1. Introduction
The transition from offline in-shop retail to e-commerce has been accelerated by the recent pandemic caused lock downs. In 2020, retail e-commerce sales worldwide amounted to 4.28 trillion US dollars and e-retail revenues are projected to grow to 5.4 trillion US dollars in 2022. However, when it comes to fashion, one of key offline experiences missed by the on-line shoppers is the changing room where a garment item can be tried-on. To reduce the return cost for the online retailers and give shoppers the same offline experience online, image-based virtual try-on (VTON) has been studied intensively recently [9], [10], [13], [14], [19], [24], [38], [39], [42], [43].