Design of an Integrated Near-Infrared Spectroscopy Module for Sugar Content Estimation of Apples

Abstract

An integrated near-infrared (NIR) spectroscopy prototype module for sugar content estimation of apples is presented. Since this is the first attempt to design an integrated NIR spectroscopy module, we followed the design process as follows. First, we estimated the sugar content of apples using a tungsten halogen light source and a 700 nm–1000 nm NIR spectrometer with a 10 nm wavelength resolution and a 16b analog-to-digital converter (ADC) resolution. Second, we determined the most effective wavelengths among 31 evenly distributed wavelengths while observing the correlation coefficient, R2, and then we reduced the ADC resolution 1b by 1b starting from 16b while also observing the R2. Lastly, we designed an integrated NIR spectroscopy module with the selected eight wavelengths and a 13 ADC resolution. The module implemented in a 0.18 μm 1P6M CMOS process occupies a die area of 0.84 mm2. By utilizing this module with eight off-chip light emitting diodes (LED) and one photo diode (PD), the measured R2 and the standard error of calibration (SEC) were 0.365 and 0.686 brix, respectively.

Analyzing the Quality Parameters of Apples by Spectroscopy from Vis/NIR to NIR Region: A Comprehensive Review

“…Several studies have shown that NIR can predict individual sugars and total sugar content with high accuracy, making it a promising tool for the fruit industry [78,[185][186][187][188][189]. This suitability of NIR spectroscopy was demonstrated relatively early.…”

“…The interest in this analysis continues in contemporary literature. For example, a design of an integrated NIR spectroscopy module for estimating sugar content in apples was recently presented by Byun [187]. The design process involved selecting effective wavelengths and reducing the analog-to-digital converter resolution.…”

Photoelectric Design Competition Test Questions Analysis and Students Comprehensive Ability Cultivation

“…Near infrared light is between visible and medium infrared light and has a wavelength range of 780nm-1100nm. The near infrared spectroscopy can be used to detect the sugar content of apple with high precision [6]. According to the theory of molecular spectroscopy, when the molecule of a substance is in the ground state, it is the most stable.…”