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Re: finding boundary in image having multiple region of interest [message #93587 is a reply to message #93586]

Tue, 30 August 2016 01:52

Helder Marchetto
Messages: 520
Registered: November 2011

Senior Member

On Tuesday, August 30, 2016 at 8:07:48 AM UTC+2, sin wrote:
> Hi all,
> I need to select roi having combined pixel area above 3493pixels and intensity above 1.25.
>
> I tried using find_boundary which gives the pixel area for pixels above the threshold for one roi that we give as input. But in one image I have multiple rois to be selected. so find_boundary will not work.
>
> I have several images like this.
>
> So do anyone have any idea to do this.
>
> The threshold should be the intensity should be more than 1.25 and the combined pixel area should be greater than 3493 pixels.
>
> thanks

Hi,
I don't understand why you tried find boundary. But I think what you're looking for is a combination of "greater then" and label_region.

subImage = myImage gt 1.25
lr = label_region(subImage)

then use histogram to identify the regions and look for the one's with more than 3493 pixels. In case of doubt, follow the example given for label_region:
http://www.harrisgeospatial.com/docs/LABEL_REGION.html

Here is what is of interest for you:

h = histogram(lr, REVERSE_INDICES=r)

; Print the mean and standard deviation of each region
FOR i=0, N_ELEMENTS(h)-1 DO if h[i] gt 3493 then $
PRINT, 'This region ', i, ', has a population greater than 3493 and has = ', h[i], $
', elements. The indices of this region are between ', r[i],' and ', r[i+1]-1

I hope this helps.

Cheers,
Helder

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[Message index]

		finding boundary in image having multiple region of interest By: gunvicsin11 on Mon, 29 August 2016 23:07
		Re: finding boundary in image having multiple region of interest By: Helder Marchetto on Tue, 30 August 2016 01:52
		Re: finding boundary in image having multiple region of interest By: gunvicsin11 on Tue, 30 August 2016 23:21
		Re: finding boundary in image having multiple region of interest By: Helder Marchetto on Wed, 31 August 2016 02:37
		Re: finding boundary in image having multiple region of interest By: gunvicsin11 on Wed, 31 August 2016 03:46

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