Prototype Mobile Vision System for Automatic Length Estimation of Olive Flounder (<i>Paralichthys olivaceus</i>) in Indoor Aquaculture
Real-time estimation of fish growth offers multiple benefits in indoor aquaculture, including reduced labor, lower operational costs, improved feeding efficiency, and optimized harvesting schedules. This study presents a low-cost, vision-based method for estimating the body length and weight of oliv...
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MDPI AG
2025-06-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/13/6/1167 |
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| author | Inyeong Kwon Hang Thi Phuong Nguyen Paththige Waruni Prasadini Fernando Hieyong Jeong Sungju Jung Taeho Kim |
| author_facet | Inyeong Kwon Hang Thi Phuong Nguyen Paththige Waruni Prasadini Fernando Hieyong Jeong Sungju Jung Taeho Kim |
| author_sort | Inyeong Kwon |
| collection | DOAJ |
| description | Real-time estimation of fish growth offers multiple benefits in indoor aquaculture, including reduced labor, lower operational costs, improved feeding efficiency, and optimized harvesting schedules. This study presents a low-cost, vision-based method for estimating the body length and weight of olive flounder (<i>Paralichthys olivaceus</i>) in tank environments. A 5 × 5 cm reference grid is placed on the tank bottom, and images are captured using two fixed-position RGB smartphone cameras. Pixel measurements from the images are converted into millimeters using a calibrated pixel-to-length relationship. The system calculates fish length by detecting contour extremities and applying Lagrange interpolation. Based on the estimated length, body weight is derived using a power regression model. Accuracy was validated using both manual length measurements and Bland–Altman analysis, which indicated a mean bias of −0.007 cm and 95% limits of agreement from −0.475 to +0.462 cm, confirming consistent agreement between methods. The mean absolute error (MAE) and mean squared error (MSE) were 0.11 cm and 0.025 cm<sup>2</sup>, respectively. While optimized for benthic species such as olive flounder, this system is not suitable for free-swimming species. Overall, it provides a practical and scalable approach for non-invasive monitoring of fish growth in commercial indoor aquaculture. |
| format | Article |
| id | doaj-art-1184bb9849ea4032b4021b3a0b08d2dc |
| institution | DOAJ |
| issn | 2077-1312 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | MDPI AG |
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| series | Journal of Marine Science and Engineering |
| spelling | doaj-art-1184bb9849ea4032b4021b3a0b08d2dc2025-08-20T03:16:18ZengMDPI AGJournal of Marine Science and Engineering2077-13122025-06-01136116710.3390/jmse13061167Prototype Mobile Vision System for Automatic Length Estimation of Olive Flounder (<i>Paralichthys olivaceus</i>) in Indoor AquacultureInyeong Kwon0Hang Thi Phuong Nguyen1Paththige Waruni Prasadini Fernando2Hieyong Jeong3Sungju Jung4Taeho Kim5Department of Smart Fisheries Resource Management, Chonnam National University, Yeosu 59626, Republic of KoreaDepartment of Artificial Intelligence Convergence, Chonnam National University, Gwangju 61186, Republic of KoreaInterdisciplinary Program of Smart Aquafarm, Chonnam National University, Yeosu 59626, Republic of KoreaDepartment of Artificial Intelligence Convergence, Chonnam National University, Gwangju 61186, Republic of KoreaSmart Aquaculture Research Center, Chonnam National University, Yeosu 59626, Republic of KoreaSmart Aquaculture Research Center, Chonnam National University, Yeosu 59626, Republic of KoreaReal-time estimation of fish growth offers multiple benefits in indoor aquaculture, including reduced labor, lower operational costs, improved feeding efficiency, and optimized harvesting schedules. This study presents a low-cost, vision-based method for estimating the body length and weight of olive flounder (<i>Paralichthys olivaceus</i>) in tank environments. A 5 × 5 cm reference grid is placed on the tank bottom, and images are captured using two fixed-position RGB smartphone cameras. Pixel measurements from the images are converted into millimeters using a calibrated pixel-to-length relationship. The system calculates fish length by detecting contour extremities and applying Lagrange interpolation. Based on the estimated length, body weight is derived using a power regression model. Accuracy was validated using both manual length measurements and Bland–Altman analysis, which indicated a mean bias of −0.007 cm and 95% limits of agreement from −0.475 to +0.462 cm, confirming consistent agreement between methods. The mean absolute error (MAE) and mean squared error (MSE) were 0.11 cm and 0.025 cm<sup>2</sup>, respectively. While optimized for benthic species such as olive flounder, this system is not suitable for free-swimming species. Overall, it provides a practical and scalable approach for non-invasive monitoring of fish growth in commercial indoor aquaculture.https://www.mdpi.com/2077-1312/13/6/1167olive flounderlength estimationimage processingLagrange’s interpolating polynomial algorithmlength–weight relationship |
| spellingShingle | Inyeong Kwon Hang Thi Phuong Nguyen Paththige Waruni Prasadini Fernando Hieyong Jeong Sungju Jung Taeho Kim Prototype Mobile Vision System for Automatic Length Estimation of Olive Flounder (<i>Paralichthys olivaceus</i>) in Indoor Aquaculture Journal of Marine Science and Engineering olive flounder length estimation image processing Lagrange’s interpolating polynomial algorithm length–weight relationship |
| title | Prototype Mobile Vision System for Automatic Length Estimation of Olive Flounder (<i>Paralichthys olivaceus</i>) in Indoor Aquaculture |
| title_full | Prototype Mobile Vision System for Automatic Length Estimation of Olive Flounder (<i>Paralichthys olivaceus</i>) in Indoor Aquaculture |
| title_fullStr | Prototype Mobile Vision System for Automatic Length Estimation of Olive Flounder (<i>Paralichthys olivaceus</i>) in Indoor Aquaculture |
| title_full_unstemmed | Prototype Mobile Vision System for Automatic Length Estimation of Olive Flounder (<i>Paralichthys olivaceus</i>) in Indoor Aquaculture |
| title_short | Prototype Mobile Vision System for Automatic Length Estimation of Olive Flounder (<i>Paralichthys olivaceus</i>) in Indoor Aquaculture |
| title_sort | prototype mobile vision system for automatic length estimation of olive flounder i paralichthys olivaceus i in indoor aquaculture |
| topic | olive flounder length estimation image processing Lagrange’s interpolating polynomial algorithm length–weight relationship |
| url | https://www.mdpi.com/2077-1312/13/6/1167 |
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