Pose and Biopsy Sensing for Capsule Robot Based on Conditioned Multiple Magnets Tracking

Capsule robots (CRs) with biopsy functions is of great importance in clinical diagnosis. However, localization and sensing method for biopsy CR was still lacking in clinical scenarios. In this study, we provide a novel constraint multimagnet sensing method to locate the biopsy CR and evaluate the pop-out length of the biopsy needle, which is based on multimagnet tracking and constraints from the relationship between the magnets inside the biopsy CR. In-vitro experiments with biopsy CR have been conducted to verify the proposed method. The mean position error was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1.83\pm 0.21$</tex-math></inline-formula> mm. The mean orientation error is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.013\pm 0.004^\circ$</tex-math></inline-formula>. The mean pop-out length error of all the samples is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1.67\pm 0.32$</tex-math></inline-formula> mm. The proposed method can locate the biopsy CR effectively, making it a valuable addition to noninvasive gastrointestinal diagnosis and treatment.