Hyperspectral imaging for quality assurance of plasma-functionalised packaging
PECVD barrier layers, applied to plastic films in a continuous process, offer substantial potential for the economical production of sustainable, high-performance barrier materials. Quality assurance of these thin (few nanometres), transparent, and recyclable coatings in the laboratory is currently a tedious and time-consuming process. The project Hyper Spectral Imaging (HSI) examines whether, and if so under which conditions, hyperspectral imaging can provide online quality assurance for such layer systems.
© IKVHyperspectral imaging (HSI) analyses not only individual points but captures a relevant and representative surface area of a film, delivering a complete optical spectrum for each image pixel in real time. Changes in the chemical composition of the layers can thus be detected. The objective is to enable immediate correction of production processes as a result.
The development of this quality assurance methodology proceeds in several steps. Initially, reference measurements (layer thickness measurements, infrared spectroscopic analyses, scanning electron microscopy investigations, and barrier performance assessments) are conducted using established laboratory methods to unequivocally characterise samples of varying quality. These data form the foundation for evaluation algorithms. A particular challenge arises from the fact that hyperspectral measurements in industrial environments are subject to greater interference than in laboratory settings. Factors such as temperature fluctuations, vibrations, or varying web tensions must be accounted for. Through the development of evaluation procedures for HSI, it is assessed whether and to what extent the system functions reliably under real production conditions.
An additional focus lies on the optimisation of measurement technologies, in particular on the selection of appropriate wavelength ranges, optical resolution, and measurement speeds. The parameters are investigated systematically and tailored to the specific requirements of film production. At project completion, specifications for an HSI quality assurance system shall be available. These encompass technical requirements for the measurement devices as well as validated evaluation algorithms that enable reliable classification of coating qualities.
Project data and funding
We would like to thank the BMWE for funding the IGF project (funding code 24516 N) and the project partners for their cooperation.
Project duration: 01.11.2025 – 31.10.2027
