Area measurements

[Douglas Benn-2]

The Area measurement in Analyze is defined as the Area of selection in square pixels.

In the attached image there are 3 outlined objects. 0bject 580 is much smaller and anterior than object 581 which is in the center of the head. It looks like the area of 581 should be at least 2-3 times 580. However, from the results below 581 is only about 10% larger. Can anybody please explain this?

Object     Image ID     Area       X       Y      Slice
579 04:ID001122228 1936 253.06 311.66   228
580 04:ID001122228 319 166.33 201.65   228
581 04:ID001122228 353 240.86 298.37   228

Thanks.

Douglas

Dr Douglas K Benn, BDS,DDS, M.Phil., Ph.D., Dipl. Dental Radiology (Royal College of Radiologists, England).
Professor and Director of Oral & Maxillofacial Radiology
Dept of General Dentistry
Creighton University Dental School
2802 Webster St, Boyne 210
Omaha
Nebraska 68178

Tel: [phone]
Fax: [phone]

[David Webster]

Douglas,

I binarized your image using Process/Binary/Make Binary. Then I used the
rectangular RIU tool and duplicate to make smaller image copies of objects
580 and 581. The I used Binary/Fill Holes to convert these to solid
silhouettes. Finaly, I used Analyze/Analyze Particles to compute their
areas. I repeated the process for the whole image to measure object 579.
The results are shown below.  Object 581  is about 4 times bigger in area
than 579.

could you have been measuring the ara of the outlines only and not the
filled in ouitlines?

David Webster

579 Drawing of 04.jpg    127967 255 1
580 Drawing of 04-2.jpg 749 255 1
581 Drawing of 04-1.jpg 3001 255 1


On Thu, May 6, 2010 at 8:37 PM, Benn, Douglas K.
<[hidden email]>wrote:

> The Area measurement in Analyze is defined as the Area of selection in
> square pixels.
>
> In the attached image there are 3 outlined objects. 0bject 580 is much
> smaller and anterior than object 581 which is in the center of the head. It
> looks like the area of 581 should be at least 2-3 times 580. However, from
> the results below 581 is only about 10% larger. Can anybody please explain
> this?
>
> Object     Image ID     Area       X       Y      Slice
> 579     04:ID001122228  1936    253.06  311.66     228
> 580     04:ID001122228  319     166.33  201.65     228
> 581     04:ID001122228  353     240.86  298.37     228
>
> Thanks.
>
> Douglas
>
> Dr Douglas K Benn, BDS,DDS, M.Phil., Ph.D., Dipl. Dental Radiology (Royal
> College of Radiologists, England).
> Professor and Director of Oral & Maxillofacial Radiology
> Dept of General Dentistry
> Creighton University Dental School
> 2802 Webster St, Boyne 210
> Omaha
> Nebraska 68178
>
> Tel: [phone]
> Fax: [phone]
>
>
>

[Michael Schmid]

Hi Douglas,

probably there is an interior hole in object 581. It won't be shown  
in the 'outline' output of 'Analyze Particles'.

Michael
________________________________________________________________

On 7 May 2010, at 05:37, Benn, Douglas K. wrote:

> The Area measurement in Analyze is defined as the Area of selection  
> in square pixels.
>
> In the attached image there are 3 outlined objects. 0bject 580 is  
> much smaller and anterior than object 581 which is in the center of  
> the head. It looks like the area of 581 should be at least 2-3  
> times 580. However, from the results below 581 is only about 10%  
> larger. Can anybody please explain this?
>
> Object     Image ID     Area       X       Y      Slice
> 579 04:ID001122228 1936 253.06 311.66   228
> 580 04:ID001122228 319 166.33 201.65   228
> 581 04:ID001122228 353 240.86 298.37   228
>
> Thanks.
>
> Douglas

[Douglas Benn-2]

Dear David & Michael,

Thanks for your suggestions.

Michael, I don't think there are any included holes.

David, I don't know why it would just be measuring the pixels in the
outline.

Wayne is going to have a look.

Best wishes.

Douglas

-----Original Message-----
From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of
David Webster
Sent: Friday, May 07, 2010 1:14 AM
To: [hidden email]
Subject: Re: Area measurements

Douglas,

I binarized your image using Process/Binary/Make Binary. Then I used the
rectangular RIU tool and duplicate to make smaller image copies of
objects
580 and 581. The I used Binary/Fill Holes to convert these to solid
silhouettes. Finaly, I used Analyze/Analyze Particles to compute their
areas. I repeated the process for the whole image to measure object 579.
The results are shown below.  Object 581  is about 4 times bigger in
area
than 579.

could you have been measuring the ara of the outlines only and not the
filled in ouitlines?

David Webster

579 Drawing of 04.jpg    127967 255 1
580 Drawing of 04-2.jpg 749 255 1
581 Drawing of 04-1.jpg 3001 255 1


On Thu, May 6, 2010 at 8:37 PM, Benn, Douglas K.
<[hidden email]>wrote:

> The Area measurement in Analyze is defined as the Area of selection in
> square pixels.
>
> In the attached image there are 3 outlined objects. 0bject 580 is much
> smaller and anterior than object 581 which is in the center of the
head. It
> looks like the area of 581 should be at least 2-3 times 580. However,
from
> the results below 581 is only about 10% larger. Can anybody please
explain

> this?
>
> Object     Image ID     Area       X       Y      Slice
> 579     04:ID001122228  1936    253.06  311.66     228
> 580     04:ID001122228  319     166.33  201.65     228
> 581     04:ID001122228  353     240.86  298.37     228
>
> Thanks.
>
> Douglas
>
> Dr Douglas K Benn, BDS,DDS, M.Phil., Ph.D., Dipl. Dental Radiology

(Royal

> College of Radiologists, England).
> Professor and Director of Oral & Maxillofacial Radiology
> Dept of General Dentistry
> Creighton University Dental School
> 2802 Webster St, Boyne 210
> Omaha
> Nebraska 68178
>
> Tel: [phone]
> Fax: [phone]
>
>
>