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Hmmm, so you would, when collecting large data images, say 4 images, 100MB in size, per second, in the middle of the night, from home, reject seeing compressed images on your data collection software, while the "real thing" is lingering behind somewhere, to be downloaded and stored later? As opposed to not seeing the images (because your home internet access cannot keep up) and only inspecting 1 in a 100 images to see progress?

I think there are instances where compressed (lossy or not) images will be invaluable. I know the above situation was not the context, but (y'all may gasp about this) I still have some friends (in the US) who live so far out in the wilderness that only dial-up internet is available. That while synchrotrons and the detectors used get better all the time, which means more MB/s produced.

James has already said (and I agree) that the original images (with all information) should not necessarily be thrown away. Perhaps a better question would be "which would you use for what purpose", since I am convinced that compressed images are useful.

I would want to process the "real thing", unless I have been shown by scientific evidence that the compressed thing works equally well. It seems reasonable to assume that such evidence can be acquired and/or that we can be shown by evidence what we gain and lose by lossy-compressed images. Key might be to be able to choose the best thing for your particular application/case/location etc.

So yes, James, of course this is useful and not a waste of time.

Mark


-----Original Message-----
From: Miguel Ortiz Lombardia <[log in to unmask]>
To: CCP4BB <[log in to unmask]>
Sent: Tue, Nov 8, 2011 12:29 pm
Subject: Re: [ccp4bb] image compression

Le 08/11/2011 19:19, James Holton a écrit :
> At the risk of putting this thread back on-topic, my original question
> was not "should I just lossfully compress my images and throw away the
> originals".  My question was:
> 
>  "would you download the compressed images first?"
> 
> So far, noone has really answered it.
> 
> I think it is obvious that of course we would RATHER have the original
> data, but if access to the original data is "slow" (by a factor of 30 at
> best) then can the "mp3 version" of diffraction data play a useful role
> in YOUR work?
> 
> Taking Graeme's request from a different thread as an example, he would
> like to see stuff in P21 with a 90 degree beta angle.  There are
> currently ~609 examples of this in the PDB.  So, I ask again: "which one
> would you download first?".  1aip? (It is first alphabetically).  Then
> again, if you just email the corresponding authors of all 609 papers,
> the response rate alone might whittle the number of datasets to deal
> with down to less than 10.  Perhaps even less than 1.
> 
> -James Holton
> MAD Scientist
> 

Hmm, I thought I had been clear. I will try to be more direct:

Given the option, I would *only* download the original,
non-lossy-compressed data. At the expense of time, yes. I don't think
Graeme's example is very representative of our work, sorry.

As long as the option between the two is warranted, I don't care. I just
don't see the point for the very same reasons Kay has very clearly exposed.

Best regards,

-- 
Miguel

Architecture et Fonction des Macromolécules Biologiques (UMR6098)
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