2x2 bin without colour

[Datalord]

By accident I have now twice managed to set up a shooting session and set binning to 2x2. Both of these sessions result in something I can't de-bayer no matter what I do, which setting I choose. 

Is there something special about binned colour pictures? 

[furrysocks2]

@Datalord... standard 2x2 binning sums 4 pixels into one: two green, one blue and one red get added together to give mono - no colour information left.

You can bin colour, some cameras might, but standard 2x2 is not how.

 

[Datalord]

Thanks, confirms my trouble. I'll delete those pictures and recover a bit of harddrive...

[toxic]

18 minutes ago, Datalord said:

Thanks, confirms my trouble. I'll delete those pictures and recover a bit of harddrive...

dont delete if there any good just stack then at 2x then just use them as luminance for when you get colour

[Datalord]

22 minutes ago, toxic said:

dont delete if there any good just stack then at 2x then just use them as luminance for when you get colour

butbut, they are half resolution. I can't stack that, at least not in DSS.

[toxic]

i do it quite often just load up all the binn 2 files of the object and stack them at 2 times you will be surprised at what comes out.

this is a binn 2 image or rather its binn 2 RGB stacked at 2 times and added to binn 1 NB data as luminance all from last year all with the same mono camera and filters. hope to do it again this year 

dont chuck out data unless it is beyond recovery 

[Datalord]

16 hours ago, toxic said:

i do it quite often just load up all the binn 2 files of the object and stack them at 2 times you will be surprised at what comes out.

this is a binn 2 image or rather its binn 2 RGB stacked at 2 times and added to binn 1 NB data as luminance all from last year all with the same mono camera and filters. hope to do it again this year 

Ok, what is the process? Stretch the bin2 somehow post stack or pre stack? Or reduce the bin1 and stack with bin2?

[ollypenrice]

If your real resolution is limited by the seeing you might find little difference between the binned and unbinned subs.

Olly

[Datalord]

1 hour ago, ollypenrice said:

If your real resolution is limited by the seeing you might find little difference between the binned and unbinned subs.

Olly

It was an accident. The driver of the camera somehow reset itself to 2x2 for reasons only gods would know. I'm always doing 1x1, which gives me glorious 24MP I can crop from.

[ollypenrice]

Just now, Datalord said:

It was an accident. The driver of the camera somehow reset itself to 2x2 for reasons only gods would know. I'm always doing 1x1, which gives me glorious 24MP I can crop from.

But my point is that you should look at the binned data to see how the real resolution compares with the unbinned. In theory it's halved but in practice it might not be and might be useful as luminance... Just take a good look at it to see.

Olly

[Datalord]

Just now, ollypenrice said:

But my point is that you should look at the binned data to see how the real resolution compares with the unbinned. In theory it's halved but in practice it might not be and might be useful as luminance... Just take a good look at it to see.

Olly

I'm too much of a rookie to understand that. The binned pictures are 11MB compared to the unbinned at 47MB, with the resolution being a quarter. How would that not be a loss of data?

 

[ollypenrice]

22 minutes ago, Datalord said:

How would that not be a loss of data?

 

If the seeing and/or guiding is not good enough for you to succeed in capturing the resolution of which your system is capable then the detail seen in the final picture might be no worse in the binned than the unbinned image. This actually happens a lot.

To be clear, we are talking about two kinds of resolution. One is the pixel scale of your system. How much sky lands on each pixel. The unit is arcseconds per pixel. I'll give a simplified explanation which ignores a number of real phenomena in imaging to explain the underlying point. A DSLR camera in an SCT might give 0.5 arcseconds per pixel so, in theory, two stars separated by half an arcsecond should be separated by one pixel. However, the seeing might be blurring the incoming beams of starlight over a scale of 1 arcsecond. This makes it impossible for your system, in real life, to separate those stars. So the 'other' definition of resolution is that which is affected by atmospheric turbulence. Your result (your real result) will be governed by that which is the worse.

Or imagine a clear, still day. You set up your daytime camera on a tripod and photograph some distant text 500 metres away. You can just resolve the individual letters. Then somone lights a bonfire between you and the text. There's no smoke but the atmosphere becomes turbulent between you and the signpost, so now the instability of the atmosphere makes it impossible to resolve the same letters. The camera resolution has not changed but the possible resolution has changed.

Olly

[Datalord]

Ahh, right, makes sense. In which case I could have a 5000MP resolution and I would still bin it down. Alright, I'll save the data to see if I can use it once I get a proper colour shoot of the target.

[toxic]

5 hours ago, ollypenrice said:

If the seeing and/or guiding is not good enough for you to succeed in capturing the resolution of which your system is capable then the detail seen in the final picture might be no worse in the binned than the unbinned image. This actually happens a lot.

To be clear, we are talking about two kinds of resolution. One is the pixel scale of your system. How much sky lands on each pixel. The unit is arcseconds per pixel. I'll give a simplified explanation which ignores a number of real phenomena in imaging to explain the underlying point. A DSLR camera in an SCT might give 0.5 arcseconds per pixel so, in theory, two stars separated by half an arcsecond should be separated by one pixel. However, the seeing might be blurring the incoming beams of starlight over a scale of 1 arcsecond. This makes it impossible for your system, in real life, to separate those stars. So the 'other' definition of resolution is that which is affected by atmospheric turbulence. Your result (your real result) will be governed by that which is the worse.

Or imagine a clear, still day. You set up your daytime camera on a tripod and photograph some distant text 500 metres away. You can just resolve the individual letters. Then somone lights a bonfire between you and the text. There's no smoke but the atmosphere becomes turbulent between you and the signpost, so now the instability of the atmosphere makes it impossible to resolve the same letters. The camera resolution has not changed but the possible resolution has changed.

Olly

what a great explanation i new there had to be a reason why my data was some times just as good at binn 2 as it was at binn 1 now i understand why  thanks very much Olly i wont go balder from all the head scratching now ha ha ha

[ollypenrice]

8 hours ago, toxic said:

what a great explanation i new there had to be a reason why my data was some times just as good at binn 2 as it was at binn 1 now i understand why  thanks very much Olly i wont go balder from all the head scratching now ha ha ha

Understanding came too late for me to avoid baldness!

Olly

[ollypenrice]

14 hours ago, Datalord said:

Ahh, right, makes sense. In which case I could have a 5000MP resolution and I would still bin it down. Alright, I'll save the data to see if I can use it once I get a proper colour shoot of the target.

The other thing to consider is that you will only ever see imagers post an image at full size (one camera pixel afforded one screen pixel) when their data is rock solid (and they are not worried about people pinching it from the net ). Getting data to that level of perfection is possible but takes a very, very long time. A data set which looks fine at 66% is going to need a near-eternity of extra exposure time to be similarly good at 100%!) So if you are going to resample your data downwards for presentation it might not suffer too much anyway.

Olly