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Mathieu, a question for you: how can I know if Matlab png format is lossless or lossy?<br> I don't have any information to help me and I found on wikipedia this definition:<br><b><br>"<br>Portable Network Graphics</b> (<b>PNG</b>) is a <a href="http://en.wikipedia.org/wiki/Raster_graphics" title="Raster graphics">bitmapped</a> <a href="http://en.wikipedia.org/wiki/Graphics_file_format" title="Graphics file format" class="mw-redirect">image format</a> that employs <a href="http://en.wikipedia.org/wiki/Lossless_data_compression" title="Lossless data compression">lossless data compression</a>.<br><br>[...]<br><br>PNG uses a 2-stage compression process:<br>
<ul><li>pre-compression: filtering (prediction)</li><li>compression: DEFLATE</li></ul>
PNG uses a non-patented <a href="http://en.wikipedia.org/wiki/Lossless_data_compression" title="Lossless data compression">lossless data compression</a> method known as <a href="http://en.wikipedia.org/wiki/DEFLATE" title="DEFLATE">DEFLATE</a>, which is the same algorithm used in the <a href="http://en.wikipedia.org/wiki/Zlib" title="Zlib">zlib</a> compression library.<br><br>"<br><br>But I don't find anything about PNG lossy compression.... <br>Really, it is a simple curiosity because I could save my image in PGM or PPM how to told me...but, since I'm not expert in this field, I would know something about it.<br><br>Thanks for your time,<br>Regards<br>Daniela<br><br>> From: mathieu.malaterre@gmail.com<br>> Date: Tue, 25 May 2010 17:28:01 +0200<br>> Subject: Re: [Insight-users] DicomSeriesReadImageWrite2_Problem to read dcmSeries<br>> To: luis.ibanez@kitware.com<br>> CC: danysunflower@hotmail.it; insight-users@itk.org<br>> <br>> On Tue, May 25, 2010 at 5:21 PM, Luis Ibanez <luis.ibanez@kitware.com> wrote:<br>> > If keeping image precision is critical for your<br>> > application, you may want to save the images<br>> > in a lossless format (e.g. png) and still do the<br>> > same trick in ITK to read the series of slices.<br>> <br>> Just for reference, PNG allow both lossless and lossy compression<br>> mechanism. You should pick the right one.<br>> <br>> Otherwise go for the old timer: PGM/PPM :)<br>> <br>> -- <br>> Mathieu<br> <br /><hr />Tanti account di posta? <a href='http://www.windowslive.it/hotmail/UnicaCasellaDiPosta.aspx' target='_new'>Unisci tutto sotto Hotmail</a></body>
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