Matlab Hilbert Transform in C++

Question

First, please excuse my ignorance in this field, I'm a programmer by trade but have been stuck in a situation a little beyond my expertise (in math and signals processing).

I have a Matlab script that I need to port to a C++ program (without compiling the matlab code into a DLL). It uses the hilbert() function with one argument. I'm trying to find a way to implement the same thing in C++ (i.e. have a function that also takes only one argument, and returns the same values).

I have read up on ways of using FFT and IFFT to build it, but can't seem to get anything as simple as the Matlab version. The main thing is that I need it to work on a 128*2000 matrix, and nothing I've found in my search has showed me how to do that.

I would be OK with either a complex value returned, or just the absolute value. The simpler it is to integrate into the code, the better.

Thank you.

Answer 1

The MatLab function hilbert() does actually not compute the Hilbert transform directly but instead it computes the analytical signal, which is the thing one needs in most cases. It does it by taking the FFT, deleting the negative frequencies (setting the upper half of the array to zero) and applying the inverse FFT. It would be straight forward in C/C++ (three lines of code) if you've got a decent FFT implementation.