cross sectional area

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cross sectional area

Sarah Mohamed

Hi,
I wonder if you can kindly answer my question about measuring cross-sectional area of cells using image j.
i have images with scale bar 50 um (X20)  and scale bar 20 um (X40) but i dont have a pic of a ruler at 2 magnification power
can i set set the scale bar in image J by using the pic scale bar as the known distance and change the scale for each magnification power?
will i be able to compare  results of both CSA?
Also, will the resulted area be in square micrometer?
Thanks in advance.
Kind Regards,
Sarah M. Mosaad, M.Sc.
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Re: cross sectional area

Michael Schmid
Hi Sarah,

if you have a scale bar, make a line from the beginning to the end of the scale bar and use Analyze>Set Scale.  The field "Distance in Pixels" will be the line length, then just enter the know distance (20 or 50) and unit of length (um).

The area you get with 'Measure' or 'Analyze Particles' will then be in square micrometer.

Of course, if the scale bar is not accurate, this will affect your calibration.  So it might be a good idea to take an image of an object with known size (e.g. a ruler) and check whether the scale bar is correct.

http://serc.carleton.edu/eyesinthesky2/week2/get_to_know_imagej.html#calibrate_scale_bar
http://occm.otago.ac.nz/resources/Spatial-Calibration-of-an-Image.pdf

Michael
________________________________________________________________
On Jan 6, 2016, at 06:19, Sarah Mosaad wrote:

>
> Hi,
> I wonder if you can kindly answer my question about measuring cross-sectional area of cells using image j.
> i have images with scale bar 50 um (X20)  and scale bar 20 um (X40) but i dont have a pic of a ruler at 2 magnification power
> can i set set the scale bar in image J by using the pic scale bar as the known distance and change the scale for each magnification power?
> will i be able to compare  results of both CSA?
> Also, will the resulted area be in square micrometer?
> Thanks in advance.
> Kind Regards,
> Sarah M. Mosaad, M.Sc.

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Re: cross sectional area

Sarah Mohamed

Hi Michael,
Thanks a lot, i appreciate it.
Kind Regards,
Sarah
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Thursday, 07 January 2016, 11:13AM +0200 from Michael Schmid <[hidden email]>:
Hi Sarah,
if you have a scale bar, make a line from the beginning to the end of the scale bar and use Analyze>Set Scale.  The field "Distance in Pixels" will be the line length, then just enter the know distance (20 or 50) and unit of length (um).
The area you get with 'Measure' or 'Analyze Particles' will then be in square micrometer.
Of course, if the scale bar is not accurate, this will affect your calibration.  So it might be a good idea to take an image of an object with known size (e.g. a ruler) and check whether the scale bar is correct.
http://serc.carleton.edu/eyesinthesky2/week2/get_to_know_imagej.html#calibrate_scale_bar
http://occm.otago.ac.nz/resources/Spatial-Calibration-of-an-Image.pdf
Michael
________________________________________________________________
On Jan 6, 2016, at 06:19, Sarah Mosaad wrote:

>
> Hi,
> I wonder if you can kindly answer my question about measuring cross-sectional area of cells using image j.
> i have images with scale bar 50 um (X20)  and scale bar 20 um (X40) but i dont have a pic of a ruler at 2 magnification power
> can i set set the scale bar in image J by using the pic scale bar as the known distance and change the scale for each magnification power?
> will i be able to compare  results of both CSA?
> Also, will the resulted area be in square micrometer?
> Thanks in advance.
> Kind Regards,
> Sarah M. Mosaad, M.Sc.
--
ImageJ mailing list:  http://imagej.nih.gov/ij/list.html

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ImageJ mailing list: http://imagej.nih.gov/ij/list.html