A physics-informed, vision-based method to reconstruct all deformation modes in slender bodies

Paper (arXiv) - ICRA 2022

The code to reproduce the result for the paper is in v0.1. The current version is under further development for utilization. While we are trying our best to keep the code back-compatible, past version might require installing deprecated packages and python.

Demo Data

How to install

cd <path to the repository>
git clone https://github.com/GazzolaLab/BR2-vision-based-smoothing.git
cd BR2-vision-based-smoothing
# <optional> activate virtual environment
pip install .

Unit-Tests

cd BR2-vision-based-smoothing
# <optional> activate virtual environment
pytest

Requirements

All the tools are developed using Python3.9 and openCV. We recommend installing dependencies using poetry. To visualize the data, we used ffmpeg tool to render video.

• PyElastica (The PyQt may not operate in some OS environment)

Publication

Kim, Chang, Shih, Uppalapati, Halder, Krishnan, Mehta and Gazzola A physics-informed, vision-based method to reconstruct all deformation modes in slender bodies, IEEE ICRA 2022

@inproceedings{kim2022smoothing,
title = "A physics-informed, vision-based method to reconstruct all deformation modes in slender bodies",
author = "Kim, {Seung Hyun} and Chang, {Heng Sheng} and Shih, {Chia Hsien} and Uppalapati, {Naveen Kumar} and Udit Halder and Girish Krishnan and Mehta, {Prashant G.} and Mattia Gazzola",
year = "2022",
doi = "10.1109/ICRA46639.2022.9811909",
series = "Proceedings - IEEE International Conference on Robotics and Automation",
booktitle = "2022 IEEE International Conference on Robotics and Automation, ICRA 2022",
}

How To Use

To process the video data, check out section (Calibration Steps) for camera calibration and (Optical Flow: Data Point Tracking) for the point tracking. To process reconstruction (smoothing) algorithm, check out section (Reconstruction (Smoothing)).

Typical Workflow

flowchart LR
    collect[("Data Collection")]
    preproc{{"Preprocess </br> - undistort </br> - rotate </br> - synchronize </br> - crop </br> - trim"}}
    dltcal{{"DLT Calibration"}}
    oflow{{"Optical Flow"}}
    dlt{{"DLT - 3D poses"}}
    smth{{"Smoothing"}}

    collect --> preproc --> dltcal --> dlt --> smth
    preproc --> oflow --> dlt

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Preprocessing Video

Order matters

Anything inside the box can be run as a cli command.

flowchart LR
a("command") ==> b["$command --help"]

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flowchart TD
    collect[("Data Collection")]
    subgraph Preprocess
        proc1("undistort and rotate all video")
        proc2("sync video")
        proc3("crop video")
        trim("trim video intervals by LED <br> trim video intervals manual")
        proc1 --> proc2 --> proc3 --> trim
    end
    out1[("Experiment Footage")]
    out2[("DLT Calibration Footage")]

    collect --> Preprocess --> out1
    Preprocess --> out2

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DLT Calibration

flowchart TD
    collect[("DLT Calibration Footage")]
    DLT[("dlt-parameters (npz)")]
    subgraph DLT-Calibration
        cal1("extract calibration frames")
        cal2("select calibration points")
        cal3("dlt calibration")
        cal1 -->|static frames| cal2 --> cal3
    end
    collect --> DLT-Calibration --> DLT

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Optical Flow

flowchart TD
    collect[("Experiment Footage")]
    T[("tracking data (h5)")]
    RT["render tracking video"]
    subgraph Optical-Flow
        opt1("set optical flow inquiry")
        opt2("run optical flow")
        opt2m("run manual tracking")
        opt3("edit optical flow")
        
        opt1 --> opt2 --> C{satisfied?}
        opt1 --> opt2m --> C
        C -->|no: trim trajectory| opt3 --> opt1
        C -->|yes| D(("save"))
    end
    collect --> Optical-Flow --> T

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Smoothing

flowchart TD
    Origin["select origin"]
    T[("tracking data (h5)")]
    DLT[("dlt-parameters (npz)")]
    smt1["interpolate poses"]
    smt2["run smoothing"]
    smt3["visualize smoothing"]
    
    Origin --> smt1
    T --> smt1
    DLT --> smt1
    smt1 --> smt2
    smt2 -->|optional| smt3

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Path Configuration

All data paths and output paths can be changed in br2_config.ini file. Recommended file structure is as follow:

. <working directory>
├── br2_config.ini
├── calibration.pkl
├── marker.yaml
├── data
│   ├── raw
│   │   ├── cam1.MOV
│   │   ├── cam2.MOV
...
│   ├── dlt-calibration
│   │   ├── cam1.MOV
│   │   ├── cam2.MOV
...

Miscellaneous tools

We provide other CLI video processing tools for convenience. Check out --help to see the options.

• overlay_framemark
• render_tracking_video
• tip_twist_angle: global twist-angle measurement
• bend_curve_angle: global bend curvature measurement