在线草图识别中的用户适应性研究

提出一种在线草图识别用户适应性解决方法，该方法分别采用支撑向量机主动式增量学习和动态用户建模技术进行笔划和复杂图形的识别．支撑向量机主动式增量学习方法通过主动“分析”用户增量数据，并根据用户反馈从中选择重要数据作为训练样本，可有效地鉴别用户手绘笔划特征，快速地识别用户输入笔划．动态用户建模技术则采用增量决策树记录草图的笔划构成及其手绘过程，有效捕捉用户的复杂图形手绘习惯，进而利用模糊匹配在草图绘制过程中预测和识别复杂图形．实验表明：该方法具有很好的效果，为解决在线草图识别及其用户适应性问题提供参考．     

基于用户建模的手绘草图识别

在线草图识别包括预处理、特征提取、图形规整和用户建模等几个方面的问题。其中用户建模是手绘草图识别的核心和关键问题。提出了一种在线草图识别用户建模方法,方法用动态用户建模技术进行笔划和复杂图形的识别。方法采用增量决策树记录草图的笔划构成及其手绘过程,实现对复杂手绘草图的用户建模和在线识别。实验表明所提出的方法不仅能得到较好的检索结果,而且具有较好的用户适用性     

基于笔画划分的手绘交通事故现场图识别

将手绘草图识别技术融于交通事故现场图形的识别中，提高了事故现场图的绘制效率。针对现场图形的基本特征，引入直线、折线、圆扣圆弧四种基本图素，将用户输入的具体图形划分为多笔画的组合，经过图形特征识别、图形拟合扣规整过程，实时地识别扣预测用户的基本图形构造意图。基本笔画按其空间关系组合后，利用图形构成与图形模板作相似性计算，及时捕捉扣反馈用户输入图形的组成意图，达到理想的现场图形识别效果。     

在线草图识别中用户手绘习惯建模方法

手绘草图是概念设计和思路外化的一种高效的表达方式。用户绘制草图时存在的多种形式，及其随意性和模糊性使得用户适应性问题逐渐成为草图识别的核心课题。本文提出了一种在线草图识别的用户建模方法来捕捉绘制草图时的用户习惯，主要包括两个方面的内容：一是基于SVM的主动式增量学习方法，二是基于动态用户建模的手绘复杂图形的识别方法。前者与传统的增量式学习方法相比，在识别精度相同的情况下所需的训练时间和训练数据集要少得多。后者则是基于笔划信息以及笔划间的顺序和空间关系信息，采用增量式决策树捕捉用户的输入习惯和过程信息。实验证明了本文方法在在线草图识别中的有效性和高效性。     

一个面向构思的手绘草图识别系统

手绘图形输入是用户设计意图的一种自然有效的表达方式。本文介绍了一个手绘图形识别系统-SketchEI。SketchEI由五个部分构成：用户交互、输入预处理、图形识别器、草图管理器以及用户适应性。SketchEI把它们有机地组合在一起并且给出了一个相对完整的手绘图形识别技术理论体系。     

支持方案设计的手绘图形输入工具

手绘图形输入是表达设计意图，实现抽象概念与具体图形间相互转换的自然而有效手段之一、提出并初步实现了一个面向方案设计、采用在线图形识别方法和相似性相关反馈技术的手绘图形输人工具．在线图形识别方法将用户输入的笔画经过图形预处理、特征识别、图形拟合和规整等过程，即时地识别和预测用户的基本图形构造意图；相似性相关反馈技术则在基本图形按其空间和时间关系组合后，利用图形构成及其空间关系与图形模板的相似性计算，及时地捕捉和反馈用户输入图形的组成意图．实验表明：该工具具有很好的基本图形识别效果和良好的用户交互特性，为方案设计工具的研究提供了新的思路．     

基于空间关系的手绘草图检索

手绘草图是人类最自然的人机交互方式,在普适计算模式下手绘草图将得到越来越多的应用,手绘草图的检索也成为一个新的课题。本文提出一种高效的草图检索方法,该方法以独立于用户绘制习惯的手绘草图统一表示为基础,以手绘草图空间关系为检索相似度匹配特征,并采用特征点调整的相关反馈机制优化检索结果。实验表明本文提出的方法具有很好的检索效果。     

基于自适应HMM的在线草图识别方法

用户适应性是在线手绘草图识别的一个关键问题。本文以实现草图识别的自适应性为目标,对草图识别中的用户适应性问题进行了深入的研究和实验,提出了一种自适应草图识别解决方法,并针对在线草图识别的特点,提出了一种基于笔划曲率,速率以及整体几何特性的组合特征。本文重点研究并实现了基于自适应HMM的草图识别,在已有HMM的基础上,针对在线草图识别的特点,提出了状态数可变自适应HMM的学习方法。实验表明本文所提出的方法具有很好的效果。     

在线手绘草图识别中的用户建模方法

提出了一种在线手绘草图识别的用户建模方法。该方法首先利用用户输入笔划的速率和曲率特性进行笔划特征点抽取和笔划分段,从而将用户的输入草图分解成基本图元表示;进而,利用决策树收集和记录用户输入草图的时序信息,实现对复杂手绘草图的用户建模和在线识别,并通过对用户输入模式使用频率的统计实现对用户模型的动态管理和更新。实验表明:该方法不仅能显著提高复杂图形的识别效率,而且具有在线训练能力。     

用RCR特征和NN识别实时手绘工程草图

针对实时手绘工程草图(简称手绘草图)的识别，引入草图重心、重径距和正规化重径(RCR)等图形特征概念，提出手绘草图的神经网识别方法．该方法以图素具有统计意义的正规化重径作为特征、以图素交叉方式组织正规化重径的值作为学习样本，应用弹力传播的Rprop算法训练BP神经网，一次训练即可得到能够识别任意倾角和位置手绘草图图素的识别器．从而达到了理想的识别效果．     

基于草图的人机交互技术研究进展

从草图识别和语义理解这两个方面对基于草图的人机交互技术的研究状况进行了分析和总结．对草图识别方法按其模式单元定义（笔划、图元、特征和组合图形）进行了分类和剖析;对草图语义理解所涉及的语义获取、语义解释和语义应用这三个关键问题及其解决方法进行了分析和阐述;并分别从基于草图的人机交互技术的几何模糊性、用户适应性和应用独旁性及其关系角度提出了这一领域的主要研究课题及其解决思路．     

A new query reweighting method for document retrieval based on genetic algorithms

In this paper, we present a new method for query reweighting to deal with document retrieval. The proposed method uses genetic algorithms to reweight a user's query vector, based on the user's relevance feedback, to improve the performance of document retrieval systems. It encodes a user's query vector into chromosomes and searches for the optimal weights of query terms for retrieving documents by genetic algorithms. After the best chromosome is found, the proposed method decodes the chromosome into the user's query vector for dealing with document retrieval. The proposed query reweighting method can find the best weights of query terms in the user's query vector, based on the user's relevance feedback. It can increase the precision rate and the recall rate of the document retrieval system for dealing with document retrieval.     

DeepSketch 3

Freehand sketches are a simple and powerful tool for communication. They are easily recognized across cultures and suitable for various applications. In this paper, we use deep convolutional neural networks (ConvNets), state-of-the-art in the field of sketch recognition, to address several applications of automatic sketch processing: complete and partial sketch recognition, sketch retrieval using query-by-example (QbE), and sketch-based image retrieval (SBIR) i.e the retrieval of images using a QbE paradigm but where the query is a sketch. We first focus on improving sketch recognition. For this purpose we compare different ConvNet architectures, training paradigms and data fusion schemes. This enabled us to outperform previous state-of-the-art in two large scale benchmarks for sketch classification. We achieved a mean average accuracy of 79.18% for the TU-Berlin sketch benchmark and 93.02% for the sketchy database. For partial sketch recognition, we were able to produce a system that achieves a mean average accuracy of 52.58% with only 40% of the strokes. We then conduct a comprehensive study of ConvNets features to enhance sketch retrieval and image retrieval, using a kNN similarity search paradigm in the ConvNet feature space. For the sketch retrieval tasks, we compare the performance obtained with features extracted from various depths (ConvNet layers) using one of the best performing model from the previous work. For the sketch-based image retrieval (SBIR), a sketch query is used to retrieve images of objects that belong to the same category, or even with a shape and pose close to the sketch query. The main challenge in the field of SBIR is to obtain efficient cross-domain features for sketch-image similarity measure. For this, besides comparing features extracted from different depth, we additionally compare different training approaches (some novel) for the ConvNets applied to sketches and images. Eventually, our best SBIR system achieves state-of-the-art results on the sketchy database (close to 40% recall at k = 1).

     

面向草图检索的相关反馈方法

引入基于有偏SVM的学习机制,提出了一种面向草图检索的相关反馈方法.该方法以草图的全局和结构内容表示与匹配为基础,采用基于有偏SVM学习机制实现相关反馈,可有效地捕捉用户的查询兴趣,改善检索性能.最后通过实例验证了该方法的有效性.     

Bayesian relevance feedback for content-based image retrieval

Despite the efforts to reduce the so-called semantic gap between the user's perception of image similarity and the feature-based representation of images, the interaction with the user remains fundamental to improve performances of content-based image retrieval systems. To this end, relevance feedback mechanisms are adopted to refine image-based queries by asking users to mark the set of images retrieved in a neighbourhood of the query as being relevant or not. In this paper, the Bayesian decision theory is used to estimate the boundary between relevant and non-relevant images. Then, a new query is computed whose neighbourhood is likely to fall in a region of the feature space containing relevant images. The performances of the proposed query shifting method have been compared with those of other relevance feedback mechanisms described in the literature. Reported results show the superiority of the proposed method.     

基于贝叶斯网络的在线草图识别算法

针对手绘草图识别算法大多采用限制用户绘制习惯来实现笔画分组的问题,提出一种基于贝叶斯网络的手绘草图识别算法。该算法将手绘草图识别中的笔画分组和符号识别统一为一个过程,用贝叶斯网络拓扑结构来表达草图结构信息。基于该网络,根据最大后验概率对连续输入的笔画进行动态最优分组,同时在线预测每组笔画的符号类别。实验结果表明,该方法是一种有效的在线递进式笔画分组和识别算法,在电路符号手绘识别中达到71.3%的过程识别率和85%的最终识别率。     

SVM-based active feedback in image retrieval using clustering and unlabeled data

In content-based image retrieval, relevance feedback is studied extensively to narrow the gap between low-level image feature and high-level semantic concept. However, most methods are challenged by small sample size problem since users are usually not so patient to label a large number of training instances in the relevance feedback round. In this paper, this problem is solved by two strategies: (1) designing a new active selection criterion to select images for user's feedback. It takes both the informative and the representative measures into consideration, thus the diversities between these images are increased while their informative powers are kept. With this new criterion, more information gain can be obtained from the feedback images; and (2) incorporating unlabeled images within the co-training framework. Unlabeled data partially alleviates the training data scarcity problem, thus improves the efficiency of support vector machine (SVM) active learning. Systematic experimental results verify the superiority of our method over existing active learning methods.