PyThermLIA: A Python library to implement digital lock-in processing

PyThermLIA is a free and open-source Python library that implements a Digital Lock-in Amplifier for processing videos recorded by generic digital cameras. This library processes data from a temporal image sequence using an algorithm that applies the discrete Fourier transform to perform offline lock-in analysis. The functionality of the PyThermLIA was validated by processing a long temporal image sequence obtained with a thermographic camera in a widely known active lock-in infrared thermography experiment. The amplitude and phase lag images extracted from processing are displayed via a graphical user interface testing, only developed for this purpose. The results were compared with those obtained using a thermographic camera embedded lock-in module.