A detailed calculating method of {HEAD ~ the position} of {TAIL ~ the touch point C} is familiar to one skilled in the art and is not be described here 
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A detailed calculating method of { HEAD ~ the position } of { TAIL ~ the touch point C } is familiar to one skilled in the art and is not be described here
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH