Non-Destructive Prediction of Fruit Ripeness and Firmness Using Hyperspectral Imaging and Lightweight Machine Learning Models

TL;DR

This study demonstrates that lightweight machine learning models using only three visible wavelengths can accurately predict fruit ripeness and firmness, offering a cost-effective alternative to hyperspectral imaging and deep learning.

Contribution

It systematically compares classical machine learning algorithms on hyperspectral data and identifies minimal spectral data needed for high-accuracy predictions.

Findings

Tree-based models outperform deep learning in this task.

Only three visible wavelengths achieve over 94% accuracy.

Low-cost multispectral sensors can replace expensive hyperspectral systems.

Abstract

Post-harvest fruit quality assessment is essential for reducing food waste, yet reliable non-destructive methods typically depend on expensive hyperspectral cameras and computationally intensive deep learning models. These systems typically require GPU resources, large-scale training data, and domain expertise, limiting their feasibility for many real-world agricultural settings. This study systematically evaluates 20 classical machine learning algorithms on hyperspectral imaging data for simultaneous ripeness classification and firmness prediction across five fruit species, using cross-validated experimental design with Bayesian hyperparameter optimization. Data preprocessing strategy, particularly class balancing and spectral transformations, contributes as much to prediction accuracy as algorithm choice. Our results show that tree-based machine learning models can outperform state-of-the-art deep earning models reported in Fruit-HSNet. Moreover, the findings indicate that only three visible-range wavelengths are needed to recover over 94% of full-spectrum accuracy, demonstrating that low-cost multispectral sensors combined with lightweight machine learning models can serve as practical alternatives to expensive hyperspectral cameras and complex deep learning approaches for practical fruit quality sorting.