We propose a novel spatially continuous framework for convex relaxations
based on functional lifting. Our method can be interpreted as a
sublabel-accurate solution to multilabel problems. We show that previously
proposed functional lifting methods optimize an energy which is linear between
two labels and hence require (often infinitely) many labels for a faithful
approximation. In contrast, the proposed formulation is based on a piecewise
convex approximation and therefore needs far fewer labels. In comparison to
recent MRF-based approaches, our method is formulated in a spatially continuous
setting and shows less grid bias. Moreover, in a local sense, our formulation
is the tightest possible convex relaxation. It is easy to implement and allows
an efficient primal-dual optimization on GPUs. We show the effectiveness of our
approach on several computer vision problems.

本文提出了一种基于函数提升的新型空间连续凸松弛框架，旨在解决多标签问题，与之前提出的基于函数提升的方法相比，本方法基于分段凸近似，因此需要更少的标签；与最近的基于 MRF 的方法相比，本方法在一个空间连续设置中进行，并且显示较少的栅格偏差；此外，本文的公式在局部意义上是可能得到的最紧凑的凸松弛，易于实现并允许在 GPU 上进行高效原始 - 对偶优化。本方法在几个计算机视觉问题上的效果证明了其有效性。

非凸能量松弛的子标记精确方法

Sublabel-Accurate Relaxation of Nonconvex Energies

Many modern multiclass and multilabel problems are characterized by
increasingly large output spaces. For these problems, label embeddings have
been shown to be a useful primitive that can improve computational and
statistical efficiency. In this work we utilize a correspondence between rank
constrained estimation and low dimensional label embeddings that uncovers a
fast label embedding algorithm which works in both the multiclass and
multilabel settings. The result is a randomized algorithm for partial least
squares, whose running time is exponentially faster than naive algorithms. We
demonstrate our techniques on two large-scale public datasets, from the Large
Scale Hierarchical Text Challenge and the Open Directory Project, where we
obtain state of the art results.

本文提出了利用排名约束估计与低维标签嵌入之间的对应关系来发现一种新的、快速的标签嵌入算法，并展示了其在多类问题和多标签问题中的应用，最终实现了指数级的运行时间优化，其中在两个大规模公共数据集上的结果优于现有技术。