TouchSDF

Implementation of the paper TouchSDF: A DeepSDF Approach for 3D Shape Reconstruction Using Vision-Based Tactile Sensing

Content

• Installation
• Usage
• Data making
• Training
• Known Issues

Installation

The installation instructions reported in this file were tested on macOS Monterey - Apple M1. This repository also runs on Ubuntu and CentOS 7, but dependency issues between PyTorch and PyTorch3D need to be manually resolved.

conda create -n touchsdf python=3.8
conda activate touchsdf
conda env update -n touchsdf --file environment.yml

Clone the repository and run the following command from the root directory:

pip install -e .

Create the required directories:

bash create_directories.sh

The required library point-cloud-utils cannot be currently pip-installed on macOS M1 due to an ImportError. Build it from source by referring to the official documentation. Please note: I am not the author of this library. Once the source code is cloned, simply run python setup.py install from its root directory.

This repository provides pretrained models for DeepSDF and Local surface prediction, so the extraction of touch data and SDF values is not necessary to use this method. However, if desired, you can still perform this extraction by following the instructions outlined in the Data making and Training sections.

Usage

This section provides an example of usage to predict the shape of an object using pretrained models.

To collect touches and predict the geometry of an object, run:

python scripts/pipeline_tactile_deepsdf.py --show_gui --num_samples 20 --obj_folder '02942699/6d036fd1c70e5a5849493d905c02fa86' --folder_sdf '24_03_190521' --lr_scheduler --folder_touch '30_05_1633' --mode_reconstruct 'fixed' --epochs 5000 --lr 0.0005 --patience 100 --resolution 256 --lr_multiplier 0.95 --num_samples_extraction 20 --positional_encoding_embeddings 0 --augment_points_std 0.0005 --augment_multiplier_out 5 --clamp --clamp_value 0.1

To speed up the simulation press G. Collisions between the arm and the object during sampling are expected, as the collision between the two elements is set to False for speed purposes. This does not affect the resulting contact geometry. The script creates a new folder results/runs_touch_sdf/<FOLDER_RESULT>. Please note: as some operations (e.g. weight_norm) do not work on the M1 architecture, inference will run on the CPU. As a result, inference is very slow (up to 1hr for 20 touches and 5000 epochs). On a RTX 3090 GPU, inference takes approx. 5 minutes for the same data points. To change the object to reconstruct, please modify the argument --obj_folder by choosing among the objects under the folder ShapeNetCoreV2urdf. Additional information regarding these objects can be found in the section Data making.

The output is stored in the directory shown at the end of the inference procedure, e.g. 08_06_221924_7367/infer_latent_08_06_223240/19/..:

• final_mesh.obj: the predicted mesh.
• original_touch.html: interactive plot showing point clouds of the predicted local surfaces and original object mesh.
• original_final.html: interactive plot showing point clouds of the predicted object mesh and original object mesh.
• final_touch.html: interactive plot showing point clouds of the predicted local surfaces and predicted object mesh.

Additionally, a file containing the predicted chamfer distance chamfer_distance.txt is stored in results/runs_touch_sdf/<FOLDER_RESULT>.

Data making

In this repository, we used the objects from the ShapeNet dataset. The ShapeNetCore.V2 dataset only contains non-watertight .obj meshes. However, (1) the PyBullet simulator requires .urdf meshes and (2) DeepSDF works best on watertight meshes. Therefore, the obj files need to be converted into watertight urdf and obj meshes for this approach to work. The current repository provides a few examples of shapes in their correct format. Due to the double blind review process, libraries used to process additional shapes cannot be linked here. Further instructions will be added once the review process is complete. The required data structure for the urdf and obj watertight meshes is the following:

root
 ├── data
 │   ├── ShapeNetCoreV2urdf
 │   │   ├── 02942699 
 |   |   |   ├── 1ab3abb5c090d9b68e940c4e64a94e1e
 |   |   |   |   ├── model.urdf
 |   |   |   |   ├── model.obj

SDF values need to be extracted to train the DeepSDF model:

python data_making/extract_sdf.py --num_samples_on_surface 20000 --num_samples_in_bbox 10000 --num_samples_in_volume 5000

Data necessary to train the local surface prediciton model is extracted as follows:

python extract_touch_charts.py --num_samples 10

Training

To train the local surface prediction model:

python model/train_touch.py --epochs 1000 --batch_size 16  --loss_coeff 1000 --lr_scheduler --lr_multiplier 0.8

The train the DeepSDF model:

python model/train_sdf.py --epochs 150 --lr_model 5e-4 --lr_latent 4e-2 --sigma_regulariser 0.01 --num_layers 8 --batch_size 20480 --lr_multiplier 0.9 --patience 5 --lr_scheduler --latent_size 128 --inner_dim 512 --clamp --clamp_value 0.05 --positional_encoding_embeddings 0

The batch size needs to be adjusted to the dataset dimension. For 1300 shapes, a batch size of 20480 results in a 15 hours training (RTX 3090).

Known issues

• If --show_gui is not passed as argument on macOS M1, the collected touches are empty. This can be solved by recalibrating the sensors. On Ubuntu and CentOS 7, show_gui can be safely set as False to speed up the data collection procedure.
• Set PYOPENGL_PLATFORM=egl before running scripts requiring rendering when using Ubuntu. Example: PYOPENGL_PLATFORM=egl python scripts/pipeline_tactile_deepsdf.py.
• Compatibility issues between PyTorch and PyTorch3D on Ubuntu. Please refer to https://github.com/facebookresearch/pytorch3d/blob/main/INSTALL.md for instructions.
• CPU inference is very slow.