OK , I found the issue, the image posted on the tutorial page(the 640x480 one) is not the original image. this is the original image (6,016x4,000)!:
The image size has a direct impact on the parameters. the 640x480 image on the tutorial page seems too small and has lost too much information, so I couldnt get muct out of it, the best result I could get was using r=6 and snr around 100 or 200! I guess whereas for the original image r=15 and snr=5200 works well.