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Lossless HRV data
For 24 hours from 1300 today, EUMETSAT are transmitting HRV with
lossless Wavelet compression. My initial impressions are: - even with JPEG (quality 82) there was a noticeable improvement on images which were histogram equalised to make full use of the dynamic range. - I needed to use PNG save format rather than JPEG to see the full extent of the differences - there is a definite improvement - detail is now visible that could not be seen before and the blockiness is completely gone. - it also shows that if you use Save visible as JPEG in the MSG Data Manager then you maybe need a higher quality setting than the default value of 82. - The greater bandwidth consumed is obvious on the graphs! The 30- minute average has gone from something over 108KB/s to around 138KB/s. http://www.david-taylor.myby.co.uk/mrtg/hermes_dvb.html Cheers, David
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Douglas Deans <douglas@...>
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From: "David Taylor" <david-taylor@blueyonder.co.uk> To: <MSG-1@yahoogroups.com> Sent: Wednesday, October 29, 2003 2:36 PM Subject: [MSG-1] Lossless HRV data For 24 hours from 1300 today, EUMETSAT are transmitting HRV with Out of curiosity I turned the JPEG quality up to 100. Added nearly 12Mb on to the save file size. Didn't realise it would be that dramatic. I suppose 100% on JPEG should be about the same as PNG... it more or less is from a file size point of view. Regards Douglas.
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Robert Moore
David, by the time I had a look at this most of the illumination had gone from
Europe, so I went south. With HRV set at 100, saved as JPEG, the images were incredible. The port of Luanda and the Cape Town hinterland showed marvellous detail. Await tomorrow's images of Europe with interest though I doubt we'll get this degree of detail ... but let's see. Robert Quoting David Taylor <david-taylor@blueyonder.co.uk>: For 24 hours from 1300 today, EUMETSAT are transmitting HRV with ------------------------------ Professor Robert Moore Department of Sociology, Social Policy and Social Work Studies The University of Liverpool Eleanor Rathbone Building Bedford Street South Liverpool L69 7ZA tel and fax: 44 (0) 1352 714456
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