Ultraviolet-visible/near infrared spectroscopy and hyperspectral imaging to study the different types of raw cotton

Abstract

Different types of raw cotton were investigated by a commercial ultraviolet-visible/near infrared (UV-Vis/NIR) spectrometer (210–2200 nm) as well as on a home-built setup for NIR hyperspectral imaging (NIR-HSI) in the range 1100–2200 nm. UV-Vis/NIR reflection spectroscopy reveals the dominant role proteins, hydrocarbons and hydroxyl groups play in the structure of cotton. NIR-HSI shows a similar result. Experimentally obtained data in combination with principal component analysis (PCA) provides a general differentiation of different cotton types. For UV-Vis/NIR spectroscopy, the first two principal components (PC) represent 82 % and 78 % of the total data variance for the UV-Vis and NIR regions, respectively. Whereas, for NIR-HSI, due to the large amount of data acquired, two methodologies for data processing were applied in low and high lateral resolution. In the first method, the average of the spectra from one sample was calculated and in the second method the spectra of each pixel were used. Both methods are able to explain ≥90 % of total variance by the first two PCs. The results show that it is possible to distinguish between different cotton types based on a few selected wavelength ranges. The combination of HSI and multivariate data analysis has a strong potential in industrial applications due to its short acquisition time and low-cost development. This study opens a novel possibility for a further development of this technique towards real large-scale processes.

Characterization of Pharmaceutical Tablets Using UV Hyperspectral Imaging as a Rapid In-Line Analysis Tool

“…A regular way to reduce this effect is to convert measured raw spectra to reflectance spectra by the following formula [ 6 , 11 ]: where R and R 0 represent the reflected intensity by the sample and a specific reference material with high reflectance capability. I sample is the intensity of the original image data, I dark is the intensity of the dark current image data and I reference is the intensity of the white reflectance image [ 3 ]. For a better comparison of the reflectance spectra to the extinction spectra in solution (absorbance) the negative decadic logarithm is calculated as −log R/R 0 .…”

“…A large number of remote sensing applications have been developed over the last decade [ 1 ]. This also led to establish non-destructive imaging systems that are able to quickly identify quality problems within the scanned area [ 2 , 3 ]. Spectral imaging involves both spectral and spatial information of any particular sample or region within an area of interest, thus each pixel represents spectral and spatial information.…”

“…This robust technique in combination with real-time chemometric analysis can be easily integrated into an industrial production environment. This enabled chemical sensing systems for very different applications in the fields of food quality monitoring, textile classification, agriculture, detection target of military, astronomy, life science, medicine and pharmaceutical drugs [ 2 , 3 , 12 , 13 , 14 , 15 ]. Traditional methods such as UV-Vis spectroscopy, high performance liquid chromatography (HPLC) or mass spectrometry (MS) are, in contrast, time consuming, expensive and require sample preparation and destruction [ 2 , 6 ].…”

UV Hyperspectral Imaging as Process Analytical Tool for the Characterization of Oxide Layers and Copper States on Direct Bonded Copper

“…Science and engineering progress Sensors 2021, 21, 7332 2 of 13 has driven the development of sensor technology in the past years [2,3]. This led to novel optical sensors, such as hyperspectral imagers, to identify quality problems [4,5].…”

“…Hyperspectral imaging is a technique that integrates a conventional spectroscopic system with imaging in order to acquire spectral and spatial information from the area of interest [6][7][8][9]. Therefore, hyperspectral imaging enables quantitative analysis with improved levels of accuracy [4,10,11]. It is considered as a rapid, non-destructive and robust method.…”