Width measurement

[Girault France]

Dear all,
 
I would like to measure the maximum width of particles. Using the
breath, I only get only maximum width that is perpendicular to the
Feret's diameter, and using the width deduced from the ellipse fitting,
it doesn't match with the real width... Basically, I'm trying to measure
the maximum width of particles that is perpendicular to their
orientation. Is there any plugin that makes such measurement?
 
 
Thanks a lot,
 
 
France

[Robert Dougherty]

You might try Measure-ROI and related plugins at
http://www.optinav.com/Measure-Roi.htm.

Bob

Robert P. Dougherty, Ph.D.
President, OptiNav, Inc.
Phone [phone]
Fax [phone]
www.optinav.com
 

> I would like to measure the maximum width of particles. Using the
> breath, I only get only maximum width that is perpendicular to the
> Feret's diameter, and using the width deduced from the ellipse fitting,
> it doesn't match with the real width... Basically, I'm trying to measure
> the maximum width of particles that is perpendicular to their
> orientation. Is there any plugin that makes such measurement?
>
>
> Thanks a lot,
>
>
> France

[Gabriel Landini]

On Tuesday 20 February 2007 21:54:01 Robert Dougherty wrote:
> You might try Measure-ROI and related plugins at
> http://www.optinav.com/Measure-Roi.htm.

> > I would like to measure the maximum width of particles. Using the
> > breath, I only get only maximum width that is perpendicular to the
> > Feret's diameter, and using the width deduced from the ellipse fitting,
> > it doesn't match with the real width... Basically, I'm trying to measure
> > the maximum width of particles that is perpendicular to their
> > orientation. Is there any plugin that makes such measurement?

Particles8_Plus also calculates the "proper" breadth:

The largest axis perpendicular to the Feret (not necessarily colinear). That
means that the distances on both sides of the Feret may be at different
places (and it is not derived from the ellipse fitting).

I guess that this is same as in Bob's plugin.

You can find this in the Morphology collection of plugins and macros:

http://www.dentistry.bham.ac.uk/landinig/software/software.html

The macro:
DrawFeret&Breadth.txt
shows these 2 drawn into the image.

Another measure you may want to do is the "Minimal Bounding Box" (which is
*not* the same as the "Bounding Box Along the Feret Diameter" (also available
in Particles8_Plus). However, I know of no plugins to do this. The algorithm
for this is called "Rotating Calipers":

http://cgm.cs.mcgill.ca/~godfried/research/calipers.html

but I haven't had the time to implement it yet.

Gabriel.

never