Automated line calling system

Abstract

A system and appertaining method are described to detect whether a projectile impact occurs on one side of a boundary line or the other. The system utilize force sensing resistor-based sensors that may be configured in sections or groups and connected to a control system with a display. An impact classification system is provided for distinguishing between various events, including a footstep, ball impact and tennis racquet contact. A sensor monitoring system is provided for determining the health of sensors and provding an error indication if sensor problems exist. A service detection system is provided when the system is used for tennis that permits activation of selected groups of sensors and deactivation of others.

1 . A system for determining whether a ball bounce occurs on an inside of a boundary line or an outside of the boundary line, comprising: 
 a) a sensor or sensor sections comprising an output that provides either an analog signal or a multilevel digital signal related to a force present on the sensor or sensor section;    b) a signal analysis unit comprising: 
 b1) an input connected to the sensor signal output;  
 b2) circuitry or a memory containing predetermined information related to a footstep characteristic curve and a ball bounce characteristic curve, the characteristic curve information comprising at least one of duration of activation information, amplitude information, peak information, frequency information, or curve shape information;  
 b3) a classifier configured to classify a signal received from the sensor as at least one of: 1) a ball bounce by utilizing the ball bounce characteristic curve information, and 2) a footstep by utilizing the footstep characteristic curve information;  
 b4) the classifier comprising an event output at which a signal is output, the event output signal comprising at least an OUT event indicating a ball bounce classified outside of the boundary line.  
   
   
   
       2 . The system as claimed in  claim 1 , wherein the sensor or sensor sections comprise: 
 an IN portion located on the inside of the boundary line, the IN portion having a signal output that is a part of the sensor output; and    an OUT portion located on the outside of the boundary line, the OUT portion having a signal output that is a part of the sensor output;    the classifier utilizing the IN portion signal output in order to classify a signal representing an IN event.    
   
   
       3 . The system as claimed in  claim 1 , wherein multiple sensor sections are utilized, and the classifier event outputs associated with each sensor section are provided to inputs of an event integrator, the event integrator serving to further filter multiple classifier event outputs.  
   
   
       4 . The system as claimed in  claim 1 , wherein the signal is transformed into a conductance signal prior to being classified.  
   
   
       5 . The system as claimed in  claim 1 , wherein signals from multiple adjacent sensor sections are combined prior to being classified.  
   
   
       6 . The system as claimed in  claim 1 , wherein: 
 the circuitry or memory containing predetermined information further contains information related to a racquet characteristic curve; and    the classifier is further configured to classify: 3) a racquet hit by utilizing the information related to a racquet hit characteristic curve.    
   
   
       7 . The system as claimed in  claim 1 , wherein: 
 the characteristic curve information comprises duration of activation information having predetermined time duration values or ranges at a predetermined or calculated measurement threshold signal level;    the classifier further comprising circuitry or algorithms configured for determining a duration of an input signal at the predetermined threshold signal level and comparing the input signal duration against the predetermined time duration values or ranges for utilization in the classifying of the signals.    
   
   
       8 . The system as claimed in  claim 7 , wherein: 
 the characteristic curve information additionally comprises amplitude information, the classifier further comprising circuitry or algorithms configured for utilizing the amplitude information in classifying the signals.    
   
   
       9 . The system as claimed in  claim 7 , wherein: 
 the information comprising duration of activation information further comprises predetermined time duration values or ranges at an additional predetermined threshold signal level;    the classifier circuitry or algorithms further configured for determining an additional duration of the input signal at the additional predetermined threshold signal level and further comparing the additional input signal duration against the additional predetermined time duration values or ranges for utilization in the classifying of the signals.    
   
   
       10 . The system as claimed in  claim 1 , wherein: 
 the information comprising duration of activation information further comprises predetermined peak detection values    the classifier circuitry or algorithms being further configured for determining the number of peaks in the input signal within a predetermined time duration and further comparing the number and size of peaks against the peak detection values.    
   
   
       11 . The system as claimed in  claim 1 , wherein the calculated measurement threshold signal level is calculated based on a relationship with a base-level signal.  
   
   
       12 . The system as claimed in  claim 1 , wherein the classifier further comprises a transform into the frequency domain such as a Fast Fourier Transforms (FFTs) or a wavelet transform, the classifier utilizing the frequency information in operating on the sensor signal and utilizing characteristic curve information containing frequency information.  
   
   
       13 . The system as claimed in  claim 1 , wherein the classifier further comprises a correlator to compare sampled sensor signal data with characteristic curve shape information.  
   
   
       14 . The system as claimed in  claim 1 , wherein the force sensing resistor comprises at least one layer of force sensing ink or paint and at least one layer of conductive material applied between sealed strips of plastic.  
   
   
       15 . The system as claimed in  claim 1 , wherein the force sensing resistor comprises at least one layer of force sensing rubber and at least one layer of conductive material applied between sealed strips of plastic.  
   
   
       16 . A system for determining whether a ball bounce occurs on an inside of a boundary line or an outside of the boundary line, comprising: 
 a) a sensor or sensor sections comprising an output that provides either an analog signal or a multilevel digital signal related to a force present on the sensor or sensor section;    b) a health monitoring system comprising: 
 b1) an input for monitoring a signal related to each sensor or sensor section;  
 b2) at least one of circuitry and an algorithm for distinguishing a properly operating sensor or sensor section from one that is improperly operating indicating an error; and  
 b3) an output for providing an indication of a sensor, sensor section, or system error; and  
   c) an error notification system comprising an input connected to the output of the health monitoring system and an output connected to a user notification device.    
   
   
       17 . The system as claimed in  claim 16 , wherein: 
 the sensors or sensor sections comprise a leakage resistor; and    the health monitoring system comprises circuitry for detecting a signal related to a current flow through the leakage resistor thereby indicating a connected and possibly correctly operating sensor and for detecting the absence of this signal thereby indicating a disconnected or malfunctioning sensor or sensor section, the health monitoring system configured to provide an error output to the error notification system given the absence of this signal.    
   
   
       18 . The system as claimed in  claim 16 , wherein: 
 the health monitoring system comprises a table containing values or ranges indicative of proper operating values or ranges for the sensors, and comparator circuitry or algorithms for comparing a signal received at the respective monitoring inputs with the values or ranges contained in the table, the health monitoring system configured to provide an error output to the error notification system if the signal is outside of the value or ranges indicative of a proper operation of the sensors or sensor sections.    
   
   
       19 . The system as claimed in  claim 16 , further comprising a base-level signal calculator, the base-level signal calculator comprising: 
 an input at which is received a signal from one or more of the sensors;    a calculator configured to establish a base-level sensor signal when the sensor is not under pressure; and    a comparator configured to determine if the base-level sensor signal is above or below a predetermined threshold; and    an output connected to the input of the health monitoring system at which information related to the base-level sensor signal is provided.    
   
   
       20 . The system as claimed in  claim 19 , wherein the base-level signal calculator further comprises: 
 a timer configured to periodically trigger an adjustment of the base-level signal during play;    a memory for holding signal values between periodic triggering of the timer; and    a mechanism for eliminating the signal values stored in the memory that exceed values related to ball bounces, footsteps and racquet hits and determining a new base-level signal based on an average of remaining signal values.    
   
   
       21 . A system for determining whether a ball bounce occurs on an inside of a boundary line or an outside of the boundary line, comprising: 
 a) a sensor or sensor sections comprising an output that provides either an analog signal or a multilevel digital signal related to a force present on the sensor or sensor section;    b) a serve condition detection system, comprising: 
 b1) an input configured to receive an indication of a service and an indication of a service court for which the service is to occur; and  
 b2) an activation mechanism for activating a sensor group associated with service lines related to the service court and deactivating sensor groups associated with service lines unrelated to the service court.  
   
   
   
       22 . The system as claimed in  claim 21 , wherein: 
 a sensor located behind one of the baselines provides its output to the input of the serve condition detection system; and    the detection system being configured to determine which service court sensor group to activate based on a predetermined prolonged signal from the sensors behind one of the baselines indicative of a person standing behind the baseline.    
   
   
       23 . The system as claimed in  claim 21 , further comprising one or more wireless or wired devices configured to provide a signal indicative of the service area to the input of the serve condition detection system.  
   
   
       24 . The system as claimed in  claim 21 , further comprising a switch for activating and deactivating the serve condition detection system.