“…The methods can be categorized into point-based [14,29,37,53,63,64,65] and projection-based [1,15,46,74,75,83] approaches. To learn from fewer labels, various strategies were proposed with point-based methods: enforcing geometric prior [85], local neighborhood propagation [30,44], for smarter use of the rare labels some used active learning [77], pseudo labelling [38,59,73], graph propagation [44,59], self-training [38,89], temporal matching [59,67].…”