HiDyn (2022-2025)
Illuminating the Future: The HiDyn Project (2022-2025)
Embracing the forefront of metrology innovation, the Metrology Research Institute stands as a participant in the European Partnership of Metrology Programme (EPM) project HiDyn—a pioneering venture aimed at shaping the future of luminance distribution measurements for glare and obtrusive light using high-dynamic-range (HDR) imaging systems.
Meeting Environmental and Safety Concerns
The EU's Green Public Procurement Criteria for Road Lighting and Traffic Signals magnifies the significance of addressing light pollution—a concern that disrupts both the well-being of humans and the balance of ecosystems. However, measuring light pollution is no simple task, especially given the complex contrasts in natural environments. High dynamic range (HDR) imaging provides a solution by capturing multiple exposures of the same image, preserving vital details. Yet, the lack of uncertainty statements and traceability in commercial HDR systems has limited their usability and comparability.
Project Overview
Coordinated by the Physikalisch-Technische Bundesanstalt (PTB) and led by Johannes Ledig, Project HiDyn (21NRM01) embodies a mission to empower traceability and characterization of HDR imaging luminance systems. More than that, it was a project that fostered the standardization of luminance distribution measurement methods—a crucial aspect for understanding glare, light pollution, and other critical lighting assessments.
The HiDyn project was concerned about light pollution's environmental and safety impacts. By developing HDR luminance standards that are essential for characterizing HDR imaging measurement systems, and by formulating metrics and guidelines for assessing associated uncertainties, we're steering towards a brighter future.
Our Role
Our focus involved two main tasks. First, conducting HDR luminance measurements using the high contrast luminance reference standard source, developed within the project. Second, we performed HDR luminance measurements of the high contrast luminance reference standard developed within the project.
We developed distinct algorithms for simulating the performance of different HDR systems to get accurate luminance measurements in high-contrast scenes. This methodology involves simulating a set of LDR (low dynamic range) images at various exposure times with a camera model that considers digital and optical errors, use of different HDR merging algorithms to produce an HDR luminance image, and comparison of the performance of those algorithms against original metrics.
The algorithms we developed were an important step in choosing and completing the HDR methods used in the 21NRM01 HiDyn toolbox. By simulating different HDR systems, testing several merging methods, and checking how they performed with many exposure levels, we were able to see which approaches worked best for accurate luminance measurements. These results led to the selection of four reliable HDR merging methods—best-exposure, weighted averaging (in linear and logarithmic form), and linear regression—which were then added to the open-source MATLAB toolbox. The toolbox can handle LDR image series, exposure times, dark-frame correction, raw file conversion, and camera calibration. It produces HDR images in MATLAB and .hdr formats and includes simple instructions for applying needed corrections such as flat-field, distortion, and non-linearity. This work helps users of different ILMDs (Imaging luminance measurement device ) create trustworthy HDR luminance maps , making tasks in road lighting, glare studies, and light-pollution research easier and more consistent.
As a second role in the project, we performed HDR luminance measurements of the high-contrast luminance reference standard developed within the project. These measurements were taken at defined positions using different ILMDs. For each measurement, we evaluated the results and reported the luminance together with all parameters needed for building the uncertainty budget, allowing the compatibility of the measurements to be assessed.
More information
Explore the project website to dive deeper into the realm of HiDyn.