Re: Color thresholding and obtaining Lab values

Posted by Rie Sadohara on
URL: http://imagej.273.s1.nabble.com/Color-thresholding-and-obtaining-Lab-values-tp5020700p5020730.html

Yes I did. I just noticed that I can "Restore Selection" after converting
the image to Lab stack! So now, I think the following procedure can exclude
black and white parts and then apply this selection to Lab stack. This way,
I can obtain L, a, b values from only the color-thresholded area. It seems
to work, but I would appreciate your comments, as how to get Lab values is
not clearly explained in the manual.

1. Open --> Open my photo, which is an RGB color image.
2. Image --> Adjust --> Color threshold... --> 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. Edit --> Selection --> Add to manager
    - in the ROI Manager menus select More --> Multi Measure
    - in the menu presented, select "Measure all 3 slices" and deselect
"One row per slice"
5. Image --> Type --> Lab stack.
6. Edit --> Selection --> Restore selection (The outline of my ROI comes
back on the Lab stack images)
7. Plugins -> Stack -> Measure stack


Thank you,

Rie


On 24 May 2018 at 11:59, Straatman, Kees (Dr.) <[hidden email]> wrote:

> Did you do your step 4: >   Image --> Type --> Lab stack?
>
> Kees
>
> -----Original Message-----
> From: Rie Sadohara [mailto:[hidden email]]
> Sent: 24 May 2018 16:58
> To: [hidden email]
> Subject: Re: Color thresholding and obtaining Lab values
>
> Dr. Staatman,
>
> Thank you for the suggestion. I was able to add the thresholded area to
> selection, and it was circled by light blue lines.
> However, when I hit Measure, it only gives the area and gray area values,
> because it is what is checked in the Analyze -> Set Measurements... option.
> There is no L, a, b values to be selected in that option. It seems that I
> need to convert the image to Lab stack then hit Measure (or Plugins ->
> Stack -> Measure stack) to obtain L, a, and b values. But when the image is
> converted to Lab stack, the selection is lost, and the L, a, b values are
> based on the entire image including the portions that I do not want to
> include.
>
> I guess my question is: Is it possible to convert the color-thresholded
> selection to a Lab stack, or is there a way to measure L, a, b values
> without converting the image into Lab stack?
>
> Kind regards,
>
> Rie
>
>
>
>
>
>
> On 24 May 2018 at 03:24, Straatman, Kees (Dr.) <[hidden email]>
> wrote:
>
> > Dear Rie,
> >
> > To measure only your selection you can use:
> > - Edit > Selection > Add to Manager
> > - in the ROI Manager menus select More > Multi Measure
> > - in the menu presented select "Measure all 3 slices" and deselect
> > "One row per slice"
> >
> > I hope this solves your problem.
> >
> > Best wishes
> >
> > Kees
> >
> >
> > Dr Ir K.R. Straatman
> > Senior Experimental Officer
> > Advanced Imaging Facility
> > Centre for Core Biotechnology Services University of Leicester
> > www.le.ac.uk/advanced-imaging-facility
> >
> >
> > -----Original Message-----
> > From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of
> > Rie Sadohara
> > Sent: 22 May 2018 22:13
> > To: [hidden email]
> > Subject: Color thresholding and obtaining Lab values
> >
> > 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
> >
> >
> > --
> > ImageJ mailing list: http://imagej.nih.gov/ij/list.html
> >
> > --
> > 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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> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
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--
----------------------------------------------------------------------------------------------------------------------
*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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