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
On 11/8/2011 5:17 AM, Graeme Winter wrote:
> Dear Herbert,
>
> Sorry, the point I was getting at was that the process is one way, but
> if it is also *destructive* i.e. the original "master" is not
> available then I would not be happy. If the master copy of what was
> actually recorded is available from a tape someplace perhaps not all
> that quickly then to my mind that's fine.
>
> When we go from images to intensities, the images still exist. And by
> and large the intensities are useful enough that you don't go back to
> the images again. This is worth investigating I believe, which is why
> I made that proposal.
>
> Mostly I listen to mp3's as they're convenient, but I still buy CD's
> not direct off e.g. itunes, and yes a H264 compressed video stream is
> much nicer to watch than VHS.
>
> Best wishes,
>
> Graeme
>
> On 8 November 2011 12:17, Herbert J. Bernstein
> <[log in to unmask]> wrote:
>> Um, but isn't Crystallograpy based on a series of
>> one-way computational processes:
>> photons -> images
>> images -> {struture factors, symmetry}
>> {structure factors, symmetry, chemistry} -> solution
>> {structure factors, symmetry, chemistry, solution}
>> -> refined solution
>>
>> At each stage we tolerate a certain amount of noise
>> in "going backwards". Certainly it is desirable to
>> have the "original data" to be able to go forwards,
>> but until the arrival of pixel array detectors, we
>> were very far from having the true original data,
>> and even pixel array detectors don't capture every
>> single photon.
>>
>> I am not recommending lossy compressed images as
>> a perfect replacement for lossless compressed images,
>> any more than I would recommend structure factors
>> are a replacement for images. It would be nice
>> if we all had large budgets, huge storage capacity
>> and high network speeds and if somebody would repeal
>> the speed of light and other physical constraints, so that
>> engineering compromises were never necessary, but as
>> James has noted, accepting such engineering compromises
>> has been of great value to our colleagues who work
>> with the massive image streams of the entertainment
>> industry. Without lossy compression, we would not
>> have the _higher_ image quality we now enjoy in the
>> less-than-perfectly-faithful HDTV world that has replaced
>> the highly faithful, but lower capacity, NTSC/PAL world.
>>
>> Please, in this, let us not allow the perfect to be
>> the enemy of the good. James is proposing something
>> good.
>>
>> Regards,
>> Herbert
>> =====================================================
>> Herbert J. Bernstein
>> Professor of Mathematics and Computer Science
>> Dowling College, Kramer Science Center, KSC 121
>> Idle Hour Blvd, Oakdale, NY, 11769
>>
>> +1-631-244-3035
>> [log in to unmask]
>> =====================================================
>>
>> On Tue, 8 Nov 2011, Harry Powell wrote:
>>
>>> Hi
>>>
>>>> I am not a fan
>>>> of one-way computational processes with unique data.
>>>>
>>>> Thoughts anyone?
>>>>
>>>> Cheerio,
>>>>
>>>> Graeme
>>>
>>> I agree.
>>>
>>> Harry
>>> --
>>> Dr Harry Powell, MRC Laboratory of Molecular Biology, MRC Centre, Hills
>>> Road, Cambridge, CB2 0QH
>>>
>>>
>>> http://www.iucr.org/resources/commissions/crystallographic-computing/schools/mieres2011
>>>
