Method and apparatus for sport swing analysis system

Abstract

A sports swing analysis system analyzes radiation reflected from retroreflective material coupled to a sports implement in order to determine parameter values related to the swung sports implement.

1 . An apparatus for analyzing a swung sports implement coupled to retroreflective material comprising: 
 a radiation source configured to emit electromagnetic radiation toward a location in the path of a swung sports implement;    a radiation receiver configured to receive electromagnetic radiation reflected from the swung sports implement; and    a controller configured to generate at least one signal for each transition in light level reflected from the retroreflective material corresponding to the leading or trailing edge of the retroreflective material.    
   
   
       2 . The apparatus of  claim 1  wherein the implement further comprises: 
 light-absorptive material coupled to the sports implement to create at least one transition area wherein the implement presents an area of high contrast between highly absorptive and highly reflective regions.    
   
   
       3 . A golf swing analysis system for use with a golf club to be swung, comprising: 
 a retroreflective strip coupled to the golf club head;    a light source configured to emit light toward a location in a path of the swung golf club;    a light receiver configured to receive light reflected from the reflective materials; and    a processor configured to generate at least one signal for each transition in light level reflected from the reflective material attached to the club.    
   
   
       4 . The system of  claim 3  wherein the processor is further configured to: 
 differentiate a signal generated by light reflected from the attached reflective material; and    correlate the differentiated signal to transitions in light levels reflected from the reflective material.    
   
   
       5 . The system of  claim 4  wherein the processor is further configured to: 
 divide the width of the attached reflective material by the time between two transitions in light reflected from the reflective material to obtain the club head speed.    
   
   
       6 . The system of  claim 5  wherein the processor is further configured to: 
 compare the club head speed to a threshold club head speed to determine whether the transitions in light level are associated with an undesirable artifact.    
   
   
       7 . The system of  claim 4  wherein the processor is further configured to: 
 receive reflected light at a plurality of locations; and    divide the distance between two receiving locations by the time between two light transition events to obtain the club head speed.    
   
   
       8 . The system of  claim 6  wherein the processor is further configured to: 
 correlate reflected light signals for a plurality of locations to determine whether the light level transitions are associated with an undesirable artifact.    
   
   
       9 . A golf swing analysis method for use with a golf club having a strip of retroreflective material, comprising the steps of: 
 (A) emitting a light toward a location in a path of the swung golf club;    (B) receiving light reflected from the retroreflective material; and    (C) generating at least one signal for each transition in light level reflected from the retroreflective material corresponding to a leading or trailing edge of the retroreflective material.    
   
   
       10 . The method of  claim 9  wherein step (C) further comprises the steps of: 
 (C1) differentiating a signal generated by light reflected from the retroreflective material; and    (C2) correlating the differential signal to transitions in light levels reflected from the retroreflective material.    
   
   
       11 . The method of  claim 10  wherein the width of the retroreflective material is predetermined and the method further comprises the step of: 
 (D) dividing the width of the retroreflective material by the time between two transitions in light reflected from the reflected material to obtain the club head speed.    
   
   
       12 . The method of  claim 11  further comprising the step of: 
 (E) comparing the club head speed to a threshold club head speed to determine whether the transitions in light level are associated with club head movement of interest or the transitions are associated with an undesirable artifact.    
   
   
       13 . The method of  claim 9  further comprising the steps of: 
 (F) receiving reflected light at a plurality of locations; and    (G) dividing the distance between two receiving locations by the time between two light transition events to obtain the club head speed.    
   
   
       14 . The method of  claim 11  further comprising the steps of: 
 (H) correlating reflected light signals for a plurality of locations to determine whether the light level transitions are associated with club head movement of interest or the transitions are associated with an undesirable artifact.    
   
   
       15 . The method of  claim 9  further comprising the step of: 
 (J) employing a plurality of transmitters and receivers along the expected golf club head flight path; and    (K) using one or more of the receivers as a trigger for other transmitters and receivers, whereby the activation of a trigger receiver by reflected light activates non-trigger transmitters and receivers.    
   
   
       16 . The method of  claim 9  wherein the step of activating non-trigger transmitters and receivers further comprises the step of: 
 (K1) activating the transmitters at a high power level.    
   
   
       17 . The method of  claim 9  further comprising the step of: 
 (L) computing a club swing path angle.    
   
   
       18 . The method of  claim 9  further comprising the step of: 
 (M) computing a club head angle.    
   
   
       19 . The method of  claim 9  further comprising the step of: 
 (N) computing a club head lateral alignment.    
   
   
       20 . The method of  claim 9  further comprising the step of: 
 (O) computing an effective club head speed.    
   
   
       21 . A method of determining the height of a swung golf club head comprising the steps of: 
 (A) emitting a light toward as location in a path of the swung golf club;    (B) receiving light reflected from the retroreflective material; and    (C) generating at least one signal in response to the reception of light reflected from the club head,    (D) employing light reflected from a light source that is substantially perpendicular to the flight path of a golf club head and light reflected from a light source that is at an angle between perpendicular and parallel to that of the flight path of a golf club head to determine the height of the swinging golf club head.    
   
   
       22 . The method of  claim 21  wherein the steps of determining the golf club head height comprises the steps of: 
 (E) determining the time between light level transitions corresponding to the points of intersection of the retroreflective material and light beamed from a transmitter that is oriented substantially perpendicular to the flight path of a golf club head and light level transitions reflected from a light source beamed at a known angle between perpendicular and parallel to that of the flight path of a golf club head;    (F) employing the club head speed and the time between light level transitions to determine the distance between the points of intersection with perpendicular and angled beams; and    (G) employing the angle and distance between points of intersection to determine the club head height.