• ROS package for interfacing Timepix detectors on FitPIX-compatible (Advacam) or USB Lite-compatible (UTEF) readouts.
• Allows measuring with multiple sensors simulatenously.
• To be able to use it, install Linux OS compatible with ROS (Indigo or newer).
• Install ROS and FTDI drivers, see section Prerequisities.

Get the drivers:

sudo apt-get install "libftdi-*"

Create file 99-ftdi-sio.rules with following lines

ACTION=="add", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6010", MODE="0666",  RUN+="/bin/sh -c '/sbin/rmmod ftdi_sio && /sbin/rmmod usbserial'"
ACTION=="add", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", MODE="0666",  RUN+="/bin/sh -c '/sbin/rmmod ftdi_sio && /sbin/rmmod usbserial'"
ACTION=="add", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6014", MODE="0666",  RUN+="/bin/sh -c '/sbin/rmmod ftdi_sio && /sbin/rmmod usbserial'"

and place it in /etc/udev/rules.d/

Follow tutorials on http://wiki.ros.org/kinetic/Installation/Ubuntu ... the core is extracted in following commands:

sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'
sudo apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116
sudo apt-get update
sudo apt-get install ros-kinetic-desktop-full python-catkin-tools ros-kinetic-cv-bridge
apt-cache search ros-kinetic
sudo rosdep init
rosdep update
echo "source /opt/ros/kinetic/setup.bash" >> ~/.bashrc
source ~/.bashrc

Firstly, find a unique ID of your Timepix interface. Connect it to your computer and run:

roslaunch rospix list_device

A list of device names will appear. Copy the insides of double commas, corresponding to your interface. It is supposed to look similar to: Medipix2 ver 1.32 sn: 1096. Create a config yaml (or modify the example in config/) file with following contents:

# dont forget to update this number according to following contents
number_of_detectors: 1

sensor_0: # the names are fixed, just the number change

  # by this name the device is found, run "roslaunch rospix list_devices" to find it
  name: 'Medipix2 ver 1.32 sn: 1096'

  # location of the equalization file
  # location is relative to a directory specified in launch file
  equalization: 'lite_rigaku.bpc' # *.bpc is needed

  # print percentage of sensor exposure time to real time
  print_utilization: true

  defaults:
    threshold: 340    # [-]
    bias: 10.0        # [Volt]
    exposure: 1.0     # [second]
    mode: 1           # [0 = MPX, 1 = TOT]

    # dacs can be found in calibration protocol (or equalization protocol)
    dacs: [1,100,255,127,127,0,340,7,130,128,80,85,128,128]

Secondly, place a pixel configuration matrix (equalization matrix) into equalizations/ folder.

Lastly launch the node using launch file example test.launch in launch/. It loads the example config file and sets the equalization directory.

roslaunch rospix test.launch

<launch>

  <!-- launch the node -->
  <node name="rospix" pkg="rospix" type="rospix" output="screen">

    <!-- load config from config file -->
    <rosparam file="$(find rospix)/config/test.yaml" />

    <!-- specify where should the node look for equalization matrices -->
    <param name="equalization_directory" value="$(find rospix)/equalizations/" />

    <!-- PUBLISHERS -->
    <remap from="~status" to="~status" />

  </node>

</launch>

The node allows creating ("connecting") dummy detectors. Any number of dummy detectors can be connected, even while real detectors are present. Here is an example of config file record for an dummy detector:

sensor_1:

  name: 'dummy'

  photon_flux: 100            # [photons/s], whole number
  simulate_background: true   # should we simulation radiation background?
  n_images: 20                # how many images of radiation background do we have?

  defaults:
    exposure: 1.0             # [seconds]

Images for creating artificial radiation background are located in the dummy subfolder. If anyone should provide their own additional images, copy them there and adjust n_images accordingly.

After connecting to the devices, a message is published on

/rospix/status

reporting how many interfaces have been successfully opened. Namespaces will appeare for the opened, named as follows:

/rospix/sensor_0/...
/rospix/sensor_1/...
...

Following services provide control over some basic operations:

/rospix/sensor_0/do_batch_exposure
/rospix/sensor_0/do_continuous_exposure
/rospix/sensor_0/do_single_exposure
/rospix/sensor_0/interrupt_measurement
/rospix/sensor_0/set_bias
/rospix/sensor_0/set_exposure_time
/rospix/sensor_0/set_mode
/rospix/sensor_0/set_threshold
...
/rospix/sensor_1/...

Resulting images are published at

/rospix/sensor_0/image
/rospix/sensor_...

as a topic containing:

time stamp
float64 exposure_time
float64 bias
int32 threshold
string interface
int32 mode
int16[65536] image

Sample applications can be found in the rospix/utils repository.

1. T. Baca, D. Turecek, R. McEntaffer and R. Filgas, Rospix: Modular Software Tool for Automated Data Acquisitions of Timepix Detectors on Robot Operating System, Journal of Instrumentation 13(11):C11008, 2018.

The work has been done on behalf of Medipix2 collaboration and is currently supported by the Czech Science Foundation project 18-10088Y and by Czech Technical University grant no. SGS17/187/OHK3/3T/13.