Posted by
Rie Sadohara on
May 24, 2018; 3:57pm
URL: http://imagej.273.s1.nabble.com/Color-thresholding-and-obtaining-Lab-values-tp5020700p5020728.html
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
>
>
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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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