Analysis of urban surface temperature change using structure-from-motion thermal mosaicing

- With “SfM thermal mosaicing”, orthogonal LST image can be made automatically.
- By the method, LST images of central Tokyo in the summer of 2007 and 2013 were made.
- The images were compared and it is shown that there are cooler and hotter areas.
- Cooler areas were newly developed areas. Hotter areas were in loss of green spaces.
- “SfM thermal mosaicing” is very useful tool for UHI studies and urban planning.

Thermal image is important source of information in the urban climate. In this study, we proposed “structure-from-motion (SfM) thermal mosaicing” which uses only thermal images to make orthogonal land surface temperature (LST) image in the process of SfM. With this method, orthogonal LST image can be made automatically without finding many ground control points manually. For the application of the method, LST images of central Tokyo in the summer of 2007 and 2013 were made. The quality of the images was practically precise. The images were compared and it is clearly shown that the LST in 2013 became cooler than in 2007 in many areas of development. There were also hotter areas where loss of green spaces was observed. With prevailing usage of drones for obtaining airborne LST image, this automatic method to make LST image will be very useful for UHI studies and urban planning.