proj-imim:
Re: jpeg 2000
Ralf GMX 2001-Jul-22 21:08:46
I can agree that it would be nice to see in e very early state what i get
like gifs or same other jpeg´s in progressive mode, if i remember me right.
And i understand the argument, that this decoder have to integrate first
into java standart classes as a fileformat to be ready for the ptviewer.
On the other hand i found a java demo which seams for me to do the decoding
with normal java classes. Though that actualy only some classes have to
added to display the j2k files.
Also there must be something to display turing the download process.
I made some examples to compare the compression of jpeg and j2k and find out
that the two file types are very close together in the compression by the
same subjective view to these picture.
I first use infraview to get jpeg. Afterwards i went to Imageready 3 to get
a better tuning of the jpegs. The picture was a indoor 360 degree shot of
2400x738 5.1 MB BMP file.
For J2K i was using the JJ2000 java tool from the side you can find in the
list.
The lowest quality i find exaptable was 0.3 and 0.4 bpp (bit per pixel) what
is the "quality" factor you can give to the command line.
0.3 gets the file size of 65kB
0.4 gets a file size of about 87kB
The result with ImageReady3 with blur of 0.35 and quality of 20 gets visual
the same result with a file size of about 79kB.
For this picture i would say it very similare. But this is actualy only the
result of the blur.
Without the blur effect i need a much higher quality factor to get no
artefacts in the with walls.
This is much better in j2k!
Take a look by intresting in J2K to the following links wich i found in the
online article of the magazin iX which comes from Heise Verlag.
http://www.aware.com/products/compression/compression.html
http://www.jpeg.org/JPEG2000.htm#testlinks
http://jj2000.epfl.ch/
http://www.jpeg.org/public/wavedemo.zip
http://www.ece.ubc.ca/~mdadams/jasper/
http://www.jpeg2000info.com/
http://www.heise.de/ix/artikel/2001/08/108/04.shtml
-----Ursprüngliche Nachricht-----
Von: <#removed#>
An: <#removed#>
Gesendet: Freitag, 20. Juli 2001 12:52
Betreff: jpeg 2000
>
> > I did some subjective tests a while back with the then current jpeg
> > 2000 codec, but I typically only got 15-20% improvement in file
> > size over the standard jpeg codec in use today.
>
> This is a disappointment.
>
> Did you try streaming it over the web? I had been told that the wavelet
> format of JPEG 2000 would provide a nice streaming preview of the image
> that would refine as it downloaded but would show you something after
> the first 4k or
> so.
>