System and method for detecting golf swing with a ball impact

Abstract

The invention relates to a method, system, detection apparatus and computer program for recognizing a collision of a golf club with a golf ball. In the invention the recognition procedure is configured to be executed partly in a motion sensor ( 22 ) of a detection device ( 2 ), party in the processor unit ( 20 ) of the detecting device and a mobile information processing device ( 6 ). The most complex processing and computation steps are executed in the processor unit ( 60 ) of the mobile information processing device ( 6 ). Due to the shared computations the result of the algorithm is accurate. Also the power consumption of the detecting device ( 2 ) is low which provides for a long operating time and accurate hit detection at the same time.

1 . A golf swing and ball hit recognition system comprising:
 a swing detection device ( 2 ) configured to be attached to a golf player's wrist or forearm, the detection device comprising:   a battery ( 29 )   a power/energy management circuit ( 21 );   a tag reader ( 23 );   a motion sensor ( 22 );   a processor unit ( 20 ) comprising a memory unit ( 24 ) including a computer program;   the memory unit ( 24 ) and the computer program configured to, with the processor unit ( 20 ), cause the swing detection device ( 2 ) at least to process motion sensor ( 22 ) data and;   a wireless transceiver ( 28 ); and   a mobile device ( 6 ) comprising computer program to process motion data received from the swing detection device ( 2 ),   characterized in that the ball hit recognition process comprises at least one detection stage in the swing detection device ( 2 ) or in the mobile device ( 6 ) where a particular detection stage ( 220 ,  240 ,  600 ) comprises a particular gesture recognizer accomplished by program modules that are configured to recognize particular golf swing sub-gestures ( 30 ,  40 ,  41 ) or a collision event ( 42 ) between a golf club and a golf ball ( 31 ).   
     
     
         2 . The system according to  claim 1 , characterized in that a recognizer program module comprises a field-programmable gate array (FPGA) or a software application. 
     
     
         3 . The system according to  claim 1 , characterized in that the golf swing and ball hit recognition procedure is divided into a stillness recognizing phase ( 80 - 89 ), a swing recognizing phase ( 112 ,  113 ), a collision recognizing phase ( 90 - 98 ,  116 - 117 ), and a follow through recognizing phase ( 114 ,  115 ). 
     
     
         4 . The system according to  claim 1 , characterized in that the motion sensor ( 22 ) is one of the following: an accelerometer, a combination of accelerometers, a gyroscope, a combination of an accelerometer and a gyroscope, a magnetometer, or a combination of a gyroscope and a magnetometer. 
     
     
         5 . The system according to  claim 1 , characterized in that the mobile device ( 6 ) is a dedicated device or a general purpose device with added processing software. 
     
     
         6 . The system according to  claim 2 , characterized in that the gesture recognizers comprise at least one of the following program modules:
 a first program module to detect a stillness sub-gesture ( 30 ) preceding a swing sub-gesture ( 40 ,  41 );   a second program module to detect a collision event ( 42 ) of the golf club with a golf ball ( 31 );   a third program module to detect a swing gesture including a combination of a backswing ( 40 ) and a downswing sub-gesture ( 41 ), collision event ( 42 ), and a follow through sub-gesture ( 43 ).   
     
     
         7 . The system according to  claim 6 , characterized in that the first program module comprises a stillness ( 30 ) recognizer configured to detect device orientation ( 81 ,  82 ,  85 ,  86 ) and device stillness ( 83 ,  87 ,  88 ). 
     
     
         8 . The system according to  claim 7 , characterized in that the orientation and stillness sub-gesture ( 30 ) recognizer comprises a state machine with thresholds and timers configured to be executed in the motion sensor ( 22 ). 
     
     
         9 . The system according to  claim 6 , characterized in that the second program module comprises a collision event ( 42 ) recognizer configured to:
 stream data ( 90 ,  91 ) from a 3D motion sensor ( 22 );   filter ( 92 ) data of the motion sensor with a bandpass filter;   vectorize ( 93 ) the data of X, Y, and Z axis of the 3D motion sensor;   compose ( 94 ) an absolute value from the motion sensor vector data;   filter ( 95 ) said absolute values with a low pass filter;   detect ( 96 ,  97 ) the collision with the ball from said data stream of absolute values, and if detected;   initialize ( 98 ) a data transfer from the 3D motion sensor ( 22 ) to the mobile device ( 6 ).   
     
     
         10 . The system according to  claim 9 , characterized in that the second program module further comprises a state machine with thresholds and timers configured to be executed in the MPU ( 20 ) of the swing detection device ( 2 ). 
     
     
         11 . The system according to  claim 6 , characterized in that the third program module comprises a collision event ( 42 ) recognizer configured to:
 stream data from a 3D motion sensor ( 22 ) of the swing detection device ( 2 );   filter data of the motion sensor stream with a bandpass filter;   vectorize said data stream;   compose an absolute value from the motion sensor vector data;   filter said absolute values with a low pass filter;   stream the filtered values; and   detect a hit due to a peak found from stream of the filtered values.   
     
     
         12 . The system according to  claim 11 , characterized in that the third program module further comprises a backswing recognizer and a downswing recognizer configured to detect a backswing sub-gesture ( 40 ), a transition between the backswing sub-gesture ( 40 ) and a downswing sub-gesture ( 41 ) and to detect the downswing sub-gesture ( 41 ). 
     
     
         13 . The system according to  claim 11 , characterized in that the third program module comprises a peak detector including a state machine with thresholds, timers and filters that are configured to be accomplished by the third computer program module when it is executed in the CPU of the mobile device ( 6 ). 
     
     
         14 . The system according to  claim 6 , characterized in that the third program module comprising the collision recognizer is configured to:
 stream data from the motion sensor;   filter data of a 3D motion sensor with a bandpass filter;   calculate cross-correlation between the acquired signal and an example collision signal, and;   detect a hit due to a peak found from said cross-correlation signal.   
     
     
         15 . The system according to  claim 14 , characterized in that third program module is configured to be executed in the CPU of the mobile device ( 6 ). 
     
     
         16 . A swing detection device ( 2 ) configured to be attached to a golf player's wrist or forearm, the detection device comprising:
 a battery ( 29 );   a power/energy management circuit ( 21 );   a club identification reader ( 23 );   wireless transceiver ( 28 );   a motion sensor ( 22 );   a processor unit ( 20 ) comprising a memory unit ( 24 ) including a computer program module;   the memory unit ( 24 ) and the computer program module configured to, with the processor unit ( 20 ), cause the swing detection device ( 2 ) at least to process motion sensor ( 22 ) data,   characterized in that a golf ball hit recognition process comprises at least one detection stage in the swing detection device ( 2 ) and that a first detection stage comprises a particular gesture recognizer accomplished by program modules that are configured to recognize at least a first golf swing sub-gesture ( 30 ) and a second golf swing sub-gesture ( 42 ).   
     
     
         17 . The swing detection device according to  claim 16 , characterized in that the program modules comprise at least a first program module configured to recognize a stillness sub-gesture ( 30 ) when the first program module is executed in the motion sensor ( 22 ). 
     
     
         18 . The swing detection device according to  claim 17 , characterized in that the program modules comprise also a second program module configured to recognize a collision ( 42 ) of a golf cub ( 5 ) with a golf ball ( 31 ) when the second program module is executed in the processor unit ( 20 ) of the swing detection device ( 2 ). 
     
     
         19 . The swing detection device according to  claim 18 , characterized in that the second program module comprises a hit recognizer configured to:
 stream data ( 90 ,  91 ) from the 3D motion sensor ( 22 );   filter ( 92 ) data of the motion sensor with a bandpass filter;   vectorize ( 93 ) the data of the X, Y, and Z axis of the 3D motion sensor;   compose ( 94 ) an absolute value from the motion sensor vector data;   filter ( 95 ) said absolute values with a low pass filter;   detect ( 96 ,  97 ) the collision event ( 42 ) with the ball from said data stream of filtered values, and if detected;   initialize ( 98 ) a data transfer from the 3D motion sensor ( 22 ) to the mobile device ( 6 ).   
     
     
         20 . A swing detection device substantially as any one embodiment herein described with reference to the accompanying drawings.