Customs and industry collaborate to develop a unified file format for non-intrusive inspection devices

By Vyara Filipova, Technical Attaché, Procedures and Facilitation Sub-Directorate, WCO

In April 2019, the WCO SAFE Working Group endorsed a document providing a summary of the technical specification for the proposed unified X-ray file format for non-intrusive inspection (NII) devices, codenamed the Unified File Format (UFF). Endorsement of the summary document by the WCO’s Policy Commission and Council in June 2019 would close Phase 2 of the UFF Development Programme.


The WCO has been leading the initiative to develop a standard NII data format since 2016. Once universally deployed, the UFF will significantly facilitate the interoperability of NII equipment supplied by different manufacturers, as well as the exchange of images within and between Customs administrations. The UFF will also be instrumental in developing the large databases or libraries of images that are, inter alia, necessary to train analysts or machines equipped with an automated detection application.

The UFF initiative is steered by the WCO Technical Experts Group on NII (TEG-NII), which is open to all WCO Members and relevant NII industry players and co-chaired by a representative of Dutch Customs and a representative of Smiths Detection. The development work is carried out primarily by a UFF development team comprising experts from four NII vendors (L3, Nuctech, Rapiscan Systems AS&E and Smiths Detection), supported by the TEG-NII Customs Co-Chair and the WCO Secretariat.

The UFF Development Programme is being implemented in three phases. During phase 1, a proof of concept project was conducted. Phase 2 then started in October 2016, its main objectives being to develop the UFF architecture, and to test and evaluate it.


UFF Phase 2 deliverables

The architecture of the UFF is outlined in a document entitled “Technical Specification of the Proposed Unified X-ray File Format for Non-Intrusive Inspection Devices – UFF 2.0.” This document lists the technical details required for the implementation of a UFF in the various types of high-energy cargo inspection systems used by most Customs administrations. It also contains information on dataset flow, file structure, UFF versioning, file artifacts and data artifacts (XML data), as well as explanations covering data exchange and storage, digital signatures, archiving and UFF 2.0 dataset merging.

In addition to agreeing on the UFF 2.0 technical specification, each of the four vendors participating in the UFF initiative developed a UFF 2.0 converter and a UFF 2.0 viewer – software enabling the conversion of native NII images to UFF, and respectively the viewing of UFF images with all the tools and functions available in the original image viewing/processing software.


The development of the UFF 2.0 architecture, as well as the respective UFF converters and viewers, was completed in September 2018. An initial test of the UFF Phase 2 development was done through a pre-pilot with Dutch Customs, an ideal candidate as it operates NII systems produced by the four vendors engaged in the UFF 2.0 development.

During the pre-pilot, Dutch Customs provided native image files from its fleet of high-energy cargo scanning systems. A set of 15 images was provided to each of the participating NII suppliers. These images originated from a variety of devices, including single energy, dual energy, single view and dual view, both new and older systems.

Each participating NII vendor was then able to process the images through their respective converters with minimal or no errors, and to open the converted images via their respective UFF 2.0 image viewing software devices. Converted images could be viewed regardless of which NII device produced the original data files. Each file converted into a UFF output provided a unified version with equal image quality when compared to its native file version. The successful conversion and viewing of the images were demonstrated to Dutch Customs.

Following the successful completion of the Dutch Customs pre-pilot, the UFF development team selected six WCO Member Customs administrations to test the UFF 2.0 architecture and the respective UFF converters and viewers developed by the participating vendors. The six administrations representing four of the WCO regions were selected from a pool of volunteering Members that had earlier expressed their willingness to be part of the UFF 2.0 pilot.

Starting on 1 March 2019, Smiths Detection and Nuctech conducted tests with the Customs administrations of Belgium and Bulgaria. As for Rapiscan Systems AS&E and L3, they worked with US Customs and Border Protection and the Customs administrations of Colombia and Saudi Arabia. Last but not least, Rapiscan Systems AS&E and Nuctech collaborated with Hong Kong Customs to have testing done with native images generated by high-energy X-ray systems deployed in Hong Kong, China. These pilots were intended to:

  • confirm the results obtained during the pre-pilot with Dutch Customs;
  • test the capacity of the UFF to work within the environment of different Customs administrations;
  • demonstrate the value of the use of the standard.

Customs administrations submitted NII images to the respective vendor, which then converted the images to UFF and sent them back to the Customs administration that had to confirm it could view the UFF-converted images to the vendor and the WCO. Feedback showed that the quality of the converted images is identical to the quality of the native images, and that the UFF viewer tools provided the same features as the original image viewing/processing software available on the NII systems.

Going forward

Once the technical specification document is endorsed, it will be published on the WCO website, thereby closing Phase 2 of the UFF Development Programme. WCO Members wishing to deploy the UFF in their operations should include the respective requirement in their tender documents for the procurement of NII systems.

Under Phase 3, an upgraded version of the format for use by all technology providers is to be developed. The tasks for Phase 3 will be to finalize the approach adopted for this Phase, launch the standardization process, finalize and implement the UFF architecture, and address issues related to data transmission, including data security and encryption mechanisms.

Participation encouraged

Given the multiple benefits to be derived from having a UFF, the WCO would like to encourage more of its Members to consider participating in future meetings of the TEG-NII, to provide input on the further development of this global standard, and to fully support the initiative.


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