CONCRETE SURFACE TEMPERATURE MAPPING AND ANOMALY DETECTION 
WITH AIRBORNE THERMAL REMOTE SENSING 
: 2r : a, b : * d 1" 
Ryo Michishita ^^, Tadashi Sasagawa * and Peng Gong 
? PASCO Corporation, 1-1-2 Higashiyama, Meguro-ku, Tokyo, 153-0043, Japan 
-  (ryo_michishita, tadashi_sasagawa)@pasco.co.jp 
® Center for the Assessment and Monitoring of Forest and Environmental Resources (CAMFER), UC Berkeley, 
151 Hilgard Hall, Berkeley, CA, 94720-3110, U.S.A. - gong@nature.berkeley.edu 
ABSTRACT: 
Erosion control is one of the most important land development policies in Japan. Corrosion of concrete structures and 
associated structural failures can be seen in complex urban areas due to the difficulties in detection and maintenance 
of them. It is particularly true along transportation systems where retaining walls along highways are unstable. Early 
detection of such corroded spots possibly will prevent a significant amount of structural failures and loss. The 
objective of this study is to develop a temperature mapping algorithm that detects such anomalies in concrete 
structures through airborne thermal remote sensing. A new airborne thermal sensor, Thermal Airborne Broadband 
Imager (TABI), available at PASCO Corporation is utilized to acquire thermal data at 0.1 °C thermal resolution and 
with 1.5 m resolution for a study site in Japan. The shadow effect on radiant temperature was analyzed. The statistical 
T-test was used as measure in detecting concrete anomalies and proved to be effective. 
KEY WORDS: Thermal, Mapping, Detection, Engineering, Aerial, Infrared 
1. INTRODUCTION 
The Japanese government puts a great deal of effort on erosion 
control. Concrete diagnosis is one of the most noteworthy 
topies. Thermography and non-contact thermometer are used 
for testing concrete conditions. However, it is consuming time 
and expensive to test vast areas and large structures. 
Measurement in undeveloped area using these kinds of 
equipments is almost impossible. 
Thermal remote sensing data have been used for the land 
surface temperature monitoring in many application area 
including urban studies, climatology, and soil. Quattrochi 
(1999) studied the measurement and assessment of urban 
environment. Ben-Dor (1997) estimated the effect of urban heat 
island using thermal data. Ramsay (1999) developed a new 
method for volcanic mapping. 
The objective of this study is to develop a temperature mapping 
algorithm that detects the anomalies in concrete structures 
through airborne thermal remote sensing. Such anomalies may 
cause temperature differences. In this paper, we investigate the 
applicability of airborne thermal remote sensing data for 
mapping concrete structure anomalies mapping in detecting 
temperature differences. 
2. STUDY AREA AND THERMAL DATA ACQUISITION 
Kono-Takefu is located in a mountainous area at the center of 
Fukui Pref. in Japan as shown in Fig. 1. Since the occurrence of 
a large-scale landslide in July 1989, many erosion facilities 
have been built in this region. We select a study area along the 
national road #8. 
Thermal Airborne Broadband Imager 320 (TABI-320), a new 
airborne thermal sensor developed by ITRES Research Ltd. 
(Canada), was acquired by PASCO Corporation (Japan) in July 
2003 and utilized to acquire the thermal data in October 2003 
586 
over this study site. The specifications of TABI are shown in 
Table. 1. 
Table 2 lists the flight record of TABI for acquiring the thermal 
data with 1.5 m Ground Sampling Distance (GSD) in early 
afternoon (EA) and in early morning (EM). The study area 
covers 0.67 km * 7.2 km. These images were orthorectified 
with a 50 m resolution DEM released by Geographical Survey 
Institute of Japan. No atmospheric correction was done. Two 
strips of 1.5 m TABI images were mosaiced together. Fig. 2 
shows the acquired TABI images based on parameters shown in 
Table. 2. 
3. THERMAL BEHAVIOR OF LAND COVER 
MATERIALS 
Fig. 3 shows the thermal behavior of land cover materials. In 
general, the temperature of each surface cover increases after 
sunrise, continues to increase until 2:00 PM, and then decreases 
gradually. The temperature deviation depends on surface cover 
Takefu 
   
Study Area 
Kono Fukui 
_ 
Japan 
Fig. | Study Area 
Int 
  
type. 
mon 
temp 
distri 
point