10:45 AM - 12:15 PM
[STT40-P05] Brightness temperature distribution of Nasudake observed by the helicopter-mounted portable infrared camera system
Keywords:portable camera, volcano observations, infrared camera
The National Research Institute for Earth Science and Disaster Resilience (NIED) developed a portable infrared camera system: Structure and Thermal Information Capture-Portable (STIC-P) in March 2020. The STIC-P enables ground-based observations and hand-held observations from the airplane. Here, we describe the experimental observations results of brightness temperatures around the summit area of Nasudake.
NIED has been developing and utilizing an airborne remote sensing device for volcano observation since 1988. In March 2020, we developed a portable infrared camera system (STIC-P) that can be handheld and used for ground observation and oblique observation from the sky by helicopters. STIC-P consists of one infrared camera and two visible cameras, each of which can measure still images or video (30 Hz) images. In April 2021, a test observation was carried out using STIC-P onboard a helicopter over the Owakudani, Hakone, to verify the performance of STIC-P, and it was verified that Digital Surface Model (DSM) can be generated by Structure from Motion / Multi View Stereo (SfM/MVS) processing.
We continued to conduct test observations of brightness temperatures around Nasudake (Mugenjigoku) on November 14, 2021 and October 21, 2022, from a helicopter (Bell Type 206B: owned by HeliService Co., Ltd.) to realize operational volcano observations by STIC-P. The observation altitude was 2700 m above sea level, and the measuring line was an oblique observation from a circular course with a radius of 1500 m centered on the summit of Nasudake. We obtained 258 (2021) and 212 (2022) brightness temperature images for each observation, which were partially superimposed on each other.
The results of applying SfM/MVS processing to these observations enabled DSM estimation for both observations, contour mapping from the DSM and ortho-rectified images with map information to be created within a positional error of approximately 10 m, and quantitative understanding of the brightness temperature distribution, etc., on Nasudake (near Mugenjigoku). The highest brightness temperature observed on November 14, 2021 was 54.0 °C and the heat discharge rate was 0.195 MW at fumarole A on the western slope; the highest brightness temperature observed on October 21, 2022 was 62.8 °C and the heat discharge rate was 0.188 MW, also measured at fumarole A on the western slope. The distribution shape of the brightness temperature in 2021 and 2022 at the west slope fumarole A measured in each observation were evaluated to be almost similar.
The above results show that it is possible to estimate 3D information with map coordinates by applying SfM/MVS processing to multiple superimposed oblique observation images acquired by STIC-P, and quantitative comparative evaluation of geothermal areas of volcanoes can be performed. In the future, continuous accumulation of similar observation data by STIC-P will enable temporal and quantitative evaluation of geothermal areas using heat discharge rates, etc., and STIC-P is expected to be utilized as an evaluation method for volcanic geothermal areas.
NIED has been developing and utilizing an airborne remote sensing device for volcano observation since 1988. In March 2020, we developed a portable infrared camera system (STIC-P) that can be handheld and used for ground observation and oblique observation from the sky by helicopters. STIC-P consists of one infrared camera and two visible cameras, each of which can measure still images or video (30 Hz) images. In April 2021, a test observation was carried out using STIC-P onboard a helicopter over the Owakudani, Hakone, to verify the performance of STIC-P, and it was verified that Digital Surface Model (DSM) can be generated by Structure from Motion / Multi View Stereo (SfM/MVS) processing.
We continued to conduct test observations of brightness temperatures around Nasudake (Mugenjigoku) on November 14, 2021 and October 21, 2022, from a helicopter (Bell Type 206B: owned by HeliService Co., Ltd.) to realize operational volcano observations by STIC-P. The observation altitude was 2700 m above sea level, and the measuring line was an oblique observation from a circular course with a radius of 1500 m centered on the summit of Nasudake. We obtained 258 (2021) and 212 (2022) brightness temperature images for each observation, which were partially superimposed on each other.
The results of applying SfM/MVS processing to these observations enabled DSM estimation for both observations, contour mapping from the DSM and ortho-rectified images with map information to be created within a positional error of approximately 10 m, and quantitative understanding of the brightness temperature distribution, etc., on Nasudake (near Mugenjigoku). The highest brightness temperature observed on November 14, 2021 was 54.0 °C and the heat discharge rate was 0.195 MW at fumarole A on the western slope; the highest brightness temperature observed on October 21, 2022 was 62.8 °C and the heat discharge rate was 0.188 MW, also measured at fumarole A on the western slope. The distribution shape of the brightness temperature in 2021 and 2022 at the west slope fumarole A measured in each observation were evaluated to be almost similar.
The above results show that it is possible to estimate 3D information with map coordinates by applying SfM/MVS processing to multiple superimposed oblique observation images acquired by STIC-P, and quantitative comparative evaluation of geothermal areas of volcanoes can be performed. In the future, continuous accumulation of similar observation data by STIC-P will enable temporal and quantitative evaluation of geothermal areas using heat discharge rates, etc., and STIC-P is expected to be utilized as an evaluation method for volcanic geothermal areas.