Real-Time Pose Detection for Magnetic Medical Devices

Abstract

Magnetic coupling is one of the few physical phenomena capable of transmitting motion across a physical barrier. In gastrointestinal endoscopy, remote magnetic manipulation has the potential to make screening less invasive and more acceptable, thus saving lives by early diagnoses and treatment. Closed-loop control of the magnetic device position is crucial for a safe and reliable operation. In order to implement closed-loop control, the pose (position and orientation) of the device must be available in real-time. This becomes challenging if magnetic coupling is achieved by permanent magnets, since the strong magnetic field required for manipulation interferes with current localization techniques. In this work, we present a novel real-time pose detection strategy that is compatible with magnetic manipulation based on permanent magnets. The localization algorithm combines multiple sensor readings with a pre-calculated magnetic field map. The proposed approach is able to provide an average error below 5 mm in position detection, and below 19 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{\circ}$</tex></formula> for angular motion within a spherical workspace of 15 cm in radius.