[G-01] Information Design in the Contents of Earth Science Education

[G01-04] Practical training in photogrammetry using smartphones and 3D scanning app

*Takuro Ogura¹ (1.Graduate School of Education, Hyogo University of Teacher Education)

Keywords:Smartphone, 3D Scanning, photogrammetry, geoscience education, 3D model

Photogrammetry using stereo pair photographs is an essential technique for mapping the distribution and characteristics of landforms, vegetation, and forests. By creating a Digital Surface Model (DSM) from photogrammetry, topographic elevation differences and tree heights can be represented in GIS. Traditionally, high precision and accuracy DSMs could be obtained using aerial photographs taken by national agencies and companies from aircraft. In recent years, photogrammetry using UAVs (Unmanned Aerial Vehicles: drones) and SfM (Structure from Motion) has become widely spread, providing researchers and students with more opportunities to work closely with individuals to perform photogrammetry. On the other hand, it is necessary to know detailed survey planning and camera parameter settings to obtain DSMs with high accuracy and -precision using photogrammetry. Thus, I planned a simple 3D modeling training using smartphones and the 3D scanning application as a preliminary step to the UAV-SfM photogrammetry training. The 3D scanning App was WIDAR, made by WOGO, Inc (Fig. 1). WIDAR can be used on iOS and Android operating systems. By uploading photos to the cloud, 3D models can be created without depending on the smartphone's specifications if the device is connected to Wi-Fi. This teaching practice was conducted as part of the lecture class "Spatial Information and Modeling" for 3rd and 4th-year students of the Faculty of Science and Engineering, University A, and the experiment class "Field Methodology in Geoscience" for 2nd-year students of the Department of Earth Science, University B. 125 Students taking the course in the University A and 50 students taking the system in the University B. In the training course, I first explained the application's use. Then, the students were moved out of the classroom and photographed at least five objects on campus. I instructed them to be sure to include one structure and one landform. WIDAR requires multiple photographs to be taken first to create a 3D model. Therefore, the students took between 20 and 200 pictures of the object from various angles. Also, I explained the need to keep deadlines for surveying and set a 55-minute work period for the photographs. Finally, students uploaded the shared link of the 3D models they created by the designated time to "manaba," the learning management website. Their model with neighboring students and discussed necessary settings for photogrammetry, such as objects for easy 3D modeling and creative ways to take photographs. After the class, a questionnaire was administered on manaba to reorganize the students about the techniques required for photogrammetry, and their impressions and opinions were tabulated. From the students' assignments, examples of objects in which photogrammetry excels include things that are not uniform in color, have a distinct shape, and the subject does not move. They also pointed out the need to take pictures from all angles and to consider the distance between the camera and the object to perfect the 3D model. These are the basic requirements for photogrammetry generally, and it could be inferred that students could acquire photogrammetric skills in a well-organized manner. Practical training in photogrammetry using a smartphone and a 3D scanning application.