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**Content Feed**

Submitted

Radially averaged surface roughness power spectrum (PSD) only on top or bottom part of a topography

Calculates radially averaged 2D power spectrum for a certain part of surface topography

ongeveer 7 jaar ago | 13 downloads |

Submitted

1-dimensional surface roughness power spectrum of a profile or topography

Calculates 1D surface roughness power spectrum for a surface topography/or multiple line profiles

ongeveer 7 jaar ago | 25 downloads |

Submitted

Radially averaged surface roughness/topography power spectrum (PSD)

Calculates radially averaged 2D power spectrum for a surface roughness/topography

ongeveer 7 jaar ago | 27 downloads |

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...

ongeveer 7 jaar ago | 1

Submitted

Surface generator: artificial randomly rough surfaces

Generates randomly rough fractal surfaces with different fractal (Hurst) parameters

ongeveer 7 jaar ago | 39 downloads |

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...

ongeveer 8 jaar ago | 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...

ongeveer 8 jaar ago | 3

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...

ongeveer 8 jaar ago | 0

| accepted

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...

ongeveer 8 jaar ago | 5

| accepted

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...

ongeveer 8 jaar ago | 0

| accepted

Question

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...

meer dan 8 jaar ago | 1 answer | 0

### 1

answerideas 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...

bijna 9 jaar ago | 0

Question

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...

bijna 9 jaar ago | 1 answer | 0

### 1

answerQuestion

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...

bijna 9 jaar ago | 4 answers | 0

### 4

answersMake 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...

bijna 9 jaar ago | 1

| accepted

Question

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 ...

bijna 9 jaar ago | 2 answers | 1

### 2

answersQuestion

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...

bijna 9 jaar ago | 0 answers | 0

### 0

answersQuestion

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....

bijna 9 jaar ago | 0 answers | 0

### 0

answersQuestion

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...

ongeveer 9 jaar ago | 1 answer | 1

### 1

answerQuestion

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-...

ongeveer 10 jaar ago | 7 answers | 0

### 7

answersProblem 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...

ongeveer 10 jaar ago | 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...

ongeveer 10 jaar ago | 0

Question

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 ...

meer dan 10 jaar ago | 1 answer | 0

### 1

answerHow 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...

meer dan 10 jaar ago | 0

Question

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; ...

meer dan 10 jaar ago | 2 answers | 0

### 2

answersQuestion

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...

meer dan 10 jaar ago | 1 answer | 0

### 1

answerQuestion

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...

meer dan 10 jaar ago | 4 answers | 0

### 4

answersExtracting 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...

meer dan 10 jaar ago | 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...

meer dan 10 jaar ago | 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 ...

meer dan 10 jaar ago | 0