ecce _ ru EEE U — pp 
8 REPORT OF THE INSTITUTE OF INDUSTRIAL SCIENCE, UNIVERSITY OF TOKYO 
from shape but also in color tone. 
5. APPLICATION OF INFRARED PHOTOS 
5.1 Photo 3 is one of the serial photos taken while flying over the whole area along 
Tenryu River. Of these, (a) is an infrared photo and (b) is a panchromatic photo. Both 
were taken at about the same time. 
As can be seen from these photos, there is a small paddy field on the slope facing 
Tenryu River. It is left unattended 
after harvesting. 
It had been known from the 
previous survey that there was a 
crack in the paddy part A inscribed in 
photo (a) and that there was a dan- 
ger of a landslide. It is evident from 
the photo (a) that the color tone of 
the part which is about to crumble 
because of the crack differs markedly 
  
from that of other parts. 
(a) Infrared photograph. In photo(a), difference in color 
tone is also noticeable 
in part B. As a result 
of resurvey conducted 
at later dates, it was 
ascertained that there 
was a big crack there, 
too. 
It is difficult to 
detect such abnormali- 
ties from panchromatic 
photos. 
5-2 Heretofore, 
we used a miniature 
  
camera and Japan-made 
(b) Panchromatic photograph. infrared films in our 
Photo. 3 test. With a view to 
developing the test further, we fitted Aviotar lens (focal distance, 21 cm) to the aerial camera 
and used Aviphoto Infra-R film imported from abroad. 
The area photographed was the mountainous district stretching along the main stream 
of Kurobe River and part of the plains of Toyama which is located on the lower reaches and 
which is known as an alluvial fan. 
Photo 4 is one of the photos of the alluvial fan taken simultaneously by the use of 
panchromatic and infrared films. This picture shows the terrace lying in the eastern tip of 
the alluvial fan. It is approximately 40 meters higher than the present alluvian and the dip 
is steeper than the existing alluvial plane. If you compare the panchromatic photo with the 
infrared photo, you will notice that minute changes on the earth's surface can be interpretd 
far better in the latter. 
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