Re: save as jpg

Posted by Jon Harman-3 on Mar 06, 2008; 4:18pm
URL: http://imagej.273.s1.nabble.com/save-as-jpg-tp3696972p3696988.html

Hi,

Are your images in color?

ImageJ uses the Sun jpeg writer with the default settings.  By default
these settings subsample colors, but not brightness.  This results in
significant degradation of the colors in an image, but to human eyes in
a color photo this is not noticeable.

For color medical images I would think this is not a good idea.

Jpeg may not be the best image compression algorithm, but its use on the
web is overwhelming.

Maybe a solution is to add a choice to the jpeg I/O options:
Disable color subsampling.

For ImageJ I think compression size is less important than quality.  So
I would recommend that the default for ImageJ should be to not do
subsampling.


Jon

Gwen Barnes wrote:

> Hi,
>
> I'm have a question about saving images as jpg.  I set the quality to 100
> under "edit, options, I/O options", but still, when I save a tiff as a jpeg,
> I end up with jpeg artifacts.  If I use other programs, and save the same
> tiff as a quality 100 jpg, I don't get the artifacts.  Is there a way to
> save a full quality jpeg in ImageJ?  Any ideas what I need to do
> differently?  Thanks.
>
> -Gwen
>