General Tools

Python

Website
https://docs.python.org/3/
Purpose
Programming Language
Description
Python is a programming language which is heavily used by scientists and engineers. There are many packages and modules out there, which implement a lot of libraries about all topics and all of those are at your finger tips at https://pypi.python.org/.

GNU Octave

Website
https://www.gnu.org/software/octave/
Purpose
Programming Language, Numerical Computation
Description
GNU Octave is a numerical computation tool which behaves pretty similar to Matlab. It comes with many toolboxes which are focused on specific areas like image processing. It also provides a programming language, so you are able to develop your own algorithms.