function [fx, fy, ft] = computeDerivatives(im1, im2)

if size(im2,)==

    im2=zeros(size(im1));

end

% Horn-Schunck original method

fx = conv2(im1,0.25* [- ; - ],'same') + conv2(im2, 0.25*[- ; - ],'same');

fy = conv2(im1, 0.25*[- -;  ], 'same') + conv2(im2, 0.25*[- -;  ], 'same');

ft = conv2(im1, 0.25*ones(),'same') + conv2(im2, -0.25*ones(),'same');

% derivatives as in Barron

% fx= conv2(im1,(/)*[-   - ],'same');

% fy= conv2(im1,(/)*[-   - ]','same');

% ft = conv2(im1, 0.25*ones(),'same') + conv2(im2, -0.25*ones(),'same');

% fx=-fx;fy=-fy;

% An alternative way to compute the spatiotemporal derivatives is to use simple finite difference masks.

% fx = conv2(im1,[ -]);

% fy = conv2(im1,[; -]);

% ft= im2-im1;

% 利用系统对象 L-K光流法检测运动

%

clc;clear all; close all;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% 创建各类系统对象

%用于读入视频的系统对象；

hvfr= vision.VideoFileReader('SampleVideo.avi',...

    'ImageColorSpace','Intensity','VideoOutputDataType','uint8');

% 用于图像数据类型转换的系统对象；

hidtc= vision.ImageDataTypeConverter;

%用于光流法检测的系统对象；

hof=vision.OpticalFlow('ReferenceFrameDelay',);

hof.OutputValue='Horizontal and vertical components in complex form';

%用于在图像中绘制标记;

hsi=vision.ShapeInserter('Shape','Lines','BorderColor','Custom',...

    'CustomBorderColor',);

%用于播放视频图像的系统对象；

hvp = vision.VideoPlayer ('Name','Motion Vector');

while ~ isDone(hvfr)

    frame=step (hvfr);  %读入视频

    im = step (hidtc,frame); %将图像的每帧视频图像转换成单精度型

    of = step (hof,im); %用光流法对视频中的每一帧图像进行处理

    lines=videooptflowlines(of,); %产生坐标点

    if ~ isempty(lines)

        out = step(hsi,im,lines);  %标记出光流

        step(hvp,out);  %观看检测效果

    end

end

%释放系统对象

release(hvp);

release(hvfr);

clc

clear

close all

% 读取文件对象

mp4_name='Mp4\sub01\sub01_01.mp4';

videoReader = vision.VideoFileReader(mp4_name,'ImageColorSpace','Intensity','VideoOutputDataType','uint8');

% 类型转化对象

converter = vision.ImageDataTypeConverter;

% 光流对象

opticalFlow = vision.OpticalFlow('ReferenceFrameDelay', );

opticalFlow.OutputValue = 'Horizontal and vertical components in complex form';

if  % 使用的算法

opticalFlow.Method = 'Lucas-Kanade';

opticalFlow.NoiseReductionThreshold = 0.001; % 默认是0.

else

opticalFlow.Method = 'Horn-Schunck';

opticalFlow.Smoothness = 0.5; % 默认是1

end

% 显示对象

frame = step(videoReader);

figure

subplot()

himg = imshow(frame);

subplot()

hof = imshow(frame);

%用于在图像中绘制标记;

hsi=vision.ShapeInserter('Shape','Lines','BorderColor','Custom',...

 'CustomBorderColor',);

%用于播放视频图像的系统对象；

hvp = vision.VideoPlayer ('Name','Motion Vector');

% 开始播放

ii=;

while ~isDone(videoReader)

% 得到一帧

frame = step(videoReader);

% 格式转化

im = step(converter, frame);

% 计算光流

of = step(opticalFlow, im);

%产生坐标点

lines=videooptflowlines(of,);

   if ~ isempty(lines)

   out = step(hsi,im,lines); %标记出光流

   step(hvp,out);%观看检测效果

   end

% 光流图转化

ofI = computeColor(real(of), imag(of));

path=strcat('opticalFlow_img\sub01\01\',num2str(ii),'.jpg');

imwrite(ofI,path);

ii=ii+;

% figure, imshow(ofI);

% 显示

set(himg, 'cdata', frame)

set(hof, 'cdata', ofI)

drawnow

end

release(videoReader);

release(hvp);

function img = computeColor(u,v)

%   computeColor color codes flow field U, V

%   According to the c++ source code of Daniel Scharstein

%   Contact: schar@middlebury.edu

%   Author: Deqing Sun, Department of Computer Science, Brown University

%   Contact: dqsun@cs.brown.edu

%   $Date: -- :: (Wed,  Oct ) $

% Copyright , Deqing Sun.

%

%                         All Rights Reserved

%

% Permission to use, copy, modify, and distribute this software and its

% documentation for any purpose other than its incorporation into a

% commercial product is hereby granted without fee, provided that the

% above copyright notice appear in all copies and that both that

% copyright notice and this permission notice appear in supporting

% documentation, and that the name of the author and Brown University not be used in

% advertising or publicity pertaining to distribution of the software

% without specific, written prior permission.

%

% THE AUTHOR AND BROWN UNIVERSITY DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,

% INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR ANY

% PARTICULAR PURPOSE.  IN NO EVENT SHALL THE AUTHOR OR BROWN UNIVERSITY BE LIABLE FOR

% ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 

nanIdx = isnan(u) | isnan(v);

u(nanIdx) = ;

v(nanIdx) = ;

colorwheel = makeColorwheel();

ncols = size(colorwheel, );

rad = sqrt(u.^+v.^);          

a = atan2(-v, -u)/pi;

fk = (a+) / * (ncols-) + ;  % -~ maped to ~ncols

k0 = floor(fk);                 % , , ..., ncols

k1 = k0+;

k1(k1==ncols+) = ;

f = fk - k0;

for i = :size(colorwheel,)

    tmp = colorwheel(:,i);

    col0 = tmp(k0)/;

    col1 = tmp(k1)/;

    col = (-f).*col0 + f.*col1;   

    idx = rad <= ;

    col(idx) = -rad(idx).*(-col(idx));    % increase saturation with radius

    col(~idx) = col(~idx)*0.75;             % out of range

    img(:,:, i) = uint8(floor(*col.*(-nanIdx)));

end;    

%%

function colorwheel = makeColorwheel()

%   color encoding scheme

%   adapted from the color circle idea described at

%   http://members.shaw.ca/quadibloc/other/colint.htm

RY = ;

YG = ;

GC = ;

CB = ;

BM = ;

MR = ;

ncols = RY + YG + GC + CB + BM + MR;

colorwheel = zeros(ncols, ); % r g b

col = ;

%RY

colorwheel(:RY, ) = ;

colorwheel(:RY, ) = floor(*(:RY-)/RY)';

col = col+RY;

%YG

colorwheel(col+(:YG), ) =  - floor(*(:YG-)/YG)';

colorwheel(col+(:YG), ) = ;

col = col+YG;

%GC

colorwheel(col+(:GC), ) = ;

colorwheel(col+(:GC), ) = floor(*(:GC-)/GC)';

col = col+GC;

%CB

colorwheel(col+(:CB), ) =  - floor(*(:CB-)/CB)';

colorwheel(col+(:CB), ) = ;

col = col+CB;

%BM

colorwheel(col+(:BM), ) = ;

colorwheel(col+(:BM), ) = floor(*(:BM-)/BM)';

col = col+BM;

%MR

colorwheel(col+(:MR), ) =  - floor(*(:MR-)/MR)';

colorwheel(col+(:MR), ) = ;