The researchers developed a method to calculate the leaf area index (LAI) of soybean canopies using 3D reconstruction. They used images of soybean plants taken at different growth stages and reconstructed the 3D structure of the canopy. By analyzing the canopy, they were able to accurately estimate the LAI. The dynamic simulation model they created had an accuracy above 0.99, allowing for rapid detection and prediction of LAI in soybean canopies. This technology can help in managing the growth and development of soybean plants more effectively.