High-speed parallel segmentation algorithms of MeanShift for litchi canopies based on Spark and Hadoop

Abstract

The MeanShift algorithm is a nonparametric method based on gradient ascent and it can effectively handle complex variations in lychee orchard scenes as well as changes in lychee tree canopies due to its adaptability, multi-scale analysis capabilities, and robustness, making it widely used in the segmentation processing of drone-based remote sensing images of lychee orchards. However, due to the high computational complexity of the MeanShift algorithm, its performance in processing large-scale drone remote sensing images of lychee tree canopies is not highly efficient, leading to low segmentation efficiency, which hampers its broader application. To address these issues, this study proposes high-speed MeanShift parallel segmentation algorithms for drone remote sensing images of lychee tree canopies based on MapReduce and Spark distributed computing frameworks. In this study, a cluster consisting of four nodes with Hadoop and Spark was set up, and 4000 drone remote sensing images were used as test data to evaluate the algorithm. Experimental results show that, the MeanShift algorithm based on MapReduce reduced the task execution time by 86.1% compared to the traditional MeanShift algorithm, while the MeanShift algorithm based on Spark reduced the task execution time by 88.0%, without compromising segmentation accuracy. The MeanShift parallel segmentation algorithm based on Hadoop and Spark platform can overcome the bottleneck of task execution efficiency and significantly enhance computational speed on a single machine.