[Q] captured image saved but

OS: Windows XP
ARToolkit Version: 7.0

I grabbed a frame and saved it into a ppm file, but the color seems  
very much strange, does not show a correct one; well partly it is  
correct but change frame by frame.

My code is like this (from simpleTest):

     dataPtr = arVideoGetImage();
     arVideoCapStop();
     arDrawMode2D();
     for (i=k=0; i<Height; i++) for (j=0; j<Width; j++)
         b[i][j] = dataPtr[k+2];
         g[i][j] = dataPtr[k+1];
         r[i][j] = dataPtr[k+0];
         k+= 4;
     }
     write_PPM (filename, r,g,b);
     arDispImage (dataPtr, 0, 0);
     arVideoCapStart();
     arVideoCapNext();

Strange to say, the color of the saved file is not consistent.

Any comments please.
Best,
Y.

From:	Yongduek SEO <yndk@s ...........>	Received:	May 26, 2005
To	artoolkit@h ..................
Subject:	[Q] captured image saved but
OS: Windows XP ARToolkit Version: 7.0 I grabbed a frame and saved it into a ppm file, but the color seems very much strange, does not show a correct one; well partly it is correct but change frame by frame. My code is like this (from simpleTest): dataPtr = arVideoGetImage(); arVideoCapStop(); arDrawMode2D(); for (i=k=0; i<Height; i++) for (j=0; j<Width; j++) b[i][j] = dataPtr[k+2]; g[i][j] = dataPtr[k+1]; r[i][j] = dataPtr[k+0]; k+= 4; } write_PPM (filename, r,g,b); arDispImage (dataPtr, 0, 0); arVideoCapStart(); arVideoCapNext(); Strange to say, the color of the saved file is not consistent. Any comments please. Best, Y.

From:	Philip Lamb <phil@e ..........>	Received:	May 27, 2005
To	Yongduek SEO <yndk@s ...........>
Subject:	Re: [Q] captured image saved but
On 26/05/2005, at 8:50 PM, Yongduek SEO wrote: > OS: Windows XP > ARToolkit Version: 7.0 > > I grabbed a frame and saved it into a ppm file, but the color seems > very much strange, does not show a correct one; well partly it is > correct but change frame by frame. > > My code is like this (from simpleTest): > > dataPtr = arVideoGetImage(); > arVideoCapStop(); Do not call arVideoCapStop() unless you are finished capturing. Certainly not every frame! > arDrawMode2D(); > for (i=k=0; i<Height; i++) for (j=0; j<Width; j++) > b[i][j] = dataPtr[k+2]; > g[i][j] = dataPtr[k+1]; > r[i][j] = dataPtr[k+0]; > k+= 4; > } On Windows, the colour components in each pixel are ordered bgra. So your indexes should be k+0, k+1, and k+2. > write_PPM (filename, r,g,b); > arDispImage (dataPtr, 0, 0); > arVideoCapStart(); Remove this as well. > arVideoCapNext(); > > Strange to say, the color of the saved file is not consistent. > > Any comments please. > Best, > Y. > > Hope this helps. Phil.