Measuring focus / sharpness

[David Faulstich Diniz Reis]

Hi!

 

I want to know IF anyone already made na algorithm to measure the image´s
sharpness.

 

I am trying to automatically apply an sharpness algorithm if needed.

 

Reading I discover that we need to discover the spatial frequency. Mesure
high spatial frequency / low frequency, and based on this result, apply the
sharpness algorithm.

 

Thank you in advance.

 

David

 

www.infosolo.com.br

[hidden email]

[phone]

 

[Andreas Maier]

Hi,

usually you need an edge in the image to measure the "sharpness". Form
an edge you could estimate the modulation transfer function.
Do your images share a certain characteristic (as a certain edge) ?

Best,

Andreas

Am 7/1/2010 11:41 AM, schrieb David Faulstich Diniz Reis:

> Hi!
>
>
>
> I want to know IF anyone already made na algorithm to measure the image´s
> sharpness.
>
>
>
> I am trying to automatically apply an sharpness algorithm if needed.
>
>
>
> Reading I discover that we need to discover the spatial frequency. Mesure
> high spatial frequency / low frequency, and based on this result, apply the
> sharpness algorithm.
>
>
>
> Thank you in advance.
>
>
>
> David
>
>
>
> www.infosolo.com.br
>
> [hidden email]
>
> [phone]
>
>
>
>    

--
Dr.-Ing. Andreas Maier
Stanford University
Department of Radiology
The Lucas Center for Imaging
Mail Code 5488, Route 8
Stanford, CA  94305
http://med.stanford.edu/profiles/Andreas_Maier/

[David Faulstich Diniz Reis]

The pictures are scanned documents.

I need to validate the scanned document.

I think all the document have edges. :-)

The MTF plugin could help me?
<a href="http://rsb.info.nih.gov/ij/plugins/download/mtf/MeasureMTF_.html#measureMTF%">http://rsb.info.nih.gov/ij/plugins/download/mtf/MeasureMTF_.html#measureMTF%
28ij.ImagePlus%29



Thanks!

-----Mensagem original-----
De: Andreas Maier [mailto:[hidden email]]
Enviada em: quinta-feira, 1 de julho de 2010 16:08
Para: ImageJ Interest Group
Cc: David Faulstich Diniz Reis
Assunto: Re: Measuring focus / sharpness

Hi,

usually you need an edge in the image to measure the "sharpness". Form
an edge you could estimate the modulation transfer function.
Do your images share a certain characteristic (as a certain edge) ?

Best,

Andreas

Am 7/1/2010 11:41 AM, schrieb David Faulstich Diniz Reis:

> Hi!
>
>
>
> I want to know IF anyone already made na algorithm to measure the image´s
> sharpness.
>
>
>
> I am trying to automatically apply an sharpness algorithm if needed.
>
>
>
> Reading I discover that we need to discover the spatial frequency. Mesure
> high spatial frequency / low frequency, and based on this result, apply

the

> sharpness algorithm.
>
>
>
> Thank you in advance.
>
>
>
> David
>
>
>
> www.infosolo.com.br
>
> [hidden email]
>
> [phone]
>
>
>
>    

--
Dr.-Ing. Andreas Maier
Stanford University
Department of Radiology
The Lucas Center for Imaging
Mail Code 5488, Route 8
Stanford, CA  94305
http://med.stanford.edu/profiles/Andreas_Maier/