Monitoring plant phenology using phenocam: A review

Plant phenology is the study of cyclic and seasonal rhythms in plants with respect to environmental stresses. Tools to monitor the changes in plant canopy, assess plant growth and performance on a continuous basis is critical for sustainable agriculture. Phenocam is a dedicated surveillance digital camera that captures repeated photographs of the plant canopy at a desired time interval over the duration of plant growth. A phenocam network represents a collection of phenocams that feed to networked servers. The digital images are stored in a server until processed further. The stored images are then subjected to image processing methods to extract useful quantitative information. Furthermore, it could be a more reliable alternative remote sensing platform compared to conventional remote sensing methods (e.g., satellite, airplanes, drones), as it captures near-surface characteristics with high resolution and it is free from possible environmental obstructions. Advances in imaging and image processing techniques are making the phenocam technology to assess the plant health continuously and accurately. In this emerging field of phenocam technology, a reasonable quantity of literature was available. This paper reviews various important visual plant characteristics, basic image processing techniques, applications of phenocam in the field, and outlines future perspectives and developments.