Constructing a 3-D model of corn to be used in hydrological studies

We developed a detailed three dimensional digital model of a corn plant to be used in the modeling of the interception of rainfall by corn. The model was built using commercial photogrammetry software, which utilizes digital photography to calculate the coordinates of points in space. We selected a 9-leaf healthy individual and digitized each of the leaves separately, resulting in 40 to 80 points per leaf. This effort required a total of 116 pictures taken from multiple angles in a local corn field. In addition to points on the surface of the leaf of interest, we captured points on the stem of the plant and on other leaves to use in the final step of putting the nine individual models together in the same absolute reference system. Our focus was on the delineation of edges and midrib of the leaves, and their horizontal and vertical orientation. In the present work we describe a nondestructive procedure that can be applied in the field, allowing for the tracking of the structure of plants along their growing cycle.