Vision-based vehicles in Japan: machine vision systems and drivingcontrol systems

This paper surveys three intelligent vehicles developed in Japan, and in particular the configurations, the machine vision systems, and the driving control systems. The first one is the Intelligent Vehicle, developed since the mid 1970's, which has a machine vision system for obstacle detection and a dead reckoning system for autonomous navigation on a compact car. The machine vision system with stereo TV cameras is featured by real time processing using hard-wired logic. The dead reckoning function and a new lateral control algorithm enable the vehicle to drive from a starting point to a goal. It drove autonomously at about 10 km/h while avoiding an obstacle. The second one is the Personal Vehicle System (PVS), developed in the late 1980's, which is a comprehensive test system for a vision-based vehicle. The machine vision system captures lane markings at both road edges along which the vehicle is guided. The PVS has another machine vision system for obstacle detection with stereo cameras. The PVS drove at 10-30 km/h along lanes with turnings and crossings. The third one is the Automated Highway Vehicle System (AHVS) with a single TV camera for lane-keeping by PD control. The machine vision system uses an edge extraction algorithm to detect lane markings. The AHVS drove at 50 km/h along a lane with a large curvature     

Moment-based multi-lane detection and tracking

Lane-detection methods are still facing robustness issues when confronted with challenging road surfaces, road markings and illumination conditions. Such combined challenges occur infrequently but are crucial for driving safety. Although advanced learning-based methods (using deep learning) demonstrate an impressive performance, they rely on plenty of training images for varying scenes and their performance is limited for scenes not covered by the training data. Also, multi-lane detection is indispensable for determining the exact position of both ego-car and surrounding vehicles as well as lane changing behavior on the road. In this paper we propose a new multi-lane detection algorithm, detecting all visible lane boundaries in front of the ego-car. In contrast to the Hough transforms often used for lane boundaries detection, our approach uses moments to calculate the deflection angles and the centroids of lane segments, achieving more precise lane boundaries. We propose a novel algorithm based on moments and Kalman filtering to achieve lane tracking. State-of-the-art neural-network-based methods are compared with the proposed method concretely. Experimental results show that our method outperforms other (recently published) multi-lane detection algorithms regarding detection rate as well as accuracy.     

基于车底阴影的车前障碍物检测

基于计算机视觉的道路车辆检测是智能车辆导航的核心问题,实时准确地检测前方运动车辆的位置信息是车辆安全驾驶的前提。文中采用车底阴影的前方运动车辆检测算法,在基于车道线检测的基础上,通过车底阴影检测,实时准确地检测前方车辆。该算法通过使用Otsu阈值分割提取出车道线,生成AOI区域,再进行两次自适应阈值分割提取车底与路面的交线,从而检测出前方运动车辆。经过在高速公路上对运动车辆检测实验证明,该算法基本满足车辆安全驾驶的需求,并能准确实时地检测出前方运动车辆,进而减少了交通事故的发生。     

基于LDA与混沌粒子群算法的车道线识别方法研究

与传统的车道线检测算法不同,本文采用LDA算法对道路图像进行针对性灰度化处理。加大车道线与道路的差异,然后使用抛物线模型对车道线进行拟合,采用混沌粒子群算法对抛物线参数进行优化,以车道线的灰度特征和梯度特征作为混沌粒子群的适应度函数,经过多次的迭代得到抛物线拟合车道线的参数最优值,进而识别出车道线。实验结果表明,本文算法能在复杂环境下识别出车道线,对视频帧序列中的车道线连续追踪具有良好效果。     

结构化道路车道线的鲁棒检测与跟踪

针对智能车在视觉导航过程中车道线检测的鲁棒性和实时性问题,提出一种适用于结构化道路的车道线鲁棒检测与跟踪方法。首先,简化的Sobel算子提取车道线边缘图像,将边缘图像与改进的Otsu方法得到的车道线分割图像进行融合,实现对车道线标记点的鲁棒检测;然后,采用迭代最小二乘方法拟合车道线标记点并去除干扰点,并根据拟合参数建立车道线模型;最后,引入尺度无迹卡尔曼滤波(SUKF)对车道线进行跟踪。通过对多段实地采集的视频进行了仿真实验,结果表明,该方法对于高速公路车道线的检测率可达到99%,并具有较好实时性能;对于受损和弄污的城市道路车道线也体现出较好的鲁棒性和时间性能。     

IMMPDAF Approach for Road-Boundary Tracking

Robust road-boundary extraction/tracking is one of the main problems in autonomous roadway navigation. Although the road boundary can be defined by various means including lane markings, curbs, and borders of vegetation, this paper focuses on road-boundary tracking using curbs. A vehicle-mounted (downward tilted) 2-D laser-measurement system is utilized to detect the curbs. The tracking problem is difficult because both the vehicle is moving and the target is disappearing, reappearing, and maneuvering in clutter. The interacting-multiple-model probabilistic-data-association filter (IMMPDAF) is proposed to solve the problems after detailed analysis. Track initiation, confirmation, and deletion are performed using the sequential-probability-ratio test. Extensive simulations followed by experiments in a campus environment show that the road-boundary tracking utilizing curbs is possible and robust through IMMPDAF     

基于MATLAB的高速公路车辆违章占道分析及预警系统

系统通过MATLAB的图像处理功能对摄像头拍摄的视频图像进行处理,采用基于面积检测的背景差分法识别车辆位置,运用霍夫变化和卡尔曼滤波处理得到图像中路段的车道线,进而判断车辆所处车道.运用帧间差分法准确测出车辆速度,结合高速公路行车规定,即可判断出车辆是否处于违规占道行驶状态.系统可以识别违规车辆的车牌号,结合设定的LE...     

道路检测算法及其DSP实时实现

基于智能车视觉导航系统平台，在TMS320C6201定点数字信号处理器上实现了一种基于HSV色彩空间的道路检测算法。该算法能够从道路图像序列中成功地提取黄色和白色标志线，达到每秒14帧的处理速度。同时，本文深入探讨了TMSC6000DSP上的实时视频处理技术，如软件流水线以及其它一些DSP编程实现的问题。     

Structure-prior deep neural network for lane detection

Lane detection is an important task of road environment perception for autonomous driving. Deep learning methods based on semantic segmentation have been successfully applied to lane detection, but they require considerable computational cost for high complexity. The lane detection is treated as a particular semantic segmentation task due to the prior structural information of lane markings which have long continuous shape. Most traditional CNN are designed for the representation learning of semantic information, while this prior structural information is not fully exploited. In this paper, we propose a recurrent slice convolution module (called RSCM) to exploit the prior structural information of lane markings. The proposed RSCM is a special recurrent network structure with several slice convolution units (called SCU). The RSCM could obtain stronger semantic representation through the propagation of the prior structural information in SCU. Furthermore, we design a distance loss in consideration of the prior structure of lane markings. The lane detection network can be trained more steadily via the overall loss function formed by combining segmentation loss with the distance loss. The experimental results show the effectiveness of our method. We achieve excellent computation efficiency while keeping decent detection quality on lane detection benchmarks and the computational cost of our method is much lower than the state-of-the-art methods.     

单目智能车道偏离预警系统

车道偏离预警系统是继安全气囊之后的汽车安全辅助系统,该系统主要任务是采用基于机器视觉的方法提取车道线并进行预警决策。文章利用TMS320DM642视频处理器作为中央处理器,设计出基于DM642的车道偏离预警系统硬件架构,算法方面对图像进行灰度化、二值化和边缘提取做预处理,然后设置感兴趣区域(ROI),利用基于相位编组的改进Hough变换(RHT)进行车道线检测,根据车道偏离预警条件进行预警决策,当车辆在驾驶员非意识时偏离车道线的情况下实施报警。试验结果证明,本系统能够提前2.5s进行车道偏离的预警工作,并能够排除路面标记的影响,满足车道偏离预警系统实时、鲁棒的性能要求。     

Quality-guided lane detection by deeply modeling sophisticated traffic context

Lane detection is a useful technique in modern autonomous vehicles systems, which assists vehicle to accurately localize itself according to detected road lines. Traditional methods leveraged edge detection and Hough transform based algorithms to plot lines along the detected lane. Noticeably, they did not take the informative feature road gradient into account. In addition, most previous deep learning-based algorithms consider lane detection as pixel-wise lane segmentation, where only fixed number of lanes can be detected. In order to solve these limitations, we propose a quality guided lane detection algorithm by modeling the sophisticated traffic context, where variable number of lanes can be satisfactorily handled. Specifically, we first leverage chessboard images for camera calibration to calculate correspondence between real world and image coordinate system. Subsequently, we capture image regions of interest that only contains lane information by leveraging the prior knowledge and image quality scores. Afterwards, we design an end-to-end two-stage CNN architecture for lane detection, where binary lane mask is utilized for lane matching. Comprehensive experiments have demonstrated that our proposed method can cope with variable number of lanes effectively.     

基于RGB彩色通道的结构化道路车道线检测

车道线检测是车辆智能辅助系统的重要组成部分,为提高检测准确性,文中采用一种基于RGB颜色特征的车道线检测方法。根据车道线颜色特征设计转移函数标记图像中的车道线区域,并应用基于形态学的边缘检测算法提取车道线边缘,最终检测出车道线。文中算法原理简单,在车道线边缘识别上,具有较高的准确度,对自动车辆车道线检测有一定的意义。     

基于视觉的车道状态估计

车道状态估计是车辆辅助驾驶系统的关键功能。本文提出了一种基于教育处机视觉的车道状态估计新方法。提出了车道标线在图像平面中的一种描述,讨论了其性质,并应用于车道的检测。利用真实世界中车辆在二维图像平面中的透视特征,提出了基于二值有序变换（BROT）的障碍物检测新方法。由于采用单目视觉方法检测前方车辆以控制车辆的横向偏离和纵向间距,降低了系统的复杂度,实验结果显示了新方法的有效性。     

Vehicle counting based on double virtual lines

Traditionally, magnetic loop detectors are often used to count vehicles passing over them in intelligent transportation system. Real-time image sequences are captured by video surveillance system. Virtual loop, which emulates the functionality of inductive loop detectors, is placed on images. It is more convenient, but it occurs in false detection and discrimination when vehicles are lane departure due to overtaking or crossing. This paper presents an effective approach for vehicle counting based on double virtual lines (DVL). Double virtual lines are assigned on images, which are across bidirectional multi-lane. The region between DVL is the detection zone, rather than virtual loop zone in each lane, so as to reduce the proportion of false detection and misjudgment from lane departure for vehicles. Then, in the detection zone, the dual-template convolution is designed to detect and locate moving vehicles to eliminate the mapping of one to many, many to one. The effective rules are given in terms of the constraint of the horizontal and vertical distances to improve the accuracy of vehicle counting. Experimental comparisons with the other method demonstrate the performance of the proposed method.     

Parking Space Recognition for Autonomous Valet Parking Using Height and Salient‐Line Probability Maps

An autonomous valet parking (AVP) system is designed to locate a vacant parking space and park the vehicle in which it resides on behalf of the driver, once the driver has left the vehicle. In addition, the AVP is able to direct the vehicle to a location desired by the driver when requested. In this paper, for an AVP system, we introduce technology to recognize a parking space using image sensors. The proposed technology is mainly divided into three parts. First, spatial analysis is carried out using a height map that is based on dense motion stereo. Second, modelling of road markings is conducted using a probability map with a new salient‐line feature extractor. Finally, parking space recognition is based on a Bayesian classifier. The experimental results show an execution time of up to 10 ms and a recognition rate of over 99%. Also, the performance and properties of the proposed technology were evaluated with a variety of data. Our algorithms, which are part of the proposed technology, are expected to apply to various research areas regarding autonomous vehicles, such as map generation, road marking recognition, localization, and environment recognition.     

基于扩展卡尔曼滤波器的车道线检测算法

提出一种将道路结构模型信息与扩展卡尔曼滤波器(EKF,extended Kalman filter)相结合的车道线检测算法。基于扫描线的自适应边缘检测算子进行边缘点的检测,针对车道模型建立了适合算法的自定义参数空间,进行边缘点的投票,提取出候选车道线,解决了传统Hough变换中处理速度慢的问题。根据道路几何学和车辆动力学建立新的车道模型,增加了车道信息待估计的参数,并利用车道线的特征约束排除干扰线得到车道线的内边界,结合EKF对车道线边界点坐标参数进行跟踪估计,以保证算法的稳定性与鲁棒性。实验结果表明,本文算法能够处理绝大多数的复杂车道情况,在实时性、鲁棒性和检测率上都取得很好的效果。     

利用卷积神经网络的车道线检测方法

车道线检测是自动或智能辅助驾驶的核心问题之一。本文主要研究单目视觉下车道线检测算法。车道线具有多样性,其存在的环境又具有复杂性,因此准确高效车道线检测是一个具有挑战性的问题。本文提出了一种新的车道线检测算法,在传统车道检测方法中引入深度学习模型,主要包括下了步骤:首先使用基于车道线先验特征的图像增强算法进行边缘增强,对于边缘增强后的图像采用线段检测器进行线段提取,然后利用卷积神经网络构造线段分类器排除线段噪声,最后通过对消失点聚类排除无关线段,并按斜率聚类产生主车道线。实验表明,本文实现的算法具备较强的鲁棒性和很高的检测准确度。      

Vehicle detection by means of stereo vision-based obstacles features extraction and monocular pattern analysis.

This paper presents a stereo vision system for the detection and distance computation of a preceding vehicle. It is divided in two major steps. Initially, a stereo vision-based algorithm is used to extract relevant three-dimensional (3-D) features in the scene, these features are investigated further in order to select the ones that belong to vertical objects only and not to the road or background. These 3-D vertical features are then used as a starting point for preceding vehicle detection; by using a symmetry operator, a match against a simplified model of a rear vehicle's shape is performed using a monocular vision-based approach that allows the identification of a preceding vehicle. In addition, using the 3-D information previously extracted, an accurate distance computation is performed.     

一种新型多车道车流量检测算法

为了实时有效地检测道路路口车流量信息,并为交通控制和管理提供准确的交通流数据,提出了一种新型的车流量检测算法。通过利用现有的路面标记进行图像对称分割并计算图像灰度值方差,来判断有无车辆通过,进而实现车流量计算。仿真结果表明,该算法不仅简单,易于实现,而且检测准确率高,实时性好,能够有效地为智能交通灯控制提供信息数据。     

单目视觉下结构化车道实时检测

车道检测是高级驾驶员辅助系统的重要组成部分。本文对视频进行实时处理，实现对结构化车道线的实时检测。首先使用行方向的Sobel算子对处理区域进行边缘增强，接着在处理后的区域使用LSD(Line Segment Detector)进行线段提取，提取的线段集合包含代表车道线的线段。最后通过线段倾角以及相对位置过滤线段集合，并结合线段稳定帧数来筛选出最佳候选车道线。