{
  "id": 10443344,
  "title": "Radiance-Invariance Evaluation of a Compact LED-Based Source for Imager Radiance Transfer",
  "url": "https://urgent.news/2026/09/28/radiance-invariance-evaluation-of-a-compact-led-based-source-for",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-28T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.27.754831v1?rss=1"
  },
  "original_language": "en",
  "account": "Fluorescence imaging currently lacks reproducibility and standardization across devices, hindering comparisons and repeatability. To address this, researchers need a calibrated source that can reliably transfer known radiance levels to imaging systems. This study aimed to create and test a small, calibrated solid-state emitter target (RET) suitable for this purpose, as well as evaluate methods for assessing radiance consistency, imager sensitivity, and extending radiance transfer to specific image regions.\n\nThe researchers tested the LED-based RET's radiance output by measuring it from different distances between the source and the aperture, and at various collection aperture sizes. They used a previously developed formula that combines the known source radiance and the collection setup to calculate the imager's sensitivity (R{lambda}). They examined the stability of this sensitivity across different working distances and lens apertures. Additionally, they compared the results when using digitally defined regions of interest (ROIs) versus traditional physical apertures.\n\nThe results showed that the RET's radiance remained consistent across all tested distances and aperture sizes, with no significant differences observed (p = 0.88 for distance and p = 0.15 for aperture). Similarly, the imager's sensitivity stayed stable across varying working distances for the tested lens configurations (p = 0.48 and p ≥ 0.99). The sensitivity also remained consistent across different lens apertures, except for minor variations at the f/11 setting that could be attributed to practical aperture tolerances.\n\nFurthermore, the digitally defined ROIs yielded the same sensitivity values as those obtained with the physical apertures, confirming that the radiance transfer approach can be applied to image-defined regions. This method provides a reliable way to assess compact LED-based sources for maintaining consistent radiance levels and suitability for SI-traceable radiance transfer. The techniques can be adapted to other LED-based sources, although additional testing for angular characteristics and uncertainty analysis would be needed to broaden their applicability.",
  "summary": "Significance: Fluorescence imaging remains largely qualitative and device-specific, limiting reproducibility and intersystem comparisons. SI-traceable radiometric characterization requires calibrated sources suitable for transferring known radiance to imaging systems. Aim: Establish and evaluate a compact, calibrated solid-state radiometric emitter target (RET) for SI-traceable radiance transfer,…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}