In recent years, the use of computer systems for identifying people has become increasingly popular. Clear facial images and detailed facial features are often provided to the system to improve identification accuracy, but if they are misused, privacy can be compromised. The authors are currently building a next-generation video blog system that can do the following: capture images of passersby with cameras, blur the facial images of all the people, remove the blurring for specific people who have registered their facial images for public viewing, and then upload them as video blogs in real time in a hands-free manner. By comparing the similarities between the obscured data in the user's stored data and the data captured by the camera and immediately obscured and sent to the edge server, the authors devised a system that enables person identification but does not pass clear facial images and features to the system. The authors focused on the possibility of using noise strength added to features and random seeding of features as a common quasi-encryption key to protect privacy. This paper assesses the extent to which the intensity of noise in this system obscures person identification. The results show that privacy can be protected by adding epsilon noise below a certain strength to the features, and the noise strength and the random number seed for noise generation can be used as a common quasi-cryptographic key.

In recent years, there has been an urgent need to improve safety and efficiency to avoid dangerous situations. In this paper, the authors proposes a visualization system of near-future information by augmented reality (AR) to avoid dangerous situations. The proposed system utilizes the position and speed information of the user and obstacles, predicts crashes, and recommends avoidance actions such as changing course or stopping. Experiments were conducted under different conditions by the implemented system to determine how many seconds into the future it would be safer for the user and easier to take avoidance action. The experiment results showed that the avoidance rate was almost the same for 2 seconds or longer, but the best rate was for 3 seconds ahead.

Recent technological advances in Virtual Reality (VR) and Augmented Reality (AR) enable users to experience a high-quality virtual world. Using VR to experience the virtual world, the user's entire view becomes the virtual world, and the user's physical movement is generally limited because the user cannot see the surrounding situation in the real world. Using AR to experience the virtual world, we generally use special sensors such as LiDAR to detect the real space and superimpose the virtual world on the real space. However, it is difficult for devices without such special sensors to detect real space and superimpose a virtual world at an appropriate position. This study proposes two methods for replacing the background: a method using depth estimation and a method using semantic segmentation. This study also confirmed that the system can be used with sufficient removal accuracy and response time by using appropriate image size for the environment and that a safe and highly immersive virtual world experience can be achieved.

In this paper, the authors propose a real-time AR visualization system that enables the user to visually grasp the future snow-covered situation at the current location, aiming to support residents and visitors in heavy snow areas. The proposed system generates snow-covered spatial information that reflects the snow-covered situation on spatial information in the real world sensed by 3D LiDAR, and composes it on the video image captured by a camera. This paper describes a lightweight method of spatial information processing by reducing the amount of spatial data transmission.

In this paper, we propose a tree construction method to collect and composite distributed videos on the live broad-casting system called “same world broadcasting system”. The same world broadcasting system generates and delivers a video in which video objects captured at the different places are displayed as if they were located in the same world. Our tree construction method employs an “occlusion graph” that represents the overlap relations of the video objects to give a heuristic solution to find a tree of network structure to collect and composite videos which provides a high-quality video in heterogeneous environments. We implemented the tree construction algorithm and conducted computer simulations considering different scenarios. Our simulation results show that our proposal can find a good collection tree within a practical amount of time.

Recent technological advances in Virtual Reality (VR) and Augmented Reality (AR) enable users to experience a high-quality virtual world. In VR applications, the user's physical movement is generally restricted because the situation around the real world cannot be seen. AR allows users to experience virtual worlds without restrictions on physical movement, but the extent to which they are replaced as virtual worlds is limited. In this research, assuming the use of smartphones and tablet devices, a partial virtual world system is implemented by removing only the background part from the real-time real-world image taken by the camera and replacing it with a virtual background.

Many systems and services for VR spaces use avatars to represent the appearances of each user. In those systems and services, the users communicate with each other via their avatars. Currently, various techniques and researches have been studied for avatar appearance. However, the existing techniques and studies mainly regard avatars as the self-expression of each user and do not mention the influences on communication from others. In communication content, avatars are one of self-expression of each user and one of the communication tools. Therefore, this paper describes an investigation of how avatar appearances affect communication from others. The result from the research showed that the degree of deformation of avatars affects communication from others in various situations such as informal and formal situations.

Recently, live video broadcasting is frequently used due to the COVID-19 pandemic. More realistic and comfortable experiments can be realized if multiple real-time videos from different places are displayed on a single screen. This paper calls such live broadcasting "same world broadcasting" as if all objects exist in the same space. In this paper, we propose a distributed system for the same world broadcasting. We evaluate the proposed system using the experimental implementation in a LAN environment and an open testbed environment. The experiment results show that the proposed system can reduce the processing time to collect and compose many real-time videos.

Due to the increase in the speed of wireless communication in recent years, video-on-demand (VoD) systems has got great attention. In conventional VoD systems, when the number of clients receiving video data increases, the problems of longer playback interruptions or longer buffering times occur. Accordingly, several research focus on the VoD systems that adopt broadcast-type distribution (B-VoD). In B-VoD systems, video files are divided into several parts and distribution servers broadcast them in the sequences of predetermined broadcast schedules to reduce interruption time. However, conventional broadcasting methods do not consider the issues that occur in actual B-VoD systems, such as initial buffering delay and the increases of data sizes caused by video file division. Interruption time can be further reduced by considering them. Hence, in this research, we propose a data segment scheduling method for B-VoD systems. We measure the performance of our proposed method on an actual B-VoD system utilizing radio broadcasting (VHF-band) to achieve a broadcast-type distribution. The results of the experiments confirmed that, under the condition of an uninterrupted playback, the waiting time until the start of a playback can be reduced by up to 85% under our proposed method by dividing the requested video data into 6 parts and broadcasting the parts in parallel.

Due to the recent popularization of live video distributions, live video distributors such as YouTubers have attracted great attention. Some of them shoot videos of themselves using smartphones while moving and distribute the videos via the Internet. One of the major consideration points of live video distributions on the Internet is trust between distributors and viewers, since various public concerns such as threats or attacks to distributors occur in live video distribution situations with no trust. To solve these concerns and enable safety live video distributions on the Internet, we propose a novel live video distribution architecture. In trusty situations, the systems under our proposed architecture add more video captions to give various information to the viewers. Otherwise, the systems add more effects to hide information. We also define three policies for distributors to manage trust.

Internet live broadcasting services such as USTREAM, TwitCasting have become popular. These services give broadcasters an ability which can broadcast videos via the Internet. By adding video effects and audio effects, live streaming services can realize as if broadcasters were in a different world. In this paper, we call this kind of live streaming `Different Worlds Broadcasting'. However if many viewers request the effect in a short period of time or use some heavy load effect, it takes much time to render those effects and the frame rate gets worse. Therefore, currently users can use only small load effects such as superimposing small firework effect on the video, adding simple echo effect on the sound. Rendering effects in a short time, users can add more effects or the frame rate cat get better. In this paper, we propose a distributed video processing system for Internet live broadcasting services with video effect and audio effect. The proposed system take a video by broadcaster's PC or smartphone and transmit it to effect servers to add various effects. Effected video stream is transmitted to the broadcast server of the Internet live broadcasting service.

The recent development of stream delivery technology made Internet broadcasting services popular. In live Internet broadcasting, broadcasters or viewers often add video or sound effects (we call this kind of live broadcasting, `different worlds broadcasting'). Therefore, we have proposed a distributed Internet live broadcasting system with video and audio effects. In this paper, we describe the implementation of our proposed system and its demonstration system using real-time facial animation.