基于流形学习和混合模型的视频摘要方法

视频摘要是进行视频浏览、视频检索、视频索引等视频应用的前提,而且视频摘要类似于文本的摘要,也是对视频内容的一个简短概括。为了自动获得既包含视频的主要信息,而冗余信息又少的视频摘要,提出了一种基于流形学习和有限混合模型的自动视频摘要方法。该方法通过对视频序列进行流形建模,首先得到视频场景的初次分割;然后对包含内容较多的场景,使用等距降维方法计算视频帧的特征向量;最后将视频帧的特征向量输入到混合模型进行聚类分析,得到更细粒度的摘要结果。为了实现视频摘要的自动处理,所采用的混合模型需要具有模型选择功能。混合模型的聚类结果和流形建模的结果共同构成了视频摘要。视频分割片段的实验结果表明,在不需人为干预的情况下,所提供的视频摘要不仅包含视频主要内容,而且冗余信息少。     

Expressive Speech Animation Synthesis with Phoneme‐Level Controls

This paper presents a novel data‐driven expressive speech animation synthesis system with phoneme‐level controls. This system is based on a pre‐recorded facial motion capture database, where an actress was directed to recite a pre‐designed corpus with four facial expressions (neutral, happiness, anger and sadness). Given new phoneme‐aligned expressive speech and its emotion modifiers as inputs, a constrained dynamic programming algorithm is used to search for best‐matched captured motion clips from the processed facial motion database by minimizing a cost function. Users optionally specify ‘hard constraints’ (motion‐node constraints for expressing phoneme utterances) and ‘soft constraints’ (emotion modifiers) to guide this search process. We also introduce a phoneme–Isomap interface for visualizing and interacting phoneme clusters that are typically composed of thousands of facial motion capture frames. On top of this novel visualization interface, users can conveniently remove contaminated motion subsequences from a large facial motion dataset. Facial animation synthesis experiments and objective comparisons between synthesized facial motion and captured motion showed that this system is effective for producing realistic expressive speech animations.     

流形学习中非线性维数约简方法概述

较为详细地回顾了流形学习中非线性维数约简方法,分析了它们各自的优势和不足.与传统的线性维数约简方法相比较,可以发现非线性高维数据的本质维数,有利于进行维数约简和数据分析.最后展望了流形学习中非线性维数方法的未来研究方向,期望进一步拓展流形学习的应用领域.