Object Detection Using LiDAR and Camera Fusion in Off-road Conditions

Seoses hüppelise huvi kasvuga autonoomsete sõidukite vastu viimastel aastatel on suurenenud ka vajadus täpsemate ja töökindlamate objektituvastuse meetodite järele. Kuigi tänu konvolutsioonilistele närvivõrkudele on palju edu saavutatud 2D objektituvastuses, siis võrreldavate tulemuste saavutamine 3D maailmas on seni jäänud unistuseks. Põhjuseks on mitmesugused probleemid eri modaalsusega sensorite andmevoogude ühitamisel, samuti on 3D maailmas märgendatud andmestike loomine aeganõudvam ja kallim. Sõltumata sellest, kas kasutame objektide kauguse hindamiseks stereo kaamerat või lidarit, kaasnevad andmevoogude ühitamisega ajastusprobleemid, mis raskendavad selliste lahenduste kasutamist reaalajas. Lisaks on enamus olemasolevaid lahendusi eelkõige välja töötatud ja testitud linnakeskkonnas liikumiseks.Töös pakutakse välja meetod 3D objektituvastuseks, mis põhineb 2D objektituvastuse tulemuste (objekte ümbritsevad kastid või segmenteerimise maskid) projitseerimisel 3D punktipilve ning saadud punktipilve filtreerimisel klasterdamismeetoditega. Tulemusi võrreldakse lihtsa termokaamera piltide filtreerimisel põhineva lahendusega. Täiendavalt viiakse läbi põhjalikud eksperimendid parimate algoritmi parameetrite leidmiseks objektituvastuseks maastikul, saavutamaks suurimat võimalikku täpsust reaalajas.Since the boom in the industry of autonomous vehicles, the need for preciseenvironment perception and robust object detection methods has grown. While we are making progress with state-of-the-art in 2D object detection with approaches such as convolutional neural networks, the challenge remains in efficiently achieving the same level of performance in 3D. The reasons for this include limitations of fusing multi-modal data and the cost of labelling different modalities for training such networks. Whether we use a stereo camera to perceive scene’s ranging information or use time of flight ranging sensors such as LiDAR, ​ the existing pipelines for object detection in point clouds have certain bottlenecks and latency issues which tend to affect the accuracy of detection in real time speed. Moreover, ​ these existing methods are primarily implemented and tested over urban cityscapes.This thesis presents a fusion based approach for detecting objects in 3D by projecting the proposed 2D regions of interest (object’s bounding boxes) or masks (semantically segmented images) to point clouds and applies outlier filtering techniques to filter out target object points in projected regions of interest. Additionally, we compare it with human detection using thermal image thresholding and filtering. Lastly, we performed rigorous benchmarks over the off-road environments to identify potential bottlenecks and to find a combination of pipeline parameters that can maximize the accuracy and performance of real-time object detection in 3D point clouds

Human Motion Trajectory Prediction: A Survey

With growing numbers of intelligent autonomous systems in human environments, the ability of such systems to perceive, understand and anticipate human behavior becomes increasingly important. Specifically, predicting future positions of dynamic agents and planning considering such predictions are key tasks for self-driving vehicles, service robots and advanced surveillance systems. This paper provides a survey of human motion trajectory prediction. We review, analyze and structure a large selection of work from different communities and propose a taxonomy that categorizes existing methods based on the motion modeling approach and level of contextual information used. We provide an overview of the existing datasets and performance metrics. We discuss limitations of the state of the art and outline directions for further research.Comment: Submitted to the International Journal of Robotics Research (IJRR), 37 page

Lidar-based Obstacle Detection and Recognition for Autonomous Agricultural Vehicles

Today, agricultural vehicles are available that can drive autonomously and follow exact route plans more precisely than human operators. Combined with advancements in precision agriculture, autonomous agricultural robots can reduce manual labor, improve workflow, and optimize yield. However, as of today, human operators are still required for monitoring the environment and acting upon potential obstacles in front of the vehicle. To eliminate this need, safety must be ensured by accurate and reliable obstacle detection and avoidance systems.In this thesis, lidar-based obstacle detection and recognition in agricultural environments has been investigated. A rotating multi-beam lidar generating 3D point clouds was used for point-wise classification of agricultural scenes, while multi-modal fusion with cameras and radar was used to increase performance and robustness. Two research perception platforms were presented and used for data acquisition. The proposed methods were all evaluated on recorded datasets that represented a wide range of realistic agricultural environments and included both static and dynamic obstacles.For 3D point cloud classification, two methods were proposed for handling density variations during feature extraction. One method outperformed a frequently used generic 3D feature descriptor, whereas the other method showed promising preliminary results using deep learning on 2D range images. For multi-modal fusion, four methods were proposed for combining lidar with color camera, thermal camera, and radar. Gradual improvements in classification accuracy were seen, as spatial, temporal, and multi-modal relationships were introduced in the models. Finally, occupancy grid mapping was used to fuse and map detections globally, and runtime obstacle detection was applied on mapped detections along the vehicle path, thus simulating an actual traversal.The proposed methods serve as a first step towards full autonomy for agricultural vehicles. The study has thus shown that recent advancements in autonomous driving can be transferred to the agricultural domain, when accurate distinctions are made between obstacles and processable vegetation. Future research in the domain has further been facilitated with the release of the multi-modal obstacle dataset, FieldSAFE

Intelligent Multi-Modal Sensing-Communication Integration: Synesthesia of Machines

In the era of sixth-generation (6G) wireless communications, integrated sensing and communications (ISAC) is recognized as a promising solution to upgrade the physical system by endowing wireless communications with sensing capability. Existing ISAC is mainly oriented to static scenarios with radio-frequency (RF) sensors being the primary participants, thus lacking a comprehensive environment feature characterization and facing a severe performance bottleneck in dynamic environments. To date, extensive surveys on ISAC have been conducted but are limited to summarizing RF-based radar sensing. Currently, some research efforts have been devoted to exploring multi-modal sensing-communication integration but still lack a comprehensive review. Therefore, we generalize the concept of ISAC inspired by human synesthesia to establish a unified framework of intelligent multi-modal sensing-communication integration and provide a comprehensive review under such a framework in this paper. The so-termed Synesthesia of Machines (SoM) gives the clearest cognition of such intelligent integration and details its paradigm for the first time. We commence by justifying the necessity of the new paradigm. Subsequently, we offer a definition of SoM and zoom into the detailed paradigm, which is summarized as three operation modes. To facilitate SoM research, we overview the prerequisite of SoM research, i.e., mixed multi-modal (MMM) datasets. Then, we introduce the mapping relationships between multi-modal sensing and communications. Afterward, we cover the technological review on SoM-enhance-based and SoM-concert-based applications. To corroborate the superiority of SoM, we also present simulation results related to dual-function waveform and predictive beamforming design. Finally, we propose some potential directions to inspire future research efforts.Comment: This paper has been accepted by IEEE Communications Surveys & Tutorial

Developed Clustering Algorithms for Engineering Applications: A Review

Clustering algorithms play a pivotal role in the field of engineering, offering valuable insights into complex datasets. This review paper explores the landscape of developed clustering algorithms with a focus on their applications in engineering. The introduction provides context for the significance of clustering algorithms, setting the stage for an in-depth exploration. The overview section delineates fundamental clustering concepts and elucidates the workings of these algorithms. Categorization of clustering algorithms into partitional, hierarchical, and density-based forms lay the groundwork for a comprehensive discussion. The core of the paper delves into an extensive review of clustering algorithms tailored for engineering applications. Each algorithm is scrutinized in dedicated subsections, unraveling their specific contributions, applications, and advantages. A comparative analysis assesses the performance of these algorithms, delineating their strengths and limitations. Trends and advancements in the realm of clustering algorithms for engineering applications are thoroughly examined. The review concludes with a reflection on the challenges faced by existing clustering algorithms and proposes avenues for future research. This paper aims to provide a valuable resource for researchers, engineers, and practitioners, guiding them in the selection and application of clustering algorithms for diverse engineering scenarios

Aerial Vehicle Tracking by Adaptive Fusion of Hyperspectral Likelihood Maps

Hyperspectral cameras can provide unique spectral signatures for consistently distinguishing materials that can be used to solve surveillance tasks. In this paper, we propose a novel real-time hyperspectral likelihood maps-aided tracking method (HLT) inspired by an adaptive hyperspectral sensor. A moving object tracking system generally consists of registration, object detection, and tracking modules. We focus on the target detection part and remove the necessity to build any offline classifiers and tune a large amount of hyperparameters, instead learning a generative target model in an online manner for hyperspectral channels ranging from visible to infrared wavelengths. The key idea is that, our adaptive fusion method can combine likelihood maps from multiple bands of hyperspectral imagery into one single more distinctive representation increasing the margin between mean value of foreground and background pixels in the fused map. Experimental results show that the HLT not only outperforms all established fusion methods but is on par with the current state-of-the-art hyperspectral target tracking frameworks.Comment: Accepted at the International Conference on Computer Vision and Pattern Recognition Workshops, 201