Filtering specific wavenumber range in Fourier Transforms result.
Hello. I am currently dealing with the interference signal from the Coherence Scanning interferometer. My plan for processing the signal is as follows:
Applying a discriminator to normalize the signal to the center amplitude at zero,
Zero padding the signal to increase the resolution in the frequency domain.
Doing FFT to convert the interference signal from scanning distance to spatial frequency domain ( um to rad/um).
Filtering out the interested domain ( my light source is 380 nm to 780 nm, so I only care about the range from 8 ~ 17 rad/um).
Calculating and unwrapping the phase from the filtered result.
Compensating the phase with the phase error calculated by material properties.
Doing IFFT with the compensated phase to convert it back to an interference signa
Figure 1. Original phase from interferogram.
Figure 2. Calculated phase error.
The problem is the wavenumber range of the interference signal is 0 to ~ 25 rad/um while the phase error I calculated only supports from 6~30 rad/um. I would like to know if there are any ways to take out entirely then wavenumber range from 8 ~17 rad/um and do the rest of my work on this range. I also shared my code and raw data here.
Thank you all for reading my problem. Hope you guys have a nice weekend.Hello. I am currently dealing with the interference signal from the Coherence Scanning interferometer. My plan for processing the signal is as follows:
Applying a discriminator to normalize the signal to the center amplitude at zero,
Zero padding the signal to increase the resolution in the frequency domain.
Doing FFT to convert the interference signal from scanning distance to spatial frequency domain ( um to rad/um).
Filtering out the interested domain ( my light source is 380 nm to 780 nm, so I only care about the range from 8 ~ 17 rad/um).
Calculating and unwrapping the phase from the filtered result.
Compensating the phase with the phase error calculated by material properties.
Doing IFFT with the compensated phase to convert it back to an interference signa
Figure 1. Original phase from interferogram.
Figure 2. Calculated phase error.
The problem is the wavenumber range of the interference signal is 0 to ~ 25 rad/um while the phase error I calculated only supports from 6~30 rad/um. I would like to know if there are any ways to take out entirely then wavenumber range from 8 ~17 rad/um and do the rest of my work on this range. I also shared my code and raw data here.
Thank you all for reading my problem. Hope you guys have a nice weekend. Hello. I am currently dealing with the interference signal from the Coherence Scanning interferometer. My plan for processing the signal is as follows:
Applying a discriminator to normalize the signal to the center amplitude at zero,
Zero padding the signal to increase the resolution in the frequency domain.
Doing FFT to convert the interference signal from scanning distance to spatial frequency domain ( um to rad/um).
Filtering out the interested domain ( my light source is 380 nm to 780 nm, so I only care about the range from 8 ~ 17 rad/um).
Calculating and unwrapping the phase from the filtered result.
Compensating the phase with the phase error calculated by material properties.
Doing IFFT with the compensated phase to convert it back to an interference signa
Figure 1. Original phase from interferogram.
Figure 2. Calculated phase error.
The problem is the wavenumber range of the interference signal is 0 to ~ 25 rad/um while the phase error I calculated only supports from 6~30 rad/um. I would like to know if there are any ways to take out entirely then wavenumber range from 8 ~17 rad/um and do the rest of my work on this range. I also shared my code and raw data here.
Thank you all for reading my problem. Hope you guys have a nice weekend. fft, signal processing MATLAB Answers — New Questions
