Re: Integrated Density Unit help? please

Posted by lechristophe on Jun 19, 2008; 9:35pm
URL: http://imagej.273.s1.nabble.com/Integrated-Density-Unit-help-please-tp3695786p3695790.html

This is indeed a quite tricky question, see the previous discussion
some time ago on this list :
http://www.nabble.com/Integrated-Density-and-Image-Scale-td16402023.html

It appears that the ID measurement takes into account the image
spatial scale (if you change the scale of an image and measure it
again, your ID values change accordingly). I still don't understand
why (it is contradictory to the definition of ID given in the ImageJ
doc), but it seems to be valid.

I ended up systematically resetting the scale of all images before
processing in my macros to avoid having problems with files that are
imported with or without scaling information...

Christophe

On Thu, Jun 19, 2008 at 17:29, Thomas Boudier
<[hidden email]> wrote:

> ok I understand your trouble. The area here corresponds to the number of
> pixels and does not take into account the spatial calibration. So the
> integrated density has the unit of pixel values, that is to say gray levels.
>
> Thomas
>
>> Thanks for reply. I have read the documentation about integrated density.
>> There it is said that it is sum of pixels values inside the object but I
>> scaled pixels as µm and there is written also that it is equal to the
>> product of area and mean gray values. That's why I was confused about the
>> unit. Because all the images used are the scaled images. Should I consider
>> this integrated density without unit in my case or should I consider it as
>> pixels which are µm in my case. I hope that I was a little bit clear in my
>> question.
>>
>> Cordially.
>>
>> Kashif ZEESHAN
>> (00 33 6 74 90 18 10)
>> Doctorant, Biopesticide Group,
>> Laboratoire Universitaire de
>> Biodiversité et d'Ecologie Microbienne (LUBEM),
>> 6 Rue de l'Université,
>> 29334, Quimper Cedex,
>> France
>> -----Message d'origine-----
>> De : ImageJ Interest Group [mailto:[hidden email]] De la part de
>> Thomas
>> Boudier
>> Envoyé : jeudi 19 juin 2008 16:23
>> À : [hidden email]
>> Objet : Re: Integrated Density Unit help? please
>>
>> Hi Kashif,
>>
>> Maybe you should have a look to the documentation ;-) , Integrated density
>> is the sum of pixel values inside the object, it is not a geometrical
>> measure like area or volume.
>>
>> Thomas
>>
>>
>>>
>>> HI experts
>>>
>>> I need some help about Integrated Density. My scale is in µm. Now I want
>>>
>>
>> to
>>
>>>
>>> know what will be the unit of Integrated Density? For Area, it is µm2 and
>>> for Feret's Diameter µm and for circularity, no unit at all. Can you
>>>
>>
>> kindly
>>
>>>
>>> help me in this regard?
>>>
>>>
>>> Cordially.
>>>
>>>
>>> Kashif ZEESHAN
>>>
>>> (00 33 6 74 90 18 10)
>>>
>>> Doctorant, Biopesticide Group,
>>>
>>> Laboratoire Universitaire de
>>>
>>> Biodiversité et d'Ecologie
>>> Microbienne (LUBEM),
>>>
>>> 6 Rue de l'Université,
>>>
>>> 29334, Quimper Cedex,
>>>
>>> France
>>>
>>>
>>>
>>>
>>
>>
>>
>
>
> --
> /*****************************************************/
>  Thomas Boudier, MCU Université Paris 6,
>  UMR 7101 / IFR 83. Bat A 328, Jussieu.
>  Tel : [phone]  Fax : [phone]
> /****************************************************/
>