Hardy's Multi-Quadric method of calibrating a wireless electromagnetic localization system for intestinal micro-devices

Article type: Research Article

Authors: Guo, Xudong^{a; *} | Yan, Rongguo^a | Wang, Cheng^a

Affiliations: [a] School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China

Correspondence: [*] Corresponding author: Xudong Guo, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China. Tel.: +86 21 55271115; Fax: +86 21 55270695; E-mail: [email protected]

Abstract: A wireless electromagnetic localization method for tracking a medical micro-device in the gastrointestinal tract has been proposed and a prototype for the localization system has been developed. In the electromagnetic localization system, several excitation coils were mounted above the abdomen of human body to generate a varying electromagnetic field one by one. Then a wireless magnetic sensor was used to measure the magnetic field strength at the location of the micro-device. Thus the position and orientation of the micro-device could be obtained by solving the inverse problem of magnetic fields. In order to improve the localization precision, a global error correction technique based on the Hardy's Multi-Quadric scattered data interpolation method was investigated to correct the static errors. In the calibration experiment, dependencies between true locations of the micro-device and the corresponding tracked locations within the operational space were established. Based on these data sets, the Hardy's Multi-Quadric correction function was derived. The experimental results show that the localization error can be greatly reduced by using the Hardy's Multi-Quadric correction method. The advantage of the approach is that it allows for smooth continuous mapping from the tracked space to the true space within the entire tracked space.

Keywords: Electromagnetic localization, a wireless magnetic sensor, calibration, Hardy's Multi-Quadric method, intestinal micro-devices

DOI: 10.3233/JAE-121609

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 251-258, 2013