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's a project that's fostering the standardization of luminance distribution measurement methods—a crucial aspect for understanding glare, light pollution, and other critical lighting assessments.

The HiDyn project is 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 upcoming focus involves conducting HDR luminance measurements using the high contrast luminance reference standard source, developed within the project. 

First progress

We have 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. We tested algorithms that take nine LDR images of the same object with different exposure times to create one HDR, using different merging methods, like (i) identifying the LDR pixel signal captured next below a certain margin to the clipping level, (ii) by taking the weighted average of LDR pixel signals captured at various integration times, and (iii) estimating the slope of the I_j versus t_i function, where I_j is the pixel count signal for the pixel j and t_i is the integration time of the camera. An example is shown in Figure 1 below.

In future endeavors, this software will investigate the impact of various factors such as camera nonlinearity, internal stray-light, and lens flare on HDR luminance measurements. Furthermore, the overarching goal is to validate an image processing chain for HDR luminance image capture, taking these factors into account. This process involves identifying the necessary input data for the HDR algorithm. The comparability of HDR luminance measurements across different camera technologies will be demonstrated. The goal is to establish HDR luminance measurements for high-contrast images as a reference for different imaging systems such as ILMD, professional and scientific cameras, while also examining the uncertainty associated with each measurement to evaluate compatibility.

More information

Explore the project website to dive deeper into the realm of HiDyn and the brighter future it holds. For direct inquiries, connect with our contact persons: Ville Mantela and Yasaman Rezazadeh.