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Random Gaussian Surface Generation
Hei Michelle, although it is already late for you, but maybe this could help someone else. Now, you can easily use below code to...
fast 9 Jahre vor | 1
Why am i getting huge values on low frequencies of my PSD ?
Hello, We don't know what you expect to see in your power spectrum. You just mentioned you see some weird high peaks in your...
mehr als 9 Jahre vor | 0
How to calculate the Power spectral denstity(PSD) function for rough surface from surface profile z(x,y)? i wanted to plot log C(q) vs log (q). Can anybody help me to calculate the PSD For rough surface?
Hello, Probably a little bit late to answer but use below codes for the exact same purposes: For 2D PSD: <http://se.mat...
mehr als 9 Jahre vor | 4
IFFT of a Hanning windowed FFT Image
Hello, You have used your absolute values to plot your image. Now, to reverse the operation you need the full fft results whi...
mehr als 9 Jahre vor | 0
| akzeptiert
How can I get this pattern?
Dear Xaris, I took a look at the standard. First of all, the definition of velocity and acceleration PSD in the standard is d...
mehr als 9 Jahre vor | 5
| akzeptiert
Fourier Transform - position to velocity derivative
Hello, Your problem when assigning frequencies to fft results is only related to the shift of frequencies. The frequencies wh...
fast 10 Jahre vor | 0
| akzeptiert
Frage
nonlinear curve fit: how to optimize?
I have a custom model which I want to fit to my data. The model works manually, i.e. when I know approximately the fit paramater...
etwa 10 Jahre vor | 1 Antwort | 0
1
Antwortideas to smooth a sharpe corner of a graph?
Thanks a lot for all your ideas, I really appreciate them. I finally used curve fitting in MATLAB using pchip interpolation in 1...
mehr als 10 Jahre vor | 0
Frage
Design filter to pass high frequencies but reduce amplitudes for low frequencies to half (not zero)
I don't have experience in filter design. Could anyone tell me the possibility, limitations as well as MATLAB commands to design...
mehr als 10 Jahre vor | 1 Antwort | 0
1
AntwortFrage
ideas to smooth a sharpe corner of a graph?
I'm trying to smooth a sharpe corner of a graph similar to what I've shown in the image below: <</matlabcentral/answers/upl...
mehr als 10 Jahre vor | 4 Antworten | 0
4
AntwortenMake ifft2 to give real output
I found my answer, so maybe useful for someone else as well. I need to apply conjugate symmetry condition for 2D fourier transf...
mehr als 10 Jahre vor | 1
| akzeptiert
Frage
Make ifft2 to give real output
I'm trying to generate a randomly rough surface(isotropic surface). Suppose I have the absolute values of fourier components of ...
mehr als 10 Jahre vor | 2 Antworten | 1
2
AntwortenFrage
2D butterworth filter on a surface
Hello, I need to apply lowpass/highpass filters on a surface topography. What I have in mind is to filter data from a cut-off...
mehr als 10 Jahre vor | 0 Antworten | 0
0
AntwortenFrage
Error estimation during converting point cloud to STL file
I have a 3D point cloud of a topography and I convert it to STL file format by means of this function in MATLAB: <http://www....
mehr als 10 Jahre vor | 0 Antworten | 0
0
AntwortenFrage
image stitching: ideas to solve singular or badly scaled matrix
I'm trying to do image mosaicing according to this example of MATLAB: <http://se.mathworks.com/help/vision/examples/feature-b...
mehr als 10 Jahre vor | 1 Antwort | 1
1
AntwortFrage
Problem in exporting figure: Can anyone fix a bug in this code?
Dear all, I'm using this code to magnify part of my figure: <http://www.mathworks.com/matlabcentral/fileexchange/26007-on-...
fast 12 Jahre vor | 7 Antworten | 0
7
AntwortenProblem in exporting figure: Can anyone fix a bug in this code?
Dear all, I was checking the original code again and I saw this statement in it as known issues: % - The size and posi...
fast 12 Jahre vor | 0
Problem in exporting figure: Can anyone fix a bug in this code?
Jan, Thanks for your answer, unfortunately, I don't know how to debug the original code! But for the other questions you asked I...
fast 12 Jahre vor | 0
Frage
What are low frequencies in an image while they don't exist in reality?
I'm really frustrated by these frequency components and their assignments. I have images(3D profiles) which are height profiles ...
fast 12 Jahre vor | 1 Antwort | 0
1
AntwortHow many periods it is needed for fft to give us a proper estimate over frequency?
Dear Wayne, Thanks a lot for your answer. I played with Fs a little bit and even for Fs = 10(twice the highest frequency), it...
fast 12 Jahre vor | 0
Frage
How many periods it is needed for fft to give us a proper estimate over frequency?
Dear all, I have a basic question. Imagine a simple sinusoidal defined as below: Fs = 150; t = 0:1/Fs:0.2; f = 5; ...
fast 12 Jahre vor | 2 Antworten | 0
2
AntwortenFrage
Error using arrayfun : Non scalar in Uniform output
Hello, I have a cell array (Z) of size (480*1) where in each row I have the individual double arrays that I want(e.g. 1*70 do...
fast 12 Jahre vor | 1 Antwort | 0
1
AntwortFrage
Grouping continuous nonzero in a row vector
Dear All, Is there any MATLAB function to ease grouping continuous nonzero elements of a row vector? I will explain further i...
fast 12 Jahre vor | 4 Antworten | 0
4
AntwortenExtracting Spatial frequency from fourier transform (fft2 on Images)
qx_1=zeros(m,1); for k=0:m-1 qx_1(k+1)=(2*pi/m)*(k); end qx_2 = fftshift(qx_1); % for removing discontinuity...
etwa 12 Jahre vor | 1
Extracting Spatial frequency from fourier transform (fft2 on Images)
If I get it right, you need a 2D graph of power spectral density versus frequencies. When you do a 2D fft on an image, you get a...
etwa 12 Jahre vor | 1
How to fit a curve to a power spectrum curve which follows power law
Hi, Go to cftool, then select your data and choose power; set number of terms to '1' if it follows this equation: y = a*x^b ...
etwa 12 Jahre vor | 0
POWER LAW FITMENT (POWER LAW WITH CUTOFF AND LOGNORMAL) IN CURVE FITTING TOOL
Hi, I'm doing the same. There is no such option. You need to visually split your frequency response and fit a power law to up...
etwa 12 Jahre vor | 0
curve fitting a power function
I have the same problem. This method of converting to logarithmic scale and then use polyfit to fit a linear curve to data gives...
etwa 12 Jahre vor | 0
Frage
2D FFT of an image shows some invalid values for high frequencies
I uploaded my 2D FFT magnitude image here: <https://dl.dropboxusercontent.com/u/82779497/2D_FFT.png> If you take a look at...
mehr als 12 Jahre vor | 2 Antworten | 0
2
AntwortenFrage
Set of parallel lines in a matrix along different directions(not x and y direction)
Dear all, I don't have an idea about how to proceed with this problem! Imagine, I have a 480x748 matrix; I need set of parall...
mehr als 12 Jahre vor | 2 Antworten | 0
