Re: Color thresholding and obtaining Lab values

Posted by Joel Sheffield on
URL: http://imagej.273.s1.nabble.com/Color-thresholding-and-obtaining-Lab-values-tp5020700p5020713.html

You can set a range in Analyze particles to exclude small dots, and even
certain shape parameters.  Look at the menu options.  Also, consider using
the watershed procedure to isolate specific beans - if that is important to
you.



Joel B. Sheffield, Ph.D
Department of Biology
Temple University
Philadelphia, PA 19122
Voice: 215 204 8839
e-mail: [hidden email]
URL:  *https://bio.cst.temple.edu/~jbs/ <https://bio.cst.temple.edu/~jbs/>
<http://tinyurl.com/khbouft>*

On Tue, May 22, 2018 at 7:52 PM, Rie Sadohara <[hidden email]>
wrote:

> Dr. Sheffiled,
>
> Thank you for the suggestion. I have already tried it, but it recognizes
> numerous small dots (very very tiny compared to the beans) as particles,
> and ignores the beans in the image. I do not know why, but it does not work
> as I would like it to.
>
> Rie
>
> On 22 May 2018 at 19:15, Joel Sheffield <[hidden email]> wrote:
>
> > How about using Analyze Particles?
> >
> >
> >
> > Joel B. Sheffield, Ph.D
> > Department of Biology
> > Temple University
> > Philadelphia, PA 19122
> > Voice: 215 204 8839
> > e-mail: [hidden email]
> > URL:  *https://bio.cst.temple.edu/~jbs/ <https://bio.cst.temple.edu/~
> jbs/>
> > <http://tinyurl.com/khbouft>*
> >
> > On Tue, May 22, 2018 at 5:13 PM, Rie Sadohara <[hidden email]>
> > wrote:
> >
> > > Hello all,
> > >
> > > I am trying to get Lab values from images of yellow beans. There are
> some
> > > black and white parts in the image, so I want to remove those parts and
> > > measure the yellowness of the bean seeds. Below are the steps I took,
> but
> > > Lab values are calculated from the entire image. Could someone tell me
> > how
> > > to do it right?
> > >
> > > 1. Open --> Open my photo, which is an RGB color image.
> > > 2. Image --> Adjust --> Color threshold... --> Then set the threshold
> of
> > > L* value to be 71-216 so that the black and white parts will be
> excluded.
> > > --> Select.
> > > 3. The yellow parts (of which I want to know the Lab values) are
> circled
> > > with yellow lines now.
> > > 4.  Image --> Type --> Lab stack.
> > > 5. Analyze --> Measure. for each stack (L, a, and b)
> > > 6. The returned Lab values are based on the entire image. It works as
> > > though there had been no color thresholding.
> > >
> > > My understanding is that the parts that are circled with bright yellow
> > > lines after color thresholding are the area that are going to be used
> for
> > > Lab measurements? (Please see the attachment. In the image, the yellow
> > > parts (my ROI) are segregated correctly, but how can I get Lab values
> out
> > > of this region?)
> > >
> > > Any advice would be greatly appreciated,
> > >
> > > Rie
> > >
> > >
> > > --
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> > >
> >
> > --
> > ImageJ mailing list: http://imagej.nih.gov/ij/list.html
> >
>
>
>
> --
> ------------------------------------------------------------
> ----------------------------------------------------------
> *Rie** Sadohara  *
> Graduate Research Assistant
> Department of Plant, Soil and Microbial Sciences
> Michigan State University
> Plant and Soil Science Building
> 1066 Bogue St, Room A364
> East Lansing, MI 48824
> Email: *[hidden email] <[hidden email]>*
> Find delicious bean recipes here:
> *https://colorfulhealthfulflavorfulblog.wordpress.com/
> <https://colorfulhealthfulflavorfulblog.wordpress.com/>*
> ------------------------------------------------------------
> -------------------
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