ZePHyR: Zero-shot Pose Hypothesis Rating

ZePHyR is a zero-shot 6D object pose estimation pipeline. The core is a learned scoring function that compares the sensor observation to a sparse object rendering of each candidate pose hypothesis. We used PointNet++ as the network structure and trained and tested on YCB-V and LM-O dataset.

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Get Started

First, checkout this repo by

git clone --recurse-submodules [email protected]:r-pad/zephyr.git

Set up environment

1. We recommend building the environment and install all required packages using Anaconda.

conda env create -n zephyr --file zephyr_env.yml
conda activate zephyr

2. Install the required packages for compiling the C++ module

sudo apt-get install build-essential cmake libopencv-dev python-numpy

3. Compile the c++ library for python bindings in the conda virtual environment

mkdir build
cd build
cmake .. -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)") -DPYTHON_INCLUDE_DIR=$(python -c "from distutils.sysconfig import get_python_inc; print(get_python_inc())")  -DPYTHON_LIBRARY=$(python -c "import distutils.sysconfig as sysconfig; print(sysconfig.get_config_var('LIBDIR'))")
make; make install

4. Install the current python package

cd .. # move to the root folder of this repo
pip install -e .

Download pre-processed dataset

Download pre-processed training and testing data (ycbv_preprocessed.zip, lmo_preprocessed.zip and ppf_hypos.zip) from this Google Drive link and unzip it in the python/zephyr/data folder. The unzipped data takes around 66GB of storage in total.

The following commands need to be run in python/zephyr/ folder.

cd python/zephyr/

Example script to run the network

To use the network, an example is provided in notebooks/TestExample.ipynb. In the example script, a datapoint is loaded from LM-O dataset provided by the BOP Challenge. The pose hypotheses is provided by PPF algorithm (extracted from ppf_hypos.zip). Despite the complex dataloading code, only the following data of the observation and the model point clouds is needed to run the network:

• img: RGB image, np.ndarray of size (H, W, 3) in np.uint8
• depth: depth map, np.ndarray of size (H, W) in np.float, in meters
• cam_K: camera intrinsic matrix, np.ndarray of size (3, 3) in np.float
• model_colors: colors of model point cloud, np.ndarray of size (N, 3) in float, scaled in [0, 1]
• model_points: xyz coordinates of model point cloud, np.ndarray of size (N, 3) in float, in meters
• model_normals: normal vectors of mdoel point cloud, np.ndarray of size (N, 3) in float, each L2 normalized
• pose_hypos: pose hypotheses in camera frame, np.ndarray of size (K, 4, 4) in float

Run PPF algorithm using HALCON software

The PPF algorithm we used is the surface matching function implmemented in MVTec HALCON software. HALCON provides a Python interface for programmers together with its newest versions. I wrote a simple wrapper which calls create_surface_model() and find_surface_model() to get the pose hypotheses. See notebooks/TestExample.ipynb for how to use it.

The wrapper requires the HALCON 21.05 to be installed, which is a commercial software but it provides free licenses for students.

If you don't have access to HALCON, sets of pre-estimated pose hypotheses are provided in the pre-processed dataset.

Test the network

Download the pretrained pytorch model checkpoint from this Google Drive link and unzip it in the python/zephyr/ckpts/ folder. We provide 3 checkpoints, two trained on YCB-V objects with odd ID (final_ycbv.ckpt) and even ID (final_ycbv_valodd.ckpt) respectively, and one trained on LM objects that are not in LM-O dataset (final_lmo.ckpt).

Test on YCB-V dataset

Test on the YCB-V dataset using the model trained on objects with odd ID

python test.py \
    --model_name pn2 \
    --dataset_root ./data/ycb/matches_data_test/ \
    --dataset_name ycbv \
    --dataset HSVD_diff_uv_norm \
    --no_valid_proj --no_valid_depth \
    --loss_cutoff log \
    --exp_name final \
    --resume_path ./ckpts/final_ycbv.ckpt

Test on the YCB-V dataset using the model trained on objects with even ID

python test.py \
    --model_name pn2 \
    --dataset_root ./data/ycb/matches_data_test/ \
    --dataset_name ycbv \
    --dataset HSVD_diff_uv_norm \
    --no_valid_proj --no_valid_depth \
    --loss_cutoff log \
    --exp_name final \
    --resume_path ./ckpts/final_ycbv_valodd.ckpt

Test on LM-O dataset

python test.py \
    --model_name pn2 \
    --dataset_root ./data/lmo/matches_data_test/ \
    --dataset_name lmo \
    --dataset HSVD_diff_uv_norm \
    --no_valid_proj --no_valid_depth \
    --loss_cutoff log \
    --exp_name final \
    --resume_path ./ckpts/final_lmo.ckpt

The testing results will be stored in test_logs and the results in BOP Challenge format will be in test_logs/bop_results. Please refer to bop_toolkit for converting the results to BOP Average Recall scores used in BOP challenge.

Train the network

Train on YCB-V dataset

These commands will train the network on the real-world images in the YCB-Video training set.

On object Set 1 (objects with odd ID)

python train.py \
    --model_name pn2 \
    --dataset_root ./data/ycb/matches_data_train/ \
    --dataset_name ycbv \
    --dataset HSVD_diff_uv_norm \
    --no_valid_proj --no_valid_depth \
    --loss_cutoff log \
    --exp_name final

On object Set 2 (objects with even ID)

python train.py \
    --model_name pn2 \
    --dataset_root ./data/ycb/matches_data_train/ \
    --dataset_name ycbv \
    --dataset HSVD_diff_uv_norm \
    --no_valid_proj --no_valid_depth \
    --loss_cutoff log \
    --val_obj odd \
    --exp_name final_valodd

Train on LM-O synthetic dataset

This command will train the network on the synthetic images provided by BlenderProc4BOP. We take the lm_train_pbr.zip as the training set but the network is only supervised on objects that is in Linemod but not in Linemod-Occluded (i.e. IDs for training objects are 2 3 4 7 13 14 15).

python train.py \
    --model_name pn2 \
    --dataset_root ./data/lmo/matches_data_train/ \
    --dataset_name lmo \
    --dataset HSVD_diff_uv_norm \
    --no_valid_proj --no_valid_depth \
    --loss_cutoff log \
    --exp_name final

Cite

If you find this codebase useful in your research, please consider citing:

@inproceedings{icra2021zephyr,
    title={ZePHyR: Zero-shot Pose Hypothesis Rating},
    author={Brian Okorn, Qiao Gu, Martial Hebert, David Held},
    booktitle={2021 International Conference on Robotics and Automation (ICRA)},
    year={2021}
}

Reference

• We used the PPF implementation provided in MVTec HALCON software for pose hypothese generation. It is a commercial software but provides free license for student.
• We used bop_toolkit for data loading and results evaluation.