9:30 AM - 9:45 AM
[STT34-03] Operation and development of airborne portable thermal imaging camera systems
Keywords:a portable cameras system, volcano observations, infrared camera
The National Research Institute for Earth Science and Disaster Resilience (NIED) has developed a portable infrared camera system: Structure and Thermal Information Capture-Portable (STIC-P), which will enable handheld observations from the sky using aircraft in March 2020. STIC-P does not require a dedicated aircraft and allows oblique airborne observation of volcanoes outside the eruption alert level zone and can produce ground-based orthorectified images through SfM/MVS processing. NIED conducted an experimental operation of STIC-P for volcanic observations from 2021 to 2023 to determine the quantitative brightness temperature distribution and heat discharge rate, which contribute to the understanding of volcanic thermal activity. The instrument is also constantly being improved. At present it is still ground-based, but the spatial resolution has been improved by increasing the number of pixels in the infrared camera, and the wavelength range of the infrared camera has been made multi-band so that the distribution of volcanic gas (sulphur dioxide gas) concentrations can be visualized. In this report, we describe the 2021-2023 observations of Mt. Nasu as a result of volcanic experimental operations and recent developments, including an uncooled infrared camera with a larger number of pixels, an uncooled and cooled infrared camera for observing different wavelengths (multiband) in the infrared.
In the observations of Mt. Nasu from 2021 to 2023, experimental observations of brightness temperatures, etc. around Mt. Nasu (the Avici hell) from a helicopter (Bell Type 206B: owned by HeliService Inc.) were made by STIC-P on 14 November 2021, 21 October 2022, and 26 October 2023. The observation conditions were as follows: the observation altitude was 2700 m above sea level, the measurement line was oblique from a circumferential measurement line with a radius of 1500 m centred on Mt. Nasu, and multiple superimposed brightness temperature image data were acquired. SfM/MVS processing was applied to these images to produce orthorectified images. From that, the brightness temperature distribution, etc. at Mt. Nasu (near the Avici hell ) could be quantified. The highest brightness temperature observed on 14 November 2021 was 54.0 °C, measured at fumarole A on the western slope, with a heat discharge rate of 0.195 MW. The highest brightness temperature observed on 21 October 2022, also measured at fumarole A, was 62.8°C, with a heat discharge rate of 0.188 MW. The highest brightness temperature observed on 26 October 2023, also measured at fumarole A, was 51.2°C, with a heat discharge rate of 0.140 MW. The brightness, temperature distribution and shape of fumarole A on the western slope measured during these observations were judged to be similar over a period of about two years. This suggests that SPIC-P can be used to determine thermal activity.
The latest development is a camera that increases the pixel number of the current infrared camera from VGA (640 x 480) to XGA (1024 x 768), improving the instantaneous field of view from the current 0.69mrad to 0.47mrad. In the development of a multi-band infrared camera, an uncooled camera (VGA) and cooled cameras (QVGA and VGA) have been developed to selectively observe the 8-9 µm infrared region with the aim of visualizing sulphur dioxide gas. Aso Nakadake and Mt. Asama in 2020-2023, these cameras were used to visualize the distribution of sulphur dioxide gas in the plume and to estimate its concentration (approximately 0.5-20ppmv). An airborne version of these instruments is under development. Airborne test observations will be carried out in the future.
In the observations of Mt. Nasu from 2021 to 2023, experimental observations of brightness temperatures, etc. around Mt. Nasu (the Avici hell) from a helicopter (Bell Type 206B: owned by HeliService Inc.) were made by STIC-P on 14 November 2021, 21 October 2022, and 26 October 2023. The observation conditions were as follows: the observation altitude was 2700 m above sea level, the measurement line was oblique from a circumferential measurement line with a radius of 1500 m centred on Mt. Nasu, and multiple superimposed brightness temperature image data were acquired. SfM/MVS processing was applied to these images to produce orthorectified images. From that, the brightness temperature distribution, etc. at Mt. Nasu (near the Avici hell ) could be quantified. The highest brightness temperature observed on 14 November 2021 was 54.0 °C, measured at fumarole A on the western slope, with a heat discharge rate of 0.195 MW. The highest brightness temperature observed on 21 October 2022, also measured at fumarole A, was 62.8°C, with a heat discharge rate of 0.188 MW. The highest brightness temperature observed on 26 October 2023, also measured at fumarole A, was 51.2°C, with a heat discharge rate of 0.140 MW. The brightness, temperature distribution and shape of fumarole A on the western slope measured during these observations were judged to be similar over a period of about two years. This suggests that SPIC-P can be used to determine thermal activity.
The latest development is a camera that increases the pixel number of the current infrared camera from VGA (640 x 480) to XGA (1024 x 768), improving the instantaneous field of view from the current 0.69mrad to 0.47mrad. In the development of a multi-band infrared camera, an uncooled camera (VGA) and cooled cameras (QVGA and VGA) have been developed to selectively observe the 8-9 µm infrared region with the aim of visualizing sulphur dioxide gas. Aso Nakadake and Mt. Asama in 2020-2023, these cameras were used to visualize the distribution of sulphur dioxide gas in the plume and to estimate its concentration (approximately 0.5-20ppmv). An airborne version of these instruments is under development. Airborne test observations will be carried out in the future.