FOSPEX - Fourier Spectrum Explorer

An interactive application to explore the fourier spectrum of an image and find possible notch filters.

Used core frameworks and libraries:

• Frontend: NPM, Vue.js, Quasar
• Backend: FLASK, matplotlib, Pillow, OpenCV

Frontend

To run frontend, enter

cd frontend
quasar dev

Backend

Make sure you have installed all requirements:

cd backend
pip install -r requirements.txt

To run the backend, enter:

python main.py

Troubleshooting

Mac OS X Error: Python is not installed as a framework. when starting backend main.py

This is because matplotlib is installed via PIP. To solve this, enter this into your console:

echo backend: TkAgg >> ~/.matplotlib/matplotlibrc

Theory: Fourier transformation and frequency spectrum

There is a lot of explanation in the internet. Some of useful resources are:

• Aditi Majumder, M. Gopi: Introduction to Visual Computing. Core Concepts in Computer Vision, Graphics, and Image Processing (2018)
• Ritchie Vink: Understanding the Fourier Transform by example
• Paul Bourke: Image filter
• K Hong: Signal Processing with NumPy II - Image Fourier Transform : FFT & DFT
• Jessica Lu: Fourier Transforms of Images in Python