Research On Ultrasonic Positioning Algorithm For Capsule Endoscope

Capsule endoscopy is a non-invasive and painless solution,which is widely used in clinical practice.Accurate positioning of the capsule endoscope can not only locate the diseased area,but also achieve targeted drug release.However,due to the non-uniformity and high attenuation properties of human tissues.It is challenging for the existing positioning methods to accurately locate the capsule endoscope.Fortunately,the acoustic impedances of different human tissue are very similar.Therefore,this paper proposes a capsule endoscope positioning algorithm based on Ultrasonic Positioning Algorithm Based on Absolute Expectation(UAE).The content is as follows:(1)This paper designs an active ultrasound positioning method,which can locate the capsule endoscope accurately in the body.Based on the acoustic parameters of human tissues,a real human tissue model was established,which verified the feasibility of the scheme.(2)Due to the limited power consumption,small size of the capsule endoscope,significant coherent multipath interference,it complicates or even corrupts arrival time estimation.This paper combines the absolute value expectation and the sliding window to form a new time domain feature.Even under the significant multipath environment,the arrival time can also be accurately estimated.Further,a positioning algorithm is designed and implemented.(3)We have implemented our design with FPGA and evaluated it in simulation and animal tissues.Our experiments show that the average error of positioning the target in the human body using ultrasonic signals in the simulation experiment is about 1.2cm;the average error of the UAE positioning algorithm in animal tissue is about 1.6cm.