Using Debayer in PIPP

[Space Cowboy]

I mentioned on another thread that I was experiencing smoother images when using PIPP quality selection tool before stacking in AS!2. When seeing was good they were actually too smooth.

I've had another look and its down to using debayer in PIPP. Either bilinear or smooth hue debayer produce a smoother image. If debayer is not selected the image sharpness is identical to an AS!2 stacked image that has not been processed in PIPP.

2 images below both stacking 963 frames with identical wavelets and no other processing :

PIPP bilinear debayer then AS!2 :

Straight AS!2 stack without PIPP:

[cgarry]

Hi Stuart,

Ah, that explains everything. PIPP obviously debayers each frame in the traditional way whereas AS!2 does not debayer as all, it simply stacks the pixels it has from each frame and relies on the movement of the object to fill in the gaps over the entire stack.

Cheers,

Chris

[neil phillips]

I for one thought you could see the effect, Just like Chris. Just goes to show no one guessed it was debayer. Untill you figured it out.

[cgarry]

Stuart,

Could this be the reason that you have said in the past that you preferred using colour data from the camera rather than raw data?

Chris

[Space Cowboy]

I've always considered y800 data noiser than yuy2 avis Chris though it would be interesting to compare a pipp debayered avi with a yuy2 avi.

[Space Cowboy]

Ok, here is another comparison. 3 images below using pipp bilinear debayer, yuy2 colour and straight y800 raw stacked in AS!2 (they are all stacked in AS!2 using 1010 frames and identical wavelets)

The yuy2 image was taken straight after the other 2 so seeing was very similar. Clearly the bilnear pipp image is even smoother than yuy2 colour!

PIPP bilinear : Dec 1st 2012 23-29

yuy2 colour : 23-33

y800: 23-29

[Freddie]

Isn't YUY2 compressed to some degree? If so, I guess that will have an impact, taking out some of the detail?

[cgarry]

Another useful comparison Stuart. I would not have thought the sub-sampled colour of the YUY2 format would have introduced any noise, if anything I would expect it to loose a tiny amount of detail. I wonder if the initial debayering that was done in the camera to generate the YUY2 video was a simple nearest neighbour debayering algorithm and that reason for the extra noise.

Cheers,

Chris

[Space Cowboy]

I reckon bilinear will suit Saturn with the high gain needed.

[cgarry]

Yes, that does make sense. Though I have yet to see Saturn this time round with all the bad weather...

[Space Cowboy]

Sorry Chris thats my fault since getting a new cam its brought all this wind and snow,