Early-Season Crop Classification Based on Local Window Attention Transformer with Time-Series RCM and Sentinel-1

Abstract

Crop classification is indispensable for agricultural monitoring and food security, but early-season mapping has remained challenging. Synthetic aperture radar (SAR), such as RADARSAT Constellation Mission (RCM) and Sentinel-1, can meet higher requirements on the reliability of satellite data acquisition with all-weather and all-day imaging capability to supply dense observations in the early crop season. This study applied the local window attention transformer (LWAT) to time-series SAR data, including RCM and Sentinel-1, for early-season crop classification. The performance of this integration was evaluated over crop-dominated regions (corn, soybean and wheat) in southwest Ontario, Canada. Comparative analyses against several machine learning and deep learning methods revealed the superiority of the LWAT, achieving an impressive F1-score of 97.96% and a Kappa coefficient of 97.08% for the northern crop region and F1-scores of 98.07% and 97.02% for the southern crop region when leveraging time-series data from RCM and Sentinel-1, respectively. Additionally, by the incremental procedure, the evolution of accuracy determined by RCM and Sentinel-1 was analyzed, which demonstrated that RCM performed better at the beginning of the season and could achieve comparable accuracy to that achieved by utilizing both datasets. Moreover, the beginning of stem elongation of corn was identified as a crucial phenological stage to acquire acceptable crop maps in the early season. This study explores the potential of RCM to provide reliable prior information early enough to assist with in-season production forecasting and decision making.

Crop Growth Analysis Using Automatic Annotations and Transfer Learning in Multi-date Aerial Images and Orthomosaics

“…For example, if a crop is not growing as expected during a critical growth stage, it might indicate a problem that needs to be addressed. By monitoring these periods of rapid growth and stress trends over time, optimal growing conditions can be identified as it is crucial to maximize crop yield and health [41]. Stress in crops could be due to a variety of factors such as pests, disease, poor soil health, or adverse weather conditions.…”

A Two-Stage SAR Image Generation Algorithm Based on GAN with Reinforced Constraint Filtering and Compensation Techniques

“…Synthetic aperture radar (SAR) enjoys a good reputation in the domain of remote sensing due to its imaging capability which is independent of flight altitude and weather condition. It is widely used in environmental surveillance [1], military reconnaissance [2], automatic target recognition (ATR) [3], crop monitoring [4] and other civil use [5].…”