keypiontall.m

自己编写的实现时间序列中的关建点搜索

function [g,keypoint]=keypiontall(data,K,t)
%function [ keyda1,keyda2,keydata ] = keypoint( data,m,n,t)
%UNTITLED1 Summary of this function goes here
%  Detailed explanation goes here
%keyda1 存储夹角方法取得的关键点
%keyda2 存储幅值方法取得的关键点
%data is the time series data which you want to search key point
%m is the threshold value of angle
%n is the threshold value of amplitude
%t is the time per sample-rate

%keyda1(:,1)=data(:,1);
[d,n]=size(data); %d 为行，n 为例


for i=1:d
for j=2:n-1
   %求斜率
   a=[data(i,j)-data(i,j-1)]/t;
   b=[data(i,j)-data(i,j+1)]/t;
   if a*b==1
       e(i)=pi/2;
   else 
   c=(b-a)/(1-a*b);
   e(j)=atan(c);    %计算出的夹角  

   end
end
 
   [f,ind]=sort(e); %夹角排序
      g(i,:)=ind(1:K);
 
end

%hist 
[m,n]=hist(g,n-1);  % the m record the element's times
[a,b]=size(m)
for i=1:a
inde(i)=sum(m(i,:));
end
[p,q]=sort(inde);
keypoint=q(1:K);