The Steinbeis Transfer Center for Sensorics and Information Systems – SensIn‘ has been working in collaboration with the Mainz-based company Phrealog as part of a project called FLIMSYS. Sponsored by the German Federal Ministry for Education and Research (BMBF), the aim is to develop an image-based measurement technique that makes it possible to work out the speed and direction of local groundwater flows in specific locations or around drilled wells.
The technique involves using a measurement probe with a free-flowing chamber to make minute floating particles visible in the groundwater. It does this by directing a laser beam into a drilled well and capturing visible patterns of particles on camera. These are then analyzed for pattern changes over time (particle imaging velocimetry, or PIV). The resulting vector data is then used to record the water flow in the well. This is a direct reflection of flows in the groundwater in the immediate vicinity. The process is used for hydrogeological inspections in the water utilities industry, in environmental protection, in civil engineering, and for geothermal energy purposes. The aim of the ongoing development project is to design a modular measurement system that can be used to take simultaneous measurements at various depths within the groundwater at a given location. Further down the line, it is hoped not just to capture water flows but also the different physical and chemical properties of the groundwater, depending on the given requirements. The benefit of the system that is currently being developed is that it can capture flowing movements extremely accurately, improving productivity and thus paving the way for sustained use in monitoring scenarios.
At the heart of the new system lies a camera system that was specially developed for the project. This delivers video sequences up to XSGA resolution via I2C and SPI interfaces. The laser can be controlled and directed and there is also a compass sensor complete with I/O ports. The interfaces make it easier to integrate further sensor systems. The modular version of the system has an individual camera system within each module. These can be linked up with data cables to allow each individual module to be controlled and monitored individually. Each module is contained within a high-pressure housing and equipped with the required optical components to be connected to other modules via sections of cable and form a “measurement chain.” This delivers simultaneous data from different depths. Image data and the data supplied by the integrated sensors is forwarded via GigE to a computer for processing. The new measurement architecture made it necessary to come up with a new kind of camera system to work with the control and image processing software. As a result, as part of the collaboration between Phrealog the Steinbeis Transfer Center for Sensorics and Information Systeme – SensIn’, a new measurement operating system was developed. This is called PHREASOFT and it has been specially adapted to the camera equipment and the nature of the task. As a measurement operating system, PHREASOFT includes system controls and the ability to read onboard sensors, capture measurement images, evaluate these, and transmit and store this measurement data. Since the overall aim was to develop software that is platform-independent, the project partner wrote the software in Java to allow for various types of platforms. One particular challenge with the development of PHREASOFT is the bidirectional communication between the proprietary driver and the Java components. This meant that data formats had to be adapted and peripheral components had to be synchronized. The configuration data, measurement values and results are stored in corresponding XML files for other uses later down the line. To manage the complexities of the task, the PHREASOFT software involves intensive use of multitasking.
In parallel to the technological development work, the University of Mainz, the Fraunhofer ITWM and Phrealog are also working in collaboration to develop an expert system called PHREASIM. This will make it possible to simulate and map water flow scenarios in wells. First field trials are scheduled to take place in the summer of 2015.
The PHREALOGx measurement system is an important step forward in capturing groundwater flows in-situ. Hand in hand with the PHREASIM expert system, it is now possible to assess and interpret acquired flow data in a more realistic setting than was previously possible. An important aim with the newly developed system is to be able to use it as a stationary monitoring instrument in groundwater measurement networks. One of the major advantages of this system is that, depending on the measure requirements, the existing system interfaces can be expanded to integrate other sensors into the system, without having to change the existing technical equipment and communication infrastructure.
Farjana Huq completed her master’s thesis on the above topic as part of a project for her degree in Sensor Systems Technology at Karlsruhe University of Applied Sciences.
Silvana Mehmetaj works as an assistant to Prof. Dr. Thorsten Leize who founded the Steinbeis Transfer Center for Sensorics and Information systems – SensIn’ at Karlsruhe University. Work at the center focuses among other things on software development, model-based drafting and implementation, bus system security, security issues in automation technology, cryptology, and sensors.
Dr. Marc Schottler is the founder of Phrealog, a company specialized in groundwater flow measurement and drilled wells.
Silvana Mehmetaj, Prof. Dr. Thorsten Leize
Steinbeis Transfer Center Sensorics and Information Systems - SensIn‘ (Karlsruhe)
Dr. Marc Schöttler