Version</th>	Date</th>	System image</th>	API reference</th>	Source</th></tr></thead>
v0.3.0</td>	2024-09-16</td>	legacy image</a></td>	doc/v0.3.0/</a></td>	tag</a></td></tr>
v0.2.0</td>	2023-12-06</td>	legacy image</a></td>	---</td>	tag</a></td></tr>
v0.1.0</td>	2023-11-10</td>	legacy image</a></td>	---</td>	tag</a></td></tr> </tbody></table> The single legacy image covers all pre-1.0.0 versions from v0.1.0 to v0.3.0. The project documentation refers to the latest release; older images are archived for reproducibility and should be used at your own risk.</p> Citation</h4> If you use OpenRRI in scientific work, please cite the original paper on the Range-Resolved Interferometry method (DOI: 10.1364/OE.23.009415</a>) and, where possible, also link to openrri.org</a>.</p> Literature 2023-11-13T00:00:00+00:00 </a> 1. Kissinger, Thomas, Thomas OH Charrett, and Ralph P. Tatam.</em> "Range-resolved interferometric signal processing using sinusoidal optical frequency modulation." Optics express 23.7 (2015): 9415-9431.</a></p> </a> 2. Kissinger, Thomas, et al.</em> "Fiber segment interferometry for dynamic strain measurements." Journal of Lightwave Technology 34.19 (2016): 4620-4626.</a></p> </a> 3. James, Stephen W., et al.</em> "Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run: 1. Measurement of strain." Smart Materials and Structures 31.7 (2022): 075014.</a></p> </a> 4. Kissinger, Thomas, et al.</em> "Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run: 2. Measurement of shape." Smart Materials and Structures 31.7 (2022): 075015.</a></p> </a> 5. Shmagun, Vitalii, et al.</em> "Comparison of fiber interferometric sensor with a commercial interferometer for a Kibble balance velocity calibration." Measurement Science and Technology (2023).</a></p> </a> 6. Shmagun, Vitalii, et al.</em> "Absolute distance measurements for in-situ interferometer characterisation using range-resolved interferometry." Measurement Science and Technology 33.12 (2022): 125024.</a></p> Imprint 2023-10-18T00:00:00+00:00 Institute for Process Measurement and Sensor Technology Technische Universität Ilmenau Jun.-Prof. Thomas Kissinger PF 100565 98684 Ilmenau/ Germany</p> +49 (0) 3677 69-2823 thomas.kissinger@tu-ilmenau.de</a> openrri@tu-ilmenau.de</a> www.tu-ilmenau.de/ipms/nfm</a></p> Copyright</h4> Copyright 2023-2026, TU Ilmenau, OpenRRI, All rights reserved. All texts, images and graphics are subject to copyright and other laws for the protection of intellectual property. Duplication, processing, distribution and any form of commercialisation of such material beyond the scope of the copyright law shall require the prior written consent of its author or creator. Downloads and copies of this site are only permitted for private use. They may not be copied for commercial purposes or for distribution, nor may they be modified and used on other websites. Legally protected images and third-party content are labelled as such. Should you become aware of a copyright infringement, please inform us accordingly. We will remove such infringements immediately.</p> Liability notice</h4> The information on this website has been compiled with the greatest possible care. Despite the most careful checks, we cannot guarantee that it is free of errors. Therefore, any guarantee or liability for the accuracy, timeliness and completeness of the information and data provided is excluded. This also applies to all other websites referred to directly or indirectly or which can be reached via a hyperlink from our website. We are not responsible for the content of such websites.</p> Further information</h4> We welcome any comments or suggestions regarding our website. Please send them to the webmaster</a> or open an issue</a> in the bug tracker.</p> Last change: 27.04.2026</p> Licence and Copyright 2023-10-18T00:00:00+00:00 OpenRRI is a project provided by the Institute for Process Measurement and Sensor Technology, TU Ilmenau</a>.</p> Licensing</h4> The OpenRRI software consisting of the OpenRRI Python library as well as the example scripts and applications, is licensed under the GNU Lesser General Public License Version 3 (LGPLv3)</a>. Copies of the full, unmodified license texts are provided in the `COPYING</code> file for the` `GPLv3</a> and in the COPYING.LESSER</code> file for the supplemental LPGLv3</a>.</p>` `Citation request</h4> If you are using the OpenRRI project for any work that forms part of a scientific publication, you are kindly requested to cite the original paper on the Range-Resolved Interferometry (RRI) method (DOI: https://doi.org/10.1364/OE.23.009415</a>) and, if possible, also link to the OpenRRI project ("https://www.openrri.org</a>") within that publication.</p>`

Getting Started

2026-04-27T00:00:00+00:00

OpenRRI ships in two parts: a prepared Linux/FPGA system image for the Red Pitaya STEMlab 125-14 board, and the openrri</code></a> Python library for data acquisition and RRI signal processing. This page is a short orientation. Theproject wiki</a> holds the full step-by-step instructions and is the authoritative reference.</p>

What you need</h4> A laser diode that supports mode-hop-free frequency modulation over a range of at least 6 GHz (~50 pm at 1550 nm).</li> A matching laser driver.</li> A photodetector for the wavelength in use.</li> A data acquisition board with at least one ADC and one DAC sharing the same trigger or clock. We use the Red Pitaya STEMlab 125-14 and provide a ready-made system image. See the tested hardware list</a> for known-good components.</li> </ul> 1. Flash the Red Pitaya SD card</h4> Download the latest system image from the Releases</a> page and flash it to the SD card supplied with the Red Pitaya (or any card 8 GB or larger). On Windows, Balena Etcher</a> works well; on Linux, gnome-disk-utility</code> does the job.</p> Read more: Preparing SD Card</a>.</p> 2. Connect the board</h4> Insert the SD card, power the board with 5 V, and connect it to your computer over Ethernet. We recommend a dedicated USB-Ethernet adapter. The board ships configured for the static IP 10.42.0.10</code>; configure your adapter to be on the same subnet. Both the IP and the network configuration can be changed on the board if needed.</p> Read more: Establishing Connection</a>.</p> 3. Install and use the Python library</h4> Install the library with its DAQ extras into a fresh virtual environment:</p> git clone https://gitlab.com/openrri/openrri.git cd openrri python3 -m venv venv source venv/bin/activate # Linux # venv/Scripts/activate # Windows pip install .[daq] </code></pre> Open a board connection, output a sinusoidal modulation signal on DAC 1 and read back a short ADC trace:</p> from openrri.daq import DAQFactory, BoardType, InterfaceType daq_config = { "board": { "board": BoardType.REDPITAYA, "soldered": False, }, "interface": { "interface": InterfaceType.WebSocket, "ip": "10.42.0.10", }, } board = DAQFactory.from_config(daq_config) # Modulation output: 20 kHz, 0.2..0.5 V, no phase shift: board.start_modulation(20_000, 0.2, 0.5, 0, channels=[1]) # 1 ms ADC sample acquisition: data = board.get_data_raw(0.001, channels=[1]) </code></pre> Read more: OpenRRI Python API overview</a> and the API reference</a> for the latest release.</p> Where to go next</h4> Full wiki Getting Started guide</a> for the complete walk-through, including interferometer adjustment and RRI processing.</li> API reference</a> for the latest release.</li> Example scripts on GitLab</a> covering common use cases.</li> </ul>

Releases

2026-04-27T00:00:00+00:00

The OpenRRI project ships in two parts: a prepared Linux/FPGA system image for the Red Pitaya STEMlab 125-14 board, and the openrri</code></a> Python library for data acquisition and RRI signal processing. This page lists the current and previous releases of both. Full release notes are tracked on theGitLab Releases tab</a>.</p>

Latest release: v0.4.0 (2026-04-20)</h4>
Version 0.4.0 introduces a WebSocket-based DAQ interface that brings
multichannel modulation, software-adjustable sample rates, continuous
streaming and live RRI processing. Storage moved to the
HDF5 format</a>.</p>
Red Pitaya STEMlab 125-14 system image</strong></p>

Factory boards: openrri-v0.4.0-factory.img.xz</a> (sha256</a>)</li>
Soldered boards: openrri-v0.4.0-soldered.img.xz</a> (sha256</a>)</li>
</ul>
The soldered variant is for boards that have been
modified</a>
to provide a 0..2 V DAC output range. Use the factory variant for unmodified
boards.</p>
Python library</strong></p>

Source tag: openrri v0.4.0</a></li>
API reference: openrri.org/doc/v0.4.0/</a></li>
Install from the source tag:</li>
</ul>
git clone --branch v0.4.0 https://gitlab.com/openrri/openrri.git
cd openrri
pip install .[daq]
</code></pre>
Highlights</strong></p>

New WebSocket DAQ interface with board discovery, multichannel modulation and software-adjustable sample rates.</li>
Continuous long-term streaming up to 8 MSps and short-term capture up to 125 MSps.</li>
Live, updating range-view and RRI channel demodulation plots.</li>
HDF5 storage for raw, demodulated and peak-detected data.</li>
</ul>
Full release notes for v0.4.0</a></p>
Previous releases</h4>
Version</th> Date</th> System image</th> API reference</th> Source</th></tr></thead>

v0.3.0</td> 2024-09-16</td> legacy image</a></td> doc/v0.3.0/</a></td> tag</a></td></tr>
v0.2.0</td> 2023-12-06</td> legacy image</a></td> ---</td> tag</a></td></tr>
v0.1.0</td> 2023-11-10</td> legacy image</a></td> ---</td> tag</a></td></tr>
</tbody></table>
The single legacy image covers all pre-1.0.0 versions from v0.1.0 to v0.3.0.
The project documentation refers to the latest release; older images are
archived for reproducibility and should be used at your own risk.</p>
Citation</h4>
If you use OpenRRI in scientific work, please cite the original paper on the
Range-Resolved Interferometry method
(DOI: 10.1364/OE.23.009415</a>) and, where
possible, also link to openrri.org</a>.</p>


Literature
2023-11-13T00:00:00+00:00
</a>
1. Kissinger, Thomas, Thomas OH Charrett, and Ralph P. Tatam.</em> "Range-resolved interferometric signal processing using sinusoidal optical frequency modulation." Optics express 23.7 (2015): 9415-9431.</a></p>
</a>
2. Kissinger, Thomas, et al.</em> "Fiber segment interferometry for dynamic strain measurements." Journal of Lightwave Technology 34.19 (2016): 4620-4626.</a></p>
</a>
3. James, Stephen W., et al.</em> "Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run: 1. Measurement of strain." Smart Materials and Structures 31.7 (2022): 075014.</a></p>
</a>
4. Kissinger, Thomas, et al.</em> "Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run: 2. Measurement of shape." Smart Materials and Structures 31.7 (2022): 075015.</a></p>
</a>
5. Shmagun, Vitalii, et al.</em> "Comparison of fiber interferometric sensor with a commercial interferometer for a Kibble balance velocity calibration." Measurement Science and Technology (2023).</a></p>
</a>
6. Shmagun, Vitalii, et al.</em> "Absolute distance measurements for in-situ interferometer characterisation using range-resolved interferometry." Measurement Science and Technology 33.12 (2022): 125024.</a></p>


Imprint
2023-10-18T00:00:00+00:00
Institute for Process Measurement and Sensor Technology

Technische Universität Ilmenau

Jun.-Prof. Thomas Kissinger

PF 100565

98684 Ilmenau/ Germany</p>
+49 (0) 3677 69-2823

thomas.kissinger@tu-ilmenau.de</a>

openrri@tu-ilmenau.de</a>

www.tu-ilmenau.de/ipms/nfm</a></p>
Copyright</h4>
Copyright 2023-2026, TU Ilmenau, OpenRRI, All rights reserved. All texts, images and graphics are subject to copyright and other laws for the protection of intellectual property. Duplication, processing, distribution and any form of commercialisation of such material beyond the scope of the copyright law shall require the prior written consent of its author or creator. Downloads and copies of this site are only permitted for private use. They may not be copied for commercial purposes or for distribution, nor may they be modified and used on other websites. Legally protected images and third-party content are labelled as such.

Should you become aware of a copyright infringement, please inform us accordingly. We will remove such infringements immediately.</p>
Liability notice</h4>
The information on this website has been compiled with the greatest possible care. Despite the most careful checks, we cannot guarantee that it is free of errors. Therefore, any guarantee or liability for the accuracy, timeliness and completeness of the information and data provided is excluded. This also applies to all other websites referred to directly or indirectly or which can be reached via a hyperlink from our website. We are not responsible for the content of such websites.</p>
Further information</h4>
We welcome any comments or suggestions regarding our website. Please send them to the webmaster</a> or
open an issue</a> in the bug tracker.</p>
Last change: 27.04.2026</p>


Licence and Copyright
2023-10-18T00:00:00+00:00
OpenRRI is a project provided by the Institute for Process Measurement and Sensor Technology, TU Ilmenau</a>.</p>
Licensing</h4>
The OpenRRI software consisting of the OpenRRI Python library as well as the example scripts and applications, is licensed under the GNU Lesser General Public License Version 3 (LGPLv3)</a>. Copies of the full, unmodified license texts are provided in the COPYING</code> file for the GPLv3</a> and in the COPYING.LESSER</code> file for the supplemental LPGLv3</a>.</p>
Citation request</h4>
If you are using the OpenRRI project for any work that forms part of a scientific publication, you are kindly requested to cite the original paper on the Range-Resolved Interferometry (RRI) method (DOI: https://doi.org/10.1364/OE.23.009415</a>) and, if possible, also link to the OpenRRI project ("https://www.openrri.org</a>") within that publication.</p>