( 2 ) the backbone is almost constantly pointing at a fixed direction ( see [ 1 ]). the above physical rules dictate the motion of the golfer &# 39 ; s upper body . deduced from these rules , to obtain a golfer &# 39 ; s upper body mechanics , we only need to calculate : how to calculate the backbone positions of the player 100 is shown in fig1 and fig2 . fig1 contains a sequence of golf swing frame pictures two fixed locations m 1 and m 2 are marked on the golfer &# 39 ; s backbone and are connected with a line ( see fig1 ). the same process is repeated for all the frames . we will then have a set of lines note that for the reason of simplicity m 1 and m 2 are not drawn on all the frames . once we have the geometry of ( b 1 , b 2 . . . b 5 ), the next step is to get the ( x , y , z )- coordinates of ( b 1 , b 2 . . . b 5 ). to get the ( x , y , z )- coordinates we need both the front and side views . 201 and 203 of fig2 shows the ( x , y ) components of b 1 . 202 and 204 of fig2 shows the ( y , z ) components of b 1 . add the z - component of ( y , z ) to ( x , y ) and we will have the ( x , y , z )- coordinates of b 1 . repeat the same process for all the frames and we will have all the ( x , y , z )- coordinates of b 1 , b 2 . . . b 5 . with the backbone positions defined , we can now calculate the upper body rotation angles around the backbone . in 301 of fig3 for each frame photo we select two fixed locations m 3 and m 4 on the shoulder . connect m 3 and m 4 with a line . repeat the same process for all the frames . we will then have a set of lines : let a 1 be the upper body rotating angle of the first frame . note that to calculate a 1 , is equivalent to calculate the rotating angle which rotates line s 1 to s 2 around the backbone b 1 ( see 302 of fig3 ). also note that the calculation of a 1 is straight forward . there is no need to calculate the z - component of s 1 and s 2 . we only need to treat the z - component of s 1 as zero and ignore the z - component of s 2 . repeat the same process for all the frames . we will then have all the angles in fig4 , we redraw all the backbones bi ( i = 1 , 2 . . . 5 ) by giving ( 1 ) equal distance on x - direction and ( 2 ) the length of bi equals ai . the diagram we obtained is called the body acceleration diagram diag - body 402 ( fig4 ) and it represents the upper body mechanics of the golfer . the upper body acceleration diagram can be used to determine if the golfer moves his / her upper body correctly . the determination is done by comparing the diagram generated by the golfer with a correct one stored in database . see diag - bodyd 401 ( fig4 ). the diagram stored in database is either known as the expert knowledge or predefined conditions . 401 of fig4 is a correct acceleration diagram stored in database and 402 is an incorrect acceleration diagram generated by the golfer . from the comparison of these two diagrams , the system can obviously make a suggestion to the player that he / she needs to rotate his / her upper body more during the down swing . same as the upper body , the hip mechanics of a golf swing ( i . e . the angle that the hip rotates around the backbone ) can also be calculated in the same way . the only difference is that to calculate the angles we use the waist lines instead of the shoulder lines ( s 1 , s 2 . . . s 5 ). fig5 shows how to construct the waist lines . select two fixed locations m 1 and m 2 on the waist , and then connect m 1 and m 2 with a line w 1 . note that only w 1 is drawn in fig5 . for the simplicity of drawing , w 2 , w 3 . . . w 5 are not shown . ( rules - b ) ( a ) during a golf swing , the club head stays in a plane and this plane is known as the swing plane ([ 1 ]). ( b ) the golfer &# 39 ; s hand ( or arm ) will also stay in a slightly different plane . in 601 of fig6 pl is the swing plane of the club head and pn is the plane normal of pl . the ( x , y z )- coordinates of pn are shown in 601 and 602 of fig6 . in 701 of fig7 , two fixed points m 1 and m 2 are selected on the club . connect m 1 and m 2 we will have a line . repeat the same process and we will have a set of lines note that for simplicity only c 1 and c 2 are drawn . in 702 of fig7 , we define the angle an 1 as the rotating angle from c 1 to c 2 around the plane normal pn . similar to the calculation of the said body angle a 1 , the calculation of an 1 is also straight forward . repeat the same calculation and we will have all the club angles in fig8 we construct a diagram by giving the y - values at xi equals ani , where i = 1 , 2 . . . 5 . the diagram we obtained here is called the club acceleration diagram diag - cha 802 , shown in fig8 . similar to body acceleration , the club acceleration diagram can also be used to determine if the golfer moves his / her club correctly . the determination is done by comparing the diagram generated by the golfer with a correct one stored in database . see diagram diag - chad 801 ( fig8 ). the diagram stored in database is either known as the expert knowledge or predefined conditions . fig8 shows a correct acceleration diagram diag - chad 801 stored in database and an incorrect acceleration diagram diag - cha 802 generated by the golfer . from the comparison of these two diagrams , once again the system can obviously make suggestion to the player that he / she needs to accelerate the club more during the down swing . the hand ( or arm ) mechanics can also be calculated in the same way as the club rotation . the only differences are : ( a ) hand ( or arm ) rotates around a slightly different plane pl ′. the plane normal pn ′ of pl ′ is very close to pn . the ( x , y , z )- coordinates of pn ′ can also be obtained in the same way as pn . ( h 1 , h 2 . . . h 5 ) or arm lines instead of club lines ( c 1 , c 2 . . . c 5 ). fig9 shows how to construct lines ( h 1 , h 2 . . . h 5 ) and ( am 1 , am 2 . . . am 5 ). three fixed locations m 1 , m 2 and m 3 are selected . line h 1 is constructed by connecting m 1 and m 2 and the line am 1 is constructed by connecting m 1 and m 3 . note that only h 1 and am 1 are drawn in fig9 . for simplicity , the rest of lines are not drawn . similarly , once the hand ( or arm ) mechanics are calculated , we can also construct the hand ( or arm ) acceleration diagram diag - cha 802 ( fig8 ). furthermore the system can then make suggestion to the player by comparing the diagram generated by the golfer with the one stored in database . see diag - chad 801 ( fig8 ). once again the diagram stored in database is either known as the expert knowledge or predefined conditions . fig1 shows the data flow of the system . video photos 1001 are the input to the system . physical rules 1002 are used for calculation . the body mechanics are calculated in 1003 . the results of 1003 are passed to 1004 for swing analysis . the results of 1004 are used by 1005 to give advices to the golfer . note that in calculating the body mechanics of a golf swing , rules rules - a and rules - b are used as the foundation of the calculation . for other sports such as baseball or tennis the player &# 39 ; s body mechanics will satisfy a different set of physical rules . to calculate the body mechanics , these different rules should be used .
the invention is a motion training method . the motion of golf swing will be emphasized . in order to guide a golfer through a proper swing , his / her swing must be analyzed first . to analyze the swing , a set of frame photos will be needed . from those frame photos , the invented method will provide a rule based method to calculate the body mechanics / forces of the golfer . once the body mechanics / forces are known , the system will then determine the swing is correct or incorrect . if the swing is incorrect , the system will then make suggestions to the golfer about how to correct his / her swing .