Abstract
Oyster racks identification relies on manual in situ assessment and often leads to a compensation dispute in aquacultural damage assessment. This study proposes an efficient classification method to identify oyster racks using unmanned aerial vehiclesw (UAVs) images. After image preprocessed by the morphology-based opening operation and mosaicing, the Canny edge detection algorithm, an edge line reparation algorithm, and the multiresolution segmentation techniques are applied to recognize the boundary of oyster racks and the number of oyster racks are further obtained. In this study, a case study was carried out in the District 23 of Dongshi fishing port on September 4, 2015 and October 5, 2015 to evaluate the influence of the Typhoon Dujuan. Based on the image identification, eight horizontal racks were destroyed by the storm surges and strong winds, but the raft-string racks were increased by 60, which were steered from neighbor districts. The damaged ratio of oyster racks was successfully identified and 38 racks were eligible for disaster relief. Comparing to the current manual in situ damage assessment process taking over one month, the proposed process provides a timely and quantitative assessment by efficiently identifying oyster racks on the UAV images within one week, which demonstrated that the proposed process is a promising way for the efficient damage assessment of oyster racks.
Highlights
O YSTER culture, an important shallow water industry that can be dated back to more than 300 years ago during Dutch colonial period, is a major type of aquaculture in Taiwan [1], [2]
This paper proposes an efficient process to identify oyster racks using the unmanned aerial vehiclesw (UAVs) images for a timely and quantitative assessment of oyster rack damages caused by storms
The present study utilized the oyster racks boundaries resulted from the Canny edge detection with the edge line reparation algorithm for further damage assessment
Summary
O YSTER culture, an important shallow water industry that can be dated back to more than 300 years ago during Dutch colonial period, is a major type of aquaculture in Taiwan [1], [2]. Based on a recent scientific report in 2016, the cultured species in Taiwan is the Portuguese oyster, Crassostrea angulata [3]. The primary oyster culture area is located in the southwestern coastal Taiwan including Hsinchu, Changhua, Yunlin, and Manuscript received December 13, 2017; revised March 16, 2018; accepted May 7, 2018. Date of publication June 13, 2018; date of current version August 21, 2018. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org
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