WIP - WORK IN PROGRESS

description:

tool for decoding and processing wefax

theory:

WEFAX (Also known as Weatherfax, HF-FAX, Radiofax, and Weather Facsimile) is a slow scan analog image transmission mode used for the transmission of weather charts and meteorological reports

WEFAX's format is a derivative of the Automatic Picture Transmission (APT) originally developed for transmission from the polar satellites of the USA.

WEFAX has 60, 90, 100, 120, 180 and 240 LPM (Lines per minute) speeds, and two IOC (Index of Cooperation) modes, IOC 576 and IOC 288. Most weather forecasts are sent in IOC 576.

Signal	Duration	IOC576	IOC288	Remarks
Start tone	5s	300 Hz	675 Hz	200 Hz for colour fax modes.
Phasing signal	30s			Black line interrupted by a white pulse.
Image	Variable	1200 lines	600 lines	At 120 lpm.
Stop tone	5s	450 Hz	450 Hz
Black	10s

installation:

git clone https://github.com/wojlin/WEFAX.git
cd WEFAX
pip install flask
pip install flask_socketio
pip install numpy
pip install scipy
pip install matplotlib
pip install Pillow
pip install pyaudio
pip install wave

usage:

python3 main.py

TODO:

• f̶i̶x̶ ̶U̶I̶ ̶b̶u̶g̶ ̶w̶h̶e̶n̶ ̶f̶i̶l̶e̶n̶a̶m̶e̶ ̶i̶s̶ ̶t̶o̶o̶ ̶l̶o̶n̶g̶
• f̶i̶x̶ ̶U̶I̶ ̶b̶u̶g̶ ̶w̶h̶e̶n̶ ̶i̶m̶a̶g̶e̶ ̶f̶r̶a̶m̶e̶ ̶h̶e̶i̶g̶h̶t̶ ̶i̶s̶ ̶t̶o̶o̶ ̶b̶i̶g̶ ̶i̶n̶ ̶i̶m̶a̶g̶e̶ ̶p̶r̶e̶v̶i̶e̶w̶
• f̶i̶x̶ ̶U̶I̶ ̶b̶u̶g̶ ̶w̶h̶e̶n̶ ̶i̶m̶a̶g̶e̶ ̶f̶r̶a̶m̶e̶ ̶h̶e̶i̶g̶h̶t̶ ̶i̶s̶ ̶t̶o̶o̶ ̶b̶i̶g̶ ̶i̶n̶ ̶g̶a̶l̶l̶e̶r̶y̶
• fix convert bug when wav files have low spikes (cut unused frequencies before hilbert transform)
• fix memory allocation problem
• m̶o̶r̶e̶ ̶r̶e̶s̶p̶o̶n̶s̶i̶v̶e̶ ̶p̶r̶o̶g̶r̶e̶s̶s̶ ̶b̶a̶r̶
• fix demodulation problem in live decoding
• finish live decoding
• implement more test cases
• add alerts and bugs report

BUGS AND PROBLEMS:

Port audio error in sunddevice package

raise OSError('PortAudio library not found')
OSError: PortAudio library not found

solution:

sudo apt-get install libportaudio2
sudo apt-get install libasound-dev