March 2025 - Publication of the 3rd Newsletter: Update at midterm
Recently, project 22NRM05 - MeLiDos reached its midpoint. This is an occasion to review what has been achieved so far through our several newsletters, in particular our newly released 3rd edition. Please check out a summary below and find the complete newsletters here.
The MeLiDos team met in November 2024 at METAS, Bern, Switzerland for the Month 18 meeting.
Update on device characterisation
Three different models of solar UV dosimeters and four models of wearable light loggers have been acquired and distributed among the partners. The process of determining suitable characterization methods is ongoing, with several ideas being tested.
Characterization under skylight of solar UV loggers in Davos, Switzerland
Right now the methods being tested are compared to usual laboratory calibration procedures to select the most suitable ones for logger-type devices. As an example, a light logger which records a data point every 10 seconds would take a long time to have its spectral sensitivity evaluated with conventional methods. Using a set of well-selected LED emmitters would provide a cost- and time-efficient alternative albeit with degraded uncertainty, which would regardless not be a major issue in field measurements where measurement uncertainty comes primarily from device position, wearer movement, etc.
Field data collection
Data collection started in fall 2024 in some of our 6 selected sites and will be completed by the beginning of summer 2025 by all partners. There is great collaboration between the partners for the transfer of experiences from field measurements, dosimeter use and survey procedures. Several stakeholders have also approached the Consortium to use or adapt the data collection protocol and software developed in the project and already published.
Picture of the participants with the dosimeters
On that particular note, we are delighted to see ever more interest in the software package LightLogR from research groups all around the world. Notably, the package nears publication in the Journal of Open Source Software (JOSS, access the preprint here). We are preparing a major update that will bring solar-time-based functionality to the package - enabling powerful calculations and visualizations based on dusk, dawn, noon, etc. Look out for LightLogR 0.5.0 "Civil dawn“ in the coming days!
Towards spatial resolution in light logging
The WP3 team has completed its investigation into the privacy issues posed by spatially resolved light loggers. This analysis drew on several similar use cases, including dash cams, CCTV, and Google Street View. In summary, the proposed mitigation strategies include minimizing the amount of data collected, using built-in blur algorithms before exploiting high-resolution images, securing data storage and transfer, and making the data processing methods and technical details publicly available. Furthermore, the team also formulated recommendations for characterizing spatially resolved devices, based on the technical report CIE 244:2021 (Characterization of Imaging Luminance Measurement Devices) and their experience with conventional light loggers.
On the technical front, the team is continuing to develop data methods for camera-based devices, both to compare to and expand on existing metrics in light dosimetry. The team has also identified two promising directions for a PoC spatially-resolved light dosimeter, and hope to disclose more in the next newsletter this summer.