结合对象分割的运动行人检测

目标检测大量应用于监控系统的行人检测以及人脸识别,是当前深度学习的研究热点.监督学习利用人工标注大量数据集训练出针对特定场景的行人检测器.但是人工标注方法费时费力,本文针对监督学习需要人工标注数据集的缺点,研究了一种半自动标注行人的方法.针对静止的单目摄像机拍摄的监控视频,利用光流信息提供的初始前景可能性,以及跨越时间的视觉相似性来迭代地更新初始的前景可能性,分割出运动的行人,根据分割的前景对象,提出了一种半自动标注行人的方法.实验结果显示,本文的方法可以为行人检测系统提供大量数据集,且效率上明显优于传统人工标注的方法.     

基于场景模型与统计学习的鲁棒行人检测算法

提出一种基于场景模型和统计学习的行人检测算法. 针对训练行人检测器时面临的动态场景的复杂性和行人样本多样性等问题, 通过背景建模, 从场景的背景图像上提取有限的负样本用于训练, 大幅度提高了分类器的检测率, 同时降低了虚警; 提出一种快速弱分类器选择算法, 根据正、负样本特征大小的分布和期望的检测率, 直接求解特征大小的阈值范围, 能够满足在线训练和更新检测器的要求; 提出一种基于正样本错误率的训练算法, 先根据正样本加权错误率选择弱分类器, 快速提高检测率, 在训练结束后调整最终分类器的加权系数, 在保证检测率的同时尽可能降低虚警率. 实验中构建了一个试验视频数据库和行人样本库, 数据库包括雨、雪、阴影、季节变化、摄像机平移、旋转、缩放等情况, 并设计实现了一个实时行人检测系统BMAT (Background modeling and Adaboost training), 实验结果证明了算法的有效性.     

基于马赛克自编码器的多场景行人检测优化方法

现阶段多场景下的行人检测模型存在的主要问题在于训练数据样本多样性不足，在开放的测试环境下效果较差，不同场景之间存在数据鸿沟。针对上述问题，提出了一种基于马赛克自编码器（MAE）的多场景行人检测优化方法。首先，采用随机生成方法对原始训练数据进行自动扩充；然后，围绕数据、模型和结果等重要影响因素，分别对检测模型训练前中后三个阶段进行优化；最后，实现从通用大模型到专用小任务的自适应迁移。实验结果表明，在不增加额外标注数据的情况下，在多个公开数据集之间进行场景迁移，以常用的Caltech Pedestrian作为目标数据集，与当前最优结果 Pedestron方法对比，在Reasonable、Small和Heavy子数据集上的每张图片误检率（FPPI）分别下降0.4个百分点、0.7个百分点和2.6个百分点，从而验证了模型泛化性的显著提升；另一方面，针对实际应用构建多场景行人检测数据集，验证集的平均准确率（AP）提升1.9个百分点，进一步验证MAE生成数据对模型准确性的提升作用。     

基于HOG和Haar特征的行人追踪算法研究

行人在真实场景的检测和追踪是多目标检测和追踪研究中的一个重要问题,尤其是在真实的三维场景中的多行人之间的遮挡、拥挤以及背景的变化对多目标检测和追踪研究造成了严重的挑战。在多目标检测中利用了Haar特征、HOG特征,在行人正面向相机运动时,采用Haar特征检测器检测人脸,并结合Haar运动模型完成行人的检测,当行人侧向运动时,采用HOG特征,利用层次-部分模型进行行人的检测和追踪,在完成行人的检测之后,利用最大权重独立集合算法完成帧间目标的关联。通过对 ETH、TUD以及本地样本库的检测和追踪结果表明,采用Haar特征和HOG特征的检测算法对于行人的正面和侧面都具有较高的检测准确率、精确度。     

深度学习行人检测方法综述

行人检测技术在智能交通系统、智能安防监控和智能机器人等领域均表现出了极高的应用价值,已经成为计算机视觉领域的重要研究方向之一。得益于深度学习的飞速发展,基于深度卷积神经网络的通用目标检测模型不断拓展应用到行人检测领域,并取得了良好的性能。但是由于行人目标内在的特殊性和复杂性,特别是考虑到复杂场景下的行人遮挡和尺度变化等问题,基于深度学习的行人检测方法也面临着精度及效率的严峻挑战。本文针对上述问题,以基于深度学习的行人检测技术为研究对象,在充分调研文献的基础上,分别从基于锚点框、基于无锚点框以及通用技术改进（例如损失函数改进、非极大值抑制方法等）3个角度,对行人检测算法进行详细划分,并针对性地选取具有代表性的方法进行详细结合和对比分析。本文总结了当前行人检测领域的通用数据集,从数据构成角度分析各数据集应用场景。同时讨论了各类算法在不同数据集上的性能表现,对比分析各算法在不同数据集中的优劣。最后,对行人检测中待解决的问题与未来的研究方法做出预测和展望。如何缓解遮挡导致的特征缺失问题、如何应对单一视角下尺度变化问题、如何提高检测器效率以及如何有效利用多模态信息提高行人检测精度,均是值得进一步研究的方向。     

基于广义霍夫变换的室外场景行人检测研究

提出一种基于广义霍夫变换的室外场景行人检测方法.首先从少量标注图片中随机地提取行人图像碎片构造碎片字典,然后使用图像碎片对每一幅训练图片计算特征向量.为了能够在静态图片中快速地检测行人,使用Gentleboost算法训练检测器,在每一次迭代时学习一个决策树桩弱分类器,该弱分类器可以从高维特征向量中选择一个当前区分度最好的碎片特征.在运行检测器时,所有的弱分类器在测试图片中对于行人的可能出现位置进行投票.最后,将各个弱分类器的投票结果进行叠加,并用设定的检测阈值剔除得分较低的检测结果后得到检测输出.在LabelMe数据集上的实验表明,该方法可以快速地在静态图片中检测出行人,需要较少的训练数据且有效地解决了部分遮挡问题.     

小样本学习研究综述

小样本学习旨在通过少量样本学习到解决问题的模型.近年来在大数据训练模型的趋势下,机器学习和深度学习在许多领域中取得了成功.但是在现实世界中的很多应用场景中,样本量很少或者标注样本很少,而对大量无标签样本进行标注工作将会耗费很大的人力.所以,如何用少量样本进行学习就成为了目前人们需要关注的问题.本文系统梳理了当前小样本学习的相关工作,具体介绍了基于模型微调、基于数据增强和基于迁移学习三大类小样本学习模型与算法的研究进展;本文将基于数据增强的方法细分为基于无标签数据、基于数据合成和基于特征增强三类,将基于迁移学习的方法细分为基于度量学习、基于元学习和基于图神经网络三类.本文还总结了目前常用的小样本数据集,以及代表性的小样本学习模型在这些数据集上的实验结果,随后对小样本学习的现状和挑战进行了概述,最后展望了小样本学习的未来发展方向.     

小样本图像目标检测研究综述

近年来,以深度学习为基础的图像目标检测技术取得了显著成就,并涌现了许多成熟的检测模型,但这些模型均需要利用大量的标注样本进行训练,而在实际场景当中,往往很难获取到相应规模的高质量标注样本,从而限制了其在特定领域的应用和推广。由于对样本数量的依赖性小,小样本条件下的图像目标检测技术逐渐得到研究和发展。基于小样本图像目标检测当前的研究现状,系统阐述了主流的小样本图像目标检测的问题定义、当前主要方法及实验设计,并指出其潜在应用方向,在此基础上,简要介绍了与之相关的广义小样本目标检测,最后分析了小样本图像目标检测技术面临的挑战并探讨了应对方案。     

工控网络异常检测中基于灵敏度的动态迁移算法

随着工控网络信息化程度的不断提高，工控网络逐渐变得更加开放，一方面给工业生产提供了便捷，但另一方面也带来了安全隐患。工控网络作为重要的基础设施，一旦受到攻击将产生严重损害。近年来不少学者使用网络异常检测技术来发现工控网络中潜在的安全隐患，取得不错的成果。然而工控网络中的数据往往缺少标注，这限制了传统监督学习类算法在工控网络安全领域的应用。基于非监督学习的算法可以在缺少标注的场景下实现异常检测，但是往往存在算法性能较差的问题，而迁移学习类算法可以通过在源域上学习后迁移到只有少量标注的目标域实现在少标注情况下的较高性能。为了进一步提高在缺少标注的工控网络中进行异常检测的性能，本文提出一种工控网络异常检测中基于灵敏度的动态迁移算法。首先该算法基于迁移学习的思想，在有标注的源域中进行训练后迁移到缺乏标注的目标域，可以在缺少标注的工控网络环境下进行异常检测。其次得益于门控循环单元的记忆效应，该算法可以有效利用工控网络数据内在的时序关联性，进一步提高算法异常检测的能力。同时该算法中的基于参数灵敏度因子对参数进行动态迁移的方法，改进了传统迁移学习微调方法对源域和目标域数据底层特征学习不均衡的不足。在...     

基于支持对挖掘的主动学习行人再识别

基于监督学习的行人再识别方法需要大量人工标注的数据,对于实际应用并不适用。为了降低大规模行人再识别的标注成本,提出了一种基于支持对挖掘主动学习(support pair active learning, SPAL)的行人再识别方法。具体地,建立了一种无监督主动学习框架,在该框架中设计了一种双重不确定性选择策略迭代地挖掘支持样本对并提供给标注者标注;其次引入了一种约束聚类算法,将有标签的支持样本对的关系传播到其他无标签的样本中;最后提出了一种由无监督对比损失和监督支持样本对损失组成的混合学习策略来学习具有判别性的特征表示。在大规模行人再识别数据集MSMT17上,该方法相比于当前最先进的方法,标注成本降低了64.0%,同时mAP和rank1分别提升了11.0%和14.9%。大量实验结果表明,该方法有效地降低了标注成本并且优于目前最先进的无监督主动学习行人再识别方法。     

Fusion of multispectral data through illumination-aware deep neural networks for pedestrian detection

Multispectral pedestrian detection has received extensive attention in recent years as a promising solution to facilitate robust human target detection for around-the-clock applications (e.g., security surveillance and autonomous driving). In this paper, we demonstrate illumination information encoded in multispectral images can be utilized to boost the performance of pedestrian detection significantly. A novel illumination-aware weighting mechanism is present to depict illumination condition of a scene accurately. Such illumination information is incorporated into two-stream deep convolutional neural networks to learn multispectral human-related features under different illumination conditions (daytime and nighttime). Moreover, we utilized illumination information together with multispectral data to generate more accurate semantic segmentation which is used to supervise the training of pedestrian detector. Putting all of the pieces together, we present an effective framework for multispectral pedestrian detection based on multi-task learning of illumination-aware pedestrian detection and semantic segmentation. Our proposed method is trained end-to-end using a well-designed multi-task loss function and outperforms state-of-the-art approaches on KAIST multispectral pedestrian dataset.     

A novel small-scale pedestrian detection method base on residual block group of CenterNet

Pedestrian detection is widely used in intelligent supervision and assisted driving. With the development of deep learning, the accuracy of pedestrian detection has been greatly improved. In actual scenes, there are often pedestrians who are far away from the camera. Such pedestrians usually have small image sizes, while existing algorithms still have defects such as missed detection for similar small-scale pedestrian detection, which will reduce the accuracy of operation. Therefore, this paper designs a Three ResNet Blocks based on CenterNet detection model. Aiming at the limited ability of a single feature extraction block to extract semantic information at different levels in the network, this paper proposes Three ResNet Blocks, which is a simple and effective multi-block group. This block group integrates three different basic blocks, each of which extracts pedestrian information separately to enhance information flow in the network structure and make detection results more accurate. In addition, combined with the advantages of activation function in the model expression, the relu6 activation function is introduced to improve the performance of the detector by preventing numerical explosion being sensitive to decimal. Comprehensive experiments on pedestrian detection datasets (Caltech and ETH) show that the proposed method exhibits excellent accuracy and detection speed, especially for small-scale pedestrian detection.     

Transferred IR pedestrian detector toward distinct scenarios adaptation

The presence of inevitable disparity in distributions between the training data and test data is one of the main reasons that result in downgraded performance for infrared (IR) pedestrian detection across distinct scenarios, and it is expensive and sometimes difficult to label sufficient new training data from target scenarios to re-train a scene-specific detector. In this paper, a novel boosting-style method for data-level transfer learning termed DTLBoost is proposed. Specifically, sample importance measurement is first presented to evaluate the similarities between the samples across distinct scenarios using k-nearest neighbors-based model. Then the most informative samples from former scenarios are selected to extend the training data and help to build a base learner iteratively. In addition, degree of classification disagreement among base learners is formulated and incorporated into the weight updating rules of training samples, which helps to select the samples from former scenarios with positive transferability and encourage different base learners to learn different parts or aspects of samples from target scenarios. The proposed method has been evaluated on two types of IR pedestrian detection applications, including pedestrian detection for both driving assistance systems and video surveillance. Experimental results demonstrate that the proposed method achieves promising improvement on detection performance toward both new scenes and viewpoints adaptation.     

Scene-specific pedestrian detection based on transfer learning and saliency detection for video surveillance

Pedestrian detection is a fundamental problem in video surveillance and has achieved great progress in recent years. However the performance of a generic pedestrian detector trained on some public datasets drops significantly when it is applied to some specific scenes due to the difference between source training samples and pedestrian samples in target scenes. We propose a novel transfer learning framework, which automatically transfers a generic detector to a scene-specific pedestrian detector without manually labeling training samples from target scenes. In our method, we get initial detected results and several cues are used to filter target templates whose labels we are sure about from the initial detected results. Gaussian mixture model (GMM) is used to get the motion areas in each video frame and some other target samples. The relevancy between target samples and target templates and the relevancy between source samples and target templates are estimated by sparse coding and later used to calculate the weights for source samples and target samples. Saliency detection is an essential work before the relevancy computing between source samples and target templates for eliminating interference of non-salient region. We demonstrate the effectiveness of our scene-specific detector on a public dataset, and compare with the generic detector. Detection rates improves significantly, and also it is comparable with the detector trained by a lot of manually labeled samples from the target scene.     

基于深度学习的行人轨迹预测方法综述

为了规划合理的路径以规避行人,针对行人轨迹预测的研究具有广泛的应用价值.基于手工特征的传统方法难以预测复杂场景下的行人轨迹.深度学习以人工神经网络为架构,具有强大的学习能力,在各个领域取得了显著的效果.基于深度学习的行人轨迹预测方法已逐渐发展为一种趋势.为了宏观把握基于深度学习的行人轨迹预测的研究状况,首先,对不同方法进行组织与分类,比较不同方法的优缺点,讨论不同方法在行人轨迹预测领域的应用与发展;其次,根据行人轨迹预测模型的设计差异,对比不同算法对模型性能产生的影响;最后,针对行人轨迹预测中存在的问题,对基于深度学习的行人轨迹预测方法的未来发展进行了展望.     

一种基于三角特征的行人检测算法

基于视频的行人检测技术是计算机视觉领域的重要问题,特征提取是行人检测技术的关键,大量的特征提取方法是基于Papageorgiou提出的矩形特征,但对于行人的边缘特性描述并不准确。针对adaboost算法,分析行人姿态的边缘特性,提出了四种较为有效的三角特征描述人体的外形局部特征,并推导了三角特征计算量与计算耗时的关系。与传统的矩形特征、非对称特征相比,三角特征能更有效的描述行人姿态,提高了行人检测的鲁棒性。     

Pedestrian detection based on sparse coding and transfer learning

Pedestrian detection is a fundamental problem in video surveillance and has achieved great progress in recent years. However, training a generic detector performing well in a great variety of scenes has proved to be very difficult. On the other hand, exhausting manual labeling efforts for each specific scene to achieve high accuracy of detection is not acceptable especially for video surveillance applications. To alleviate the manual labeling efforts without scarifying accuracy of detection, we propose a transfer learning framework based on sparse coding for pedestrian detection. In our method, generic detector is used to get the initial target samples, and then several filters are used to select a small part of samples (called as target templates) from the initial target samples which we are very sure about their labels and confidence values. The relevancy between source samples and target templates and the relevancy between target samples and target templates are estimated by sparse coding and later used to calculate the weights for source samples and target samples. By adding the sparse coding-based weights to all these samples during re-training process, we can not only exclude outliers in the source samples, but also tackle the drift problem in the target samples, and thus get a well scene-specific pedestrian detector. Our experiments on two public datasets show that our trained scene-specific pedestrian detector performs well and is comparable with the detector trained on a large number of training samples manually labeled from the target scene.     

基于改进WLD描述子的行人检测方法研究

近年来,行人检测研究受到越来越多的关注。提出一种使用改进的Weber局部描述子（IWLD）实现行人检测的方法,该方法有效地吸取HOG和Weber局部描述子方法的优势。将提出的IWLD用来刻画滑动窗口,从而实现行人检测。在INRIA行人数据库上的实验结果验证提出的IWLD检测子的有效性,与传统的行人检测方法（HOG和HOG—LBP）比较,该方法更优。     

基于HOG特征的行人视觉检测方法

行人检测是近年来计算机视觉领域中备受关注的前沿方向和研究热点.以单目视觉传感器作为外界环境信息获取的主要手段,建立了一个包含行人分割、识别的检测系统.根据行人特有的一些特征,提出了基于垂直边缘和边缘对称性的行人分割方法,并进行精确定位.在行人识别阶段利用HOG特征进行特征提取,然后利用线性支持向量机进行行人识别.对大量...