Re: Re: How to access pixels - urgent question

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@xxxxxxxxx> 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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