人体重心动摇轨迹包络面积的快速算法

传统的人体重心动摇轨迹包络面积计算方法是先确定包络所有点的凸包形状，再计算凸包的面积，其最优时间复杂度接近O(nlbn)。针对上述问题给出一种近似凸包计算方法，通过计算点集在不同旋转角度下的坐标，查找X轴和Y轴的最大最小极值点，快速标定构成凸包点，确定凸包形状。算法的时间复杂度接近于O(n)。实际应用证明，该算法能满足精度要求，提高人体重心动摇轨迹包络面积计算速度。

Fast Algorithm for Envelope Area of Body Barycenter Swaying Trajectory

The envelope area of the body barycenter swaying trajectory is one of sensitive indicators that discriminates the balanced capacity of dizziness patient.Traditional computing method firstly determines the shape of convex hull enveloping all points and then calculates the area of convex hull,it need sort all points,time complexity of algorithm close to O（nlbn） on the best cases.This paper introduces a kind of algorithm of approximate convex hull,calculates coordinates of different rotation angle,looks up the point set of maximum and minimum along X-axis and Y-axis,quickly marks the points and make sure the shape of convex hull.Time complexity of algorithm close to O（n）.It is proved that the algorithm can meet accuracy requirement of balance test system,and increase calculation speed.