Outline and area of clusters of objects

[enriquezudaire]

Dear all

I'm trying to generate the outline and automatically measure the area of several clusters of objects on a image (8-bit). I thought convex hull could help, but I see several problems the first being, how to generate several convex hull polygons on the same image.
Any ideas on how to approach this problem?
Thanks
Kike


__________________________________
Dr. Zudaire Ubani, Enrique
Staff Scientist
Angiogenesis Core Facility
National Cancer Institute
Office Of the Director
National Institutes of Health
Advanced Technology Center
8717 Grovemont Circle Suite 115
Gaithersburg, MD 20877
TEL. [phone]
FAX. [phone]
[e-mail]
 
"Mind is like a parachute; it
only works when open"

[dscho]

Hi,

On Thu, 12 Feb 2009, enriquezudaire wrote:

> I'm trying to generate the outline and automatically measure the area of
> several clusters of objects on a image (8-bit). I thought convex hull
> could help, but I see several problems the first being, how to generate
> several convex hull polygons on the same image.

You usually have to handle the clusters separately; then you can create
the convex hulls.  By combining the convex hulls, you should get what you
want.  The bigger problem is to describe what makes a cluster, precise
enough that you can turn that into a macro or plugin.

Ciao,
Dscho

[enriquezudaire]

Hi

I don't necessarily have to use convex hull. I just need a way to get within the same outline all the elements in a defined cluster. Images contain several of these clusters. Since the particles in a cluster are closer together may be using distances between particles (or some like that) could work. Any ideas?
Thanks
Kike


__________________________________
Dr. Zudaire Ubani, Enrique
Staff Scientist
Angiogenesis Core Facility
National Cancer Institute
Office Of the Director
National Institutes of Health
Advanced Technology Center
8717 Grovemont Circle Suite 115
Gaithersburg, MD 20877
TEL. [phone]
FAX. [phone]
[hidden email]
 
"Mind is like a parachute; it
only works when open"
 
 

-----Original Message-----
From: Johannes Schindelin [mailto:[hidden email]]
Sent: Thursday, February 12, 2009 3:34 PM
To: Zudaire, Enrique (NIH/NCI) [E]
Cc: List IMAGEJ
Subject: Re: Outline and area of clusters of objects

Hi,

On Thu, 12 Feb 2009, enriquezudaire wrote:

> I'm trying to generate the outline and automatically measure the area of
> several clusters of objects on a image (8-bit). I thought convex hull
> could help, but I see several problems the first being, how to generate
> several convex hull polygons on the same image.

You usually have to handle the clusters separately; then you can create
the convex hulls.  By combining the convex hulls, you should get what you
want.  The bigger problem is to describe what makes a cluster, precise
enough that you can turn that into a macro or plugin.

Ciao,
Dscho