Posted by
Oky on
Dec 09, 2013; 6:21am
URL: http://imagej.273.s1.nabble.com/Conifer-needle-surface-area-minus-shadows-tp5005845p5005852.html
Hello,
With the previous good suggestions, if you use no cover with your scanner
when you scan the samples, the scanned image will have black background but
your needles have no shadows. It looks like dark field micrographs.
I used this trick when I measure surface areas of 20 wood blocks at one
scan. Also it is going to be much easier to apply automatic threshold for
the needles.
One thing you should be aware of images of samples. When the samples are
located away from the scan axis (center part of the scanner along scan head
movement) of your scanner will have side view. That might affect
significant influence on the surface area that you want to measure
depending on shape of your samples.
I hope this helps you make measurement easier and more accurate.
Best regards,
Ohkyung
On Mon, Dec 9, 2013 at 8:03 AM, Tree-Doc <
[hidden email]> wrote:
> I have about 250 scans of conifer tree needles and need to measure their
> surface area. I've been using Threshold Colour to adjust the HSB to remove
> part of the shadow, but I notice that depending on the exact threshold
> numbers I use, my resulting area calculation will vary by 25% or more (not
> good).
>
> Is there a better way to do this to achieve more accurate results?
>
> My methods: Adjust HSB to remove as much of the shadow as I can without
> removing green needle.
> Converting to binary.
> Despeckling the noise.
> Process>Binary>Close to capture the white center streaks in the needles.
> Filling the Holes.
> And analyzing particles
>
> Here is an example of the images I'm working with. I know the scans aren't
> ideal, but capturing better images in not an option.
> <
http://imagej.1557.x6.nabble.com/file/n5005845/4L0001_exp.jpg>
>
>
>
> --
> View this message in context:
>
http://imagej.1557.x6.nabble.com/Conifer-needle-surface-area-minus-shadows-tp5005845.html> Sent from the ImageJ mailing list archive at Nabble.com.
>
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> ImageJ mailing list:
http://imagej.nih.gov/ij/list.html>
--
Ohkyung Kwon
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