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Subject: Re: Motion estimation vs. background subtraction
Date: Mon, 1 Jun 2009 16:44:03 +0000 (UTC)
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"Abhishek " <highlytoxicboy@gmail.com> wrote in message <h00vb2$p8i$1@fred.mathworks.com>...
> "Dave Robinson" <dave.robinson@somewhere.biz> wrote in message <fr8rvq$rfs$1@fred.mathworks.com>...
> > "Torvald Helmer" <torvald.helmer@mathworks.com> wrote in 
> > message <fr8o5t$m76$1@fred.mathworks.com>...
> > > I am conducting a project which consists of object 
> > > tracking. There I want to have a good segmentation of the 
> > > moving objects from the background. The background may 
> > have 
> > > noise-factors like light changes, and wind in trees.
> > > 
> > > What kind of segmentation is best? Should I use just 
> > > background subtraction, or is it best with motion 
> > > estimation?
> > > 
> > > Doeas anybody have some thoughts on this subject?
> > > 
> > > Thanks, Helmer.
> > 
> > 1) Use a colour camera
> > 
> > 2) Convert to Normalized RGB to remove the effect of 
> > illumination variation.
> > 
> > 3) Over a protracted period, with no moving target in the 
> > scene, calculate the mean background intensity of each 
> > individual pixel, together with its associated standard 
> > deviation.
> > 
> > 4) Select a confidence level (e.g. 3xsigma) whereby the 
> > difference between the mean image and the current image is 
> > deemed to be statistically similar - note that regions that 
> > are naturally liable to change (e.g. trees moving) will 
> > have a very high sigma, and will consequently be very 
> > tolerant of any changes in the scene.
> > 
> > 5) Generate a binary image of all regions that contain 
> > pixels that are outside your confidence range (e.g. 
> > Pixel_Difference > 3*PixelSigma;
> > 
> > 6) Track your moving image using something like blob 
> > centroid.
> > 
> > Regards
> > 
> 
> > Dave Robinson
> 
> Hello Dave,
> 
> I tried the same exact method you've put down here, but the normalized RGB image I'm getting is devoid of any worthwhile information of the image. 
> 
> Have a look here : 
> 
> http://img524.imageshack.us/img524/7079/sdafdfs.png
> 
> This is not how it should look, right?

Without looking at your original image, I couldn't really make a judgement, put an full RGB image  on the same site, and I might get a chance to look at it.

Dave Robinson