Re: How to access pixels - urgent question

Hi,
i think this code is great but i need it to work for multi channel 
image. How can i use the iplgetpixel or if this code can be changed 
to work for multi channel image.
thx

--- In OpenCV@xxxxxxxxxxxxxxx, Luiz Curado <lutitus@...> wrote:
>
> So, lets go in that code...
>    
>   uchar getPixel( IplImage*img, int lin, int col ) {
>    return ((uchar*)(img->imageData + img->widthStep*lin))[col] ; 
> }
>    
>   - uchar is a unsigned char type (8 bits)
>   - img is a pointer to my IplImage
>   - lin, col are the line and column of the pixel
>   - imageDate is an "array" that contains the pixels: first line, 
second line, etc, all in the same "array"
>   - img->widhStep is the size of each line in my IplImage
>    
>   Now, it becomes more clear, dont? 
>    
>   img->imageData + img->widthStep*lin
>    
>   => With this piece of code, i'm in the beggining of line "lin"
>    
>   <my line>[col] ; 
>    
>   => With this piece of code, i'm in the column "col" of 
line "lin" 
>    
>   I hope this can help. :)
>    
>   Regards,
>    
>   Luiz Reginaldo
> 
> evaspies <evaspies@...> escreveu:
>   Hi Luis,
> 
> thanx for your help.
> But I dont quite understand this!
> 
> can you please comment that code?`
> 
> Thnx a lot
> 
> 
> 
> --- In OpenCV@xxxxxxxxxxxxxxx, Luiz Curado <lutitus@> wrote:
> >
> >   Hi, 
> >    
> >   Try this:
> >    
> >   uchar getPixel( IplImage*img, int lin, int col ) {
> >   return ((uchar*)(img->imageData + img->widthStep*lin))[col] ; 
> >   }
> >    
> >   void setPixel( IplImage*img, int lin, int col, uchar valor ) {
> >   ((uchar*)(img->imageData + img->widthStep*lin))[col] = valor ;
> >   }
> >   
> > Regards,
> >    
> >   Luiz Reginaldo
> >   
> > evaspies <evaspies@> escreveu:
> >   Hi guys.
> > 
> > Im trying to access Pixels of a grayscale image to get a
> > representantive   value. best of all would be if the value lies
> > between 0 für black and 255 für white.
> > Do you have an Idea?
> > I tried to use iplGetPixel, but that function is only for 3 or 4
> > channel pictures.
> > 
> > Thanx for xour help!
> > 
> > 
> > 
> > 
> > 
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