Hyperspectral system trade-offs for illumination, hardware and analysis methods: a case study of seed mix ingredient discrimination

Abstract

The discrimination power of a hyperspectral imaging system for image segmentation or object detection is determined by the illumination, the camera spatial–spectral resolution, and both the pre-processing and analysis methods used for image processing. In this study, we methodically reviewed the alternatives for each of those factors for a case study from the food industry to provide guidance in the construction and configuration of hyperspectral imaging systems in the visible near infrared range for food quality inspection. We investigated both halogen- and LED-based illuminations and considered cameras with different spatial–spectral resolution trade-offs. At the level of the data analysis, we evaluated the impact of binning, median filtering and bilateral filtering as pre- or post-processing and compared pixel-based classifiers with convolutional neural networks for a challenging application in the food industry, namely ingredient identification in a flour–seed mix. Starting from a basic configuration and by modifying the combination of system aspects we were able to increase the mean accuracy by at least 25 %. In addition, different trade-offs in performance-complexity were identified for different combinations of system parameters, allowing adaptation to diverse application requirements.

Comparison of different illumination systems for moisture prediction in cereal bars using hyperspectral imaging technology

“…The discrimination power of an HSI system for image segmentation or object detection is determined by the illumination, the spatial-spectral resolution of the camera, the signal-to-noise ratio, and both the preprocessing and analysis methods used for image processing. 1 HSI is a real-time, non-destructive method that can be used for food quality analysis and control that combines spectroscopy and imaging techniques. 2 Compared to traditional multispectral imaging technology, HSI can provide a wider spectral resolution.…”