DE3633305A1 - PVDF location detector system for monitoring, for example, the lines bounding a tennis court - Google Patents

Abstract

A PVDF location detector system for monitoring, for example, the lines bounding a tennis court, which is characterised by a three-strip system which is integrated into a line segment to be monitored and comprises three strips (1, 2, 3) of a pressure-sensitive material, preferably PVDF, which are preferably arranged on a plastic support system parallel to one another in the direction of the court-bounding line and are at a distance (d) from one another which is preferably equal to the average diameter of the balls used, the middle strip (2) running in the actual court-bounding line (ef1), and an evaluation device, which establishes the relationship between the signal amplitudes emitted by the pressure-sensitive strips (1, 2, 3) and, depending on the signal amplitude configuration, emits a signal corresponding to this configuration, namely one signal ("in") for balls bouncing inside the court and one signal ("out") for balls bouncing outside the court. The evaluation device also senses by means of a comparator threshold, set by a one-off experiment, the size of the vertical pulse of the bouncing ball, to be able to sense bouncing situations which otherwise could not be unequivocally sensed. <IMAGE>

Description

The present invention relates to a PVDF location detector system stem for monitoring, for example of tennis court loading boundary lines.

For monitoring the important in tennis for the course of the game Boundary lines of the playing field must be determined objectively whether a ball hitting the ground is valid ("in") or is invalid ("out"). The current ball speed should not play a decisive role in this.

The most common solution to this problem is so far in it, six people (linesman) for the game Field around with the task of distributing the ball hit points according to the previously mentioned points of view through visu to assess all recording.

For some time now this has been the case at important tennis tournaments So-called "magic eye" is used, which the specially when opening important lines monitored and so the decision in the case of extremely high-speed balls, also objek activated (optical detection, supporting system).

An automatic monitoring system of whatever kind stem that would use single-strip sensors could not between a sound source to the left or right of the Distinguish stripe direction.  

The present invention is based on the object PVDF location detector system of the type mentioned at the beginning create, in which the line segment to be monitored in a Strip system made of pressure-sensitive PVDF films (piezo effect) is integrated. The location detector system should be able to be clear on which side of the line the ball touches the ground.

The object underlying the invention is achieved by a PVDF location detector system of the type mentioned and according to the preamble of the claim solved by the in the characterizing part of the claim specified Characteristics is characterized.

The use of a multi-strip system allows this partially, clearly determine which side the line the ball has touched the ground.

In the following, the present invention is based on a Figure, which is a preferred embodiment for the Er invention concerns, described in detail.

The figure shows in part a) a top view of an inventive three-strip system which is integrated in the line segment to be monitored. The middle of the three PVDF strips, preferably arranged on a plastic carrier, represents the actual field-delimiting line (efl) . The strip lying on top in the plan view lies on the inside of the field ("in") and the strip lying on the bottom in plan view lies on the outside of the field ( "out"). The strips are at a distance d from one another.

Part b) of the figure shows a view in the direction of the strip, which clearly shows the structure of the system.

Part c) of the figure schematically shows the monitoring principle.  

The signature given here ("1 <2 <3") means that strip 1 delivers the smallest signal, strip 3 provides the largest signal, etc. The signature ("1 <2 <3") means ("out"), and the signature ("3 <2 <1") means ("in"). In these signatures, the ball hits the ground outside the entire sensor system or touches an outer stripe, which corresponds to the simplest case. The following additional signatures can occur where the ball hits the stripe system, where "∼" means that the signal situation cannot be clearly separated electronically:

(3 <2∼1) means that the ball between strips 1 u. 2 ("in") hits, (3 <2 <1) means that the ball ("in") hits stripe 2 .

The cases mentioned so far are from the fiction system is clearly recorded.

The signature (3∼2 <1) means a critical case in which the ball between strips 2 u. 3 hits.

If you choose the distance d between two strips equal to the ball diameter D (d = D) , you get from the signature the statement that the ball has touched strips 2 and 3 . This is partly wrong if the ball hits the ground with a small vertical component of the momentum. Here it deforms too little to really be able to touch both lines. The size of the vertical pulse can, however, be detected by the signal amplitude. According to the invention, a comparator threshold is set so that the signature (3∼2 <1) judges the ball as ("out") if the comparator threshold has not been exceeded. This threshold has to be determined by experiment.

The detector system according to the invention can measure this correct all cases, even extremely rare ones to capture.  

The system described is basically the same as in the application very easy. It could be refined even further (Runtime → phase difference). However, this is even at Requirements that far exceed those of arbitration judge systems are not necessary.

The present invention is of course not based on limited an application of the type described above.

Claims (1)

PVDF location detector system for monitoring, for example tennis court boundary lines, characterized by a three-strip system integrated into a line segment to be monitored, consisting of three strips ( 1, 2, 3 ) preferably arranged on a plastic carrier system parallel to one another in the direction of the field-limiting line pressure-sensitive material, preferably PVDF, which are at a distance (d) from one another which is preferably equal to the average diameter of the balls used, the central strip ( 2 ) running in the actual field-delimiting line (efl) , and an evaluation device which relates the signal amplitudes emitted by the pressure-sensitive strips ( 1, 2, 3 ) to one another and, depending on the signal amplitude configuration, a signal corresponding to this configuration, namely a signal ("in") for balls hitting within the field or a signal ( "out") for balls hitting the field are which evaluation device further detects the magnitude of the vertical pulse of the impinging ball by means of a comparator threshold set by a single experiment, in order to be able to detect otherwise unambiguously ascertainable impact situations.