Posted by
Christophe CHAMOT on
Sep 13, 2005; 6:21pm
URL: http://imagej.273.s1.nabble.com/Information-regarding-formats-tp3704893p3704895.html
Le mardi 13 septembre 2005 à 19:05 +0200, Pedro J Camello a écrit :
> Please, could anybody in the list indicate some online source of
> information regarding conversion between graphic types?
>
> My problem is that, to make some measurments, I need to open a series of
> bmp images (as a stack) with RGB color format and convert to
> grayscale-stack manageable format. I do it but...the new pixel values
> are absolutely no sense for me. Even the original RGB values (three
> values, of course) are not useful. However, the original application
> (Metafluor Analyst) shows the original RGB values as one single value.
> Therefore, I think some learning about the maths involved in image
> coinversion could help me
>
> Thanks
Hello,
If you just do Image > type and check "8-bits" from an RGB image, ImageJ
just calculate the average value in the 3 layers (Red, green and blue).
The greatest value is then 255/3 = 85 for a 1 color image.
In Metafluor, if you have only one value, the software probably
represents your data with a look-up table. Even if it saves in RGB
format.
The quick way to have your values is to separate the RGB layers with
Image > Color > RGB Split. You'll have three separate staks (2 black
ones and the third of your color of interest with values ranging from 0
to 255).
hope it helps ...
--
CHAMOT Christophe
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