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Re: saving images

Posted by Michael Schmid on Dec 12, 2007; 2:06pm
URL: http://imagej.273.s1.nabble.com/saving-images-tp3697796p3697799.html

Hi Markus,

saving your marks in a jpeg is possible - simply create a line
or area selection and press "draw" or "fill" with a suitable
foreground color (color of the eyedropper tool).
If you have a big image, maybe you won't see a line if you view
it with less than 100% zoom factor: The line could be between
the pixels displayed on the screen.

Anyhow, you should NOT do this for the following reason:

Jpeg is a lossy compression, and each time you save the image,
more compression artifacts will creep in. Jpeg is especially bad
for sharp edges such as those of a line or dot used as a
marker.
So it is MUCH better if you don't save your markers with the
image but rather create, e.g. a point selection (shift-click
with the point selection tool to add points; double-click on
the tool to select whether they have numbers as labels).
Then, save it as a separate file via the ROI Manager:
Type "t" to add the selection to the roi manager, select the
selection(s) that you want to save and type "save".
BTW, doing it this way will also use much less disk space
(roi files are small).

If you want to automate it, a macro could save the roi with a
name related to the image in the same directory and another
macro could open the image and roi together.
Using the Macro Recorder (Plugins>Macros>Record) and having a
look at the macro documentation and sample macros
   http://rsb.info.nih.gov/ij/developer/index.html
should help.

Michael
________________________________________________________________

On 12 Dec 2007, at 14:37, Markus Dyck wrote:

> Hello all again, sorry to be a pain in the rear.
>
> I need to ask for advice again regarding trying to save images with  
> marks
> on them.
> Maybe I was not specific - here is what I do: I open an image  
> (about 25MB
> with good resolution to work with), I then use the drawing tool with
> individual marks so I can mark certain points on the jpeg. For later
> reference, I need to have these marks saved on the picture. I try  
> save as
> with different name, I try ROI and save, but whenever I am opening the
> jpeg I renamed, only the picture opens with no marks I put on. Can  
> any of
> you epxerst on ImageJ please tell me how to do this step by step. I  
> got
> some advice from list members, but this seems not to work.
>
> Thank you so much for your assistance - also have a good holiday  
> season!
>
> Markus Dyck, Instructor [MNRM, AWB]
> Environmental Technology Program
> Nunavut Arctic College
> P.O. Box 600
> Iqaluit, NU
> Canada  X0A 0H0
> Ph: (867) 979-7282
> Fx: (867) 979-7101