According to the Kyoto protocol, forest and non-forest area are distinguished using crown cover ratio. So the establishment of the method to estimate the crown cover ratio of forest is urgently necessary. The formula which could be estimated crown cover ratio at in the high precision was made by using the spectral band ratio. In order to confirm the robustness of the formula, the next process produced 4 types stimulation image data. The pixels of the canopy crown were extracted from the ordinal CAST image first. Then, The pixels of the background except for the canopy crown were replaced with the spectral of water, soil, moss and the grass. The estimated canopy cover ratio had changed by the difference in the background types. From this result, the limit of the estimated formula became clear. Then, the mixture classification technique was applied to estimate canopy cover ratio. When it was compared with the ground truth data, it showed a tendency to estimate it low as that result but the strong correlation existed between the truth and the estimated ratio. This research shows that the possibility to estimate the crown cover ratio accurately with mixture classification technique.
Various functions of forests are expected currently. Representative examples are the absorption and fixation of carbon dioxide and other functions of forests, and the biodiversity of Satoyama coppice forests which provide an environment to coexist with familiar nature. A method to effectively and multilaterally understand various kinds of basic information about a forest area is demanded in order to clarify such public functions of forests. In this study, the applicability of an airborne laser scanner, which is expected to be an effective means to collect topographical and tree height information about a forest area, is verified at Tama Forest Science Garden in Hachioji, Tokyo.
Micro-environmental factors fluctuate seasonally and spatially under the canopy of deciduous broadleaved forest. A 6-band hand-held radiometer was applied to evaluate the effectiveness of spectro-radiometric method for estimating aboveground biomass (AB) and leaf area index (LAI) of understory plant (Sasa senanensis) at the Takayama experiment site in Gifu, central Japan. Measurement was limited in early spring season between snow melting and leaf development of forest canopy. The correlation and regression analyses using 45 sample dataset collected at neighboring site showed that the AB was linearly related to the Ratio Vegetation Index using 850 nm and 650 nm reflectance with R2=0.811, while LAI was exponentially related to the Normalized Difference Vegetation Index using 850 nm and 699 nm reflectance with R2=0.836. It was higher in correlation coefficient done by conventional destructive method. Distribution maps of AB and LAI of the one-ha experimental site were created applying these equations. Total AB and mean LAI of Sasa canopy in whole experiment site were estimated as 5.99±3.70 D.W. t ha-1, and 1.71±0.93, respectively. This research suggested that the possibility of radiometric method to obtain bio-information of heterogeneous natural vegetation easily and timely.
An investigation of the accuracy potential of IKONOS lm satellite imagery is reported. Two sensor orientation/triangulation models, the RPC models with bias compensation and the affine projection model, are applied to stereo- and three-image configurations of Geo imagery with the aim of achieving 3D geopositioning to sub-metre accuracy. Test results from the Melbourne IKONOS Testfield are reported and these show that with modest provision of quality ground control, IKONOS Geo imagery can yield 3D object point determination to an accuracy of 0.5m in planimetry and 0.7m in height. The accuracy achieved is not only consistent with expectations for rigorous sensor orientation models, but is also readily attainable in practice with only a small number of ground control points being required.