11-26-2012 08:47 AM
How you guys doing ?
Well to put it bluntly , i just need some help right here , i hope you can cooperate guys .
I am working on a thesis for my final year project . and i am using labview in it, but i am facing some dificulties .
I have implemented an ECG circuit that detedts the tiny electrical impulses of the human heart . I am trying to acquire the ECG signal via serial port in order to display it using labview .
I did it . but i am experiencing some dificulties while designing the filters . I have implemented buterworth filters with 10-25 HZ as low and high cutoff frequencies. i have also used so many ways but none of them had helped .
Could you please suggest anything useful ?
Any help would be greatly appreciated .
Thank you
Bill David
11-26-2012 09:46 AM
Hi Bill,
I just want to quickly point you to a couple of resources where you are more likely to get assistance with your questions. There are several similar discussion and a lot of knowledgeable users within the Biomedical User Group. The NI Discussion Forums are another option. There is a very active community on the forums and you will likely see a very quick response to your questions.
Thanks,
Matt
11-26-2012 09:49 AM
Thanl you Matt for the reply yes i will follow the links hoping that i get some help .
Again thank you .
11-26-2012 10:31 AM
Can you post your code? I can take a look at it if you like. You can also send it to my email in my profile if you would prefer.
11-26-2012 10:53 AM
Dear friend
i would love to attach my VI to have a look at it but the web browser that i am using is not allowing me to attach any file . can you please provide me some filtering techniques samples taht i can find useful in my application ?
I wanted to use the discrete wavelet transform to denoise the signal . but just need some instructions to follow in order to denoise my signal .
Thanks alot .
Bill David
11-26-2012 12:01 PM
Well, a 10 Hz low cutoff seems really high for ECG. If this is in humans, ECG usually ranges between 1 and 2 Hz repetition rate with a minmum bandwidth of about 20 Hz to get a good representation of the signal. A low cutoff around 0.1 Hz might be more appropriate to remove baseline drift. Sampling rate of about 50 Hz would good enough for ECG, but I don't know what kind of noise sources you are trying to filter out. Do you have a hardware filter built into your ECG detection circuit. If so, what is the cutoff of that circuit?
11-26-2012 12:19 PM
Dear friend thank you for the very fast reply
YES i do have a filter in my built circuit . I actually used a second order low passive filter with cutoff frequency of 15.9 HZ . now when trying to acquire the signal via serial port the QRS COMPLEX could be distinguished from the signal . I mean they 25 % appear in the signal . but it seems that noises are disturbing the signal .
Talking about the kind of noise I am dealing with I am sure that even ECG's that you can find in clinics and hospitals give you a signal with baseline wandering . this is the first noise i am facing . and we do not have a doubt the power line interference .
I JUST need a specialized filter design to obtain readable ECG signal with clean QRS complex.
any suggestions
REGARDS
11-26-2012 01:00 PM
Do you have the Wavelet Analysis toolkit, or are you planning on using the Wavelet Transform in the Signal Processing Toolkit?
11-26-2012 01:02 PM
yes sir i have it . registered version
11-26-2012 01:23 PM
Send me an email and I will send you a vi that you can look at for denoising. What version of LabVIEW do you run?
mailto:pursley@helix.nih.gov