Folding-based compression of point cloud attributes

• Authors: Maurice Quach, Giuseppe Valenzise and Frederic Dufaux
• Affiliation: Université Paris-Saclay, CNRS, CentraleSupélec, Laboratoire des signaux et systèmes, 91190 Gif-sur-Yvette, France
• Funding: ANR ReVeRy national fund (REVERY ANR-17-CE23-0020)
• Links: [Paper]

Experimental data

We provide the full experimental data used for the paper. This includes:

• trained models for all patches
• compressed and decompressed patches, images and point clouds
• objective metrics for each patch and each point cloud

Download experimental data

Getting started

Prerequisites

• Python 3.6.9
• TensorFlow 1.15.0 with CUDA 10.0.130, cuDNN 7.4.2 and GCC 7
• BPG codec: bpgenc and bpcdec should be available in your PATH
• MPEG G-PCC codec mpeg-pcc-tmc13: necessary only to compare results with G-PCC, to obtain more recent versions you need to register on the MPEG Gitlab and request the permissions for MPEG/PCC
• MPEG metric software v0.12.3 mpeg-pcc-dmetric: available on the MPEG Gitlab, you need to register and request the permissions for MPEG/PCC
• MPEG PCC dataset: refer to Common Test Conditions (CTCs) to download the full dataset, you can also get some point clouds from JPEG Pleno.
• packages in requirements.txt

Note 1: using a Linux distribution such as Ubuntu is highly recommended
Note 2: CTCs can be found at wg11.sc29.org in All Meetings > Latest Meeting > Output documents "Common test conditions for point cloud compression". For example, "Common test conditions for PCC", in ISO/IEC JTC1/SC29/WG11 MPEG output document N19324 is in the Alpbach meeting 130.

Configuration

Check the following:

• In 10_pc_to_patch.py, adjust the patching parameters to your convenience (in particular N_PATCHES_DEFAULT).
• In 50_run_mpeg.py, adjust the configuration parameters to your environment.
• In 91_expdata_full.py, check that the relative paths are correct for your environment. The scripts assume there is a single folder containing all the point clouds. The paths are relative to this folder.

Compiling Chamfer Distance kernels

We make use of a CUDA implementation for the Chamfer distance. As such, it is necessary to compile it using the compile.sh script and check that the tests run successfully:

cd ops/nn_distance
./compile.sh
python nn_distance_test.py

You may have to add -D_GLIBCXX_USE_CXX11_ABI=0 in this script on each g++ call depending on your compiler and tensorflow version.

Usage

We provide a set of pipelines to make experimentation easier. These scripts rely on a YAML that contains information on the experiment: 91_expdata_full.yml for example. It is also possible to write your own.

Important note : if you wish to reproduce the results of our paper, we provide the corresponding manual patches in this repository. To use these patches, copy the folder manual_patches and use it as your experimental folder.

For example, you can produce results for folding with the manual patches, produce results for G-PCC and compare the two with the following commands:

git clone https://github.com/mauriceqch/pcc_attr_folding.git
cd pcc_attr_folding/src
cp -r ../manual_patches ~/data/experiments/pcc_attr_folding_manual
python 61_run_folding.py 91_expdata_full.yml ~/data/experiments/pcc_attr_folding_manual
python 50_run_mpeg.py 91_expdata_full.yml ¬/data/experiments/gpcc
python 70_run_eval_compare.py 91_expdata_full.yml ~/data/experiments/gpcc/ ~/data/experiments/pcc_attr_folding_manual

To produce results without division into patches:

python 61_run_folding.py 91_expdata_full.yml ~/data/experiments/pcc_attr_folding_single --k 1
python 70_run_eval_compare.py 91_expdata_full.yml ~/data/experiments/gpcc/ ~/data/experiments/pcc_attr_folding_single

Batch folding pipeline

Runs the folding pipeline for each point cloud.

python 61_run_folding.py 91_expdata_full.yml ~/data/experiments/pcc_attr_folding

Folding pipeline (single point cloud)

Runs the complete folding pipeline for a point cloud:

• Divides point cloud into k patches
• Fits a grid for each patch
• Evaluates compression for each patch
• Merge the patches and compression results.

For example, to run the pipeline while divinding the point cloud into 4 patches:

python 60_folding_pipeline.py loot.ply loot/ --k 4

MPEG G-PCC

We provide a script to run MPEG G-PCC experiments.

python 50_run_mpeg.py 91_expdata_full.yml gpcc

Evaluate and compare

To compare evaluation results between GPCC and our method.

python 70_run_eval_compare.py 91_expdata_full.yml ~/data/experiments/gpcc/ ~/data/experiments/pcc_attr_folding/

Also, to compare with two versions of GPCC as in the paper.

python 72_run_eval_compare_two.py 91_expdata_full.yml ~/data/experiments/gpcc/ ~/data/experiments/gpcc-v3/ ~/data/experiments/pcc_attr_folding

Overview

├── manual_patches                      [Data] Manual patches used in the paper
├── requirements.txt                    Package requirements
└── src
    ├── 10_pc_to_patch.py               [Preprocess] Divide a point cloud into patches
    ├── 11_train.py                     [Train] Fold a grid onto a point cloud and save the obtained network
    ├── 12_merge_ply.py                 [Preprocess] Merge point cloud patches into a single point cloud
    ├── 20_gen_folding.py               [Inference] Generate a folded grid with a trained network
    ├── 21_eval_folding.py              [Eval] Refine, optimize, compress and evaluate a folded grid
    ├── 22_merge_eval.py                [Eval] Merge evaluation results at different QPs
    ├── 23_eval_merged.py               [Eval] Evaluates a merged point cloud compared to the original
    ├── 50_run_mpeg.py                  [MPEG] Runs G-PCC on all point clouds
    ├── 51_gen_report.py                [MPEG] Parse files in a G-PCC result folder and generate a JSON report
    ├── 60_folding_pipeline.py          [Folding] Runs the full folding pipeline (patches, folding, compress, eval)
    ├── 61_run_folding.py               [Folding] Runs the full folding pipeline for all point clouds
    ├── 70_run_eval_compare.py          [Eval] Compare results for all point clouds with G-PCC
    ├── 71_eval_compare.py              [Eval] Compare results with G-PCC
    ├── 72_run_eval_compare_two.py      [Eval] Compare results for all point clouds with two G-PCC result folders for all point clouds
    ├── 73_eval_compare_two.py          [Eval] Compare results with two G-PCC result folders
    ├── 80_input.py                     [Model] Input pipeline for the network
    ├── 80_model.py                     [Model] Model for the network
    ├── 90_run_tests.py                 Run tests
    ├── 91_ds_expdata.py                [Utils] Downsample all point clouds
    ├── 91_expdata_full.yml             [Config] Experimental data, list of point clouds considered
    ├── 98_highlight_borders.py         [Utils] Highlight borders on a folded grid (debugging)
    ├── 994_pc_curvature.py             [Utils] Compute point cloud curvature (debugging)
    ├── 99_pc_to_vg.py                  [Utils] Voxelize a point cloud
    ├── 99_pc_to_vg_batch.py            [Utils] Voxelize multiple point clouds
    ├── ops                             Chamfer distance files
    └── utils
        ├── adj.py                      Folded grid refinement
        ├── bd.py                       BD-RATE/BD-PSNR
        ├── bpg.py                      BPG compression (BPG is a image compression codec based on HEVC intra)
        ├── color_mapping.py            Color mapping, used for transferring colors from the grid to the point cloud and vice-versa
        ├── color_space.py              Color space conversion
        ├── curvature.py                Curvature computation
        ├── generators.py               Generators for data pipelines
        ├── grid.py                     Grid manipulation
        ├── mpeg_parsing.py             MPEG log files parsing
        ├── parallel_process.py         Parallel processing
        ├── pc_io.py                    Point Cloud Input/Output
        └── quality_eval.py             Point Cloud color distortion metrics

Invididual Usage Examples

It is possible to use the scripts individually instead of using the pipelines. We provide some usage examples below.

Training

Point cloud to patches

python 10_pc_to_patch.py loot.ply loot_patches/ --k 9

Fitting a grid on a point cloud

python 11_train.py loot.ply loot_model/ --max_steps 2000 --model 80_model --input_pipeline 80_input --grid_steps 64,128,1

Merging patches into a point cloud

python 12_merge_ply.py loot_patches/*.ply loot_merged.ply

Evaluation

Evaluate color compression

python 20_gen_folding.py loot.ply loot_results/ loot_model/ --model 80_model --input_pipeline 80_input --grid_steps auto
python 21_eval_folding.py loot_results/
python 23_eval_merged.py loot.ply loot_results/refined_opt_qp_20/loot_remap.ply

Compare evaluation results

python 29_eval_compare.py gpcc/octree-predlift/lossless-geom-lossy-attrs/Egyptian_mask_vox12 ./test_egypt/merged/

Utilities

Downsample experimental data

Create a downsampled version of experimental data for a given setup. This only works for point cloud with voxXX in their name such as longdress_vox10_1200.

python 91_ds_expdata.py 91_expdata_full.yml 8

Highlight borders

Given a folded point cloud, highlights the borders of the grid on the point cloud.

python 98_highlight_borders.py carpet_folded.ply carpet_folded_with_borders.ply

Batch downsample point clouds

Given a pattern, downsample all matching point clouds.

python 99_pc_to_vg_batch.py "pcs_vox10/**/*.ply" pcs_vox_08 --vg_size 256

Citation

@article{DBLP:journals/corr/abs-2002-04439,
  author    = {Maurice Quach and
               Giuseppe Valenzise and
               Fr{\'{e}}d{\'{e}}ric Dufaux},
  title     = {Folding-based compression of point cloud attributes},
  journal   = {CoRR},
  volume    = {abs/2002.04439},
  year      = {2020},
  url       = {https://arxiv.org/abs/2002.04439},
  archivePrefix = {arXiv},
  eprint    = {2002.04439},
  timestamp = {Wed, 12 Feb 2020 16:38:55 +0100},
  biburl    = {https://dblp.org/rec/journals/corr/abs-2002-04439.bib},
  bibsource = {dblp computer science bibliography, https://dblp.org}
}