Learned Vertex Descent: A New Direction for 3D Human Model Fitting

Enric Corona, Gerard Pons-Moll, Francesc Moreno-Noguer

Abstract:

We propose a novel optimization-based paradigm for 3D
human model fitting on images and scans. In contrast to existing approaches that directly regress the parameters of a low-dimensional statistical body model (e.g. SMPL) from input images, we train an ensemble of per vertex neural fields network. The network predicts, in a
distributed manner, the vertex descent direction towards the ground
truth, based on neural features extracted at the current vertex projection. At inference, we employ this network, dubbed LVD, within a
gradient-descent optimization pipeline until its convergence, which typically occurs in a fraction of a second even when initializing all vertices
into a single point. An exhaustive evaluation demonstrates that our approach is able to capture the underlying body of clothed people with
very different body shapes, achieving a significant improvement compared to state-of-the-art. LVD is also applicable to 3D model fitting
of humans and hands, for which we show a significant improvement to
the SOTA with a much simpler and faster method. Code is released at
https://www.iri.upc.edu/people/ecorona/lvd/