Re: Isolating the background pixels from foreground pixels

Posted by Geology Guy on
URL: http://imagej.273.s1.nabble.com/Isolating-the-background-pixels-from-foreground-pixels-tp5003764p5004170.html

Dear Karsten,

I am trying to measure the parameters of 100 particles in Image J and under "Analyze Particles", I also selected the "Summary option". My main problem now is that I deleted some of the particles as requested by my Professor from the list after the data was provided by Image J. This makes the "Summary" data not useful anymore as they do not reflect all the 100 particles I started with originally. I measured all the parameters under "Set measurement" for each particle so now I need to produce a new summary data as the values would be used in plotting graphs. I have figured out how to Area which is just a simple addition of the areas of each particle. Other parameters that are in the summary that I cannot determine from the particles data are the following:

 

 

 

Perim.

Major

Minor

Circ.

Solidity

Feret

FeretX

FeretY

FeretAngle

MinFeret

IntDen

Median

Skew

Kurt

 

I have attached 2 Excel spreadsheets. The first shows my original particles data and the highlighted rows in yellow are rows that I have deleted their data as they are bad data. I am working on my research that is due on the 31st of this month so this is very urgent. Thank you very much for your assistance. 

Yours faithfully,

Tola

On Thu, Jul 4, 2013 at 5:10 PM, Karsten Rodenacker-3 [via ImageJ] <[hidden email]> wrote:

Hi Geology Guy, possibly geologists think different.

There are gray or color images with bright background and others with a dark background. This should not be mixed up with the representation of binary images. Foreground is always the set of pixels which are thresholded (shown with the small box) in the histogram of the interactive thresholding window. They get a value of 255. The background gets 0. Still by the Options->Colors… you can select the representation of foreground and background pixels.

Maybe some clarification for you?

Karsten

(I have to confess that I rarely read manuals, I prefer trial and error)

Am 04.07.2013 um 22:49 schrieb Geology Guy <[hidden email]>:

> Dear Karsten,
> Thanks for your response. I checked the Edit> Options> Colors and the
> background is black while the Foreground is White. This is what I expect
> because after reading the Image J manual, I learnt that Image J only makes
> calculations from binary images when the background is black and the
> foreground is white.
>
> I am using the default thresholding (i.e. AUTO) and checked the DARK
> BACKGROUND BOX. Then when I was ready to do binary image a,dialogue box
> popped up and I unchecked the box next to "BLACK FOREGROUND and WHITE
> BACKGROUND". Again this setting that I am using is because the Image J
> manual recommended a background that is black and white foreground in order
> to be able to carry out calculations involving binary imaging. Or am I wrong
> somewhere maybe that's why the background pixels are getting picked up in
> the foreground when I try to calculate Area for foreground objects ONLY?
> Thanks for your help.
>
>
>
>
>
> --
> View this message in context: http://imagej.1557.x6.nabble.com/Isolating-the-background-pixels-from-foreground-pixels-tp5003764p5003766.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

Karsten
[hidden email]

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