Design and Development of a Shortwave near Infrared Spectroscopy using NIR LEDs and Regression Model

Abstract

Near infrared (NIR) spectroscopic technology has been getting more attention in various fields. The development of a low cost NIR spectroscopy is crucial to reduce the financial barriers so that more NIR spectroscopic applications will be investigated and developed by means of the NIR spectroscopic technology. This study proposes an alternative to measure shortwave NIR spectrum using one collimating lens, two slits, one NIR transmission grating, one linear array sensor, and one microcontroller. Five high precision narrow bands NIR light emitting diodes (LEDs) were used to calibrate the proposed spectroscopy. The effects of the proposed two slits design, the distance between the grating and linear array sensor, and three different regression models were investigated. The accuracy of the proposed design was cross-validated using leave-one-out cross-validation. Results show that the proposed two slits design was able to eliminate unwanted signals substantially, and the cross-validation was able to estimate the best model with root mean squared error of cross-validation of 3.8932nm. Findings indicate that the cross-validation approach is a good approach to estimate the final model without over-fitting, and the proposed shortwave NIR spectroscopy was able to estimate the peak value of the acquired spectrum from NIR LEDs with RMSE of 1.1616nm. [4], and food industry [5] to potentially replace conventional measurement approaches (e.g. sensory evaluation and chemical analysis) that are timeconsuming, expensive per measurement, destructive, or inconvenient. Near infrared spectroscopic technology is promising to be an alternative measurement approach because the acquired reflected or the transmitted near infrared energy from a sample contains information that related to the composition of C-H, N-H, and O-H bonds of the sample. Since these composition are the common and basic chemical composition of many products e.g. agriculture products and food, many researches have been conducted to investigate the relationship between a component of interests e.g. pH, glucose, and soluble solids content and the near infrared energy. Keyword: NIR LEDNear Infrared Spectroscopic research aims to relate the component of interest to the absorption of the near-infrared light energy. The amount of the absorption is related to the chemical bond of molecule. In fact, the bond among atoms naturally will vibrate, the higher state of excitement requires more energy. Light

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Investigating the Feasibility of a CMOS Camera in Developing a Shortwave Near Infrared Spectroscopy

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