Bjorn Gustavsson

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UIT, the Arctic University of Norway

1,133 total contributions since 2001

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Answered
How to calculate image resolution (full-width-at-half-maximum) of a point source?
I'd start with some simple models for your image response (2-D Gaussian, sinc^2(x).*sinc(y)^2) and fitted the parameters of thos...

2 days ago | 0

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generate random integer number with a specific mean
Have a look at the help and documentation of randi and then try and test some things. Finally have a deep think about what your ...

5 days ago | 0

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How can I save subplot figures together?
Wouldn't this do: print('-depsc2','-painters','Your2subplotfig.eps')

5 days ago | 0

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Event Detecting in Event-based ODE
In order to advice the contents of the event-function is necessary. The only thing to point out is that the ode-solvers use nume...

5 days ago | 0

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Detecting phase difference between two channels
Does something like this extract variations that are related to the breathing-pattern: phi_u = unwrap(atan2(raw_ad_data_sine,ra...

6 days ago | 0

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IGRF model Implementation (Calculating the Partial Derivatives of the Legendre Polynomials)
Have a look at the IGRF implementations available on the file exchange: international-geomagnetic-reference-field-igrf-model, in...

9 days ago | 0

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Solving an integral equation
For this I think pen-and-paper might be easier than using the symbolic toolbox. Simply differentiate both sides of your definiti...

13 days ago | 1

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save filename by values using a variable
Ok, that should be possible. Someting like this: % First lets get you the date-string-component in your desired format (guessin...

13 days ago | 1

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How can I rotate a vector by a certain amount along a specific plane?
Simply take another vector that lies in your plane, here c (you should understand why we can use c straight away). Then form an ...

16 days ago | 1

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I want my legend just like the pic. 2 variables in 2 columns at the same legend
Solve the problem at the root: legendString = "N = " + string(N) + ", M = " + string(M); ph = plot(x,N.*x'); % Better controll...

21 days ago | 0

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stack multiple 2D images
Unfortunately matlab is a bit weak when it comes to displaying volumetric data. You can use the slice function and use the alpha...

26 days ago | 0

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Poor resolution on EPS caused by fill function
As far as I understand post-script does not really support transparency. Therefore when writing figures with transparent objects...

28 days ago | 0

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All possible combination based on 2^n
You could use dec2bin: allpossibles = dec2bin(0:(2^n-1)); You'll have to extract the indices from the columns but that should...

1 month ago | 0

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ODE for the modelling of polymers degradation - products of sums, additional matrix in the function?
It seems to me that you might have your problems when calculating the products of the radicals. Your ODE-function for the couple...

1 month ago | 0

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How to plot actual amplitude on the colorbar using STFT (spectrogram)
If you read the help for spectrogram you'll find this: [...] = spectrogram(...,SPECTRUMTYPE) uses the window scaling ...

1 month ago | 1

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Flood map using Mapping toolbox
Well there are a couple of resources you can use. Steve Eddins (sp?) wrote a series of posts on upslope-area, and another on det...

1 month ago | 0

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How does pcolor basically work? Please help me understanding pcolor, color matrix, and colormap work.
If you add a call: colorbar to your tests you will see what levels of C corresponds to what colours in the colormap. That will...

1 month ago | 0

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nonlinear fit with function a*exp((q1+i*q2)*x)/sqrt(x)
This seems like you need to take a standard step from the physicsist's complex representation (which admittedly we often use a b...

1 month ago | 0

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[Image Restoration, Wiener Filter] Ifft2 gives NaN complex matrix
Just to get up to speed: that then is F-transformed to: which we can "solve" as: or after multiplying the RHS with the ...

1 month ago | 1

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Keeping values of function when solving ODE
As your ODE is written above we have to ask: Why bother? y is deterministically given provided your input parameters and the tim...

1 month ago | 1

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Deconvolution of a combination of Gaussians signal
If you have a signal that is smeared or convolved with some point-spread-function you can to some extent undo that by using eith...

1 month ago | 0

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How to solve the second-oder differential equations with two variables using ODE45 or whatever
To the best of my "reading-ability" you seem to have it right in ODE-defining function. From your equations I expect them to be ...

1 month ago | 0

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Best guess/optimization solution needed
From the information you've given this sounds like a "reasonably" straightforward optimization-problem. You could try something ...

2 months ago | 0

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How to solve differential equations involving matrices?
Based off of your description I see no difference betwee solving these 4 x 4 coupled ODEs and solving them as 16 x 1 coupled ODE...

2 months ago | 0

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Remove temporal intensity changes in image series
I'd try something like this: ImFiles = dir('*.png'); % well you have your images somehow... roi_c = [11 37 17 51]; for iIm = ...

2 months ago | 0

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Solving coupled ODEBVP using MATLAB
There's an old "proverb" going something like "when in danger when in doubt run around in circles scream and shoot". I vaguely ...

2 months ago | 0

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What MATLAB functions are underappreciated?
Just a couple of basic ones: lscov - linear regression when there is a data-covariance-matrix svd (to use together with Tikhon...

2 months ago | 0

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Getting two components for one frequency in FFT
The fft is a circular Fourier transform, there will always be some spectral leakage from frequencies that are not exactly period...

2 months ago | 1

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Local macro in STATA?
That is generally a poor programming pattern (read this as: "This is a really poor idea!"). You should aim to write your code su...

2 months ago | 0

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function for addition 2^16 modulo
Just make sure that your ints a and b are in int32 or larger number of bit-formats, then use: C = mod(a+b,2^16) HTH

2 months ago | 1