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Signal-to-Noise Ratio (SNR)

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Anderson Vinícius

Signal-to-Noise Ratio (SNR)

Hi,

Is there any ImageJ plugin to calculate the Signal-to-Noise Ratio of a
single image without a reference image?

I've seen some plugins that calculate the SNR of images but in all of them
reference images are necessary.

Thank you.

[]s
--
Anderson Vinícius Alves Ferreira
Intern at Lafarge Centre de Recherche
95 rue du Montmurier - 38291 St Quentin-Fallavier - France

Joachim Wesner

Antwort: Signal-to-Noise Ratio (SNR)

Hi there,

Sorry but measuring the SNR of a single image without reference or any
a-priori-knowledge is simply mathematically IMPOSSIBLE!

How do you tell what is true data, what is noise? The human vision system
might imply that it is still possible, but this relies on
implicit assumptions about object structure and spatial frequency spectrum
of the "true" data.

Mit freundlichen Grüßen / Best regards

Joachim Wesner
Projektleiter Optik Technologiesysteme

Leica Microsystems CMS GmbH | GmbH mit Sitz in Wetzlar | Amtsgericht
Wetzlar HRB 2432
Geschäftsführer: Dr. Stefan Traeger | Dr. David Roy Martyr | Colin Davis
www.leica-microsystems.com

Anderson Vinícius
<6anderson9@GMAIL
.COM> An
Gesendet von: [hidden email]
ImageJ Interest Kopie
Group
<[hidden email]. Thema
GOV> Signal-to-Noise Ratio (SNR)

05.07.2010 10:50

Bitte antworten
an
ImageJ Interest
Group
<[hidden email].
GOV>

Hi,

Is there any ImageJ plugin to calculate the Signal-to-Noise Ratio of a
single image without a reference image?

I've seen some plugins that calculate the SNR of images but in all of them
reference images are necessary.

Thank you.

[]s
--
Anderson Vinícius Alves Ferreira
Intern at Lafarge Centre de Recherche
95 rue du Montmurier - 38291 St Quentin-Fallavier - France

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
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Anderson Vinícius

Re: Signal-to-Noise Ratio (SNR)

Hi Joachim,

I don't need to measure the exact SNR, an estimation is enough.

I've seen a method in a thesis (http://pastel.paristech.org/4473/, page 25)
that takes the covariance (calculated by a Fourier Transform) and the
morphological opening to define the SNR.
That's why I was wondering if a plugin had already been done to measure the
SNR without a reference image.

[]s
--
Anderson Vinícius Alves Ferreira
Intern at Lafarge Centre de Recherche
95 rue du Montmurier - 38291 St Quentin-Fallavier - France

On 5 July 2010 12:04, Joachim Wesner
<[hidden email]>wrote:

> Hi there,
>
> Sorry but measuring the SNR of a single image without reference or any
> a-priori-knowledge is simply mathematically IMPOSSIBLE!
>
> How do you tell what is true data, what is noise? The human vision system
> might imply that it is still possible, but this relies on
> implicit assumptions about object structure and spatial frequency spectrum
> of the "true" data.
>
> Mit freundlichen Grüßen / Best regards
>
> Joachim Wesner
> Projektleiter Optik Technologiesysteme
>
> Leica Microsystems CMS GmbH | GmbH mit Sitz in Wetzlar | Amtsgericht
> Wetzlar HRB 2432
> Geschäftsführer: Dr. Stefan Traeger | Dr. David Roy Martyr | Colin Davis
> www.leica-microsystems.com
>
>
>
>
> Anderson Vinícius
> <6anderson9@GMAIL
> .COM> An
> Gesendet von: [hidden email]
> ImageJ Interest Kopie
> Group
> <[hidden email]. Thema
> GOV> Signal-to-Noise Ratio (SNR)
>
>
> 05.07.2010 10:50
>
>
> Bitte antworten
> an
> ImageJ Interest
> Group
> <[hidden email].
> GOV>
>
>
>
>
>
>
> Hi,
>
> Is there any ImageJ plugin to calculate the Signal-to-Noise Ratio of a
> single image without a reference image?
>
> I've seen some plugins that calculate the SNR of images but in all of them
> reference images are necessary.
>
> Thank you.
>
> []s
> --
> Anderson Vinícius Alves Ferreira
> Intern at Lafarge Centre de Recherche
> 95 rue du Montmurier - 38291 St Quentin-Fallavier - France
>
>
>
> ______________________________________________________________________
> This email has been scanned by the MessageLabs Email Security System.
> For more information please visit http://www.messagelabs.com/email
> ______________________________________________________________________
>

Gluender-4

Re: Signal-to-Noise Ratio (SNR)

Bonjour,

I agree with Joachim Wesner's statement but maybe
the background of the original question is of
some importance...

In certain situations approximations, e.g.

S + N / N

may be of some help. See for instance:

<http://www.gluender.de/Writings/WritingsTexts/HardText.html#Gl-1980-1>

Best
--

Herbie

------------------------
<http://www.gluender.de>

Widodo D. Putro

Entropy measurement

In reply to this post by Anderson Vinícius

Dear ImageJ users,

I wonder is there any ImageJ plugin to measure the entropy coefficient derived
from FFT of a stack of images?
I've used the Texture Analyzer plugin by Mr. Cabrera, but it defined the entropy
from gray level co-occurence matrix not from FFT.

Thank you,
Regards.

--
Widodo D. Putro

Institute of Technology Bandung
Jl. Ganesha 10, Bandung, Indonesia

Gea O.F. Parikesit

Re: Entropy measurement

I am not aware of any existing plugin that measures entropy directly from FFT, but you could easily write a macro for this. That being said, I wonder why would you need the FFT, rather than the grey-values itself? Are you interested in certain spatial frequencies in your images?

Best regards,
Gea Parikesit
Gadjah Mada University
http://gea.ari.googlepages.com/microfluidicsugm

--- On Tue, 6/7/10, Widodo D. Putro <[hidden email]> wrote:

From: Widodo D. Putro <[hidden email]>
Subject: Entropy measurement
To: [hidden email]
Received: Tuesday, 6 July, 2010, 10:53 PM

Dear ImageJ users,

I wonder is there any ImageJ plugin to measure the entropy coefficient derived
from FFT of a stack of images?
I've used the Texture Analyzer plugin by Mr. Cabrera, but it defined the entropy
from gray level co-occurence matrix not from FFT.

Thank you,
Regards.

--
Widodo D. Putro

Institute of Technology Bandung
Jl. Ganesha 10, Bandung, Indonesia

Marten Darmawan

Re: Entropy measurement

If you want to measure the entropy (statistical approach) for a particular
signal frequency without using GLCM (Grey Level Co-occurence Matrix), as
best as I know, it should be a new definition of entropy (texture analysis
second order). Even though it might be derived from first order statistical
approach, I don't have any idea about what information that you want to
extract from FFT result so you could obtain the entropy information. I
suggest you to use the Gabor filter if you want to obtain the statistical
information for a particular signal frequency.

Best regard,

Marten Darmawan
Gadjah Mada University

martendarmawan.wordpress.com

On Wed, Jul 7, 2010 at 11:01 AM, Gea O.F. Parikesit <[hidden email]>wrote:

> I am not aware of any existing plugin that measures entropy directly from
> FFT, but you could easily write a macro for this. That being said, I wonder
> why would you need the FFT, rather than the grey-values itself? Are you
> interested in certain spatial frequencies in your images?
>
> Best regards,
> Gea Parikesit
> Gadjah Mada University
> http://gea.ari.googlepages.com/microfluidicsugm
>
>
> --- On Tue, 6/7/10, Widodo D. Putro <[hidden email]> wrote:
>
> From: Widodo D. Putro <[hidden email]>
> Subject: Entropy measurement
> To: [hidden email]
> Received: Tuesday, 6 July, 2010, 10:53 PM
>
> Dear ImageJ users,
>
> I wonder is there any ImageJ plugin to measure the entropy coefficient
> derived
> from FFT of a stack of images?
> I've used the Texture Analyzer plugin by Mr. Cabrera, but it defined the
> entropy
> from gray level co-occurence matrix not from FFT.
>
> Thank you,
> Regards.
>
> --
> Widodo D. Putro
>
> Institute of Technology Bandung
> Jl. Ganesha 10, Bandung, Indonesia
>
>
>
>
>
>
>
>
>

Widodo D. Putro

Re: Entropy measurement

In reply to this post by Gea O.F. Parikesit

Well Gea & Marten, I'm measuring the repetition of texture spatial frequencies..
I try to measure object's coarseness by first extracting the entropy from its
FFT.
Yes, I'll write the macro. Thanks for the info

--
Widodo D. Putro

Institute of Technology Bandung
Jl. Ganesha 10, Bandung, Indonesia

________________________________
From: Gea O.F. Parikesit <[hidden email]>
To: [hidden email]
Sent: Wed, July 7, 2010 11:01:18 AM
Subject: Re: Entropy measurement

I am not aware of any existing plugin that measures entropy directly from FFT,
but you could easily write a macro for this. That being said, I wonder why would
you need the FFT, rather than the grey-values itself? Are you interested in
certain spatial frequencies in your images?

Best regards,
Gea Parikesit
Gadjah Mada University
http://gea.ari.googlepages.com/microfluidicsugm

--- On Tue, 6/7/10, Widodo D. Putro <[hidden email]> wrote:

From: Widodo D. Putro <[hidden email]>
Subject: Entropy measurement
To: [hidden email]
Received: Tuesday, 6 July, 2010, 10:53 PM

Dear ImageJ users,

I wonder is there any ImageJ plugin to measure the entropy coefficient derived
from FFT of a stack of images?
I've used the Texture Analyzer plugin by Mr. Cabrera, but it defined the entropy

from gray level co-occurence matrix not from FFT.

Thank you,
Regards.

--
Widodo D. Putro

Institute of Technology Bandung
Jl. Ganesha 10, Bandung, Indonesia

Eric Zhang

Re: Signal-to-Noise Ratio (SNR)

In reply to this post by Anderson Vinícius

hi man， I think u can select one area, made the average and calculate least square, u need a white picture