engleski

New method for tree volume estimation using digital close range photogrammetry

Experiences acquired during the elaboration of an user’s program "TREE3D" for the purpose of photogrammetric volume measurement of a standing tree are being presented. During the elaboration of the program the intention was to develop a measurement method, which ensures economic benefit, decreases field work and performs operations more or less automatically, and to obtain the required accuracy at the same time. As the adjustment method for image orientation, Direrct Linear Transformation (DLT) method was chosen due to its universality. Basic performance principles of the program, as well as the results of a test with amateur and digital camera (Kodak DC50) are being described in the paper. Measurement of tree volume is based on elaboration of 3D model of a tree. The 3D model considers array of central axis points, attributed with diameters measured on images. Apart from volume measurement, measurement of other dendrometric elements of a tree is being considered ; such as the center of gravity, crown diameter, as well as estimation of assortment structure as a base for the market value estimation of a standing tree. Possibility of direct measurement of volume increament, particularly interesting element of forest management that is commonly assessed indirectly, is considered. The idea evolved from interactive work of students from two different faculties (forestry and mathematics) and is based on up-to-date experiences acquired on Forestry Photogrammetry Department at the Faculty of Forestry University of Zagreb, and on Photogrammetry Department at the Faculty of Geodesy University of Zagreb. The Program was developed by using Borland DELPHI 2.0 program package, operates on Windows 95 and is easily adjustable to other fields of application that belong to the area of digital close range photogrammetry.

tree volume estimation; close range photogrammetry; direct linear transformation

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