ENGINEERING

Development of YOLO-based apple quality sorter

Donggun Lee1,†, Jooseon Oh2,3,†, Youngtae Choi1, Donggeon Lee1, Hongjeong Lee1, Sung-Bo Shim1,4,5,*, Yushin Ha1,4,*

1Department of Bio-industrial Engineering, Kyungpook National University, Daegu 41566, Korea
2Department of Convergence Biosystems Engineering, Chonnam National University, Gwangju 61186, Korea
3Interdisciplinary Program in IT-Bio Convergence System, Chonnam National University, Gwangju 61186, Korea
4Upland Field Machinery Research Center, Kyungpook National University, Daegu 41566, Korea
5Smart Agriculture Innovation Center, Kyungpook National University, Daegu 41566, Korea

These authors contributed equally to this work.

*Corresponding author: sbs80@knu.ac.kr, yushin72@knu.ac.kr

Abstract

The task of sorting and excluding blemished apples and others that lack commercial appeal is currently performed manually by human eye sorting, which not only causes musculoskeletal disorders in workers but also requires a significant amount of time and labor. In this study, an automated apple-sorting machine was developed to prevent musculoskeletal disorders in apple production workers and to streamline the process of sorting blemished and nonmarketable apples from the better quality fruit. The apple-sorting machine is composed of an arm-rest, a main body, and a height-adjustable part, and uses object detection through a machine learning technology called ‘You Only Look Once (YOLO)’ to sort the apples. The machine was initially trained using apple image data, RoboFlow, and Google Colab, and the resulting images were analyzed using Jetson Nano. An algorithm was developed to link the Jetson Nano outputs and the conveyor belt to classify the analyzed apple images. This apple-sorting machine can immediately sort and exclude apples with surface defects, thereby reducing the time needed to sort the fruit and, accordingly, achieving cuts in labor costs. Furthermore, the apple-sorting machine can produce uniform quality sorting with a high level of accuracy compared with the subjective judgment of manual sorting by eye. This is expected to improve the productivity of apple growing operations and increase profitability.

Keywords

apple sorting system, Jetson Nano, object detection, YOLO (You Only Look Once)

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