Overlay plots as intensity graph

[m3nth]

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The article above has a picture at the very end of an intensity plot where the data is mostly similiar but somewhat different, where differences are represented as lower intensity traces based on the frequency of their occurence.

I am looking for the easiest way to duplicate this effect in LabVIEW... overlay multiple data plots on an intensity graph/plot/whatever.

I have experimented with intensity graphs and had very little success making them work in this regard. The largest success I had was mapping each plot to a size-limited array and then incrementing each pixel in that array by 1 if the incoming waveform indexed it. It didn't look much like a plot though because it was highly pixelized (# of pixels is based on the size of the array for the intensity plot) and there were no lines connecting the pixels. It did reduplicate the basic shape of the waveform though, was very slow, and showed higher intensities where there was little variation (low noise areas) from run to run.

I have also experimented with other plots to overlay a bunch of data so that even if it wasn't an intensity plot you could still see out of character behavior. What I would really like to do however is something similiar to the picture in the article above.

Does anyone know of any suggestions or examples out there on overlaying multiple sets of data in a way where the resulting plot is not just visible or not-visible if one of the multiple plots has crossed it, but has an actual intensity based on how many plots cross it?

[altenbach]

The intensity graph is not such a bad idea, you just need to fill the gaps in the lines. Make the graph so it maps 1:1 to pixels, then interpolate the x values to hit every pixel (use interpolate array) and for each x, fill the gap in the y direction vertically for example as shown in the attached VI.

The attached quick example (LabVIEW 7.1) should get you started. (There are still a few edge effects to take care of, but nothing major.) Letme know if anything is not clear.

Alternatively, you could also display it using a picture indicator.

[m3nth]

That's pretty cool. I opened it up and went, hey, that looks a lot like my code! Except you've got the interpolation functions in there and the nicer colors which does a lot for the graph. Thanks a bunch....very good example.

[altenbach]

OK, I cleaned it up a bit and fixed the glitches for negative slopes.

The attached demo (LabVIEW 7.0) allows changing of some parameters, including the linewidth (1 or 2). Enjoy! 🙂

[altenbach]

The example posted above does not work correctly in LabVIEW 8.0 and 8.20. Using a datatye of U8 for the graph, all colors will turn white if a marker value is out of range for the datatype.

To make the program work in LabVIEW 8.0 and 8.20, we need to change the value for the highest marker from 256 to 255 and all's well. See attached.

Message Edited by altenbach on 01-06-2007 10:00 AM

[Roy_F]

This was reported to R&D (CAR # 49058) for further investigation.