiode system 64 Are zero. From the additional travel paths and the Rough position of the shot hole is then the exact shot hole position can be calculated.

The mechanical secondary scanning device 46 also enables one-sided probing of so-called fork shots or double shots with defined hole edge loading. The hole edge loading vector can be determined by vectorial addition of the level differences. Conversely, the required angular position of the centering mandrel 58 can be set in the angular position of the hole edge region to be probed, which is known from the optical rough evaluation.

In FIG. 1 also shows the lower part of an ultrasound barrier which can be used as an alternative to the mechanical secondary scanning system 46. An ultrasound transmitter with the radiation axis directed downward is then arranged on the carriage 40 in the transverse plane 38. A further carriage 66 is likewise arranged displaceably on transverse guides beneath the disk belt 16 and is fastened to a belt 68 corresponding to the drive toothed belt 42. The two belts 42, 68 are synchronized via deflection pinions. The carriage 66 carries an ultrasound receiver. The method of operation corresponds to that described with reference to the mechanical secondary scanner 46. The ultrasound barrier is adjusted to the transverse position of the shot hole roughly determined by the optical system by displacing the two carriages 40, 66, after which the pane transport and the carriage transport are changed until the ultrasound reception reaches its maximum. The correction paths of the two motors 18, 44 are then offset against the rough position in the computer.

Claims (14)

1. A method of evaluating hits on a target, in which the target or a target band (16) passes through an optical system (22), in which edge regions of the shot hole and image points of the target are detected and the distance of the centre of the shot hole from the centre of the target is computed and displayed as the result of the shot, characterized in that the shot hole is sensed by lines, the positions of the shot hole edge points for each line sensing are determined and stored, at least a part of a hole edge polygon is computed from the plurality of hole edge points and brought by minimising deviations into register with at least a part of a regular reference polygon or circle, whose centre point coordinates defining the shot hole centre are computed, and in that a ring on the target (16) adjoining the shot hole is sensed by lines and the coordinates of the centre point of the associated circular arc or two spaced circular arcs are computed from a plurality of closely adjacent ring points of this sensed target ring or reflective edge.

2. A method according to claim 1, characterized in that a single optical system (22) is used to sense the shot hole and an adjacent part of an arc of a target ring and comprises a line scanner or a surface camera, which responds both to the transmitted light passing through the shot hole and the incident light reflected from the target (16).

3. A method according to claim 1 or 2, characterized in that the coordinates of the centre of the hole and the distance of the centre of the hole from an adjacent target ring are determined by the line scanner (22) while the target (16) is moved continuously or in fine steps relative to the line scanner (22) through a path of the order of magnitude of at least a part of the shot hole diameter.

4. A method according to claim 3, characterized in that the optical system (22) receives signals from the hole edge and the target ring alternately.

5. A method according to claim 4, characterized in that during the advance of the target by half a line width the hole edge signal is detected and during the following advance by next half line width the ring signal is detected.

6. A method according to any of claims 1 to 5, characterized in that the light beam passing through the shot hole is interrupted during the ring sensing.

7. A method according to any of claims 1 to 6, characterized in that an auxiliary sensing procedure operating mechanically or ultrasonically is switched in after the optical hole sensing on overstepping a predetermined magnitude of deviation of the hole edge polygon from the reference polygon, in which procedure a secondary mechanical or ultrasonic sensing system (46) moves a predetermined distance from the optical system (22) transverse to the target transport direction and the target (16) is transported so far that the shot hole comes into the range of detection of the secondary sensing system (46) and this is adjusted on to the shot hole, in that the target (16) executes a correcting movement relative to the sensing system (46) in the transport direction and the secondary sensing system (46) executes its own correcting movement at right angles thereto, and in that the transport path of the target (16) between the two sensing systems (22, 46) and the transverse path of movement of the secondary sensing system (46) is computed in with the two correcting movements for determining the centre of the hole.

8. A method according to claim 7, characterized in that the mechanical secondary sensing system (46) comprises a prong which can be lowered into the shot hole, the prong being suspended universally and being self-centring in the shot hole, and the deflection of the prong from the neutral position in two orthogonal directions is detected as correcting movements.

9. Amethod according to claim 7, characterized in thatthe ultrasonic sensing system comprises an ultrasonic beam device with a transmitter on one side of the target and a receiver on the other side, in that the ultrasonic beam device is adjusted in the transverse direction relative to the target transport and the target is adjusted in or opposite to the transport direction until the receiver receives the maximum sound power and in that the two orthogonal adjusting movements are computed in as correcting movements for determination of the centre of the hole.

10. A device for evaluating hits on targets (16), with a housing (10), in which is arranged a motorised transport device (12, 14) for the target of the target band (16), with an optical system (22) arranged transverse to the transport direction on one side of the transport path for the target (16) and comprising a light-emitting row (28, 32) and a light receiving row parallel thereto on the other side of the transport path, which is arranged in or symmetrically relative to a transverse plane crossing the target transport path at right angles, characterized in that the light receiving row is in the form of a high resolution scanner (22) equipped with an incident light illuminating unit (32) extending over the whole line length, or a surface image receptor, acting as a single light receiving member for the transmitted light passing through the shot hole and the reflected incident light from the target (16), and an electronic recognition unit which distinguishes the electrical signals of the scanner (22) or surface image receptor generated from transmitted light from the signals generated by the reflected incident light and the signals for determination of the hole edge and for determination of the circular arc are evaluated separately.

11. A device according to claim 10, characterized in that the light emitting row (28) is switched off or dimmed during reception from the target ring.

12. Apparatus according to claim 10 or 11, characterized in that a secondary mechanical sensing system (46) is associated with the optical sensing system (scanner 22) and is mounted on a carriage (4) movable at right angles to the target transport and comprises a prong (58) adapted to be inserted in the shot hole and suspended universally from a rising platform (50) with axial play and with which a position sensor is associated, which detects the deflections in the transport direction and transverse thereto occurring on insertion of the prong (58) in the shot hole.

13. Apparatus according to claim 10 or 11, characterized in that a secondary sonar beam unit is associated with the optical sensing system (scanner 22) and is mounted on a carriage (40, 66) movable at right angles to the target transport and comprises an ultrasonic transmitter an ultrasonic receiver aligned at right angles to the target transport path on opposite sides of the target transport path, in that the sonar beam unit can be moved into the position of the shot hole coarsely determined by the optical sensing system (scanner 22) and from thence the transport device for the target (16) and the carriage (40, 66) execute correcting movements until the ultrasonic receiver receives maximum sound power and these correcting movements are computed in with the corresponding optically detected orthogonal positions of the shot hole.

14. Use of a single optical system (22) for sensing a band provided with targets, wherein this single optical system (22) has a line scanner or a surface camera for sensing a shot hole and a part of an arc of a target ring of a target adjoining this shot hole, which scanner or camera responds to the light passing through the shot hole and also to the incident light reflected from the target (16).

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