Predicting and Visualizing Citrus Color Transformation Using a Deep Mask-Guided Generative Network.

Abstract

Citrus rind color is a good indicator of fruit development, and methods to monitor and predict color transformation therefore help the decisions of crop management practices and harvest schedules. This work presents the complete workflow to predict and visualize citrus color transformation in the orchard featuring high accuracy and fidelity. A total of 107 sample Navel oranges were observed during the color transformation period, resulting in a dataset containing 7,535 citrus images. A framework is proposed that integrates visual saliency into deep learning, and it consists of a segmentation network, a deep mask-guided generative network, and a loss network with manually designed loss functions. Moreover, the fusion of image features and temporal information enables one single model to predict the rind color at different time intervals, thus effectively shrinking the number of model parameters. The semantic segmentation network of the framework achieves the mean intersection over a union score of 0.9694, and the generative network obtains a peak signal-to-noise ratio of 30.01 and a mean local style loss score of 2.710, which indicate both high quality and similarity of the generated images and are also consistent with human perception. To ease the applications in the real world, the model is ported to an Android-based application for mobile devices. The methods can be readily expanded to other fruit crops with a color transformation period. The dataset and the source code are publicly available at GitHub.

Plant phenotyping relevance

柑橘果皮色を植物果実の発達状態として画像から推定・予測する手法を開発し、セグメンテーション、生成モデル、時系列情報を統合して技術性能を評価しているため、中心的なフェノタイピング手法研究である。

Code and data availability

The paper's citrus image dataset and source code are stated to be available via the authors' GitHub repository, but the availability language is 'upon request', so access requires contacting the authors rather than a confirmed public asset.

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