Precise Positionging And Tracking Technology For Wireless Apsule Endoscopy

In the course of gastrointestinal detection,traditional cable-type endoscope will bring patients great pain.The development of wireless capsule endoscopy not only reduces the pain of patients,but also to achieve the gastrointestinal tract examination.When using capsule endoscopy,it is necessary to obtain the position parameters and direction parameters of the capsules in the human body accurately,so as to obtain the position parameters and direction parameters of the lesion tissue captured by the capsule endoscope.These parameters facilitate the doctor to accurately diagnose the condition.Accurate and fast positioning of capsules is a critical issue.In this paper,a magnetic localization algorithm is proposed,which corrects the near-field error and the human-body interference error in the magnetic localization algorithm,and proposes a six-dimensional hybrid magnetic localization algorithm to effectively solve these problems.In this paper,the magnetic induction intensity distribution model is based on the magnetic dipole model established,the model used is LM optimization algorithm.The magnetic positioning system used in this paper includes the hardware part and the software part.The hardware part includes the magnetic sensor array,signal amplification circuit,K60 embedded module;the software part includes the upper computer magnetic positioning software program.First,in order to eliminate the near-field error of the magnetic dipole model,a near-field localization algorithm is proposed.The method minimizes the error in the calculated and measured magnetic flux density from the global coordinate system to the magnet coordinate system.Secondly,in order to eliminate the interference error caused by the human body moving,the method of converting the magnetic localization result of the target permanent magnet into the reference coordinate system is put forward.In this method,two reference permanent magnets are set on the external surface of the human body.Based on these reference permanent magnets,the reference coordinate system is established and the positioning result is transformed into the coordinate system.Thereby reducing the interference of human body movement error.Finally,because the magnetic localization algorithm can only realize the five-dimensional parameter magnetic localization for the cylindrical permanent magnet(including the three-dimensional position coordinate parameter and the two-dimensional direction vector parameter),but can not get the target permanent magnet's own rotation angle parameter.In this paper,a hybrid algorithm of image location and magnetic localization is proposed.The algorithm can obtain the parameters of permanent magnet's rotation angle while realizing the permanent magnet's five-dimensional parameter magnetic localization.Dimensional magnetic orientation of the permanent magnet is realized.At the same time,the experimental results show that the method is more accurate than the magnetic localization method.