topic Re: Interpolating y values for certain x values from continously measured data in LabVIEW
https://forums.ni.com/t5/LabVIEW/Interpolating-y-values-for-certain-x-values-from-continously/m-p/3654315#M1026662
<P>Hi altenbach,</P>
<P> </P>
<P>the attached data was just an example. I don`t want to extrapolate and will limit the taken data to a reasonable range. Also the first point of y2=2314000.0000 is a wrong value and would be excluded from evaluation.</P>
<P> </P>
<P>I guess there is some exponential behaviour in the data, but unfortunately it is overlayed with other effects. That`s why I would prefer low-range interpolation to get a good fit with the actual data.</P>
<P> </P>Mon, 03 Jul 2017 17:09:57 GMTMatthiasBerl19882017-07-03T17:09:57ZInterpolating y values for certain x values from continously measured data
https://forums.ni.com/t5/LabVIEW/Interpolating-y-values-for-certain-x-values-from-continously/m-p/3654309#M1026657
<P>Hi everone,</P>
<P> </P>
<P>I have a labview programm, that continously (every ~0.1sec) reads in data (x=temperature, y1=voltage1, y2=voltage2) and saves it in a spreadsheet (example see attachment).</P>
<P> </P>
<P>From these pretty messy raw data, I want to interpolate sets of function points (x,y1,y2) at certain x-values = (0.1, 0.2, 0.3,...300 ).</P>
<P> </P>
<P>Do you have an idea, how this could be done?</P>
<P> </P>
<P>Matthias Berl</P>
<P>(beginner knowledge of labview)</P>
<P> </P>
<P> </P>Mon, 03 Jul 2017 16:41:12 GMThttps://forums.ni.com/t5/LabVIEW/Interpolating-y-values-for-certain-x-values-from-continously/m-p/3654309#M1026657MatthiasBerl19882017-07-03T16:41:12ZRe: Interpolating y values for certain x values from continously measured data
https://forums.ni.com/t5/LabVIEW/Interpolating-y-values-for-certain-x-values-from-continously/m-p/3654312#M1026659
<P>There is e.g. no x=0.1, so you would need to extrapolate. Do you have a mathematical model for the behavior? In that case, nonlinear fitting would be a good solution. Is that first point of y2=2314000.0000 real?</P>Mon, 03 Jul 2017 16:47:28 GMThttps://forums.ni.com/t5/LabVIEW/Interpolating-y-values-for-certain-x-values-from-continously/m-p/3654312#M1026659altenbach2017-07-03T16:47:28ZRe: Interpolating y values for certain x values from continously measured data
https://forums.ni.com/t5/LabVIEW/Interpolating-y-values-for-certain-x-values-from-continously/m-p/3654315#M1026662
<P>Hi altenbach,</P>
<P> </P>
<P>the attached data was just an example. I don`t want to extrapolate and will limit the taken data to a reasonable range. Also the first point of y2=2314000.0000 is a wrong value and would be excluded from evaluation.</P>
<P> </P>
<P>I guess there is some exponential behaviour in the data, but unfortunately it is overlayed with other effects. That`s why I would prefer low-range interpolation to get a good fit with the actual data.</P>
<P> </P>Mon, 03 Jul 2017 17:09:57 GMThttps://forums.ni.com/t5/LabVIEW/Interpolating-y-values-for-certain-x-values-from-continously/m-p/3654315#M1026662MatthiasBerl19882017-07-03T17:09:57ZRe: Interpolating y values for certain x values from continously measured data
https://forums.ni.com/t5/LabVIEW/Interpolating-y-values-for-certain-x-values-from-continously/m-p/3654331#M1026666
<P>Since there seem to be noise, interpolation is not a good solution. How about a polynomial, or an exponential and polynomial?</P>
<P>How about applying a smoothing function before interpolation? How about a low order polynomial of nearby points?</P>
<P> </P>
<P>Can you attach some more realistic data? What is the typical x spacing?</P>Mon, 03 Jul 2017 18:00:09 GMThttps://forums.ni.com/t5/LabVIEW/Interpolating-y-values-for-certain-x-values-from-continously/m-p/3654331#M1026666altenbach2017-07-03T18:00:09Z