Measurement and calculation methods of stem image information.

In the study, the authors investigated 2-D stem image formation collected by digital camera. The measurement of 2-D coordinate for stem information is based on close-range photogrammetry. The stem information is calculated in a simple manner, through the use of 2-D image manipulation methods. The study shows that the method is efficient and feasible. The application of computer vision technique and the difficulties in collecting stem image information are also discussed.