verified code for computing the fast furrier transform (fft) of an image

[rouhi]

Hi
i am looking for a verified code in simple c, for generating fft of an input image (.jpg). the output can be a text file including fft coefficients.
can you recommend me any source except open-cv?

[Malcolm McLean]

Hi
i am looking for a verified code in simple c, for generating fft of an input image (.jpg). the output can be a text file including fft coefficients.
can you recommend me any source except open-cv?

This is basically what you're looking for

Keep it simple, Stupid!

A 2D FFT is generated by doing 1D FFTs for all the rows, then 1D FFTs for the transformed columns.

[rouhi]

Thanks
Let me check it and see the results.
Cheers

[rouhi]

Hi Malcolm
I downloaded the kiss_fft.c and tried to compile it by mingw and code::blocks ide, under windows 7.
It seems that the code is generated for linux. am i right?
BY the way, the error in compiling kiss_fft.c is:
undefined reference to WinMain@16
It seems the program is a window application rather than a console project. is that correct?
do you have any recommendation for compiling the kiss_fft.c under windows? preferable in the mode of a console project?

[laserlight]

The error message basically means that you tried to build a program, but there was no main function found.

[Malcolm McLean]

Hi Malcolm
I downloaded the kiss_fft.c and tried to compile it by mingw and code::blocks ide, under windows 7.
It seems that the code is generated for linux. am i right?
BY the way, the error in compiling kiss_fft.c is:
undefined reference to WinMain@16
It seems the program is a window application rather than a console project. is that correct?
do you have any recommendation for compiling the kiss_fft.c under windows? preferable in the mode of a console project?

kiss_fft is basically a set of functions written in platform-independent C. There might be a few preprocessor defines in there which are specific to the platform, but I doubt it.
It's not a program in its own right. You have to drive it with calling code, either main() for a console app or WinMain() for a windows application.

[rouhi]

wow thanks, its working now. i used the code ( source: c++ - Applying Kiss FFT on audio samples and getting NaN output? - Stack Overflow) and get a sample results.
Now i should input an image data (two dimensional array) instead of the in[i].
probably i should enter the pixel values (intensity data in my case) as real values to the in[i][j] array and the rest would be intact, are you agree ?