Iris Optics
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Optical MetrologyMachine VisionData Pipelines

Rainbow Stray Light Analysis Framework

Developing image-processing and perceptual metrics for stray light characterization.

Challenge

Quantifying visually meaningful stray light artifacts (often referred to as 'rainbows') in complex optical systems was highly subjective and manual.

Approach

We developed an analysis framework using advanced image segmentation, morphology, and region metrics. We applied perceptual weighting to the data to generate repeatable output reports.

Outcome

The new framework provided faster analysis, improved comparability between different designs, and enabled better, data-driven engineering decisions.

Background

Stray light artifacts, particularly colorful “rainbow” ghosting effects, can severely degrade the user experience in near-eye displays and advanced imaging systems. However, “bad” stray light is notoriously difficult to quantify.

The Challenge

Engineering teams were relying on subjective visual inspection to evaluate stray light. One engineer might score a lens a “fail” while another scored it a “pass”. The lack of objective, repeatable metrics meant that it was impossible to track design improvements or set clear manufacturing tolerances.

The Approach

We developed a custom image-processing framework to turn subjective perception into objective data:

  1. Image Segmentation: We implemented algorithms to isolate specific stray light artifacts from the background image data.
  2. Morphological Analysis: We analyzed the shape, size, and intensity distribution of the isolated artifacts.
  3. Perceptual Weighting: Crucially, we applied weighting functions that penalized artifacts based on their location in the field of view and their color contrast against the background, mimicking human visual perception.
  4. Automated Reporting: We built tools to automatically generate standardized reports for every tested lens.

The Outcome

The framework replaced subjective arguments with objective data. Engineering teams could now directly compare the stray light performance of different optical designs, and manufacturing teams had clear, repeatable metrics to establish pass/fail criteria.