Re: Re: PCA - What next!?

I used the PCA.zip without changing the code.
   
  All I did is to add a loop to print the avg values like:
   
  for(i=0; i<avg->height; i+=10)
{
   for(j=(avg->widthStep)*i; j<(avg->widthStep)*(i+1); 
         j+=avg->nChannels)
   {
      printf("\nAVG: %d, %d, %d\n", avg->imageData[j], avg->imageData[j+1], 
avg->imageData[j+2]);;
      
     } 
  }
   
  -Fadi

Parameswaran <cegparamesh@xxxxxxxxx> wrote:
  No! Average values cannot be negative.
There is some problem with your code. I didnt experience a negative
value..

In order to display the image, you have to normalize the pixel values
between 0 and 255, and then store it in a 8 bit image.
Only 8 bit images can be displayed correctly in the Highgui window, i
suppose..

Regards, :D
Paramesh.

--- In OpenCV@xxxxxxxxxxxxxxx, Fadi Chakik <fadichakik@...> wrote:
>
> in the code inside the PCA.zip file, there is "avg" variable which
defines the images 'pixels average.
>   I tried to print it to see its value, I can see that avg has some
negative values.. is that normal! 
>   the images from which "avg" is calculated are all gray levels..
that means values of pixels are between 0..255. So the mean of
positive values should be positive! why do we find negative values for
"avg"? is there any explanation?
>    
>   However, in the HIGUI window showing the projection, I get
sometimes black images for some of the projection.
>    
>   -Fadi
> 
> Parameswaran <cegparamesh@...> wrote:
>   There are many available techniques for face recognition, which can be
> found in the face recognition homepage:
> www.face-rec.org
> 
> The simplest and best approach is PCA or eigenfaces approach, which
> can be used either to recognize, or to reduce the dimensionality.
> 
> To recognize using the weights, you can use euclidean distance,
> Correlation distance, covariance distance, and many other distances
> available.
> 
> TO save the bounding rectangle of a face, you have to set the Image
> Region of Interest(ROI) and save the image.
> After saving, reset the ROI.
> 
> Regards, :D
> Paramesh.
> 
> --- In OpenCV@xxxxxxxxxxxxxxx, "kirkl_tamworth" <kirkl_tamworth@>
> wrote:
> >
> > Hi all,
> > 
> > I have successfully compiled the PCA example provided in the files 
> > section, which outputs the eigenvalues and such. I have two queries:
> > 
> > 1. Can you help me with where I go from here to perform face-
> > recognition? I have 25 face images ready to use and would greatly 
> > appreciate some help with completing the Eigenface approach. 
> > 
> > 2. I have also managed to incorporate the face detection sample
into a 
> > C# application, but I'm not sure how to extract the face from the 
> > image, given that I know the bounding rectangle. Is there an OpenCV 
> > function that can do this for me?
> > 
> > My first query is much more important than the second and I would 
> > really, really appreciate some help with this. Thanks.
> > 
> > Kirk
> >
> 
> 
> 
> 
> 
> 
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