What is the simplest most effective way to motion detect using webcams ?

For a while now I've been searching reading and trying out some of the open source out there. With not much background in Matlab.

I'm trying to write a motion detection code based on background subtraction or temporal difference methods. And since my lack of experience when I read papers and mathematical equations I can't implement it into code and when I read source codes I can't really understand what goes on underneath.

Could you kindly point me out in the right direction. What is the best way to motion detect for a Security/ Alarm system so it needs to be fast and uninfected by noise other that intruders for closed spaces? And how can I implement it while I still understand every single line of the code?

Thank you

Answer 1

[Anand]

This one might be relevant to you:

http://www.mathworks.com/help/vision/examples/scene-change-detection.html

[Lobna]

Thank you

Answer 2

[Image Analyst]

The Mathworks web site has many pages on tracking. Most are short demos that involve the Computer Vision System Toolbox or the Image Processing Toolbox or Image Acquisition Toolbox. Do a search: http://www.mathworks.com/searchresults/?q=tracking&q1=tracking&q2=&q3=&notq=&c[]=productsservices&c[]=solutions_tn

[Lobna]

Yes I have tried the optical flow using computer vision toolbox. Very nice but I'm looking into something simpler and clearer just detects to trigger and alarm no need to tracking the moving object.

Thank you

[Image Analyst]

So what's wrong with your subtraction idea? That's simple.

[Lobna]

I know the concept of it I've done my reading I just have no idea how to implement it, And when I read people's sources I don't understand what goes on.

if you could point out to me some toolboxes general MATLAB methods and equations?

[Image Analyst]

I thought I did. Did you see the link I posted? Alternatively you could search the File Exchange for tracking applications. http://www.mathworks.com/matlabcentral/fileexchange/?search_submit=fileexchange&query=tracking&term=tracking

[Ankur Singh]

hey image analyst

in optical flow method what tells us that some motion has been detected??

[Image Analyst]

The vector field will be non-zero where there has been motion.

Answer 3

[tairman singh]

try this function function [logic]=mcheck(f,s)

sub=imabsdiff(f,s);

diff_im=im2bw(sub,.07);

diff_im = medfilt2(diff_im, [3 3]);

diff_im = bwareaopen(diff_im,500);

imbw = imfill(diff_im,'holes');

[a b c]=size(imbw);

count=im2col(imbw,[a b],'sliding');

count=sum(count);

if count<=3000

    logic=1;

else

    logic=0;

end

end

it takes two consecutive images clicked by the camera, as the input function parameters i.e 'f' and 's' and return logic '1' or '0' if it detect motion or not. Changing different values of count ,allows you to control the sensitivity.

[Lobna]

Thank you, I will try it