%%關鍵幀提取clear all;clc;tic;%start timeshot=mmread('video\\polar-bear.mpg',1:150);%讀取視頻axis offmovie(shot.frames,1,30,[45 50 0 0]);%%%播放視頻axis on%%%%%%%%%%%%%HSoptflow(shot,n)f=size(shot.frames,2);flow=zeros(f);for i=1:f-1 [x1,y1,hs,ws]=HSoptflow(shot,i); for j=1:hs-1     for k=1:ws-1         flow(i)=flow(i)+abs(x1(j,k))+abs(y1(j,k));     end endend%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%figure,plot(flow),xlabel('幀號'),ylabel('視頻幀光流變化曲線');%%變化曲線[sortflow,index]=sort(flow);for i=f:-1:1    if sortflow(i)>=150&&abs(index(i)-index(i-1))>10        %%%%%%%提取關鍵幀%%%%%%%%%         figure,imshow(shot.frames(1,index(i)).cdata),xlabel(strcat('第',int2str(index(i)),'關鍵幀'));    endend%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%