EFFICIENT ORTHO-RECTIFICATION OF OLD SMALL-SCALE AERIAL
PHOTOGRAPHS USING PRISM PRODUCTS IN JAPAN
H. Umakawa, L. Zhu and K. Tachibana
Research and Development Center, PASCO Corporation, Meguro Building annex IF, 2-8-10 Higashiyama, Meguro-ku,
Tokyo 153-0043, Japan - (hiroko_umakawa, lin zhu, kikuo_tachibana)@pasco.co.jp
Commission VI, WGIV/3
KEY WORDS: Processing, Automation, Change, DEM/DTM, Ortho Image, Satellite, Aerial
ABSTRACT:
Fortunately, in Japan, vertical aerial photographs acquisitions were started since 1940s. Furthermore, 22% of the land has been
clearly captured by PRISM until March 2007. To utilize the exuberant archives, this study evaluates how PRISM product works for
the automatic ortho-rectification process of the old small scale aerial photographs. First of all, we conducted a static analysis to
grasp the overall effects of land change. On the analysis, we tried to a streamlining of the process referring PRISM products. The
workflow with PRISM product is considered to be effective for ortho-rectifying of old aerial photographs, especially with a few
available references of the past.
1. INTRODUCTION
1.1 Background
Up to date, GIS and photogrammetry technology have achieved
a lot of development. And various research and development
have been conducted with the technology all over the world.
Now no one doubts that automatic time change detection will
also come to a reality.
Most of the cases to observe temporal changes on the land,
aerial photographs are mainly used. Those photographs are
generally acquired at different time, condition and scale.
Consequently condition of image archives is always the wild
card to plan such projects. We also use satellite images for the
purpose. Satellite image dataset on civilian use has been
available since the 1990s. Recently many high-resolution
satellite images are captured all over the world. However, even
now the price is still expensive as it was before.
Problems on archive are most serious especially when it goes in
practical use. In reality, a number of the available images and
their quality are greatly influenced due to location of the test
site and data capturing duration.
1.2 Small-Scaled Images in Japan
Fortunately, in Japan, vertical aerial photographs acquisitions
were started since 1940s. The photographs have been provided
at reasonable price by the government. In addition, the
Advanced Land Observing Satellite (ALOS) was launched in
2006 and 22% of Japanese territory has been captured by its
three-line sensor PRISM until March 2007. Concerning to
PRISM, highly accurate and automatic processed products
(DSM and Ortho image) are prospective with the start of RPC
model distribution in April 2007. Those images are very good
references to understand national land situation.
During 1955 to 1975 Japan had a high economical growth
period. Many topographic changes took place all over the cities
after that period. Almost medium and small cities archive only
limited records that describe the changes of the past. To
complete these data lack, old aerial photographs are most useful
materials. However geometrical rectification of old aerial
photographs is very difficult work. It takes a lot of time and
effort due to lack of supporting information, e.g. inner
orientation and exterior orientation parameters. It is also
difficult to collect enough number of GCPs from the existing
references.
1.3 Approach for Efficient Ortho-Rectification
This study evaluates how PRISM product works for the
automatic ortho-rectification process of old small scale aerial
photographs which are used for the mapping of land use and
landform changes. To get geo-references for ortho rectification
of old aerial photographs, we use Value Added Products of
PRISM. Since PRISM products are relatively cheaper and
updated frequently, it is readily available as a reference data.
We present the result of an analysis of topographic changes and
surviving features within 60 years of temporal changes in a test
site. Linear feature extraction method adopted to get geo-
referencing information from map sheets, and PRISM imagery.
2. TEST SITE AND MATERIALS
2.1 Test Site
The test site is located on the western side of the metropolitan
area at the center of the mainland of Japan. The prefecture has
been blessed with a number of the environments, such as: large
cities (e.g. Yokohama), medium cities, bay area (e.g. Sagami
bay) and mountains. Some of the cities in the prefecture have
important historical landmarks and large archive of references.
The central part is formed from urbanized plains. Concerning to
the western area, there is a large foothill surrounding Mt. Fuji,
and 1,500-1,600m high mountains range one after another.
Hakone volcanic region is also located in the southwest area.