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-tp5003764p5004176.html

Dear Karsten,
It was more of my Professor's choice for me to collect all the data regardless of whether I need it or not, but I will focus on the ones you have suggested for now. I thank you very much for responding on time and I hope you have a great day.


On Sat, Jul 27, 2013 at 6:40 AM, Karsten Rodenacker-3 [via ImageJ] <[hidden email]> wrote:
Hi Geology Guy,

Seemingly you have switched on all features. For the shape of particles there are IMHO only senseful:

Area (*)
Perimeter (*)
Circ (*)
Solidity (*)
Round (*)
Feret (*)
MinFeret
Minor/Major

all others are related to redirection to gray scale image or not really helpful for particle shape description, better for representation e.g. by ellipsoids.

To summarize a set of particles:

The features (*) can be summarized by the usual Mean and SD.
 
Min Feret is special, either the (global) Minimum or the span (Max-Min) could characterize the set os particles.

Feret Angle and Angle might be helpful for elongated particles, but the mean of angles is a difficult task since angles come from a number module. (to difficult for the available time!)

The mean of (Minor/Major), a ratio estimator is mean(Minor)/mean(Major) not mean(Minor/Major). SD of the ratio is a bit complicated too!

I think this list of features should be enough for characterization of a set of particles!

Hope that helps a bit

Regards
Karsten

Am 27.07.2013 um 03:47 schrieb Geology Guy <[hidden email]>:

> 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]<http://user/SendEmail.jtp?type=node&node=5003767&i=0>>:
>>

>>
>>> 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.
>>>
>>> --
>>> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>>
>> Karsten
>> [hidden email] <http://user/SendEmail.jtp?type=node&node=5003767&i=1>
>>
>> --
>> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>>
>>
>> ------------------------------
Karsten
[hidden email]

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