DEviLOG: Dynamic Evidential Lidar Occupancy Grid Mapping

This repository provides the dataset as well as the training pipeline that was used in our paper:

Data-Driven Occupancy Grid Mapping using Synthetic and Real-World Data IEEE Xplore, arXiv

Raphael van Kempen, Bastian Lampe, Lennart Reiher, Timo Woopen, Till Beemelmanns, and Lutz Eckstein
Institute for Automotive Engineering (ika), RWTH Aachen University

Abstract — In perception tasks of automated vehicles (AVs) data-driven have often outperformed conventional approaches. This motivated us to develop a data-driven methodology to compute occupancy grid maps (OGMs) from lidar measurements. Our approach extends previous work such that the estimated environment representation now contains an additional layer for cells occupied by dynamic objects. Earlier solutions could only distinguish between free and occupied cells. The information whether an obstacle could move plays an important role for planning the behavior of an AV. We present two approaches to generating training data. One approach extends our previous work on using synthetic training data so that OGMs with the three aforementioned cell states are generated. The other approach uses manual annotations from the nuScenes [1] dataset to create training data. We compare the performance of both models in a quantitative analysis on unseen data from the real-world dataset. Next, we analyze the ability of both approaches to cope with a domain shift, i.e. when presented with lidar measurements from a different sensor on a different vehicle. We propose using information gained from evaluation on real-world data to further close the reality gap and create better synthetic data that can be used to train occupancy grid mapping models for arbitrary sensor configurations.

We hope our paper and code can help in your research. If this is the case, please cite:

@INPROCEEDINGS{9988605,
  author={van Kempen, Raphael and Lampe, Bastian and Reiher, Lennart and Woopen, Timo and Beemelmanns, Till and Eckstein, Lutz},
  booktitle={2022 International Conference on Electrical, Computer, Communications and Mechatronics Engineering (ICECCME)}, 
  title={Data-Driven Occupancy Grid Mapping using Synthetic and Real-World Data}, 
  year={2022},
  doi={10.1109/ICECCME55909.2022.9988605}}

Content

• Installation
• Data
• Training
• Evaluation

Installation

We suggest to create a new conda environment with all required packages. This will automatically install the GPU version of TensorFlow with CUDA and cuDNN if an NVIDIA GPU is available. It is also necessary to fix some system paths in order for TensorFlow to correctly locate CUDA. Afterwards the environment must be re-activated.

# DEviLOG/
conda env create -f environment.yml
conda activate devilog
conda env config vars set LD_PRELOAD="$CONDA_PREFIX/lib/libcudart.so:$CONDA_PREFIX/lib/libcublas.so:$CONDA_PREFIX/lib/libcublasLt.so:$CONDA_PREFIX/lib/libcufft.so:$CONDA_PREFIX/lib/libcurand.so:$CONDA_PREFIX/lib/libcusolver.so:$CONDA_PREFIX/lib/libcusparse.so:$CONDA_PREFIX/lib/libcudnn.so"
conda activate devilog

Alternatively, it is possible to install all package dependencies in a Python 3.8 environment (e.g. by using virtualenv) with pip. Note that CMake must be installed to build the point-pillars package.

# DEviLOG/
pip install -r requirements.txt

Data

This repository contains a TensorFlow Datasets wrapper for the nuScenes dataset. Samples consisting of lidar point clouds and occupancy grid maps will automatically be generated in the training pipeline.

The nuScenes dataset can be downloaded from here (registration required). You will need the "full dataset", the "map expansion pack" and the "lidar-panoptic" package. For testing purposes, you can just download the "mini" splits instead of the full "trainval" split. The extracted folder must be placed in the manual installation directory for TensorFlow Datasets, e.g. ~/tensorflow_datasets/downloads/manual/v1.0-mini. After extracting all archives you should have the following directories:

tensorflow_datasets/downloads/manual/
  v1.0-mini/  # or 'v1.0-trainval'
    maps/
      basemap/
      expansion/
      prediction/
    panoptic/
    samples/
    sweeps/
    v1.0-mini/  # or 'v1.0-trainval'

Training

You can train a model to predict occupancy grid maps from lidar point clouds using training data created from the nuScenes dataset.

Start training the model by passing the provided config file to the training script.

# DEviLOG/model/
export TF_FORCE_GPU_ALLOW_GROWTH=true  # try this if cuDNN fails to initialize
./train.py -c config.yml

You can visualize training progress by pointing TensorBoard to the output directory (model/output by default). Training metrics will also be printed to stdout.

Evaluation

Before evaluating your trained model on the test data, set the parameter model-weights to point to the best_weights.hdf5 file in the Checkpoints folder of its model directory.

# DEviLOG/model/
./evaluate.py -c config.yml --model-weights output/<YOUR-TIMESTAMP>/Checkpoints/best_weights.hdf5

The evaluation results will be exported to the Evaluation folder in your model directory.

Acknowledgement

This research is accomplished within the project ”UNICARagil” (FKZ 16EMO0284K). We acknowledge the financial support for the project by the Federal Ministry of Education and Research of Germany (BMBF).