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Bjorn Gustavsson


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UIT, the Arctic University of Norway

946 total contributions since 2001

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Answered
Using the cpsd function
Simply use the spectrogram function to calculate the spectrograms of your two time-series, something like this: [S1,F1,T1] = sp...

3 días ago | 0

Answered
3d Plot “pile up 100 2d images” in 3d plane
You can use the function slice (see the help and documentation for details), but to do that you'll have to use 3-D arrays as inp...

6 días ago | 0

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Answered
Probability density function calculation from data
Step 1, combine the daily rain-data to a 20-by-365 matrix: for iY = 20:-1:1 rain_20years(iY,:) = rain_daily{iY}; % You'll ...

6 días ago | 0

Answered
data fitting by Integration with variable limit with a unknown parameter.
You can do something like this: y_fcn = @(CT,x) CT(1) * 74.826 * (x./CT(4)).^3 * integral(t.^4.*exp(t)./(exp(t)-1).^2), 0, CT(4...

6 días ago | 0

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Answered
video camera data processing
Simplest way might be to use VideoReader: vidObj = VideoReader('Your-video.mp4'); Frame1 = read(vidObj,1); idx1toExtract = ...

6 días ago | 0

Answered
Solving a system of ODE with Crank Nicholson
Note that you have a set of coupled ODEs not PDEs. The Crank-Nicholson method is developed for solving PDEs where we have both "...

10 días ago | 1

Answered
How to create 3D array out of multiple 2D arrays of different dimensions?
Something like this ought to work: M2Dall = {m1,m2,m3,mN}; % Puting all matrices into one cell-array. for i3 = numel(M2Dall):-...

10 días ago | 0

Answered
Pr4oblem with an ODE 45 " not enough input arguments"
Your definition of the ODEs is unconventional. I've always used to define coupled ODEs such that the dependent variables are in ...

11 días ago | 0

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Answered
How to plot contourf using following information?
You would have to make one contour-plot for each time-step: i_time = 1; contourf(lon,lat,pr(:,:,i_time)') If I understood the...

11 días ago | 1

Answered
how to create noisy image based on Poisson's noise
Well poissrnd is what you want, as far as I understand. If you have an "ideal image" with intensity I: I = repmat(1+[0:11].^2,[...

11 días ago | 0

Answered
How can I optimize function output by tuning 3 input parameters?
You'll have to modify (at least for simplicity) your function to something like this: function [Pressures] = myFunc(KpKdKi) ...

11 días ago | 0

Answered
Getting Meters per Pixel out of the camera calibration app?
If you know the size of the squares on the checkerboard and your objects are at the same distance then you only need to count th...

11 días ago | 0

Answered
How to specify points in on two curves in plot?
This seems like a task for interp1. Have a look at the help and documentation for that function. I'd do something like this: sc...

12 días ago | 0

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Answered
How do I generate a spherical image from a 3D matlab figure
Currently matlab has 'orthographic' and 'perspective' for the 'projection'-property of 3-D axes. You can perhaps get a wee bit ...

12 días ago | 0

Answered
Nonscalar arrays of function handles are not allowed; use cell arrays instead.
You get the error in newton because the feval of your ydy-function returns function handles and you try to assign them to regula...

12 días ago | 0

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Answered
How to use smoothing spline to fit a closed curve?
You'll get some progress moving to radial coordinates (it will not be the same properties of a spline in radial coordinates as i...

13 días ago | 0

Answered
how to delete elements in the matlab array by overcoming the Unable error to delete elements from this array because dimension 3 has fixed size.
In your function y will not be set. You only try to remove one element from the input, that's wasting time. When I run this at t...

13 días ago | 0

Answered
When I attempt to run this code, it doesnt stop running. It will only stop when I pause it. Would appreciate any help as to how to fix this?
If your odes should have positive solutions (haven't checked them to be able to judge this), and they happen to become negative ...

14 días ago | 0

Answered
earth magnetic field model
Check the help and documentation for whatever function you use to get the "world magnetic field". In the IGRF-implementation (an...

14 días ago | 0

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Answered
Much slower valid convolution using complementary size of kernels.
No, n-dimensional fourier-transforms, multiplication of the Fourier-transforms of 5-5-8 a with T will be a fair bit faster than ...

27 días ago | 0

Answered
Curve Fitting for a function with 3 fitting parameters.
For this I typically use standard non-linear least-square-fitting. That only requires some optimisation-routine, like fminsearch...

alrededor de 1 mes ago | 0

Answered
polyfit with multiple dependent variables
The polyfit function only works for 1-D polynomials, as far as I understand things. However there is an n-dimensional polynomial...

alrededor de 1 mes ago | 0

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Answered
MATLAB's crosscorr function and R Studio ccf show different results
If you cannot find the information in the documentation, you'll have to go to the source. This is what I find in the xcorr funct...

alrededor de 1 mes ago | 0

Answered
3d plot help
Have a look at the FEX-submission joyplot, it should give you functions to make these types of plots. HTH

alrededor de 1 mes ago | 0

Answered
Analysing Noisy Video for Approximating Radiation Dose on an Observation Baloon
The way I understand your problem is that you're looking for variation in cosmic ray-flux with altitude? Or are you looking at s...

alrededor de 1 mes ago | 0

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Answered
Monod equations with ODE45
From the looks of your 3 coupled ordinary differential equations it seems unlikely that they have solutions that are neat elemen...

alrededor de 1 mes ago | 0

Answered
How to reduce chromatic aberrations in color images?
1, Use matlab to design improved lenses that are achromatic. (This is by far the best way to go about it, nothing helps better a...

alrededor de 1 mes ago | 0

Answered
to find polar curve area
The area of a circle-sector is: Use that for each small sector of your areas, add them up, then change the number of elements...

alrededor de 1 mes ago | 0

Answered
How can I plot boundary with these green points instead of these zig zag lines?
Use the function: convhull to get indices to points along the perimeter in order. See the help and documentation for details. ...

alrededor de 1 mes ago | 1

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Answered
Interpolation of non monotonic data.
The interpolation-function does something else than what you seem to try. It takes one data-vector, D, taken at a discrete set o...

alrededor de 1 mes ago | 0

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