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Information and Communication: 31
- Life Sciences
- Information and Communication
- Nanotechnology / Materials
- Manufacturing Technology
- Human and Social Sciences
- Energy
- Environment
- Tourism / Community development
- Arctic Research
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Optical Complex Amplitude Measurement Technology
Enabling the detection of spatial phase information of light: Technology for seeing the invisible
This technology enables precise detection of optical phase distribution in a single measurement without spatial completion error by using two sensors and a polarizing optical element, and is expected to have a wide range of applications such as 3D image measurement, 3D tomography, digital phase conjugation, 3D optical memory, and spatial mode optical communication.
Research
In holographic diversity interferometry, multiple image sensors are arranged in combination with a polarizing optical element to enable precise detection of optical phase distribution in a single measurement without spatial completion error. We have developed an interferometric optical system using two image sensors and have greatly improved the measurement algorithm to achieve highly accurate phase measurement and enable 3D information processing using the measured phase distribution data. This technology can be applied directly to the acquisition of 3D optical information, optical tomography by digital phase conjugation, and 3D optical memory. In this research, we have also succeeded in developing a reference light-free phase detection system that filters the signal light spatially filtered and re-interacts with the signal light. This is expected to find applications in next-generation ultrahigh-speed optical communication systems using spatial modes and in the field of remote sensing.
Atsushi Okamoto Specially Appointed Associate Professor -
Real-time Video Processing Technology
Algorithm development and its hardware implementation
In this laboratory, we are promoting research and development of various image processing algorithms and their real-time implementation, focusing mainly on image smoothing and brightness correction of video images, which are recently increasing in capacity (high resolution and high frame rate).
Research
Since the amount of data handled during image processing is generally huge, it is essential to optimize the system as a whole by combining hardware and software. In this laboratory, we are investigating the configuration of image processing systems by studying image processing algorithms and their implementations complementarily. One of the results of our research is real-time adaptive brightness correction of video images based on the Retinex theory (Fig. 1), which can adaptively correct the brightness of video images taken under conditions of large changes in illumination, such as backlighting, in real time. We are also working on high-quality image smoothing (Fig. 2) based on cost optimization, which is expected to be applied to image processing such as photo illustration, pre-processing of various image processes, brightness correction, and detail enhancement.
Hiroshi Tsutsui Associate Professor -
Recognition and Modeling Technology for Laser Scanned Point Clouds
Toward more sophisticated analysis, maintenance and management, and planning of environments and structures where human activity takes place
We are developing theories and algorithms for point cloud processing to automatically recognize and create 3D models of objects and structures that exist in environments where human activity takes place, such as rooms, roads, pole-like objects (utility poles and street lights), street trees, and buildings, from 3D laser scanned point clouds.
Research
We are researching technologies for the automatic recognition and modeling of objects and structures in indoor and outdoor environments from point clouds obtained by ground-based and vehicle-mounted 3D laser scanning systems, as well as basic point cloud data processing methods. The objects to be recognized and modeled include a wide range of arbitrarily shaped objects, rooms, pole-like objects such as utility poles and street lights, trees, road surfaces, and buildings. In addition to the technology of generating mesh models, polygon models, and CAD models from point clouds, we also conduct research on point cloud registration, segmentation, shape feature extraction, machine learning, and procedural object recognition that serves as the foundation for the technology. This technology enables detailed recognition and analysis of the environment and structures, maintenance and management, various simulations and improvement plans using 3D models that faithfully reflect the current state.
Hiroaki Date Professor -
Recommendation Techniques Using the Bandit Method
Online learning technology that maximizes cumulative gain while acquiring knowledge
We are researching a recommendation method that maximizes the user's cumulative satisfaction, not only by recommending items that the user may prefer (use of knowledge), but also items that may provide more information about the user's preferences (acquisition of knowledge) in a balanced manner.
Research
In today's internet society, recommendation technology, if it works well, can benefit both the provider and the receiver of the service. A recommendation service is not a one-time event, but an iterative process with feedback each time, and the feedback only concerns the items that are recommended. Therefore, to increase the accuracy of subsequent recommendations, it is not only important to recommend items that the user is likely to like based on the feedback history (knowledge utilization), but also items from which the user is likely to acquire more information (knowledge acquisition). The Bandit method attempts to maximize user satisfaction by balancing the use and acquisition of knowledge. We are developing a recommendation system using this method.
Atsuyoshi Nakamura Professor -
Security Certification Technology for Quantum Key Distribution Devices
Experimental certification of ultimate cryptographic security
Using quantum key distribution, we can share cryptographic keys via optical communication while maintaining a high level of secrecy, no matter how the technology advances in the future. Through our research, we offer technologies to experimentally guarantee the security of quantum cryptography using an actual device to realize its practical application.
Research
The quantum key distribution technology has passed the proof‐of‐principle phase, and research is now under way with an eye on its practical application. Since this is a technology to realize the ultimate confidential communication, field tests and other researches on it are conducted worldwide. In our laboratory, we are examining both theoretical and implementation-related aspects on quantum key distribution. In the real world, things do not always go according to the theory, and experimental results sometimes differ from those expected in theory. Our goal is to examine these discrepancies and quantitatively guarantee the security of cryptographic keys produced on real devices. To this end, we are conducting research to fill the gap between the theoretical studies and the actual device development. We believe that this research will open the way to measure and evaluate the behaviors of the actual quantum devices, and finally to realize practical quantum systems, which will contribute to future quantum networks.
Akihisa Tomita Emeritus Professor -
Soft Error Testing of Telecommunication Equipment Using a Compact Electron Accelerator Neutron Source
Preventing malfunctioning of telecommunication devices caused by cosmic rays
As the semiconductor devices of equipment that support telecommunication networks are becoming more intensively integrated, there is concern that the probability of soft errors caused by cosmic-ray neutrons will increase. To address this problem, we are conducting soft error tests of telecommunication devices using a compact accelerator-driven neutron source at Hokkaido University.
Research
As telecommunication devices increase in capacity and become more sophisticated, semiconductor devices are becoming more and more integrated. However, there is concern that cosmic ray neutrons may cause an increase in soft errors, such as bit information upset and operation confusion. Therefore, in collaboration with NTT, we have reproduced soft errors using a compact electron accelerator-driven neutron source to create a place to develop countermeasure technologies in advance. This enables the advance prediction of the failure rate in the natural environment, the detection of errors and verification of operational measures, which will lead to improved reliability of the equipment.
The feature of this technology is the use of a compact accelerator-driven neutron source. In the past, large-scale accelerator-based neutron sources were required, and it was difficult to secure sufficient test time and experimental space. However, through our research, we have demonstrated that it is possible to conduct sufficient tests even in a facility with a neutron intensity of several million times that in nature.Hirotaka Sato Associate Professor -
Spatio-temporal Control of Laguerre-Gaussian Light
Information multiplexing using the spatial phase of light
In this study, we have developed a fundamental technology for information multiplexing using Laguerre-Gaussian (LG) light, which has a characteristic spatial phase. By focusing on the spatial phase, which has not been actively used in conventional optical information processing, we aim to increase the information capacity.
Research
Optical information processing, transmission, recording and reproduction are performed using the intensity, polarization and spatially uniform phase of laser light. The transmission capacity can be increased through multiplexing using different frequencies. In contrast, the spatial characteristics of light form an unexplored area that has not been actively utilized until now. Based on this background, information multiplexing using Laguerre-Gaussian (LG) light and quantum information processing using the orbital angular momentum (topological charge) that characterizes LG light have been attracting attention as a step to overcome the limitation of information processing capacity. In this study, we have utilized material interaction and realized the mode control of LG light and the conversion and conservation of orbital angular momentum using short-pulsed light, as well as space-division multiplexing fiber transmission.
Yasunori Toda Professor -
System Control Technology Based on Mathematical Methods
From mechanical to energy management systems
System control technology based on mathematical models can be applied to a wide range of fields, from mechanical systems such as four-wheeled robots to social systems such as energy management systems. At this laboratory, we are developing control methods for nonlinear and hybrid systems in particular.
Research
Many systems, such as manipulators and automobile engines, are nonlinear systems. Many conventional methods are created in view of individual cases. In this laboratory, we are developing a unified control method using control Lyapunov functions. As an example, we are considering the development of a four-wheeled robot running on a flat surface (Fig. 1). To achieve obstacle avoidance and movement to the target position, a pseudo height difference is set (Fig. 2). The obstacles are positioned high and the target is positioned low. This allows four-wheeled robots to achieve their control objectives with only one simple rule of following the low position.
Dynamical systems that include switching of dynamics are called hybrid systems, and are known to have many applications. Recently, we have been working on the application of hybrid systems to energy management systems. In particular, we are developing an electricity consumption model for consumers.Yuh Yamashita Specially Appointed Professor -
Time-resolved Two-dimensional Surface Acoustic Wave Imaging
Excitation and detection of arbitrary frequency response by optical pulse train with fixed period
This technique visualizes the propagation of surface acoustic waves up to the GHz frequency range as a time-resolved two-dimensional image. Conventional methods involve the problem of low frequency resolution, but this method can excite and detect acoustic waves of any frequency.
Research
Visualization of acoustic wave propagation is extremely useful in the evaluation of physical properties and the design, fabrication and evaluation of functional devices using acoustic waves. For this purpose, we excite surface acoustic waves by irradiating the sample with an ultrashort optical pulse of subpicosecond duration (pump light), and observe their propagation with delayed optical pulse (probe light). Time-resolved two-dimensional images of the acoustic waves are obtained by scanning the delay time and the irradiation position of the probe light. The time resolution is in picoseconds, the spatial resolution is 1μm, and the frequency range is in GHz. Since this method uses a periodic optical pulse train, it was previously only possible to excite and detect acoustic waves at integer multiples of the repetition rate. However, with the newly developed technique, we have realized the excitation and detection of acoustic waves of any frequency. By developing this technique, we have also achieved image vibrations that are completely asynchronous to the repetition frequency of the optical pulse, thereby expanding the range of applications.
Osamu Matsuda Professor -
Vertical Takeoff and Landing Type Unmanned Aerial Vehicle
An unmanned aircraft that can fly at high speed like an airplane and hover in midair like a helicopter
We have developed a vertical takeoff and landing type unmanned aerial vehicle that can hover like a helicopter while flying at high speed by obtaining lift with its wings like an airplane. It is expected to be used, for example, to quickly fly to a stricken area in the event of a disaster and to photograph the area while hovering in the sky.
Research
There are expectations of the industrial application of unmanned aerial vehicles, as DHL and Amazon are performing tests on delivery by unmanned aircraft. These unmanned aircraft are helicopter-type vehicles called multicopters. Since they have fixed wings and fly like airplanes, they move efficiently and at a high speed, and can fly farther than ordinary multicopters with the same battery.
Atsushi Konno Professor -
Visual Expression by Computer Graphics
Supporting intellectual and creative activities with computers
We aim to support people’s creative activities using 3D computer graphics. Despite significant development of computer graphics, it is not easy to manipulate 3D information, and we are not yet ready to use this information to support our creative activities. We are exploring a mechanism to freely manipulate information in 3D space and easily create CG images.
Research
To produce images using CG, we have to prepare a huge number of parameters related to shape, camera, lighting, material, etc. To achieve the desired result, these parameters must also be adjusted by trial and error. An extended calculation time is also required to create precise images. This makes it impossible to conduct creative activities using CG. Therefore, we are developing a method to solve these problems. For parameter adjustment, we have introduced the inverse problem approach, and for computation time, we are developing a fast computation method using parallel computation. We are also applying these ideas to digital fabrication using 3D printers. We are also working on the development of a new user interface to reflect the user’s intentions more intuitively.
Yoshinori Dobashi Professor
