Curb Detection in Urban Traffic Scenarios Using LiDARs Point Cloud and Semantically Segmented Color Images

S.E.C. Deac, I. Giosan, S. Nedevschi

Proceeding of 2019 IEEE Intelligent Transportation Systems Conference (ITSC), Auckland, New Zeeland, 26-30 October,2019, pp. 3433-3440.

In this paper we propose a robust curb detection method which is based on the fusion between semantically labeled camera images and a 3D point cloud coming from LiDAR sensors. The labels from the semantically enhanced cloud are used to reduce the curbs’ searching area. Several spatial cues are next computed on each candidate curb region. Based on these features, a candidate curb region is either rejected or refined for obtaining a precise positioning of the curb points found inside it. A novel local model-based outlier removal algorithm is proposed to filter out the erroneous curb points. Finally, a temporal integration of the detected curb points in multiple consecutive frames is used to densify the detection result. An objective evaluation of the proposed solution is done using a highresolution digital map containing ground truth curb points. The proposed system has proved capable of detecting curbs of any heights (from 3cm up to 30cm) in complex urban road scenarios (straight roads, curved roads, intersections with traffic isles and roundabouts).

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Real-Time Semantic Segmentation-Based Stereo Reconstruction

V.C. Miclea, S. Nedevschi

IEEE Transactions on Intelligent Transportation Systems (Early Access), pp. 1-11, 2019, DOI: 10.1109/TITS.2019.2913883.

In this paper, we propose a novel semantic segmentation-based stereo reconstruction method that can keep up with the accuracy of the state-of-the art approaches while running in real time. The solution follows the classic stereo pipeline, each step in the stereo workflow being enhanced by additional information from semantic segmentation. Therefore, we introduce several improvements to computation, aggregation, and optimization by adapting existing techniques to integrate additional surface information given by each semantic class. For the cost computation and optimization steps, we propose new genetic algorithms that can incrementally adjust the parameters for better solutions. Furthermore, we propose a new postprocessing edge-aware filtering technique relying on an improved convolutional neural network (CNN) architecture for disparity refinement. We obtain the competitive results at 30 frames/s, including segmentation.

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Efficient instance and semantic segmentation for automated driving

A. Petrovai, S. Nedevschi

Proceeding of 2019 IEEE Intelligent Vehicles Symposium (IV 2019), Paris, France, 9 – 12 June, 2019, pp. 2575-2581.

Environment perception for automated vehicles is achieved by fusing the outputs of different sensors such as cameras, LIDARs and RADARs. Images provide a semantic understanding of the environment at object level using instance segmentation, but also at background level using semantic segmentation. We propose a fully convolutional residual network based on Mask R-CNN to achieve both semantic and instance level recognition. We aim at developing an efficient network that could run in real-time for automated driving applications without compromising accuracy. Moreover, we compare and experiment with two different backbone architectures, a classification type of network and a faster segmentation type of network based on dilated convolutions. Experiments demonstrate top results on the publicly available Cityscapes dataset.

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Environment Perception Architecture using Images and 3D Data

H. Florea, R. Varga, S. Nedevschi

Proceedings of 2018 14th IEEE International Conference on Intelligent Computer Communication and Processing (ICCP), Cluj-Napoca, Romania, September 7-9, 2018, pp. 223-228.

This paper discusses the architecture of an environment perception system for autonomous vehicles. The modules of the system are described briefly and we focus on important changes in the architecture that enable: decoupling of data acquisition from data processing; synchronous data processing; parallel computation on GPU and multiple CPU cores; efficient data passing using pointers; adaptive architecture capable of working with different number of sensors. The experimental results compare execution times before and after the proposed optimizations. We achieve a 10 Hz frame rate for an object detection system working with 4 cameras and 4 LIDAR point clouds.

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A Fast RANSAC Based Approach for Computing the Orientation of Obstacles in Traffic Scenes

F. Oniga, S. Nedevschi

Proceedings of 2018 14th IEEE International Conference on Intelligent Computer Communication and Processing (ICCP), Cluj-Napoca, Romania, September 7-9, 2018, pp. 209-214.

A low complexity approach for computing the orientation of 3D obstacles, detected from lidar data, is proposed in this paper. The proposed method takes as input obstacles represented as cuboids without orientation (aligned with the reference frame). Each cuboid contains a cluster of obstacle locations (discrete grid cells). First, for each obstacle, the boundaries that are visible for the perception system are selected. A model consisting of two perpendicular lines is fitted to the set of boundary cells, one for each presumed visible side. The main dominant line is computed with a RANSAC approach. Then, the second line is searched, using a constraint of perpendicularity on the dominant line. The existence of the second line is used to validate the orientation. Finally, additional criteria are proposed to select the best orientation based on the free area of the cuboid (on top view) that is visible to the perception system.

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Deliverable 4.4

Final specification and design of on-board sensing

This deliverable states the updates on two major aspects since Deliverable 4.1: The first aspect consists in the detailed specification of the perception goals and of the sensor model of the environment. The second aspect consists in the selection and the definition of the robust and redundant perception solution for each individual perception task based on the available or new sensors.

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Deliverable 4.3

Initial version of higher-level perception functions

The deliverable provides an initial design and implementation of the higher level perception functions referring to road surface and obstacle perception, parking spot detection, road users classification, tracking and signaling perception.

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Deliverable 4.2

Initial version of low-level perception functions

The deliverable provides an initial design and implementation of the spatio-temporal and appearance based low level representation (STAR) which represents the basis of building a virtual super-sensor that may perceive the environment like it has the capabilities of all available sensors mounted on the vehicles.

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Deliverable 4.1

Initial specification and design of on-board sensing

This deliverable states the sensing possibilities, suitable to enable vehicle’s highly automated driving capabilities, as well as to collect useful information for map related operations including map enrichment, alignment, etc.

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Fusion Scheme for Semantic and Instance-level Segmentation

Arthur Daniel Costea, Andra Petrovai, Sergiu Nedevschi

Proceedings of 2018 IEEE 21th International Conference on Intelligent Transportation Systems (ITSC 2018), Maui, Hawaii, USA, 4-7 Nov. 2018, pp. 3469-3475

A powerful scene understanding can be achieved by combining the tasks of semantic segmentation and instance level recognition. Considering that these tasks are complementary, we propose a multi-objective fusion scheme which leverages the capabilities of each task: pixel level semantic segmentation performs well in background classification and delimiting foreground objects from background, while instance level segmentation excels in recognizing and classifying objects as a whole. We use a fully convolutional residual network together with a feature pyramid network in order to achieve both semantic segmentation and Mask R-CNN based instance level recognition. We introduce a novel heuristic fusion approach for panoptic segmentation. The instance and semantic segmentation output of the network is fused into a panoptic segmentation based on object sub-category class and instance propagation guidance by semantic segmentation for more general classes. The proposed solution achieves significant improvements in semantic object segmentation and object mask boundaries refinement at low computational costs.

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