COLOR SWAP FUNCTION?

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COLOR SWAP FUNCTION?

subham rath
Dear all,
i was wondering how some important functions like color swap is not there?
or, am i missing something. i am analyzing some microscopic slides
containing blood vessels filled with pink RBCs which i wanted to convert to
black object. But I could only select all pink RBCs by color based
thresholding function. but then i can not convert them to black by any easy
method without affecting other parts of histology.

and another important query: is there any way to increase the window level
of wand tracing tool. if the color values change little bit higher or lower
the wand tool cant able to detect them making it non-functional in many
important situations. In adobe it can be done nicely.

any hint or help will be beneficial and i can try our myself after that.
Please suggest something.
thanks for noticing.
subha..
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Re: COLOR SWAP FUNCTION?

Gabriel Landini
On Friday 20 February 2009 20:57:27 subham rath wrote:
> i was wondering how some important functions like color swap is not there?
> or, am i missing something.
> i am analyzing some microscopic slides
> containing blood vessels filled with pink RBCs which i wanted to convert to
> black object. But I could only select all pink RBCs by color based
> thresholding function. but then i can not convert them to black by any easy
> method without affecting other parts of histology.

Swapping colours is a point operation, and pixels do not know anything about
high order spatial structures in your image. So by colour swapping alone you
will not be able to select pixels in the red blood cells without selecting
other similarly pink pixels outside the cells. You probably need to use a more
complex segmentation procedure for that.

You can, use the macro function:
changeValues(v1, v2, v3)
http://rsb.info.nih.gov/ij/developer/macro/functions.html

> and another important query: is there any way to increase the window level
> of wand tracing tool. if the color values change little bit higher or lower
> the wand tool cant able to detect them making it non-functional in many
> important situations. In adobe it can be done nicely.

I do not think you can. You need to read the documentation.
http://rsb.info.nih.gov/ij/docs/tools.html
It works for uniform colours only.

You can however sample a rectangular area with the colour threshold plugin
http://www.dentistry.bham.ac.uk/landinig/software/software.html
Not sure if that is what you are looking for.

Cheers,
G.