In recent years, imaging of density inside volcanoes using cosmic-ray muons has been studied. In some previous studies, observations were conducted in 2 or 3 directions to obtain 3D resolution. For higher resolution, we tried to observe a volcano from 11 directions using special photographic films. The observation and analytical techniques developed in this study may be applied to other volcanoes and large objects. Reconstructing 3D images of the volcano is in progress using the obtained data.

Bidirectional muographic measurements were taken at an ancient burial mound built in the beginning of the 6th century which later collapsed after a landslide caused by the 1596 Fushimi earthquake, one of the largest earthquakes over the last few centuries in Japan. The result indicated large-scale vertical cracks at the top of the mound which caused its collapse, and thus an intrinsic problem was suggested about the stability of the basic foundation of the mound before this earthquake.

Application of elementary particle physics to the measurements of rock overburden density structures that might be directly applicable to natural resources and undiscovered cave explorations, and even to searching for hidden chambers in historic architectural structures.

In this paper we describe a new method for recognition of digits in seven-segment displays. The method is used for adding date and time information to a dataset consisting of about 7 million auroral all-sky images taken during the time period of 1973–1997 at camera stations centred around Sodankylä observatory in Northern Finland. In each image there is a clock display for the date and time together with the reflection of the whole night sky through a spherical mirror.