A test environment is established to obtain experimental data for verifying the positioning model which was derived previously based on the pinhole imaging model and the theory of binocular stereo vision measurement. The model requires that the optical axes of the two cameras meet at one point which is defined as the origin of the world coordinate system, thus simplifying and optimizing the positioning model. The experimental data are processed and tables and charts are given for comparing the positions of objects measured with DGPS with a measurement accuracy of 10 centimeters as the reference and those measured with the positioning model. Sources of visual measurement model are analyzed, and the effects of the errors of camera and system parameters on the accuracy of positioning model were probed, based on the error transfer and synthesis rules. A conclusion is made that measurement accuracy of surface surveillances based on binocular stereo vision measurement is better than surface movement radars, ADS-B (Automatic Dependent Surveillance-Broadcast) and MLAT (Multilateration).
This study was to attempt the cutting-edge 3D remote sensing technique of static terrestrial laser scanning (TLS) for
parametric 3D reconstruction of juvenile understory trees. The data for test was collected with a Leica HDS6100 TLS
system in a single-scan way. The geometrical structures of juvenile understory trees are extracted by model fitting. Cones
are used to model trunks and branches. Principal component analysis (PCA) is adopted to calculate their major axes.
Coordinate transformation and orthogonal projection are used to estimate the parameters of the cones. Then, AutoCAD is
utilized to simulate the morphological characteristics of the understory trees, and to add secondary branches and leaves in
a random way. Comparison of the reference values and the estimated values gives the regression equation and shows that
the proposed algorithm of extracting parameters is credible. The results have basically verified the applicability of TLS for
field phenotyping of juvenile understory trees.