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Dive into the research topics where Tatsunori Hirai is active.

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Featured researches published by Tatsunori Hirai.


international conference on computer graphics and interactive techniques | 2014

Efficient video viewing system for racquet sports with automatic summarization focusing on rally scenes

Shunya Kawamura; Tsukasa Fukusato; Tatsunori Hirai; Shigeo Morishima

classroom use is granted without fee provided that copies are not made or distributed for commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for third-party components of this work must be honored. For all other uses, contact the Owner/Author. SIGGRAPH 2014, August 10 – 14, 2014, Vancouver, British Columbia, Canada. 2014 Copyright held by the Owner/Author. ACM 978-1-4503-2958-3/14/08 Efficient Video Viewing System for Racquet Sports with Automatic Summarization Focusing on Rally Scenes


conference on multimedia modeling | 2015

Affective Music Recommendation System Based on the Mood of Input Video

Shoto Sasaki; Tatsunori Hirai; Hayato Ohya; Shigeo Morishima

We present an affective music recommendation system just fitting to an input video without textual information. Music that matches our current environmental mood can enhance a deep impression. However, we cannot know easily which music best matches our present mood from huge music database. So we often select a well-known popular song repeatedly in spite of the present mood. In this paper, we analyze the video sequence which represent current mood and recommend an appropriate music which affects the current mood. Our system matches an input video with music using valence-arousal plane which is an emotional plane.


international conference on computer graphics and interactive techniques | 2013

Affective music recommendation system using input images

Shoto Sasaki; Tatsunori Hirai; Hayato Ohya; Shigeo Morishima

Music that matches our current mood can create a deep impression, which we usually want to enjoy when we listen to music. However, we do not know which music best matches our present mood. We have to listen to each song, searching for music that matches our mood. As it is difficult to select music manually, we need a recommendation system that can operate affectively. Most recommendation methods, such as collaborative filtering or content similarity, do not target a specific mood. In addition, there may be no word exactly specifying the mood. Therefore, textual retrieval is not effective. In this paper, we assume that there exists a relationship between our mood and images because visual information affects our mood when we listen to music. We now present an affective music recommendation system using an input image without textual information.


international conference on information visualization theory and applications | 2016

RSViewer: An Efficient Video Viewer for Racquet Sports Focusing on Rally Scenes

Shunya Kawamura; Tsukasa Fukusato; Tatsunori Hirai; Shigeo Morishima

This paper presents RSViewer, a video browsing system specialized for racquet sports, which reflects users’ interests. Methods to support users in browsing racquet sports matches by summarizing video composed of important rally shots have been discussed in a previous study. However, the method is not practical enough because the auditory events should be manually annotated in advance to detect such scenes. Therefore, we propose an automatic rally shot detection based on shot clustering method using white line detection. Our system calculates the importance of rally shots based on audio features. As the result, the summarized video can facilitate users find and review the information they need. The result of experiments shows that our method is effective in an aspect of efficient video browsing experience. Furthermore, we propose a high-speed playback method customized to racquet sports video and realize more efficient video browsing experience.


international conference on computer graphics and interactive techniques | 2015

A music video authoring system synchronizing climax of video clips and music via rearrangement of musical bars

Haruki Sato; Tatsunori Hirai; Tomoyasu Nakano; Masataka Goto; Shigeo Morishima

This paper presents a system that can automatically add a soundtrack to a video clip by replacing and concatenating an existing songs musical bars considering a users preference. Since a soundtrack makes a video clip attractive, adding a soundtrack to a clip is one of the most important processes in video editing. To make a video clip more attractive, an editor of the clip tends to add a soundtrack considering its timing and climax. For example, editors often add chorus sections to the climax of the clip by replacing and concatenating musical bars in an existing song. However, in the process, editors should take naturalness of rearranged soundtrack into account. Therefore, editors have to decide how to replace musical bars in a song considering its timing, climax, and naturalness of rearranged soundtrack simultaneously. In this case, editors are required to optimize the soundtrack by listening to the rearranged result as well as checking the naturalness and synchronization between the result and the video clip. However, this repetitious work is time-consuming. [Feng et al. 2010] proposed an automatic soundtrack addition method. However, since this method automatically adds soundtrack with data-driven approach, this method cannot consider timing and climax which a user prefers.


international conference on culture and computing | 2013

Affective Music Recommendation System Reflecting the Mood of Input Image

Shoto Sasaki; Tatsunori Hirai; Hayato Ohya; Shigeo Morishima

We present an affective music recommendation system using input images without textual information. Music that matches our current mood can create a deep impression. However, we do not know which music best matches our present mood. As it is difficult to select music manually, we need a recommendation system that can operate affectively. In this paper, we assume that there exists a relationship between our mood and images because visual information affects our mood when we listen to music. Our system matches an input image with music using valence-arousal plane which is an emotional plane.


international conference on multimedia and expo | 2016

A soundtrack generation system to synchronize the climax of a video clip with music

Haruki Sato; Tatsunori Hirai; Tomoyasu Nakano; Masataka Goto; Shigeo Morishima

In this paper, we present a soundtrack generation system that can automatically add a soundtrack with the length and climax points aligned to those of a video clip. Adding a soundtrack to a video clip is an important process in video editing. Editors tend to add chorus sections to the climax points of the video clip by replacing and concatenating musical segments. However, this process is time-consuming. Our system automatically detects climaxes of both the video clips and music based on feature extraction and analysis. This enables the system to add a soundtrack in which the climax is synchronized to the climax of the video clip. We evaluated the generated soundtracks through a subjective evaluation.


conference on multimedia modeling | 2016

MusicMixer: Automatic DJ System Considering Beat and Latent Topic Similarity

Tatsunori Hirai; Hironori Doi; Shigeo Morishima

This paper presents MusicMixer, an automatic DJ system that mixes songs in a seamless manner. MusicMixer mixes songs based on audio similarity calculated via beat analysis and latent topic analysis of the chromatic signal in the audio. The topic represents latent semantics about how chromatic sounds are generated. Given a list of songs, a DJ selects a song with beat and sounds similar to a specific point of the currently playing song to seamlessly transition between songs. By calculating the similarity of all existing pairs of songs, the proposed system can retrieve the best mixing point from innumerable possibilities. Although it is comparatively easy to calculate beat similarity from audio signals, it has been difficult to consider the semantics of songs as a human DJ considers. To consider such semantics, we propose a method to represent audio signals to construct topic models that acquire latent semantics of audio. The results of a subjective experiment demonstrate the effectiveness of the proposed latent semantic analysis method.


conference on multimedia modeling | 2016

Computational Cartoonist: A Comic-Style Video Summarization System for Anime Films

Tsukasa Fukusato; Tatsunori Hirai; Shunya Kawamura; Shigeo Morishima

This paper presents Computational Cartoonist, a comic-style anime summarization system that detects key frame and generates comic layout automatically. In contract to previous studies, we define evaluation criteria based on the correspondence between anime films and original comics to determine whether the result of comic-style summarization is relevant. To detect key frame detection for anime films, the proposed system segments the input video into a series of basic temporal units, and computes frame importance using image characteristics such as motion. Subsequently, comic-style layouts are decided on the basis of pre-defined templates stored in a database. Several results demonstrate the efficiency of our key frame detection over previous methods by evaluating the matching accuracy between key frames and original comic panels.


advances in computer entertainment technology | 2015

MusicMixer: computer-aided DJ system based on an automatic song mixing

Tatsunori Hirai; Hironori Doi; Shigeo Morishima

In this paper, we present MusicMixer, a computer-aided DJ system that helps DJs, specifically with song mixing. MusicMixer continuously mixes and plays songs using an automatic music mixing method that employs audio similarity calculations. By calculating similarities between song sections that can be naturally mixed, MusicMixer enables seamless song transitions. Though song mixing is the most fundamental and important factor in DJ performance, it is difficult for untrained people to seamlessly connect songs. MusicMixer realizes automatic song mixing using an audio signal processing approach; therefore, users can perform DJ mixing simply by selecting a song from a list of songs suggested by the system, enabling effective DJ song mixing and lowering entry barriers for the inexperienced. We also propose personalization for song suggestions using a preference memorization function of MusicMixer.

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Masataka Goto

National Institute of Advanced Industrial Science and Technology

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Tomoyasu Nakano

National Institute of Advanced Industrial Science and Technology

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