臨場感溢れるバーチャルリアリティーで脳内世界を再構築　　　　　　　　　　気ままなリライト９０

3D地図、防災・観光磨く - 日本経済新聞

Inspired by the prospect of tapping into a gold mine found in large datasets for immersive digital simulations aimed at tackling various real-world challenges, many municipalities are intent on showcasing virtual representations of real-world landscapes on their websites. The representations are generated using three-dimensional data, making those resources accessible to the public. Those municipal bodies are asserting that by incorporating virtual reality technology into the diverse purposes of 3D geographic models, residents' adaptability and resilience in the face of unexpected real-life problems could be enhanced. That could be achieved by honing their problem-solving skills in a virtual environment.

Municipalities are adopting a novel approach for constructing 3D models of local geographic scenes by using drones equipped with Light Detection and Ranging (LiDAR) systems to conduct surveys. The approach is emphasizing a more accurate and realistic portrayal of real-world situations than traditional aerial photogrammetry, which relies on high-resolution cameras to capture overlapping images from various viewpoints. Those images are then processed through software designed to identify common points between the images to build a 3D model of the area. The drone-hovering LiDAR survey offers its exceptional accuracy and the sheer volume of data points in the mapping. A LiDAR system is a remote sensing method to measure distances by emitting pulses of light. For each emitted pulse, the system records the time taken for each light pulse to travel to the target and back. Given the exact location of the LiDAR sensor, the system then calculates the exact three-dimensional position of the point where the light pulse is reflected. This process is repeated millions of times per second, with each reflected light pulse being recorded as a distinct data point. As those data points, referred to as a "point cloud", become denser, more detailed and accurate 3D representations of the surveyed area are integrated into a geographic context, through software tools for efficient data processing and 3D modeling.

Among the prefectures offering open-source virtual 3D geographic maps simulating real-world environments, are Shizuoka, Nagasaki, and Hyogo prefectures. Shizuoka has taken a step forward in its pioneering efforts for the use of geospatial data. Since 2019, Shizuoka has incrementally expanded its LiDAR survey coverage, achieving comprehensive mapping of residential areas by  fiscal 2021.　In non-residential areas such as the coastal shores adjacent to the prefecture, point cloud data collected is being utilized to its full potential. The integration of 3D data into a smartphone application is visualizing the ground surface in forested regions and the seafloor near the prefecture. Various applications are fully monetized for projects and activities such as fishing or marine research. Nagasaki and Hyogo are following Shizuoka's lead. Nagasaki is making high-quality point cloud data around Nagasaki City available from March, while Hyogo is releasing 3D data covering all terrains within the entire prefecture, including islands, based on LiDAR surveys. This extensive data is ready for public exploration.

The Tokyo government is enthusiastic about tapping into the benefits of virtual reality (VR) technology and 3D imagery, envisioning a future in which the technology's application goes beyond conventional uses. The emphasis is on harnessing intricate 3D maps for a wide array of purposes including disaster management, risk mitigation, urban planning, and virtual tours. This initiative is already in motion with an ongoing project focused on 3D mapping the entire city of Tokyo, with all the resulting data from the project being offered as open-source and set to be available after fiscal 2023. In Nakano Ward, Tokyo, the extensive potential of VR technology will be demonstrated in a unique project aimed at digitally preserving the iconic cultural building, Nakano Sun Plaza, slated for reconstruction this July. Through the interweaving of VR technology and the point cloud data about Nakano Sun Plaza scheduled for release in fiscal 2024, the time-honored concert hall will be transformed into a timeless landmark, providing a stunningly realistic illusion. Virtual walkthroughs of the building will give visitors a sense of physical presence within the digital environment. Although the replication of certain sensory details like smell, taste, and intricate touch sensations remains a challenge, the mental acceptance of the virtual environment as a highly engageable space allows visitors to evoke their psychological and neurological responses much like those experienced in the real world.

Virtual Reality (VR) is inching ever closer to bridging the psychological gap between the real experience and the simulated one, offering a supplementary impact on activities such as disaster preparedness drills. State-of-the-art VR systems, equipped with deep immersion and presence, have the power to deceive drill participants' brains into treating virtual experiences as though they are reality. How real the virtual environment feels to the participants depends on the degree of their psychological engagement. Profound engagement in VR comes with an effect of orchestrating superior sensory feedback via haptic gloves, captivating narratives and interactions consistent with their expectations from the real world. This combination prompts highly genuine responses to virtual stimuli, arousing powerful emotions and fostering memory imprinting akin to that experienced in real-life scenarios. The brain tends to blur the line between events unfolding in the physical world and those transpiring within the virtual realm. Such perception triggers the fight-or-flight response more swiftly during VR-based disaster preparedness drills than in physical drills. The heightened responsiveness arises from more intense perception of a physical threat, such as a fire, in the immersive VR environment.