Inside a High-Speed Web Inspection System: Line-Scan Cameras, Telecentric Optics, and UV Fluorescence

This is the anatomy of a web inspection system we built for a medical device line running adhesive product on a carrier web at 800 feet per minute - every major component, why it was chosen, and where to learn more about each one. The customer details stay private; the engineering does not.

The problem shape

Small repeating products on a fast-moving web, defects invisible under white light, and a requirement to inspect both sides without slowing the line. Manual inspection was the baseline: slow, inconsistent, and blind to anything subtle. The technical trick that unlocked the job: the adhesive carried an optical brightener, so under UV illumination the defects fluoresce - the vision problem becomes contrast the cameras can actually see.

The hardware, component by component

• Cameras: two Teledyne DALSA Piranha3 16k CMOS line-scan cameras - line-scan is the only sane architecture at web speeds; area cameras waste pixels re-imaging the same material.

• Optics: Opto Engineering telecentric lenses - telecentricity keeps magnification constant across the field, which is what makes dimensional judgments trustworthy at the edges of the image.

• Lighting: Metaphase line lights with UV filtering - the fluorescence trick only works if the illumination is uniform along the full web width.

• Frame grabbers: Teledyne DALSA Xcelera-HS - at 16k pixels per line and hundreds of kilohertz line rates, the acquisition path is a real engineering constraint, not an accessory.

• Vision software: Cognex VisionPro running on a PC platform - PC-based vision earns its complexity when you need custom defect classification and full-web data logging.

What made it work in production

Two decisions mattered more than any single component. Marking defects rather than stopping the line - a downstream marking system flags defective sections for splice-table removal, so the inspection never becomes the bottleneck. And logging everything - once every vent on every web is a database row, quality trends stop being anecdotes.

This article is part of the Saber portfolio series: real systems, real components, customer details omitted. The pattern library behind it lives in the Saber knowledge base. If your line needs eyes at 800 feet per minute, that is our day job - use the contact form.

Downloads

Free, no signup. The knowledge file is designed to be dropped into an AI assistant's context. No customer information in any of it.

• knowledge.md - high-speed web inspection field lessons (for your AI assistant)