Multimodal Deep Learning and Visible-Light and Hyperspectral Imaging for Fruit Maturity Estimation

Fruit maturity is a critical factor in the supply chain, consumer preference, and agriculture industry. Most classification methods on fruit maturity identify only two classes: ripe and unripe, but this paper estimates six maturity stages of papaya fruit. Deep learning architectures have gained resp...

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Main Authors: Cinmayii A. Garillos-Manliguez, John Y. Chiang
Format: Article
Language:English
Published: MDPI AG 2021-02-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/21/4/1288
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author Cinmayii A. Garillos-Manliguez
John Y. Chiang
author_facet Cinmayii A. Garillos-Manliguez
John Y. Chiang
author_sort Cinmayii A. Garillos-Manliguez
collection DOAJ
description Fruit maturity is a critical factor in the supply chain, consumer preference, and agriculture industry. Most classification methods on fruit maturity identify only two classes: ripe and unripe, but this paper estimates six maturity stages of papaya fruit. Deep learning architectures have gained respect and brought breakthroughs in unimodal processing. This paper suggests a novel non-destructive and multimodal classification using deep convolutional neural networks that estimate fruit maturity by feature concatenation of data acquired from two imaging modes: visible-light and hyperspectral imaging systems. Morphological changes in the sample fruits can be easily measured with RGB images, while spectral signatures that provide high sensitivity and high correlation with the internal properties of fruits can be extracted from hyperspectral images with wavelength range in between 400 nm and 900 nm—factors that must be considered when building a model. This study further modified the architectures: AlexNet, VGG16, VGG19, ResNet50, ResNeXt50, MobileNet, and MobileNetV2 to utilize multimodal data cubes composed of RGB and hyperspectral data for sensitivity analyses. These multimodal variants can achieve up to 0.90 F1 scores and 1.45% top-2 error rate for the classification of six stages. Overall, taking advantage of multimodal input coupled with powerful deep convolutional neural network models can classify fruit maturity even at refined levels of six stages. This indicates that multimodal deep learning architectures and multimodal imaging have great potential for real-time in-field fruit maturity estimation that can help estimate optimal harvest time and other in-field industrial applications.
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spelling doaj.art-17c5ca9f43a343a8a08683bf230142512023-12-03T13:19:23ZengMDPI AGSensors1424-82202021-02-01214128810.3390/s21041288Multimodal Deep Learning and Visible-Light and Hyperspectral Imaging for Fruit Maturity EstimationCinmayii A. Garillos-Manliguez0John Y. Chiang1Department of Computer Science and Engineering, National Sun Yat-sen University, Kaohsiung 804, TaiwanDepartment of Computer Science and Engineering, National Sun Yat-sen University, Kaohsiung 804, TaiwanFruit maturity is a critical factor in the supply chain, consumer preference, and agriculture industry. Most classification methods on fruit maturity identify only two classes: ripe and unripe, but this paper estimates six maturity stages of papaya fruit. Deep learning architectures have gained respect and brought breakthroughs in unimodal processing. This paper suggests a novel non-destructive and multimodal classification using deep convolutional neural networks that estimate fruit maturity by feature concatenation of data acquired from two imaging modes: visible-light and hyperspectral imaging systems. Morphological changes in the sample fruits can be easily measured with RGB images, while spectral signatures that provide high sensitivity and high correlation with the internal properties of fruits can be extracted from hyperspectral images with wavelength range in between 400 nm and 900 nm—factors that must be considered when building a model. This study further modified the architectures: AlexNet, VGG16, VGG19, ResNet50, ResNeXt50, MobileNet, and MobileNetV2 to utilize multimodal data cubes composed of RGB and hyperspectral data for sensitivity analyses. These multimodal variants can achieve up to 0.90 F1 scores and 1.45% top-2 error rate for the classification of six stages. Overall, taking advantage of multimodal input coupled with powerful deep convolutional neural network models can classify fruit maturity even at refined levels of six stages. This indicates that multimodal deep learning architectures and multimodal imaging have great potential for real-time in-field fruit maturity estimation that can help estimate optimal harvest time and other in-field industrial applications.https://www.mdpi.com/1424-8220/21/4/1288multimodalitydeep learninghyperspectral imagingfruit maturityclassification
spellingShingle Cinmayii A. Garillos-Manliguez
John Y. Chiang
Multimodal Deep Learning and Visible-Light and Hyperspectral Imaging for Fruit Maturity Estimation
Sensors
multimodality
deep learning
hyperspectral imaging
fruit maturity
classification
title Multimodal Deep Learning and Visible-Light and Hyperspectral Imaging for Fruit Maturity Estimation
title_full Multimodal Deep Learning and Visible-Light and Hyperspectral Imaging for Fruit Maturity Estimation
title_fullStr Multimodal Deep Learning and Visible-Light and Hyperspectral Imaging for Fruit Maturity Estimation
title_full_unstemmed Multimodal Deep Learning and Visible-Light and Hyperspectral Imaging for Fruit Maturity Estimation
title_short Multimodal Deep Learning and Visible-Light and Hyperspectral Imaging for Fruit Maturity Estimation
title_sort multimodal deep learning and visible light and hyperspectral imaging for fruit maturity estimation
topic multimodality
deep learning
hyperspectral imaging
fruit maturity
classification
url https://www.mdpi.com/1424-8220/21/4/1288
work_keys_str_mv AT cinmayiiagarillosmanliguez multimodaldeeplearningandvisiblelightandhyperspectralimagingforfruitmaturityestimation
AT johnychiang multimodaldeeplearningandvisiblelightandhyperspectralimagingforfruitmaturityestimation