Plant Growth Measurement Techniques using Near-Infrared Imagery

We examine the usefulness of various imaging techniques, including optical ow, for measuring plant growth for corn seedlings and Caster Oil Bean leaves. A near-infrared camera, which allows one to measure optical ow in the light and in the dark, is used. For corn seedlings we have already used optical ow to obtain 3D image velocity as a measure of growth performance. We propose two new growth metrics for measuring growth, one based on elongation of the stem/leaf and the other based on the area change of the stem/leaf. These metrics are examined by measuring the corn seedling growth under various combinations of root temperatures (warm or cold) and under various lighting conditions (light to dark). For caster oil bean leaves we use Horn and Schunck's optical ow algorithm to compute the globally consistent ow eld for a moving, growing leaf. We use 1 st order divergence of the ow to hypothesize where growth might be taking place.