Toshihide Nagano

USE OF BALLOON AERIAL PHOTOGRAPHY FOR CLASSIFICATION OF KUSHIRO WETLAND VEGETATION, NORTHEASTERN JAPAN

Kushiro wetland in northeastern Japan is a Ramsar-designated wetland of international importance (1980) that is characterized by high biodiversity and spatial heterogeneity. These characteristics of the wetland also present innumerable challenges for mapping and monitoring such unique ecosystems. Recent advances in remote sensing technology have provided many sensors with different spatial and spectral scales and resolutions. However, they are still inadequate for mapping wetland vegetation at a large scale for various reasons, such as inadequate resolution and high costs. This study was designed to evaluate the potential of balloon aerial photography to acquire high resolution (15 cm pixel size) imagery for mapping wetland vegetation in the Akanuma marsh. We used a standard 28-mm non-metric camera (Nikon-F-801), which seven specific categories (species mixes) were successfully delineated. It was possible to classify small shrubs mixed with herbaceous plants; moss bogs with pools; dwarf shrubs with sedges; and moss with alpine plants. From this research, it seems that balloon aerial photography is a powerful tool for mapping temperate wetland vegetation, allowing classification of specific and typical vegetation types to the genus and species level.

Automated 3D Forest Surface Model Extraction from Balloon Stereo Photographs

We upgraded an automated forest digital surface model (DSM) extraction method from balloon stereo photographs of a tropical peat swamp forest in Narathiwat, Thailand by evaluating the image matching accuracy and forest surface height (FSH) estimation. We modified an image correlation matching method based on the characteristics of the tree crown shapes. The mismatched area was less than 3 percent of the total area. We estimated an FSH map in a 60 m 60 m plot by both photo estimation and field measurement, and set the unit area for FSH averaging at 10 m 10 m. The root mean square of the differences between the mean photo-estimated and mean field-measured FSH was 3.8 m, which was revised to 1.9 m when the forest gaps were extracted offline. These differences were within a reasonably practical range since the range of the mean field-measured FSH was 10.0 to 21.4 m.