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

oltre 4 anni ago | 12 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

oltre 4 anni ago | 23 downloads |

Submitted

Radially averaged surface roughness/topography power spectrum (PSD)

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

oltre 4 anni ago | 32 downloads |

Answered

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...

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...

oltre 4 anni ago | 1

Submitted

Surface generator: artificial randomly rough surfaces

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

oltre 4 anni ago | 42 downloads |

Answered

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...

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...

circa 5 anni ago | 0

Answered

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...

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...

circa 5 anni ago | 3

Answered

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...

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...

circa 5 anni ago | 0

| accepted

Answered

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...

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...

circa 5 anni ago | 5

| accepted

Answered

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...

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...

oltre 5 anni 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...

oltre 5 anni ago | 1 answer | 0

Answered

ideas 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...

ideas 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...

circa 6 anni 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...

circa 6 anni ago | 1 answer | 0

Question

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...

circa 6 anni ago | 4 answers | 0

Answered

Make 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...

Make 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...

circa 6 anni 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 ...

circa 6 anni ago | 2 answers | 1

Question

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...

circa 6 anni ago | 0 answers | 0

Question

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....

circa 6 anni ago | 0 answers | 0

Question

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...

circa 6 anni ago | 1 answer | 1

Question

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-...

oltre 7 anni ago | 7 answers | 0

Answered

Problem 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...

Problem 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...

oltre 7 anni ago | 0

Answered

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...

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...

oltre 7 anni 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 ...

oltre 7 anni ago | 1 answer | 0

Answered

How 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...

How 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...

oltre 7 anni 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; ...

oltre 7 anni ago | 2 answers | 0

Question

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...

oltre 7 anni ago | 1 answer | 0

Question

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...

oltre 7 anni ago | 4 answers | 0

Answered

Extracting 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...

Extracting 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...

oltre 7 anni ago | 1

Answered

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...

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...

oltre 7 anni ago | 1

Answered

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 ...

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 ...

oltre 7 anni ago | 0