Method for Vortex Shape Retrieval and Area Calculation Based on Convex Hull Algorithm

Xu Wei,Xiaodan Hu,Huifen Li,Bo Long,Jiyu Li,Han Wu

doi:10.1109/access.2020.3046651

Xu Wei, Xiaodan Hu + Show 4 more

Open Access

https://doi.org/10.1109/access.2020.3046651

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Abstract

The shape and area of the vortex are important indicators to judge the effect of chemical liquid spraying and crop pollination by agricultural plant protection UAV. However, the traditional way of extracting the vortex related data through manual methods without an adaptive mechanism is complicated and inefficient. In order to solve this problem, the vortex image is preprocessed by adaptive iterative binarization and mean filtering. Then, the Convex Hull algorithm combined with Edge function is applied to the pre-processed image to extract the specific shape of vortex image and further calculate its area. Experimental results show that this method can be used to extract the vortex shapes and calculate the vortex area under different experimental conditions without manual intervention. Compared with the results of vortex area obtained via the manual extraction method, this method reported the average absolute error rate of 2.84%, the RMSE of 0.2903, and the correlation coefficient of 0.9965, indicating that the proposed method is more applicable to reveal the actual state of the vortex. A standardized extraction method was established to provide a standard for future vortex image research. The method in this paper lays a scientific foundation for the real-time tracking research of agricultural plant protection UAV and vortex.

Highlights

As agricultural plant protection UAVs are widely used in precision agriculture, the UAVs are required to fulfil more precise and efficient operation tasks in actual agricultural plant protection practices
ARCHITECTURE we focus on the analysis of the three features of the vortex image, and proposes a method for vortex shape retrieval and area extraction based on the convex hull algorithm
1) According to the method in this paper, the corresponding adaptive binarization iteration threshold can be obtained for vortex images in different environments, and the image preprocessing can be completed by combining with the filtering kernel

Summary

Introduction

As agricultural plant protection UAVs are widely used in precision agriculture, the UAVs are required to fulfil more precise and efficient operation tasks in actual agricultural plant protection practices. In the process of spraying pesticide, the rotor airflow generated by the UAV wraps the pesticide droplets and penetrates the crop from top to bottom, which is conducive to the uniform distribution of the droplets on various parts of the plant [1]. It is one of the effective methods to improve the deposition and uniform distribution of effective pesticides on the crops.

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