How does the ImageJ calculate standard deviation value

[jitaozhang1988]

Hi,
    I am a beginner with ImageJ. I used it to calculate the mean and STDDEV value of a selected area in a picture of bacterial cell gotten from Nanosims. But I found the STDDEV is pretty big compare to the mean value. This will invalidate the mean value. So could you tell me the details of how this software calculate standard deviation?

Thanks very much

[John Oreopoulos]

Hi,

I have a fairly large stack of images to be rendered in 3D using the "3D viewer" plugin (512x512x1134). I'd still like to view the rendering at high resolution, but I find that if I enter in a resampling factor value less than the default (2), then the 3D image is not produced and the plugin window idles. Is this a bug, or is it just not possible to render at higher resolution here?

Thanks for any tips!

John Oreopoulos

[Aaron Hendrickson]

ImageJ is calculating the standard deviation of the pixel intensities in the
area you selected....just as you would calculate the standard deviation of
any set of values. If the standard deviation is large that just means that
the pixel brightnesses sampled are not well centered around the mean.
On Oct 24, 2011 5:37 PM, "jitaozhang1988" <[hidden email]> wrote:

> Hi,
>    I am a beginner with ImageJ. I used it to calculate the mean and STDDEV
> value of a selected area in a picture of bacterial cell gotten from
> Nanosims. But I found the STDDEV is pretty big compare to the mean value.
> This will invalidate the mean value. So could you tell me the details of
> how
> this software calculate standard deviation?
>
> Thanks very much
>
> --
> View this message in context:
> http://imagej.588099.n2.nabble.com/How-does-the-ImageJ-calculate-standard-deviation-value-tp6926957p6926957.html
> Sent from the ImageJ mailing list archive at Nabble.com.
>

... [show rest of quote]