Dynamic system for real-time measurements of tunnel and road lighting using machine vision

A dedicated system for the measurement of road surface luminance for the validation of road and tunnel lighting systems in real time is presented. The system is designed to be installed on a moving vehicle in order to avoid disturbance of in traffic and to minimize the required time for the measurements. The system is the result of a PhD research and has been already used for the validation of lighting systems of several tunnels.

According to current European and International standards, related to lighting of roads and tunnels, the validation of the lighting levels is mandatory for safety reasons. Lighting measurements should be repeated at regular intervals throughout the lifetime of the installations. This is also reinforced by the need for the rational use of energy in highly energy-intensive street and tunnel lighting installations.

The equipment, that is traditionally used for such kind of measurements, presents major issues concerning the time needed for the measurements, the preparations in the field and the post processing effort. Even modern systems using digital optical sensors are designed mainly for laboratory measurements, limiting their usability to external test fields. In any case, measurements on roads and tunnels require a partial or total interruption of vehicle traffic, which put at risk the road safety and increases the complexity of the whole operation.

The road surface luminance measurement system was developed based on CCD technology and specialized image processing techniques. The equipment is installed on a vehicle, the measurements are carried out as the vehicle moves, and the measurement results can be exported in real time. The development of the system is related to the design and implementation of both devices and software algorithms for the purpose of dynamic lighting measurements on roads and tunnels. Specific calibration and testing apparatuses for each individual subsystems have been developed. At the same time, the corresponding measurement methodologies were designed and described for each type of measurement.

Figure 1 – Calibration process (left) and mounting demo of the system on a vehicle (right)

Figure 2. Mobile measurement system on field (left). View of the control software from the car (right)

Figure 3. Example of measurement result in a tunnel

Figure 4. Example of measurement result in a road interchange

Figure 5. Example of automatic image processing for measurement assessment

Figure 6. Variation of road surface luminance in a typical tunnel as derived by the measurement process.

Relevant stakeholders of offered services of this system could be:

  • Motorway owners and operators
  • Motorway maintenance service providers
  • Engineering companies
  • EPC companies
  • Independent engineers
  • Public authorities and government bodies
  • Research teams
  • etc

Up to today, the system has been used to validate the lighting system of more than 60 road tunnels and tenths or road interchanges around Greece and Balkan countries while more are under negotiations in additional countries. The measurement results were used to support the official delivery of the corresponding projects.

For more information please contact: Prof. Frangiskos Topalis, Tel. (+30) 2107723627

Lighting Laboratory website