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3DFeat-Net: Weakly Supervised Local 3D Features for Point Cloud Registration

About

This work is based on our ECCV2018 paper. 3DFeat-Net is an approach for learning features for point cloud geometric registration under weak-supervision, where the supervision is given in terms of whether 2 point clouds have very high overlap or low (or no) overlap. For details, please read our paper which can be found on arXiv.

Bibtex:

@inproceedings{yew2018-3dfeatnet, 
    title={3DFeat-Net: Weakly Supervised Local 3D Features for Point Cloud Registration}, 
    author={Yew, Zi Jian and Lee, Gim Hee}, 
    booktitle={ECCV},
    year={2018} 
}

Environment

Our code is developed and tested on the following environment:

• Python 3.5
• Tensorflow 1.4 (with Cuda 8.0)
• Numpy 1.13.3
• Scikit-learn 0.19.1

We also use MATLAB scripts for evaluation and processing of data.

Network

The network model is in models/feat3dnet.py.

Prerequisites

Before using the model, you first need to compile the customized tf_ops in the folder tf_ops (we use the customized grouping and sampling ops from PointNet++).

Check and execute tf_xxx_compile.sh under each subfolder. Update the python and nvcc file if necessary. The scripts has been updated for TF1.4, so if you're using TF version < 1.4, refer to the original script provided with PointNet++ for compilation.

Training

Preparation of data

1. Follow instructions here to download and prepare the training data
2. Also download the test data for descriptor matching (i.e. the 30,000 cluster pairs) by following the instructions here. We monitor the false alarm rate at 95% recall, as the training loss is not very informative (The provided script evaluates on all of the test data which can be slow; you can change this behavior by modifying VAL_PROPORTION in train.py)
3. Both the training and test sets should be placed in the same folder. The provided scripts assume they're placed in ../data/oxford, which should contain two subfolders: clusters and train.

Training

Training is divided into 2 stages, where the first stage only trains the descriptor subnetwork without rotation and attention. For convenience, we provide a training script which runs both parts. Simply execute./train.sh (you can configure the top few lines to select the GPU, etc).

Training takes around 1-1.5 days to saturate. During training, progress can be monitored by running tensorboard --logdir=./ckpt from the root folder, and the false alarm rate will be shown in the fp_rate graph.

Inference on Example data

1. Run inference_example.sh which will load the pretrained model in the folder ckpt and generate the keypoints and descriptors for the example data in example_data. A sample checkpoint can be downloaded from here. The output will be stored in example_data/results.
2. Run the MATLAB script scripts/computeAndVisualizeMatches.m which will match the features, estimate the relative transformation (with RANSAC) between the point clouds and display the results.

It should be straightforward to run on your own data, just make sure the data is in the expected format (see scripts_data_processing/Readme.md). Note however the following:

• z-axis should be pointing vertically upwards
• The network considers up to 64 points per cluster. For dense point clouds, it will pick the points randomly (as long the flag --randomize_points is set which will randomize the input point ordering). This means that the performance may differ slightly with each run.

Datasets

Refer to scripts_data_processing/Readme.md.