The Capsule Endoscope Positioning System

Wireless capsule endoscopy is a major breakthrough in endoscopic surgery,which overcomes the traditional cable endoscope’s two drawbacks: difficult toachieve a complete examination of the small intestine and causing much pain tothe patient, so the growth potential is limited. However, to further promote thecapsule endoscope,we have to determine the position of histopathology,resolvecapsule’s control, image’s quality, histopathological observation.This problemshave relations with the capsule’s location. Positioning the capsule endoscope hasa variety of methods. There is a method based on RF radio frequency signal,which uses eight antennas outside the human body receives the RF radiofrequency signal from the capsule, and calculate the capsule position by thealgorithm. In addition,3D ultrasound, medical imaging, such as X-rayimaging, CT and MRI can be used to locate. However, these methods are eithercomplex process, or low accuracy, it is difficult to meet the requirements.In this paper, we use magnetic positioning methods. That built-in magnetin the capsule, and use sensor array witch outside the body to detect magneticsignals, and use the magnetic dipole model to calculate its position andorientation parameters. Since magnets are static magnetic signal, the body doesnot affect, it can able to achieve high positioning accuracy. Meanwhile, thetechnology directly determine the capsules pose parameters, with fast, directcharacteristics, suitable capsule’s location.You can put magnetic sets in thecapsule outer, basically do not take up space with the capsule.In this paper, we achieve capsule endoscope positioning tracking withbasing on Honeywell HMC1043magnetoresistive sensors. In the positioningequipment, magnetoresistive sensor convert the intensity of the externalmagnetic field to a differential voltage signal, this signal is amplified by AD623,and then send to Freescale MC9S12XS128embedded system to A/Dconverte,at last send to the computer. Computer according location algorithm tooperation, and show the results.