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Re: How to eliminate smaller blob from label_region image [message #77347 is a reply to message #77346]

Mon, 22 August 2011 01:13

Wout De Nolf
Messages: 194
Registered: October 2008

Senior Member

On Sun, 21 Aug 2011 22:40:24 -0700 (PDT), vijay s
<vijayans.in@gmail.com> wrote:

> hi all,
>
> I used label_region to get individual blob id for each region.
> But few of my blobs are very small in area wise and
> i want to eliminate those from my images and retain blobs of larger
> area (say pixel area gt 10). How can i eliminate unwanted smaller
> blobs?
>
>
> thanks in advance.

By using the HISTOGRAM function:

; Minimum number of blob pixels
npix_threshold=10

; Get image
path=FILEPATH('pollens.jpg',SUBDIR=['examples','demo','demod ata'])
READ_JPEG, path, image

; Get blob indices
b = LABEL_REGION(image gt 150)

; Get population and members of each blob
h = HISTOGRAM(b, REVERSE_INDICES=r)

; Regions with small number of pixels
ind = where(h lt npix_threshold,ct)

; Remove the small regions
for i=0l,ct-1 do b[r[r[ind[i]]:r[ind[i]+1]-1]]=0

Obviously, some indices will be missing since you zero'ed them out.
You might want to fix that. It might not even be necessary to set the
small blob indices to zero. It all depends on what you will do with
the blob indices.

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[Message index]

		Re: How to eliminate smaller blob from label_region image By: David Fanning on Tue, 23 August 2011 05:02
		Re: How to eliminate smaller blob from label_region image By: Wout De Nolf on Tue, 23 August 2011 04:18
		Re: How to eliminate smaller blob from label_region image By: vijay s on Mon, 22 August 2011 23:30
		Re: How to eliminate smaller blob from label_region image By: David Fanning on Mon, 22 August 2011 05:37
		Re: How to eliminate smaller blob from label_region image By: Wout De Nolf on Mon, 22 August 2011 01:13
		Re: How to eliminate smaller blob from label_region image By: rogass on Wed, 31 August 2011 05:00

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