Introduction
Offside Technology have been used for several years to graphically analyse potential offside situations in football.
Since the introduction of video assistant referees (VARs) into the Laws of the Game in 2018, there has been an increased spotlight on the ability to accurately determine offsides and make confident decisions based upon these lines. Research carried out by FIFA between 2016 and 2019 showed that the most frequent sources of error for such virtual lines are the topography of the field (particularly the field camber), camera-angle distortion, player occlusion and the issue of tracking individual body parts.