Detection of Heat-Treated Markings on a Wooden Pallet Optical Verification of ISPM-15 Compliance

This patent describes an automated optical system for inspecting wooden pallets to confirm that the international heat-treatment marking, mandated for cross-border movement under ISPM-15, is present, legible, and authentic. It is intended for high-throughput pallet pooling operations where every unit must be verified before it ships.

The Problem

International phytosanitary standard ISPM-15 requires that any solid-wood pallet crossing borders be heat-treated or fumigated and stamped with a defined IPPC marking that identifies the treatment provider and treatment type. The marking is what customs and biosecurity inspectors look for, and a missing or unreadable stamp can result in shipments being held, fumigated at port, or rejected outright. CHEP and other pallet-pool operators handle hundreds of millions of pallet movements per year, so manual visual inspection is too slow, inconsistent, and prone to fatigue errors. A machine-vision approach that reliably detects the presence and integrity of the heat-treatment mark, despite the dirt, splinters, paint, repairs and weathering that real-world pallets accumulate, has been a long-standing operational gap.

What This Invention Does

The invention is a vision system that captures images of the pallet sides where the heat-treatment marking is expected, then applies image-processing and pattern-recognition steps to locate and verify the IPPC mark. The system handles common real-world failure modes: low contrast caused by ageing of the burned mark, partial occlusion by debris, glare, oblique camera angles, and visual look-alikes such as ink stamps or grade markings that should not be accepted as heat-treatment evidence. When the mark is found and validated, the pallet is logged as compliant; when it is missing, illegible, or fails authentication, the pallet is flagged for diversion, rework or destruction.

The disclosed method covers the imaging geometry, the pre-processing pipeline (illumination correction, contrast enhancement, region-of-interest extraction), and the matching logic that distinguishes a genuine ISPM-15 IPPC mark from incidental markings. It is engineered for in-line operation on a moving pallet conveyor.

Key Features

• Targeted optical inspection of stamp regions. Cameras and lighting positioned to capture the pallet faces where the IPPC mark is expected, optimised for the visual character of a burned-on heat-treatment stamp.
• Robust to real-world pallet condition. Image-processing steps designed to recover marks from weathered, dirty, repaired or oblique-view pallets that defeat naive thresholding.
• Discrimination of mark types. The recognition logic distinguishes genuine ISPM-15 markings from grade stamps, ink markings, or counterfeit symbols, helping prevent non-compliant pallets from being released into export streams.
• Pass and fail outcomes routed automatically. Verified pallets continue down the line; flagged units are diverted for re-inspection, repair or destruction, supporting end-to-end auditability.
• Designed for pool-scale throughput. The pipeline is built for in-line use in a pallet-pool depot, where tens of thousands of pallets are inspected per day.

Who Is Behind It?

The applicant is CHEP Technology Pty Limited, the technology arm of CHEP, the global pallet pooling business owned by Brambles Limited. CHEP operates one of the largest reusable-pallet networks in the world. The named inventor team is unusually broad and reflects an international engineering effort, including Christopher J. Gerou, Khurram Soomro, Miguel Angel Zazo De La Rocha, Francisco Jesus Hidalgo, Jose Manuel Argibay Canas, Daniel Tomer, Elazar Cohen and others. The Australian application is a divisional of AU 2022367407.

Why It Matters

ISPM-15 enforcement is a non-negotiable requirement for any timber packaging entering Australia, the EU, the US, China and most other major markets. As regulators tighten inspection regimes and as pallet pools push for higher utilisation, the cost of a single non-compliant shipment, in delays, fumigation fees or rejections, far exceeds the cost of automated upstream verification. A reliable optical inspection system that integrates with pallet-pool depot operations strengthens biosecurity protection, lowers compliance risk for shippers, and gives the pallet pool operator a defensible audit trail.

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AU 2026201805 was published in the Australian Official Journal of Patents on 2 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.