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.NET WPF · OpenCV · 21 CFR Part 11

Modernizing a regulated vaccine plaque-counting system under 21 CFR Part 11

A full platform modernization of two regulated plaque-assay counting systems on the lot-release critical path — Windows XP to a validated Windows 11/WPF platform with OpenCV detection, a SQLite audit trail, and a CCD-to-CMOS optical redesign.

Modernizing a regulated vaccine plaque-counting system under 21 CFR Part 11

Customer

A Fortune 500 vaccine manufacturer running two regulated plaque-assay counting systems used in lot release — directly on the critical path, under 21 CFR Part 11.

Challenge

The two differently-configured systems ran on Windows XP with WinForms front ends, the Matrox Image Library for vision processing, InstallShield for deployment, and a third-party application for the audit trail required under Part 11. The optical hardware had aged too — the CCD sensors were end-of-life and no longer fit for purpose.

Because the systems gated lot release, any downtime carried direct regulatory and commercial consequences. The software stack was end-of-life across the board, the optical detection algorithm was never formally validated, and a third-party PLC driver added unnecessary licensing and reliability risk.

Solution

We executed a full platform modernization while maintaining 21 CFR Part 11 compliance throughout, with extensive on-site support during and after cutover.

  • Migrated Windows XP to Windows 11 with full IQ/OQ/PQ validation support.
  • Replaced the WinForms UI with a modern WPF application.
  • Replaced the Matrox Image Library with OpenCV, redesigning the plaque-detection algorithm from the ground up.
  • Carried out an optical redesign from CCD to CMOS sensors — improving sensitivity and throughput.
  • Replaced the third-party audit trail with a SQLite-backed system holding full Part 11 compliance: electronic signatures, audit trail, and record integrity.
  • Replaced InstallShield with the WiX Toolset for repeatable, version-controlled deployment.
  • Integrated OPC-UA for PLC communication, eliminating the third-party PLC driver.
  • Built a formal optical test suite with hyperparameter tuning, validating detection performance across the full operating range against a library of positive-control images.
  • Provided extensive on-site support, including emergency response for both software and optical issues.

Both systems now run on a fully supported, validated platform. The detection algorithm is formally characterized against a positive-control library, lot-release throughput improved with the CMOS upgrade, and the audit trail is fully compliant and no longer dependent on a legacy third-party application — backed by documented test coverage.