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Youngster4591-Visitor
1-Visitor
July 26, 2018
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3D plot smoothing: How representative is it of the real data?

  • July 26, 2018
  • 3 replies
  • 7603 views

Hello,

 

    I have used Mathcad to plot an image of a Gaussian beam I obtained from a camera. Obviously the camera has pixels, each with its own pixel value that represents part of the Gaussian beams intensity. When I plot this intensity image in a 3D plot in Mathcad it displays a plot in the same dimensions as the camera image, but the data has been 'smoothed' out and now represents a more ideal Gaussian beam profile (rather than a pixelised one seen on the camera image).

   My questions are: How is this smoothing of the camera image done? How representative is this of the actual beam incident on the camera? 

   I have attached pictures of the camera image and the Mathcad contour plot (from 3D plot). I am unable to provide a data sheet as my workplace prohibits it. All I have done is import the saved data of the camera image and asked Mathcad to display it using a 3D plot.  I am new to Mathcad, so understanding how this works will be a great use. Thanks to all who have already replied. 

 

Ethan

Best answer by LucMeekes

According to the Help of Mathcad 11:

Contour Plots

Contour plots require a matrix of values, which are linearly interpolated to form level curves. Level curves can represent isotherms, isobars, equipotentials, streamlines, and many other physical phenomena. You can format a contour plot in many ways to control its appearance.

 

So: No smoothing, just interpolation.

Or: the method of smoothing is interpolation, if you will.

 

Luc

3 replies

L
LucMeekes23-Emerald IV
23-Emerald IV
July 26, 2018

As far as I can tell Mathcad does not smooth graphs and/or plots, unless you tell it to.

Can you show (pictures, Mathcad sheet files) what your problem is?

 

Luc

W
Werner_E25-Diamond I
25-Diamond I
July 26, 2018

Can you provide sample data and worksheet?

If you are using the 3D plot to display simple height data, Mathcad always tries to create a smooth surface - in this case even a surface not necessarily containing your data. Probably thats the smoothing you noticed.

For a 3D plot you usually would have to create a mesh first and feed that mesh to th 3D plot.

There might be better ways to manipulate and display your data in Mathcad 15. Prime is too limited, though.

L
LucMeekes23-Emerald IV
23-Emerald IV
July 26, 2018

Does this example of a 3D plot help?

LM_20180726_3Dplot.png

 

Success!
Luc

W
Werner_E25-Diamond I
25-Diamond I
July 26, 2018

That was what I was talking about when I wrote that Primes capabilities would be too limited. There is no Bar Plot option in Primes 3D (nor is shading or the like).

I was also thinking of inserting the data as picture might be an option, but again Prime does not offer that.

Maybe the OP will reveal which data he is dealing with and which version of the software he is using.

Y
Youngster4591-VisitorAuthor
1-Visitor
July 27, 2018

Hello Werner,

 

   I am able to use a bar plot in 3D (I am using Mathcad 14 - not prime as I have been instructed not to use that). I am not worried about displaying the data as seen by the camera image; the fact it has smoothed out the data is a good thing to be honest as it makes it easier to discuss the work I am doing. 

   I just would like to know how Mathcad fits to the data. If its a gaussian fit, how does Mathcad know the data contains a gaussian? If it is a general fit, how reliable is it when it comes to the smoothing of the data?

 

Thanks for your time, I appreciate it,

Ethan

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