[R] Calculating diameters of cirkels in a picture.

Bio7 marcel.austenfeld at uni-bielefeld.de
Fri Aug 24 10:13:35 CEST 2007

Hello Bart!

I took your picture and analysed it with ImageJ.
You can do a particle analysis with the image which measures the required

I used the "Find Edges" method Process->Find Edges and then adjusted the

After this i converted the image to 8-bit Image->Type->8-bit and thresholded
the image 
Image->Adjust->Threshold until i've got closed circles in red.

In the Analyse->Set Scale and Analyse->Set Measurements dialog I selected
the attributes to measure (Ferrets Diameter or Bounding Rectangle! You have
to adjust the appropriate

I then did a particle analysis which excluded particles < 1000
Analyse->Analyse Particles.

If you select the option "Add to Manager" all measured Particles are added
to a "Region of Interest
Manager" ROI in which you can select and measure your Particles seperately,
if you wish.

You can also fit a Ellipse to the selected Particle in Edit->Selection->Fit
Ellipse and then measure
the Particle.

If you want to see a Particle measurement in Action see my application which
uses ImageJ and R and the 
Flash tutorial in which i demonstrate a Particle measurement which is analog
to the ImageJ application.

I highly recommend you to use a new version of ImageJ because of this
capabilities, downloadable at

http://rsb.info.nih.gov/ij/ http://rsb.info.nih.gov/ij/ 

I hope this information is a help for you.

With kind regards

View this message in context: http://www.nabble.com/Calculating-diameters-of-cirkels-in-a-picture.-tf4319669.html#a12307704
Sent from the R help mailing list archive at Nabble.com.

More information about the R-help mailing list