Measurement and Calibration of Plant-Height from Fixed-Wing UAV Images

Abstract

Continuing population growth will result in increasing global demand for food and fiber for the foreseeable future. During the growing season, variability in the height of crops provides important information on plant health, growth, and response to environmental effects. This paper indicates the feasibility of using structure from motion (SfM) on images collected from 120 m above ground level (AGL) with a fixed-wing unmanned aerial vehicle (UAV) to estimate sorghum plant height with reasonable accuracy on a relatively large farm field. Correlations between UAV-based estimates and ground truth were strong on all dates (R2 > 0.80) but are clearly better on some dates than others. Furthermore, a new method for improving UAV-based plant height estimates with multi-level ground control points (GCPs) was found to lower the root mean square error (RMSE) by about 20%. These results indicate that GCP-based height calibration has a potential for future application where accuracy is particularly important. Lastly, the image blur appeared to have a significant impact on the accuracy of plant height estimation. A strong correlation (R2 = 0.85) was observed between image quality and plant height RMSE and the influence of wind was a challenge in obtaining high-quality plant height data. A strong relationship (R2 = 0.99) existed between wind speed and image blurriness.

Plant phenotyping relevance

UAV画像とSfMによる作物の草丈推定を開発・校正・検証しており、植物形質の取得手法が研究の中心です。

Code and data availability

The article describes UAV-based sorghum plant-height estimation with SfM, but contains no public phenotype dataset, imagery deposit, author analysis code, or trained model. The only URL mentioned (Mission Planner) is a generic third-party flight-planning tool, not a paper-specific asset.

No evidence-backed public reproduction asset is currently recorded.