“…Over the last few years, some monitoring techniques have been extensively applied to livestock farming [ 2 , 3 , 4 , 5 , 6 ], and several studies have utilized surveillance systems to monitor pigs automatically [ 7 , 8 , 9 , 10 ]. The aim of this study is to analyze video-based pig monitoring, using non-attached (i.e., non-invasive) sensors [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Moreover, we adopt a top-view camera [ 18 , 19 , 20 , 21 , 22 , 23 ] to resolve general issues, such as occlusion, overlapping, illumination changes, and rapid movements during pig monitoring.…”