On Saturday, May 3, 2014 at 5:59:52 PM UTC-4, wdave...@googlemail.com wrote:
> On Thursday, 11 August 2011 16:40:35 UTC+1, Jerry Avins wrote:
> > On Aug 11, 3:40�am, "steveu" <steveu@n_o_s_p_a_m.coppice.org> wrote:
> > > >On Aug 8, 11:45=A0am, "Jebarajpeter"
> > > ><jebarajselvapeter.p@n_o_s_p_a_m.jasmin-infotech.com> wrote:
> > > >> Hi all,
> > > >> I am working on baseline wander noise removal from ECG signal. I have
> > > to
> > > >> compare the performance of different algorithms. for comparison I have
> > > to
> > > >> use SNR. My question is how to calculate noise and signal power of an
> > > ECG
> > > >> signal available in the data set. I do not know what kind of noise is
> > > the=
> > > >re
> > > >> in the ECG signal.
> > >
> > > >> I have tried like this:
> > >
> > > >> 1. Filter the ECG signal with a basic filter to remove the baseline
> > > wande=
> > > >r
> > > >> signal. Then this signal is considered as Ideal signal (pure signal).
> > > =A0
> > > >> 2. Then I have applied the devised algorithm to the original ECG
> > > signal.
> > > >> So the output from the algorithm has,
> > > >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0output =3D signal + noise;
> > > >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0noise =3D ideal - output
> > > (usin=
> > > >g the algorithm)
> > > >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0signal =3D output - noise;
> > > >> using this i have calculated the SNR. Is it acceptable...? Please
> > > help!!
> > >
> > > >> Best,
> > > >> Jebaraj S.Peter
> > >
> > > >Before you dig into this, find out why the baseline wanders. Ideally,
> > > >you will remove the cause instead of remedying the effect. In any
> > > >event, you will know what you are contending with, always a good
> > > >approach to a problem.
> > >
> > > >Jerry
> > >
> > > You want him to paralyse the patient? :-) ECG traces wander due to muscle
> > > noise - i.e. the muscles other than the heart's.
> > >
> > > Steve
> >
> > See? It's always good to know what one is contending with. :-)
> >
> > Jerry
> > --
> > Engineering is the art of making what you want from things you can get.
>
> Measure your noise in the in ST segmentof the ECG. This is stationary for approx 50mS. So take a window of 30mS in the middle of the S-T and add up all the data samples and find the standard deviation.
>
> Measure the signal across the QRS postion of the ECG...approx 120mS. Do the same with the data points.
>
> Divide the signal Std by the Noise Std.
>
> Job done.
What about the samples in the PQ section? and also samples that are not in the PQRST segment? That is not considered as noise?
Reply by ●March 27, 20152015-03-27
On Monday, August 8, 2011 at 2:39:26 PM UTC-4, Vladimir Vassilevsky wrote:
> Tim Wescott wrote:
>
>
> > Because an ECG signal is either non-stationary or non-Gaussian, or
> > perhaps both, it's hard to express "SNR". Is this the measure that
> > clinicians use to rate the quality of their ECG signals? If not, what
> > is? If there is an alternative that's accepted, why not use it?
>
> There is aproximately a zillion of ECG analysers of all sorts around. A
> megatonn of paperwork is written about it. Another ECG processor is just
> what the world needs.
>
> Medics are interested in the so-called "QRS complex" parameters
> calculated from the ECG data. The quality of ECG is the accuracy of the
> QRS measurement.
>
> How do I know about this? Because I wrote a math part for a [zillion-1]
> ECG processor :-)
>
> Vladimir Vassilevsky
>
> DSP and Mixed Signal Design Consultant
>
> http://www.abvolt.com
Hi Vladimir,
Is Kurtosis of the whole recorded ECG segment a good measure of accuracy of QRS measurement..?
Thanks,
Naveen
Reply by ●May 3, 20142014-05-03
Good answer but almost 3 years too late
M
Reply by ●May 3, 20142014-05-03
On Thursday, 11 August 2011 16:40:35 UTC+1, Jerry Avins wrote:
> On Aug 11, 3:40�am, "steveu" <steveu@n_o_s_p_a_m.coppice.org> wrote:
> > >On Aug 8, 11:45=A0am, "Jebarajpeter"
> > ><jebarajselvapeter.p@n_o_s_p_a_m.jasmin-infotech.com> wrote:
> > >> Hi all,
> > >> I am working on baseline wander noise removal from ECG signal. I have
> > to
> > >> compare the performance of different algorithms. for comparison I have
> > to
> > >> use SNR. My question is how to calculate noise and signal power of an
> > ECG
> > >> signal available in the data set. I do not know what kind of noise is
> > the=
> > >re
> > >> in the ECG signal.
> >
> > >> I have tried like this:
> >
> > >> 1. Filter the ECG signal with a basic filter to remove the baseline
> > wande=
> > >r
> > >> signal. Then this signal is considered as Ideal signal (pure signal).
> > =A0
> > >> 2. Then I have applied the devised algorithm to the original ECG
> > signal.
> > >> So the output from the algorithm has,
> > >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0output =3D signal + noise;
> > >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0noise =3D ideal - output
> > (usin=
> > >g the algorithm)
> > >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0signal =3D output - noise;
> > >> using this i have calculated the SNR. Is it acceptable...? Please
> > help!!
> >
> > >> Best,
> > >> Jebaraj S.Peter
> >
> > >Before you dig into this, find out why the baseline wanders. Ideally,
> > >you will remove the cause instead of remedying the effect. In any
> > >event, you will know what you are contending with, always a good
> > >approach to a problem.
> >
> > >Jerry
> >
> > You want him to paralyse the patient? :-) ECG traces wander due to muscle
> > noise - i.e. the muscles other than the heart's.
> >
> > Steve
>
> See? It's always good to know what one is contending with. :-)
>
> Jerry
> --
> Engineering is the art of making what you want from things you can get.
Measure your noise in the in ST segmentof the ECG. This is stationary for approx 50mS. So take a window of 30mS in the middle of the S-T and add up all the data samples and find the standard deviation.
Measure the signal across the QRS postion of the ECG...approx 120mS. Do the same with the data points.
Divide the signal Std by the Noise Std.
Job done.
Reply by Jerry Avins●August 11, 20112011-08-11
On Aug 11, 3:40�am, "steveu" <steveu@n_o_s_p_a_m.coppice.org> wrote:
> >On Aug 8, 11:45=A0am, "Jebarajpeter"
> ><jebarajselvapeter.p@n_o_s_p_a_m.jasmin-infotech.com> wrote:
> >> Hi all,
> >> I am working on baseline wander noise removal from ECG signal. I have
> to
> >> compare the performance of different algorithms. for comparison I have
> to
> >> use SNR. My question is how to calculate noise and signal power of an
> ECG
> >> signal available in the data set. I do not know what kind of noise is
> the=
> >re
> >> in the ECG signal.
>
> >> I have tried like this:
>
> >> 1. Filter the ECG signal with a basic filter to remove the baseline
> wande=
> >r
> >> signal. Then this signal is considered as Ideal signal (pure signal).
> =A0
> >> 2. Then I have applied the devised algorithm to the original ECG
> signal.
> >> So the output from the algorithm has,
> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0output =3D signal + noise;
> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0noise =3D ideal - output
> (usin=
> >g the algorithm)
> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0signal =3D output - noise;
> >> using this i have calculated the SNR. Is it acceptable...? Please
> help!!
>
> >> Best,
> >> Jebaraj S.Peter
>
> >Before you dig into this, find out why the baseline wanders. Ideally,
> >you will remove the cause instead of remedying the effect. In any
> >event, you will know what you are contending with, always a good
> >approach to a problem.
>
> >Jerry
>
> You want him to paralyse the patient? :-) ECG traces wander due to muscle
> noise - i.e. the muscles other than the heart's.
>
> Steve
See? It's always good to know what one is contending with. :-)
Jerry
--
Engineering is the art of making what you want from things you can get.
Reply by steveu●August 11, 20112011-08-11
>On Aug 8, 11:45=A0am, "Jebarajpeter"
><jebarajselvapeter.p@n_o_s_p_a_m.jasmin-infotech.com> wrote:
>> Hi all,
>> I am working on baseline wander noise removal from ECG signal. I have
to
>> compare the performance of different algorithms. for comparison I have
to
>> use SNR. My question is how to calculate noise and signal power of an
ECG
>> signal available in the data set. I do not know what kind of noise is
the=
>re
>> in the ECG signal.
>>
>> I have tried like this:
>>
>> 1. Filter the ECG signal with a basic filter to remove the baseline
wande=
>r
>> signal. Then this signal is considered as Ideal signal (pure signal).
=A0
>> 2. Then I have applied the devised algorithm to the original ECG
signal.
>> So the output from the algorithm has,
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0output =3D signal + noise;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0noise =3D ideal - output
(usin=
>g the algorithm)
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0signal =3D output - noise;
>> using this i have calculated the SNR. Is it acceptable...? Please
help!!
>>
>> Best,
>> Jebaraj S.Peter
>
>Before you dig into this, find out whay the baseline wanders. Ideally,
>you will remove the cause instead of remedying the effect. In any
>event, you will know what you are contending with, always a good
>approach to a problem.
>
>Jerry
You want him to paralyse the patient? :-) ECG traces wander due to muscle
noise - i.e. the muscles other than the heart's.
Steve
Reply by HardySpicer●August 10, 20112011-08-10
On Aug 9, 5:17�am, Vladimir Vassilevsky <nos...@nowhere.com> wrote:
> Jebarajpeter wrote:
> > Hi all,
> > I am working on baseline wander noise removal from ECG signal. I have to
> > compare the performance of different algorithms. for comparison I have to
> > use SNR. My question is how to calculate noise and signal power of an ECG
> > signal available in the data set. I do not know what kind of noise is there
> > in the ECG signal.
>
> > I have tried like this:
>
> > 1. Filter the ECG signal with a basic filter to remove the baseline wander
> > signal. Then this signal is considered as Ideal signal (pure signal). �
> > 2. Then I have applied the devised algorithm to the original ECG signal.
> > So the output from the algorithm has,
> > � � � � � � � � � � �output = signal + noise;
> > � � � � � � � � � � �noise = ideal - output (using the algorithm)
> > � � � � � � � � � � �signal = output - noise;
> > using this i have calculated the SNR. Is it acceptable...? Please help!!
>
> > Best,
> > Jebaraj S.Peter
ata boy - go Vlad...
Reply by Jerry Avins●August 10, 20112011-08-10
On Aug 8, 11:45�am, "Jebarajpeter"
<jebarajselvapeter.p@n_o_s_p_a_m.jasmin-infotech.com> wrote:
> Hi all,
> I am working on baseline wander noise removal from ECG signal. I have to
> compare the performance of different algorithms. for comparison I have to
> use SNR. My question is how to calculate noise and signal power of an ECG
> signal available in the data set. I do not know what kind of noise is there
> in the ECG signal.
>
> I have tried like this:
>
> 1. Filter the ECG signal with a basic filter to remove the baseline wander
> signal. Then this signal is considered as Ideal signal (pure signal). �
> 2. Then I have applied the devised algorithm to the original ECG signal.
> So the output from the algorithm has,
> � � � � � � � � � � �output = signal + noise;
> � � � � � � � � � � �noise = ideal - output (using the algorithm)
> � � � � � � � � � � �signal = output - noise;
> using this i have calculated the SNR. Is it acceptable...? Please help!!
>
> Best,
> Jebaraj S.Peter
Before you dig into this, find out whay the baseline wanders. Ideally,
you will remove the cause instead of remedying the effect. In any
event, you will know what you are contending with, always a good
approach to a problem.
Jerry
--
Engineering is the art of making what you want from things you can get.
Reply by Vladimir Vassilevsky●August 8, 20112011-08-08
Tim Wescott wrote:
> Because an ECG signal is either non-stationary or non-Gaussian, or
> perhaps both, it's hard to express "SNR". Is this the measure that
> clinicians use to rate the quality of their ECG signals? If not, what
> is? If there is an alternative that's accepted, why not use it?
There is aproximately a zillion of ECG analysers of all sorts around. A
megatonn of paperwork is written about it. Another ECG processor is just
what the world needs.
Medics are interested in the so-called "QRS complex" parameters
calculated from the ECG data. The quality of ECG is the accuracy of the
QRS measurement.
How do I know about this? Because I wrote a math part for a [zillion-1]
ECG processor :-)
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
Reply by Tim Wescott●August 8, 20112011-08-08
On Mon, 08 Aug 2011 10:45:22 -0500, Jebarajpeter wrote:
> Hi all,
> I am working on baseline wander noise removal from ECG signal. I have to
> compare the performance of different algorithms. for comparison I have
> to use SNR. My question is how to calculate noise and signal power of an
> ECG signal available in the data set. I do not know what kind of noise
> is there in the ECG signal.
>
> I have tried like this:
>
> 1. Filter the ECG signal with a basic filter to remove the baseline
> wander signal. Then this signal is considered as Ideal signal (pure
> signal). 2. Then I have applied the devised algorithm to the original
> ECG signal. So the output from the algorithm has,
> output = signal + noise;
> noise = ideal - output (using the algorithm) signal
> = output - noise;
> using this i have calculated the SNR. Is it acceptable...? Please help!!
Because an ECG signal is either non-stationary or non-Gaussian, or
perhaps both, it's hard to express "SNR". Is this the measure that
clinicians use to rate the quality of their ECG signals? If not, what
is? If there is an alternative that's accepted, why not use it?
--
www.wescottdesign.com