Scientific paper on reflectance in radiometric adjustment

This paper examines how reflectance measurements can improve the radiometric adjustment of aerial imagery and create more consistent, physically meaningful image products. Focusing on UltraCam data, the authors present a workflow that uses ground truth measurements, camera spectral sensitivity, and sun angle information to stabilize radiometric processing and convert imagery into reflectance units.

A key emphasis of the paper is the benefit of reflectance-based adjustment for derived products such as NDVI. The study shows that converting aerial imagery from DN space to reflectance improves comparability across images acquired on different dates, under different illumination conditions, and even with different sensors. The results also demonstrate a better match with expected literature values and satellite-based reference products such as Sentinel NDVI, particularly in urban areas and sparse vegetation.

The paper further introduces a reflectance estimation model for projects where no direct ground measurements are available, making the approach highly relevant for large-scale production environments. The official ISPRS article is available online.

Download the full paper to learn more about the methodology, validation, and results.

Learn more about how to master radiometry: Key features and best practices in UltraMap photogrammetry software for high-quality aerial imagery.