Variable step least mean square adaptive filtering method for wireless capsule endoscopy positioning system

The wireless capsule endoscope (WCE) is the main method to diagnose intestinal and gastrointestinal diseases, and the positioning system is an important part of WCE. The random electromagnetic interference (EMI) problem in WCE magnetic positioning method is discussed. A mathematical model of magnetic dipole magnetic signal interference is established, the effect of random interference on magnetic signal is reduced by using the variable step least mean square (VS-LMS) self-adaptive filtering algorithm. The pulse width, peak power and occurrence time of the three influencing factors are analyzed respectively. Finally, Monte Carlo experimental method was used to analyse the statistical distribution of magnetic interference signals.