Can I export an analog signal from labview to matlab

[Simone 27]

I am trying to export an analog signal for Labview to Matlab and using a Spline Filter to establish a mean line. Is this possible?

[Andy.G]

Hey Simone,

The analogue singal that is being capatured or generated in labview will be in the form of an array of interger values, you could possibly save this to file and import it into MatLab. Alternatively there is a Mathscript node in Labview wich should allow you to import the array directly by wiring it into the node box. What exactly is it that you are trying to do in Matlab that labVIEW cannot?

[Simone 27]

For my 4th year project I am going to use the bluray laser from a PS3 for surface measurement. I can hack into the unit and get an analog signal that will be proportional to the surface roughness. I want to take this into Labview and run it through a digital filter (Gaussian or spline) to get a mean line of the roughness and all my numerical values for the peaks and valleys of the surface will be taken from this line. I might stay in Labview to do this but I am having trouble finding information on building the filter. I have the right mathematics for the filter but have no idea how they translate into building a filter....

Thank you for your reply. 

[Andy.G]

Hey Simone,

That sounds awesome! If you need any further help I’m sure our team here at NI and the forum members would be happy to get you on your feet. There are three options available to you as far as LabVIEW development is concerned. You could use a formula node to manually input the equations as seen in example 1. You could use the MATLab Script node to write out your MATLab equations in LabVIEW, see attached Image (it requires MATLab to run). Finally if your university has access to it you could use the functions provided in the Digital Filter Design Toolkit which has both the Gaussian Spline filter built in. If you let me know what University you attend I may be able to tell you if you have this toolkit available to you.

[Simone 27]

Hey Andrew,

Thank you very much for your helpful replies. I like the sound of the Digital Filter Design Toolkit, I had hoped there would be a ready made filter out there but couldn't find one mentioned through help on labview. If possible I would love to find on get direction on how to build a Robust Linear Spline Filter or possibly a Gaussian Regression Filter but the first is preferred. I'm glad you think my project is cool, i'm really excited about if if it all works out.

I'm a student in IT Sligo. Ireland.

Thanks 

[Andy.G]

Hey Simone

I have spoken to the academic team and according to them your college has access to all the toolkits and modules for LabVIEW, I would recommend you go see Ray Tobin who can provide you with a license for the Digital Filter Design Toolkit. If you can get hold of this there a quite a few Spline functions available to you which may suit your needs, if this is not possible to get I would suggest you make a new post regarding the use of formula nodes in LabVIEW. I will put that post into my queue and together we can get the math behind the filter integrated into LabVIEW.

[Coq_Rouge]

One qeuestion that is important. Is your DAQ equipment up to the task of collecting your signal.

[Munson1027]

Your project does sound really cool.

Just to put in my $0.02 about matlab script nodes. 

If you can build the filters in labview, do it.  The matlab script node will slow you down quite a bit because the data has to be transferred (and duplicated) from the labview data space into the matlab data space.  Yes, that's right, any data you pass in or out of the matlab script node will exist in both data spaces.  I have been doing this for real time image processing and it works, but it isn't great.

Aside, if someone knows how pass a reference to the data location in the labview space that matlab will be able to understand, I would love to know.

Matt

[Simone 27]

Hi, It has been pointed out to me that it is not good practict to change the question half way through a post.

I have set up a new post to continue this question.

http://forums.ni.com/t5/forums/postpage/board-id/170/submitted/true?message-subject=Building+of+a+Ro...

I apoligise fo any inconvienece caused, and hope ypo will all follow me 🙂

[Simone 27]

Hi, It has been pointed out to me that it is not good practice to change the question half way through a post.

I have set up a new post to continue this question.

http://forums.ni.com/t5/forums/postpage/board-id/170/submitted/true?message-subject=Building+of+a+Ro...

I apoligise for any inconvenience caused, and hope you will all follow me 🙂

Thank you for all your help so far....