MeanShift算法简介： http://blog.csdn.net/carson2005/article/details/7337432
思路简介：
1.截取跟踪目标矩阵rect
2.求取跟踪目标的加权直方图hist1
3.读取视频序列中的一帧， 先随机取一块与rect等大的矩形，计算加权直方图hist2。
4.计算两者比重函数，如果后者差距过大， 更新新的矩阵中心Y，进行迭代（MeanShift是一种变步长可以迅速接近概率密度峰值的方法），直至一定条件后停止。
源程序（参考过其他程序）：
function [] = select()
close all;
clear all;
%%%%%%%%%%%%%%%%%%根据一幅目标全可见的图像圈定跟踪目标%%%%%%%%%%%%%%%%%%%%%%%
I=imread('E:\数字图像处理\6\2\18.bmp');
figure(1);
imshow(I);
[temp,rect]=imcrop(I);
[a,b,c]=size(temp);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%计算目标图像的权值矩阵%%%%%%%%%%%%%%%%%%%%%%%
y(1)=a/2;
y(2)=b/2;
tic_x=rect(1)+rect(3)/2;
tic_y=rect(2)+rect(4)/2;
m_wei=zeros(a,b);%权值矩阵
h=y(1)^2+y(2)^2 ;%带宽
for i=1:a
for j=1:b
dist=(i-y(1))^2+(j-y(2))^2;
m_wei(i,j)=1-dist/h; %epanechnikov profile
end
end
C=1/sum(sum(m_wei));%归一化系数
%计算目标权值直方图qu
%hist1=C*wei_hist(temp,m_wei,a,b);%target model
hist1=zeros(1,a*b);
for i=1:a
for j=1:b
%rgb颜色空间量化为16*16*16 bins
q_r=fix(double(temp(i,j,1))/16); %fix为趋近0取整函数
q_g=fix(double(temp(i,j,2))/16);
q_b=fix(double(temp(i,j,3))/16);
q_temp=q_r*256+q_g*16+q_b; %设置每个像素点红色、绿色、蓝色分量所占比重
hist1(q_temp+1)= hist1(q_temp+1)+m_wei(i,j); %计算直方图统计中每个像素点占的权重
end
end
hist1=hist1*C;
rect(3)=ceil(rect(3));
rect(4)=ceil(rect(4));
%%%%%%%%%%%%%%%%%%%%%%%%%读取序列图像
myfile=dir('*.bmp');
lengthfile=length(myfile);
for l=1:lengthfile
Im=imread(myfile(l).name);
num=0;
Y=[2,2];
%%%%%%%mean shift迭代
while((Y(1)^2+Y(2)^2>0.5)&num<20) %迭代条件
num=num+1;
temp1=imcrop(Im,rect);
%计算侯选区域直方图
%hist2=C*wei_hist(temp1,m_wei,a,b);%target candidates pu
hist2=zeros(1,a*b);
for i=1:a
for j=1:b
q_r=fix(double(temp1(i,j,1))/16);
q_g=fix(double(temp1(i,j,2))/16);
q_b=fix(double(temp1(i,j,3))/16);
q_temp1(i,j)=q_r*256+q_g*16+q_b;
hist2(q_temp1(i,j)+1)= hist2(q_temp1(i,j)+1)+m_wei(i,j);
end
end
hist2=hist2*C;
figure(2);
subplot(1,2,1);
plot(hist2);
hold on;
w=zeros(1,a*b);
for i=1:a*b
if(hist2(i)~=0)
w(i)=sqrt(hist1(i)/hist2(i));
else
w(i)=0;
end
end
%变量初始化
sum_w=0;
xw=[0,0];
for i=1:a;
for j=1:b
sum_w=sum_w+w(uint32(q_temp1(i,j))+1);
xw=xw+w(uint32(q_temp1(i,j))+1)*[i-y(1)-0.5,j-y(2)-0.5];
end
end
Y=xw/sum_w;
%中心点位置更新
rect(1)=rect(1)+Y(2);
rect(2)=rect(2)+Y(1);
end
%%%跟踪轨迹矩阵%%%
tic_x=[tic_x;rect(1)+rect(3)/2];
tic_y=[tic_y;rect(2)+rect(4)/2];
v1=rect(1);
v2=rect(2);
v3=rect(3);
v4=rect(4);
%%%显示跟踪结果%%%
subplot(1,2,2);
imshow(uint8(Im));
title('目标跟踪结果及其运动轨迹');
hold on;
plot([v1,v1+v3],[v2,v2],[v1,v1],[v2,v2+v4],[v1,v1+v3],[v2+v4,v2+v4],[v1+v3,v1+v3],[v2,v2+v4],'LineWidth',2,'Color','r');
plot(tic_x,tic_y,'LineWidth',2,'Color','b');
end
结果截图：
