【作者】 畅雪萍；

【导师】 郑忠龙；

【作者基本信息】 浙江师范大学 ， 计算机软件与理论， 2011， 硕士

【摘要】 单样本人脸识别问题已发展成为模式识别、人工智能和机器学习领域中的一个热点和难点研究课题。目前大多数人脸识别技术的研究仅集中在怎样提高人脸识别系统的准确率上,并且严重依赖训练样本集的规模和代表性,忽略了由于采集样本的困难或者系统的存储容量有限等所造成的单样本问题。稀疏表征(Sparse Representation, SR)源于对传统信号采样和表示理论的扩展,例如Fourier和Wavelet表示。在过去几年里,SR已被证明在获取、表征和压缩高维信号方面是一个非常强大的工具,并已成功用于解决信号处理、机器学习和模式识别领域中的诸多实际问题。近来,由D. Donoho、E. Candes及T. Tao等人提出的压缩感知(Compressive Sensing,或称Compressed Sensing、Compressed Sampling, CS)理论进一步将稀疏表征思想提升到了一个新的高度。本文主要是研究基于稀疏理论的单样本人脸识别问题,目标是得到有效的改进算法以提高单样本情况下的识别性能。本文的主要研究工作如下：(1)对目前人脸识别问题、稀疏理论、单样本人脸识别问题的研究背景、意义、国内外现状及目前面临的挑战等作了综述性分析；(2)利用Shift、PCA重构、镜像对称变换、下采样等方法结合稀疏表征分类器(Sparse Representation-based Classification, SRC)方法,改善单样本人脸识别：增加了冗余样本,有效地提高了识别率,节省了计算与存储开销,增强了算法的实用性能；(3)基于稀疏表征理论SR、压缩感知理论CS以及半监督降维技术(Semi-supervised Dimensionality Reduction, SSDR),提出了一个新的基于半监督的算法——半监督的稀疏判别保局投影(Semi-supervised Sparsity Diteriminant Locality Preserving Projections, SSDLPP)。SSDLPP算法在仅仅拥有很少无标号样本的情况下,改善了DLPP (Discriminant Locality Preserving Projections, DLPP)和LPP (Locality Preserving Projections, LPP)的识别性能。本文在ORL和Yale等人脸数据库上进行了仿真实验,实验结果证明本文所提出的改进的单样本人脸识别算法取得了较好的识别性能。更多还原

【Abstract】 Single sample face recognition problem has been a hot and difficult research topic in the field of pattern recognition, artificial intelligence and machine learning. Many face recognition techniques focus on how to improve the accuracy of a recognition system, and largely depend on the. size and representative of training set. However, it seems that most of them ignore the potential problem that may stem from the face database at hand, where there may be only one sample image per person, possibly due to the difficulties of collecting samples or the limitations of storage capability of the systems, etc. Sparse representation (SR) is initially proposed as an extension of traditional signal sampling and representation theory such as Fourier representation and wavelet representation. In the past few years, SR has proven to be an extremely powerful tool for acquiring, representing, and compressing high-dimensional signals and has been successfully applied to solve many practical problems in fields of signal processing, machine learning, and pattern recognition. Recently, compressive sensing (CS) was proposed by D. Donoho, E. Candes, T. Tao et al., and makes SR a breakthrough in real applications.This paper focuses on the single sample problem based sparse representation for face recognition. The goal of this paper is to improve the recognition performance of the single sample face recognition algorithm. The main contributions of this paper are as follows:(1) This paper briefly introduces the background, significance, status and challenges of current face recognition, sparse theory, and single sample face recognition problem.(2) This paper generates the multiple images using Shift, PCA Reconstruction, Mirror-symmetry Transformation and Sampling methods combined with Sparse Representation-based Classification (SRC), to further improve the recognition performance. These proposed methods not only increase redundant samples and enhance the recognition performance but also save the computation and storage costs.(3) Motivated by the recent development of SR, CS and semi-supervised dimensionality reduction (SSDR), a novel SSDR based on l1-graph is presented, namely semi-supervised sparsity discriminant locality preserving projections (SSDLPP). SSDLPP can remarkably improve the recognition performance of discriminant locality preserving projections (DLPP) and locality preserving projections (LPP) even if we have only single training sample and very few extra unlabeled training samples.Experimental results on both two famous face datasets (ORL and Yale) show that the proposed algorithms substantially improve the recognition performance for the single sample face recognition.更多还原