Fast Fourier Transform (FFT) is Discrete Fourier Transform (DFT) algorithm. To perform FFT in Python you need to install several packages/modules/libraries. You can skip this portion if you already have it available. I am a windows user so I will show how to setup your machine for windows environment. This is an effort to provide the easiest and extensive tutorial for image processing beginners in python.
Things you need to download and install are as follows:
1. Install Python 2.7.10 (as for Python 3.4 you will face challenges for other packages) from https://www.python.org/downloads/
2. Install SciPy 0.16.0 superpack for Python 2.7 from http://sourceforge.net/projects/scipy/files/scipy/0.16.0/
3. Install NumPy 1.9.2 superpack for Python 2.7 from http://sourceforge.net/projects/numpy/files/NumPy/1.9.2/
4. Install Six 1.9.0 from https://pypi.python.org/pypi/six
5. Install Matplotlib 1.4.3 for Python 2.7 from http://sourceforge.net/projects/matplotlib/files/matplotlib/matplotlib-1.4.3/windows/
6. Install Dateutil 2.4.2 from https://pypi.python.org/pypi/python-dateutil [Install Six (see step-4) before installing Dateutil]
7. Install PIL 1.1.7 for Python 2.7 from http://www.pythonware.com/products/pil/
8. Install PyParsing 2.0.3 for Python 2.7 from http://sourceforge.net/projects/pyparsing/files/pyparsing/pyparsing-2.0.3/
9. Install OpenCV (Open Source Computer Vision) 3.0.0 from http://sourceforge.net/projects/opencvlibrary/files/opencv-win/3.0.0/