METHOD AND SYSTEM FOR DETERMINING INFORMATION OF EXTREMA DURING EXPANSION AND CONTRACTION CYCLES OF AN OBJECT

摘要

A medical system provides navigation assistance to a surgeon for navigating a flexible medical device through linked passages of an anatomical structure to a target area. For tracking, navigation, and other purposes, information of extrema is determined during expansion and contraction cycles of an object by receiving time sampled information from sensors distributed along a length of a flexible device so as to indicate the shape of the device over time while the device extends through a lumen of the object so as to conform to and resemble the shape of the lumen, displacements over time of a selected point at a selected insertion length of the flexible device into the lumen of the object relative to a reference point are determined, extrema time points are determined by identifying sign changes of the slope of the determined displacements over time, and extrema types are determined using extrema type characteristics.