How to count the number of pixels over certain grayscale value in a ROI?

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How to count the number of pixels over certain grayscale value in a ROI?

Jiseok
Hi, I am trying to count the number of pixels in a ROI which have grayscale
value over a certain threshold (for example, if the range is 0-255, count
the number of pixels with values over 30). Is there a simple way to do this?
I don't know how to write or edit plugins or macros...

Thank you.



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Re: How to count the number of pixels over certain grayscale value in a ROI?

Krs5
Set the threshold values using Image > Adjust > Threshold and add your ROI, go to Analyze > Set Measurements... and select 'Area' followed by Analyze >  Analyze Particles with 'Summary' selected you get the number of pixels under total  Area. If your image is scaled also select 'Pixel units' in Analyze Particles.

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: Jiseok [mailto:[hidden email]]
Sent: 09 March 2018 22:22
To: [hidden email]
Subject: How to count the number of pixels over certain grayscale value in a ROI?

Hi, I am trying to count the number of pixels in a ROI which have grayscale value over a certain threshold (for example, if the range is 0-255, count the number of pixels with values over 30). Is there a simple way to do this?
I don't know how to write or edit plugins or macros...

Thank you.



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Re: How to count the number of pixels over certain grayscale value in a ROI?

Stoyan Pavlov
In addition to to Kees' answer above: the "Limit to threshold" box must
also be ticked in "Set measurements..." dialog.
Good day,
Stoyan

---
Assoc.Prof. Stoyan P. Pavlov, MD, PhD
Departament of Anatomy, Histology and Embryology
Medical University "Prof. Dr. Paraskev Stoyanov", Varna
Prof. Marin Drinov Str.55
9002 Varna
 Bulgaria
Tel: +359 (0) 52 - 677 - 052
e-mail: [hidden email]
           [hidden email]

2018-03-12 10:47 GMT+02:00 Straatman, Kees (Dr.) <[hidden email]>:

> Set the threshold values using Image > Adjust > Threshold and add your
> ROI, go to Analyze > Set Measurements... and select 'Area' followed by
> Analyze >  Analyze Particles with 'Summary' selected you get the number of
> pixels under total  Area. If your image is scaled also select 'Pixel units'
> in Analyze Particles.
>
> 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: Jiseok [mailto:[hidden email]]
> Sent: 09 March 2018 22:22
> To: [hidden email]
> Subject: How to count the number of pixels over certain grayscale value in
> a ROI?
>
> Hi, I am trying to count the number of pixels in a ROI which have
> grayscale value over a certain threshold (for example, if the range is
> 0-255, count the number of pixels with values over 30). Is there a simple
> way to do this?
> I don't know how to write or edit plugins or macros...
>
> Thank you.
>
>
>
> --
> Sent from: http://imagej.1557.x6.nabble.com/
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>

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