We discuss the possibility of surveying the height and crown area of single tree in broadleaved forest by application of airborne laser scanner system. The process of this study includes : interpose the ground data for preparing accurate DTM (Digital Terrain Model) and DHM (Digital Height Model), extracting top of crown using method of segmentation-based in DHM, create crown area by means of segmentation on defined cross-section which the height can be designated. In result of our study, all of bigger trees, which compose upper crown-layer, had been extracted and the crown area on llm above ground had been computed.
There are generally two types of difficulties when someone attempts to estimate stand biomass using satellite imagery. One is technical difficulty and the other is the difficulty in obtaining statistically sufficient field samples. To overcome the latter, we examined the photogrammetry of digitized aerial photographs in an arid area of Western Australia. In this area, the stand biomass was calculated from canopy coverage. Therefore, canopy coverage was estimated from digitized aerial photographs by discriminant analysis, and then the stand biomass distribution was obtained. The estimation accuracies of canopy coverage and stand biomass were evaluated by visual interpretation of aerial photographs and by field measurement, respectively. The method using discriminant function showed high estimation precision. Thus, in this area and in similar arid areas, photogrammetry of digitized aerial photographs is considered sufficient to overcome the difficulty in obtaining statistically sufficient samples.
In the inertial navigation system, the accuracy decreases as the measuring time becomes longer because of the accumulation of errors. Kalman filter is usually used to prevent the error accumulation by combining the acceleration with some additional information such as the velocity of the system measured by, for example, a vehicle motion sensor. However, extra sensors make the system larger, heavier and more expensive. Fortunately, it is possible to know the velocity exactly without any velocity sensor if the system is at rest. Based on this obvious fact, we propose here an inertial navigation system that utilizes the velocity but has no velocity sensor, and describe the experiments performed to evaluate the usefulness of the proposed system.
The spatial arrangement of the brightness values of remotely sensed imagery bears important information for forest canopy structures. This paper presents an algorithm to estimate tree crown size and position from color orthophoto images acquired at several seasons. The seasonal change in color of leaves gives us a piece of useful information about the boundary of neighboring tree crowns. The usefulness of the algorithm for practical applications is demonstrated with an experiment on multiple orthophoto images of the northern part of Kyushu Island.