SYSTEM AND METHOD FOR MARKING OF PLAYING FIELDS

Abstract

The invention relates to a system for variable marking of a playing field (1), comprising at least two marking devices (2) designed as laser projectors, an analysis device designed to analyse a calibration pattern (3) projected onto the playing field (1) by means of a marking device (2), as well as designed to determine a distortion function from the calibration pattern (3), a control device designed to determine the position of a marking pattern (4) on the playing field (1), and a transformation device designed to apply the distortion function to the marking pattern (4) in order to obtain a target marking (5). The invention further relates to a method for variable marking of a playing field (1).

Claims

1. A system for variable marking of a playing field (1) comprising at least two marking devices (2) designed as laser projectors, an analysis device designed to analyse a calibration pattern (3) projected onto the playing field (1) by means of a marking device (2) and designed to determine a distortion function from the calibration pattern (3), a control device designed to determine the position of a marking pattern (4) on the playing field (1), and a transformation device designed to apply the distortion function to the marking pattern (4) to obtain a target marking (5).

2. The system according to claim 1, characterised in that the analysis device comprises an imaging device, wherein the imaging device is designed as a camera.

3. The system according to claim 1, characterised in that four marking devices (2) are provided.

4. The system according to claim 1, characterised in that the control device is connected to a tracking device.

5. An arrangement of a system according to claim 1 with a playing field (1), characterised in that the marking devices (2) are arranged outside an edge (6) of the playing field (1).

6. The arrangement according to claim 5, characterised in that an angle a between the marking device (2) and each position of a marking area (7) is between 30° and 90°.

7. The arrangement according to claim 5, characterised in that playing field (1) comprises at least two, preferably four, marking areas (7).

8. A method for variable marking of a playing field (1) comprising the following steps: determining the position of a marking pattern (4) on the playing field (1) by means of a control device, applying, by means of a transformation device, a distortion function to the marking pattern (4) to obtain a target marking (5), projecting the target marking (5) onto the playing field (1) by means of a marking device (2).

9. The method according to claim 8, characterised in that the distortion function is determined by: projecting a calibration pattern (3) onto the playing field (1) by means of a marking device (2), analysing a calibration projection (8) by means of an analysis device, determining the distortion function from the calibration projection (8) by means of the analysis device.

10. The method according to claim 9, characterised in that the calibration pattern (3) is a grid with rectangular, in particular square, grid lines.

11. The method according to claim 9, characterised in that the distortion function is determined by means of the analysis device by comparing the calibration pattern (3) with the calibration projection (8).

12. The method according to claim 9, characterised in that the distortion function is determined for a plurality of points X.sub.1, X.sub.2, . . . , X.sub.n of the playing field (1) is determined.

13. The method according to claim 8, characterised in that the marking pattern (4) is formed by a plurality of marking parts (4′, 4″, 4″′) wherein the marking parts (4′, 4″, 4″′) are projected onto the playing field (1) by several marking devices (2).

14. The method according to claim 8, characterised in that the method comprises the following further steps: determining an edge (6) of the playing field (1), and preventing the marking device (2) from projecting onto areas that are outside the edge (6) of the playing field (1).

15. The method according to claim 9, characterised in that the calibration pattern (3) is projected by a plurality of marking devices (2) onto a plurality of marking areas (7).

16. The method according to claim 8, characterised in that the determining of the position of a marking pattern (4) on the playing field (1) is carried out by means of a tracking device connected to the control device.

Description

[0040] In the figures:

[0041] FIG. 1 shows an arrangement of the system according to the invention with a playing field in schematic perspective view;

[0042] FIG. 2 shows a grid-shaped calibration pattern;

[0043] FIG. 3 shows the calibration projection of the calibration pattern from FIG. 2;

[0044] FIG. 4 shows a marking pattern as it should be depicted on a determined position of the playing field;

[0045] FIG. 5 shows a target marking in order to depict the marking pattern shown in FIG. 4;

[0046] FIG. 6 shows a playing field with a marking pattern in schematic top view; and

[0047] FIG. 7 shows a playing field with further marking patterns in schematic top view.

[0048] FIG. 1 shows an arrangement of the system according to the invention with a playing field 1 in schematic perspective view. The system comprises four stand columns 9 that are arranged outside the edge 6 of the playing field 1.

[0049] A marking device 2 in the form of a laser projector is arranged on each stand column 9. An imaging device designed as a camera (not shown) is arranged next to each marking device.

[0050] In embodiments not shown, the marking devices may also be attached to existing infrastructure, such as a stadium roof.

[0051] FIG. 2 shows a grid-shaped calibration pattern 3 as it can be projected by a marking device 2. As the playing field 1 is arranged at an angle to the marking device 2, a distortion results when the calibration pattern 3 is projected onto the playing field 1. The calibration projection 8 is reproduced on the playing field 1.

[0052] The calibration projection 8, as seen from one of the imaging devices, is shown in FIG. 3. It can be seen that the calibration projection 8 is distorted in perspective compared to the calibration pattern 3.

[0053] The analysis device according to the invention is designed to determine a distortion function from the calibration projection 8 captured by the imaging device and the calibration pattern 3 with predetermined geometry. The inverse distortion function may be used to calculate a marking pattern 4 from a target marking 5, as outlined in FIGS. 4 and 5.

[0054] FIG. 4 shows an exemplary target marking 5 depicted as a circle with a marking in its central point. FIG. 5 shows the marking pattern 4 to be projected by a marking device 2, resulting from using the previously determined distortion function.

[0055] FIG. 6 shows a playing field 1 in schematic top view with a marking pattern 4 generated by several marking devices 2. Each marking device 2 projects a circular arc shaped marking component 4′, 4″, 4″' onto the playing field 1. The central point can be projected simultaneously by several marking devices 2. This reduces the shadings from people being on the playing field.

[0056] FIG. 7 shows a playing field 1 with further marking patterns 4 in schematic top view. The marking pattern 4 is projected onto the playing field 1 by a single marking device 2. As can be seen in FIG. 7, the marking pattern 4 is not a complete circle, but a circular arc, which is cut off by the edge 6 of the playing field 1. The system according to the invention prevents the marking pattern 4 from being projected outside the edge 6 in order to avoid unwanted irradiation on persons outside the playing field 1.

[0057] As shown in FIGS. 1, 6, and 7, the playing field 1 is divided into 4 marking areas 7.

[0058] The raised arrangement of the marking devices 2 results in an angle a with respect to the horizontal plane between each point of the playing field 1 and the marking device. It is advantageous if the angle at any point of a marking area 7 is kept between 30° and 90° in order to prevent the angle of incidence of the laser irradiation from being too flat and therefore to prevent a hazard to persons located at the playing field.

[0059] In the following, a method according to the invention is explained in detail by means of an exemplary embodiment with reference to the figures described above.

[0060] The first method step consists in projecting a predetermined grid-shapes calibration pattern 3 onto the playing field 1. Due to the angular arrangement between the marking devices 2 and the playing field 1, the calibration pattern 3 is distorted and a calibration projection 8 becomes visible on the playing field 1.

[0061] The imaging device of the system according to the invention produces an image of the calibration projection 8 and transmits it to the analysis device. The analysis device processes the image and compares it to the known geometry of the calibration pattern 3. From this, a distortion function is determined for a plurality of points on the playing field.

[0062] Now marking patterns 4 can be reproduced on the playing field 1 without distortion.

[0063] For this purpose, the position and the shape of a marking pattern 4 is predetermined in a control device. The transformation device uses the inverse distortion function on the marking pattern 4, and a target marking 5 is projected onto the playing field 1 by the marking devices 2.

[0064] By using the inverted distortion function on the marking pattern 4, it is reproduced on the playing field 1 without distortion.

[0065] In this example, determining the position of the marking pattern 4 is carried out manually through determination of a software. Alternatively, the determination may also be carried out through a tracking device, for example by automatically determining the position of a person.

LIST OF REFERENCE SIGNS

[0066] 1 Playing field [0067] 2 Marking device [0068] 3 Calibration pattern [0069] 4 Marking pattern [0070] 4′, 4″, 4″′ Marking component [0071] 5 Target marking [0072] 6 Edge [0073] 7 Marking area [0074] 8 Calibration projection