Rospix3

Build status

ROS driver for TPX3 event-camera devices on the Advacam hardware interface, most notably the MiniPIX TPX3 with a CdTe sensor used as a single-detector Compton camera.

The driver reads out the continuous stream of hit pixels produced by the Timepix3 chip, clusters them into particle tracks (below), and publishes them as rad_msgs/ClusterList messages for downstream processing.

System overview

Rospix3 is the lowest layer of a three-package pipeline for real-time gamma radiation source localization from a single-detector Compton camera:

1. Rospix3 (this package) — drives the MiniPIX TPX3 detector and publishes the stream of detected particle clusters.
2. compton_cone_generator — pairs coincident electron/photon clusters from Rospix3 and reconstructs the Compton cone of possible source directions for each event.
3. compton_camera_filter — fuses the incoming stream of cones into a real-time full-state hypothesis of the radiation source position.

How it works

The core is the Rospix3 nodelet (src/rospix3.cpp). It is a thin ROS wrapper around the vendor Pixet Core SDK (lib/x64/pxcore.so) — it does not do any Compton-specific processing itself, it just turns the raw stream of detector hits into ROS messages.

• Init — loads parameters, dynamically loads pxcore.so (pxpClLoadPixetCore) and opens a handle to detector 0 (pxpClCreate). If use_calibration is set, it loads the per-pixel energy calibration (a/b/c/t.txt) into the SDK. It registers 5 callbacks with the SDK (message/progress/new-clusters/acquisition-start/acquisition-finished) and, if save_raw_data is set, creates a timestamped output directory for raw .t3pa dumps.
• timerMeasurement (measurement_timer_rate) — if the detector is idle and the dynamic-reconfigure flag measuring is true, starts a new acquisition window via pxpClStartMeasurement(acquisition_duration, measurement_duration, ...), optionally streaming the raw pixel data straight to a .t3pa file on disk.
• SDK callback callbackTimepixNewClustersWithPixels — fires asynchronously from the SDK whenever it has clustered a batch of hit pixels into particle tracks. For every PXPClusterWithPixels it builds a rad_msgs::Cluster (energy, pixel size, roundness, centroid x/y, time-of-arrival) together with all of its individual hit pixels, and pushes it onto an internal queue guarded by mutex_cluster_list_.
• callbackTimepixAcquisitionFinished — bookkeeping for each finished acquisition; if noisy_pixel_masking is enabled, triggers pxpClMaskNoisyPixels to blacklist hot pixels found during that acquisition.
• timerPublisher (publisher_timer_rate) — independently drains the internal queue and publishes everything accumulated since the last tick as one rad_msgs/ClusterList on cluster_list_out.

src/rospix3multisensor.cpp provides a second nodelet, Rospix3Multisensor, with the exact same logic duplicated for two hardcoded detector handles, each publishing to its own <sensor_alias>/cluster_list topic — for setups with two TPX3 devices on one host.

Compatibility

ROS Melodic / Noetic

Dependencies

ROS, catkin-tools, and other dependencies required for compiling Rospix3 with its other dependencies:

./installation/install_dependencies.sh

Clone the following packages into your workspace and compile together with Rospix3.

• mrs_lib
  • mrs_msgs
• rad_msgs

Citing this work

If you use this package in your research, please cite the following papers:

@inproceedings{baca2019timepix,
  author    = {Baca, Tomas and Jilek, Martin and Manek, Pavel and others},
  title     = {{Timepix Radiation Detector for Autonomous Radiation Localization and Mapping by Micro Unmanned Vehicles}},
  booktitle = {2019 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
  year      = {2019},
  publisher = {IEEE},
  pages     = {1--8},
}

@inproceedings{baca2021gamma,
  author    = {Baca, Tomas and Stibinger, Petr and Doubravova, Daniela and Turecek, Daniel and Solc, Jaroslav and Rusnak, Jan and Saska, Martin and Jakubek, Jan},
  title     = {{Gamma Radiation Source Localization for Micro Aerial Vehicles with a Miniature Single-Detector Compton Event Camera}},
  booktitle = {2021 International Conference on Unmanned Aircraft Systems (ICUAS)},
  year      = {2021},
  publisher = {IEEE},
}

@article{stibinger2020localization,
  author  = {Stibinger, Petr and Baca, Tomas and Saska, Martin},
  title   = {{Localization of Ionizing Radiation Sources by Cooperating Micro Aerial Vehicles With Pixel Detectors in Real-Time}},
  journal = {IEEE Robotics and Automation Letters},
  volume  = {5},
  number  = {2},
  pages   = {3634--3641},
  year    = {2020},
  doi     = {10.1109/LRA.2020.2978456},
}