A FAST AND EFFECTIVE METHOD OF MEASURING TREE STRUCTURE IN 3 DIMENSIONS

The Polhemus FasTrak™ position tracker uses magnetic fields to produce very fast and accurate measurements in 3-D space covering a radius of approximately 1.5m from its transmitter. Computer software specifically written for this project collects coordinates of branches, leaves and fruit to build up an on-screen picture of the plant. The software uses three-dimensional matrix mathematics to allow the transmitter to be relocated within the plant while maintaining the original coordinate system, thereby allowing an unlimited area to be mapped.

Accurate computer models of trees growing in the field can be created rapidly and used for a variety of research purposes. Models produced using tracker technology are being used for analysing spatial variation in fruit quality over a canopy, and for developing canopy photosynthesis models based on canopy shape and leaf area density. Measurements of shoots extension rates can be made by repeatedly mapping a plant at different times over the season to develop models of plant growth. The tracker system opens up a wide array of potential applications to plant science by measuring plant canopies. Models could be developed from the data collected to predict, for example, spray deposition or for following patterns of insect infestation.

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