Re: Color thresholding

Posted by Weller Andrew Francis on Jun 23, 2006; 5:18pm
URL: http://imagej.273.s1.nabble.com/Color-thresholding-tp3702421p3702424.html

Craig,

One thought with this. Perhaps you can decompose your colour image into
3 separate RGB channels. This will effectively give you 3 grey-scale
images, if you've used 16M colours?! See the ExtractRGBChannels.txt
macro. These 3 channels can then be treated separately when you
(auto?)threshold. They can then be recomposed into one thresholded
colour image with a better result.

Perhaps...? I am relatively new to ImageJ, so I hope it helps!?

Andy

On Fri, 2006-06-23 at 10:17 -0400, Craig Oppel wrote:

> Hello All,
>
> I am working on a project that involves microwave extraction of leaves onto
> TLC plates to quantify alkaloids in cardinal flower. The final plates have
> a yellow background with a red/orange alkaloid positive leaf imprint. I
> have tried color thresholding to eliminate the yellow background, and I can
> get acceptable results, but I am concerned because I have to make manual
> adjustments to the intensity sliders. I have found that if I first convert
> the TIFF images of the TLC plates into 8-bit gray scale images and then use
> the adjust contrast/brightness auto function I get really good results.
> What I am concerned about is I have no idea how the algorithim processes
> the picture. I am taking great pains to eliminate bias in my design. Is
> there a way to eliminate the yellow background that would ensure that all
> images are treated identically?
>
> Thank you
> Craig