Building of a Robust Spline Profile Filter using Labview

[Simone 27]

Hi Andrew,

I've been looking through the selection of spline filters, I'm still unsure of the process around implementation. Thank you for the file.

Le meas.

[Andy.G]

Hey Simone,

could you please provide me with a matrix of data you would like to pass through the spline filter, and I will show you how to do this.

[Simone 27]

Hi Andrew,

I'm a little unsure of converting the data into matrix form but here is code superimposing one signal onto another to simulate roughness embedded onto waviness on a surface profile. I have removed the waviness and it is this signal that would be then fed through the spline filter.

Le meas

[Andy.G]

He Simone,

I have created two waveforms Sin and Cos from scratch, then combined them together and finally pushed them through a spline filter. I have also included a step by step on how to create XY graphs in the code. Let me know if this is what you were looking for!

[Simone 27]

Hi Andrew,

I was away yesterday and am only getting back to this today, I'm going to have a look through your code now.

What I hope to do is create a weighted mean line through my surface profile. I've attached a picture to explain a little bit better.

Le meas.

[Simone 27]

Hi,

I have used a White Light Interferometer to collect a set of date to test the filter with, these are in excel. It is a mean line through these graphed points that I want to achieve with the spline filter. 

Thank you for your code it was extreamly useful from a learning point of view.

Le meas

[Andy.G]

Hey Simone,

I have created another example of fitting using a Spline filter; this shows how to implement the filter on graphical data. I did not use the information you have sent me because what ever read that data in formatted it poorly, and therefore it would take me some time to either manually or programmatically format the data so as the X axis points were in one column and the Y in another. If this was the case however you can use the string manipulation functions to pull the data out of the text file, convert it to a numeric and using the auto index place into an array for processing. Can I have a look at the LabVIEW code you have written thus far; perhaps I can give you some guidance in terms of architecture.

[Simone 27]

Hi,

Sorry, I've hit a stand still with the physical side to the project. Going mad here 🙂

I've doctored up some code that doesn't really do what i thought it would 🙂 fun fun fun 😞

[Andy.G]

Hey Simone,

You must remember when opening files, you cannot simultaneously open two files in the same VI, because you are referring to the reference of a file with one piece of code that will then become reserved and therefore the other piece of code trying to access that reference will error. If you want to read two sets of data within the file you can do so by having one read followed by another, like that shown in my code. If you want to produce a graph you will need time intervals between the data points, it is best to do this with the iteration count of a loop if you are creating an XY graph.

[Andy.G]

Hey Simone,

Hows it coming along?