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Tokyo Metropolitan University, Japan

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15 Papers

Player Tracking using Multi-viewpoint Images in Basketball Analysis

Topics: Entertainment Imaging Applications; Object Detection and Localization; Tracking and Visual Navigation

Authors: Shuji Tanikawa and Norio Tagawa

Affiliation: Graduate School of Systems Design, Tokyo Metropolitan University, Hino, Tokyo 191-0065, Japan

Digital Object Identifier: 10.5220/0009097408130820

Proceedings of VISAPP 2020, ISBN: 978-989-758-402-2

Quick Abstract

In this study, we aim to realize the automatic tracking of basketball players by avoiding occlusion of players, which is an important issue in basketball video analysis, using multi-viewpoint images. Images taken with a hand-held camera are used, to expand the scope of application to uses such as school club activities. By integrating the player tracking results from each camera image with a 2-D map viewed from above the court, using projective transformation, the occlusion caused by one camera is stably solved using the information from other cameras. In addition, using OpenPose for player detection reduces the occlusion that occurs in each camera image before all camera images are integrated. We confirm the effectiveness of our method by experiments with real image sequences.

Improvement of Range Resolution of FDMAS Beamforming in Ultrasound Imaging

Topics: Image Formation, Acquisition Devices and Sensors; Image Enhancement and Restoration; Medical Image Applications

Authors: Ryoya Kozai , Jing Zhu , Kan Okubo and Norio Tagawa

Affiliation: Graduate School of System Design, Tokyo Metropolitan University, Hino, Tokyo 191-0065 and Japan

Digital Object Identifier: 10.5220/0007583601980205

Proceedings of VISAPP 2019, ISBN: 978-989-758-354-4

Quick Abstract

Ultrasound imaging is applied to various fields because it is noninvasive and real-time imaging is possible. However, in diagnosis applications, ultrasound imaging is inferior in resolution to other modalities, so researches for improving resolution have been actively conducted. Recently, researches on beamforming methods have been advanced for the purpose of improving lateral resolution. In order to form a narrower beam, adaptive beamformers such as the MV (minimum variance) beamformer that adaptively changes the beamforming weights have been proposed, but these methods increase the computational complexity. Therefore, in recent years, the FDMAS (Filtered-Delay Multiply And Sum) beamformer which can realize high resolution and high contrast without using complicated calculation attracts attention. On the other hand, we proposed a method called the SCM (Super resolution FM-Chirp correlation Method) that improves range resolution based on frequency sweep. In addition, we proposed a new DAS (Delay And Sum) beam former which improves range resolution by multiplying the echo signal by the result of the SCM before DAS processing. This method is constructed in the usual RF (Radio Frequency) band. In this study, we first reconstruct the FDMAS as a baseband processing in order to improve the SNR, and apply the SCM result to the FDMAS in order to improve both range and lateral resolution.

Related Ontology Subjects/Areas/Topics (6)

Applications and Services		Image Enhancement and Restoration		Image Formation, Acquisition Devices and Sensors
Computer Vision, Visualization and Computer Graphics		Image Formation and Preprocessing		Medical Image Applications

Selective Use of Appropriate Image Pairs for Shape from Multiple Motions based on Gradient Method

Topics: Image-Based Modeling and 3D Reconstruction; Stereo Vision and Structure from Motion; Optical Flow and Motion Analyses

Authors: Norio Tagawa and Syouta Tsukada

Affiliation: Tokyo Metropolitan University, Japan

Digital Object Identifier: 10.5220/0005778805520561

Proceedings of VISAPP 2016/VISIGRAPP, ISBN: 978-989-758-175-5

Quick Abstract

For the gradient-based shape from motion, relative motions with various directions at each 3-D point on a target object are generally effective for accurate shape recovery. On the other hand, a proper motion size exists for each 3-D point having an intensity pattern and a depth that varied in each, i.e., a too large motion causes a large error in depth recovery as an alias problem, and a too small motion is inappropriate from the viewpoint of an SNR. Application of random camera rotations imitating involuntary eye movements of a human eyeball has been proposed, which can generate multiple image pairs. In this study, in order to realize accurate shape recovery, we improve the gradient method based on the multiple image pairs by selecting appropriate image pairs to be used. Its effectiveness is verified through experiments using the actual camera system that we developed.

Related Ontology Subjects/Areas/Topics (9)

Applications	Image-Based Modeling	Pattern Recognition
Computer Vision, Visualization and Computer Graphics	Motion, Tracking and Stereo Vision	Software Engineering
Geometry and Modeling	Optical Flow and Motion Analyses	Stereo Vision and Structure from Motion

Selective Use of Optimal Image Resolution for Depth from Multiple Motions based on Gradient Scheme

Authors: Norio Tagawa and Shoei Koizumi

Affiliation: Tokyo Metropolitan University, Japan

Digital Object Identifier: 10.5220/0005462500920099

Proceedings of IMTA-5 2015/VISIGRAPP, ISBN: 978-989-758-094-9

Quick Abstract

The gradient-based depth from motion method is effective for obtaining a dense depth map. However, the accuracy of the depth map recovered only from two successive images is not so high, and hence, to increase the depth information by tracking corresponding image points through an image sequence is often performed by using, for example, the Kalman filter-like technique. Alternatively, multiple image pairs generated by random small camera rotations around a reference direction can be used for gaining much information of depth without such the tracking procedure. In the framework of this strategy, in this study, to further improve the accuracy, we propose a selective use of the optimal image resolution. The appropriate resolution image is required to have a linear intensity pattern which is the most important supposition for the gradient method often used for dense depth recovery based on the theory of “shape from motion.” The performance of our proposal is examined through numerical evaluations using artificial images.

Energy Expenditure during Walking, Jogging and Running in Bare and Shod Conditions

Topics: Applied Physiology and Exercise; Health and Fitness

Authors: Junichiro Yamauchi ¹ , Hideaki Koike ² and Keiji Koyama ³

Affiliations: ¹ Tokyo Metropolitan University, Future Institute for Sport Sciences and Khon Kaen University, Japan , ² Tokyo Metropolitan University, Japan , ³ Toin University of Yokohama, Japan

Quick Abstract

This study was to compare between barefoot and wearing running shod conditions on energy expenditure during walking, jogging and running. Healthy young individuals performed walking (4km/hr), jogging (8km/hr) and running (12km/hr) on the treadmill in barefoot (BARE) and shod (SHOD) conditions. Respiratory gas analysis was performed using a computerized metabolic measurement cart on a breath-by-breath mode. Exercises with a shod condition were significantly higher energy expenditure than those with a barefoot condition in walking, jogging and running.

Related Ontology Subjects/Areas/Topics (4)

Applied Physiology and Exercise		Health, Sports Performance and Support Technology		Sport Science Research and Technology
Health and Fitness

Exploring the Use of Smartphone Accelerometer and Gyroscope to Study on the Estimation of Road Surface Roughness Condition

Topics: Environmental Monitoring and Control; Time and Frequency Response; Sensors Fusion; Engineering Applications

Authors: Viengnam Douangphachanh and Hiroyuki Oneyama

Affiliation: Tokyo Metropolitan University, Japan

Digital Object Identifier: 10.5220/0005117407830787

Proceedings of ICINCO 2014, ISBN: 978-989-758-039-0

Quick Abstract

Smartphones are potentially useful to be adopted as a cost-effective and easy to implement tool for the measurement of road surface roughness condition, which is very essential for road monitoring and maintenance planning. In this study, an experiment has been carried out to collect data from accelerometers and gyroscopes on smartphones, which are placed at different locations inside vehicles running on road sections with different roughness conditions. The collected data is processed in the frequency domain to calculate magnitudes of the vibration. It has been revealed that at the considered frequency range of 40-50Hz, there is a very strong relationship between road roughness condition and the magnitudes of vibration, calculated from each axis of the accelerometers and gyroscopes; as well as the average speed. Road roughness condition that is modelled as a linear function of the vibration magnitudes, taking into account of both data from accelerometer and gyroscope as well as the average speed, achieves better estimation than the model that takes into account the magnitude from the accelerometer and the average speed alone. The finding is potentially significant for the development of a more accurate model and a better smartphone app to estimate road roughness condition from smartphone sensors.

Related Ontology Subjects/Areas/Topics (11)

Biomedical Engineering	Informatics in Control, Automation and Robotics	Signal Processing, Sensors, Systems Modeling and Control
Biomedical Signal Processing	Intelligent Control Systems and Optimization	Time and Frequency Response
Engineering Applications	Robotics and Automation	Time-Frequency Analysis
Environmental Monitoring and Control	Sensors Fusion

Direct Depth Recovery from Motion Blur Caused by Random Camera Rotations Imitating Fixational Eye Movements

Topics: Stereo Vision and Structure from Motion; Early and Biologically-Inspired Vision; Object and Face Recognition

Authors: Norio Tagawa , Shoei Koizumi and Kan Okubo

Affiliation: Tokyo Metropolitan University, Japan

Digital Object Identifier: 10.5220/0004304001770186

Proceedings of VISAPP 2013/VISIGRAPP, ISBN: 978-989-8565-48-8

Quick Abstract

It has been reported that small involuntary vibrations of a human eyeball for fixation called ”fixational eye movements” play a role of image analysis, for example contrast enhancement and edge detection. This mechanism can be interpreted as an instance of stochastic resonance, which is inspired by biology, more specifically by neuron dynamics. A depth recovery method has been proposed, which uses many successive image pairs generated by random camera rotations imitating fixational eye movements. This method, however, is not adequate for images having fine texture details because of an aliasing problem. To overcome this problem, we propose a new integral formed method for recovering depth, which uses motion blur caused by the same camera motions, i.e. many random small camera rotations. As an algorithm, we examine a method directly recovering depth without computing a blur function. To confirm the feasibility of our scheme, we perform simulations using artificial images.

Related Ontology Subjects/Areas/Topics (5)

Computer Vision, Visualization and Computer Graphics		Image and Video Analysis		Stereo Vision and Structure from Motion
Early and Biologically-Inspired Vision		Motion, Tracking and Stereo Vision

Shape from Multi-view Images based on Image Generation Consistency

Topics: Image-Based Modeling and 3D Reconstruction; Stereo Vision and Structure from Motion; Vision for Robotics

Authors: Kousuke Wakabayashi , Norio Tagawa and Kan Okubo

Affiliation: Tokyo Metropolitan University, Japan

Digital Object Identifier: 10.5220/0004345203340340

Proceedings of VISAPP 2013/VISIGRAPP, ISBN: 978-989-8565-48-8

Quick Abstract

There are various and a lot of depth recovery methods have been studied, but a discussion about an unification of individual methods is expected not to be enough yet. In this study, we argue that the importance and the necessity of an image generation consistency. Various clues including binocular disparity, motion parallax, texture, shading and so on can be effectively used for depth recovery for the case where each or some of those are completely performed. However, in general, those clues without shading cause ideal and simplified constraints, and for several cases those clues without shading are suitable for obtaining initial depth values for the unification algorithm based on an image generation consistency. On the other hand, shading indicates a strict characteristics for image generation and should be used for the key principle for the unification. Based on the above strategy, as a first step of our scheme, through a simple problem with two-views, the unification of binocular disparity and shading without explicit disparity detection is examined based on an image generation consistency, and simple evaluation results are shown by simulations.

Related Ontology Subjects/Areas/Topics (9)

Applications	Image-Based Modeling	Robotics
Computer Vision, Visualization and Computer Graphics	Motion, Tracking and Stereo Vision	Software Engineering
Geometry and Modeling	Pattern Recognition	Stereo Vision and Structure from Motion

DEPTH PERCEPTION MODEL EXPLOITING BLURRING CAUSED BY RANDOM SMALL CAMERA MOTIONS

Topics: Active and Robot Vision; Machine Learning Technologies for Vision; Early and Biologically-Inspired Vision

Authors: Norio Tagawa , Yuya Iida and Kan Okubo

Affiliation: Tokyo Metropolitan University, Japan

Digital Object Identifier: 10.5220/0003817403290334

Proceedings of VISAPP 2012/VISIGRAPP, ISBN: 978-989-8565-03-7

Quick Abstract

The small vibration of the eye ball, which occurs when we fix our gaze on an object, is called “fixational eye movement.” It has been reported that this vibration may work not only as a fundamental function to preserve photosensitivity but also as a clue to image analysis, for example contrast enhancement and edge detection. This mechanism can be interpreted as an instance of stochastic resonance, which is inspired by biology, more specifically by neuron dynamics. Moreover, researches for a depth recovery method using camera motions based on an analogy of fixational eye movement are in progress. In this study, using camera motions especially corresponding to the smallest type of fixational eye movement called “tremor.” We have constructed the algorithms which are defined as a differential form, i.e. spatio-temporal derivatives of successive two images are analyzed. However, in these methods, observed noise of derivatives causes serious recovering error. Therefore, we newly examine a method in which a lot of images captured with the same camera motions are integrated and the observed local image blurring is analyzed for extracting depth information, and confirm its effectiveness.

Related Ontology Subjects/Areas/Topics (5)

Active and Robot Vision		Early and Biologically-Inspired Vision		Motion, Tracking and Stereo Vision
Computer Vision, Visualization and Computer Graphics		Image and Video Analysis

DIRECT COMPUTATION OF DEPTH FROM SHADING FOR PERSPECTIVE PROJECTION

Topics: Early and Biologically-Inspired Vision; Shape Representation and Matching

Authors: Kousuke Wakabayashi , Norio Tagawa and Kan Okubo

Affiliation: Tokyo Metropolitan University, Japan

Digital Object Identifier: 10.5220/0003854804450448

Proceedings of VISAPP 2012/VISIGRAPP, ISBN: 978-989-8565-03-7

Quick Abstract

We present a method for recovering shape from shading in which the surface depth is directly computed. The already proposed method solving the same problem assumes that images are captured under the parallel projection, and hence, it can be correctly used only for the relative thin objects compared with the distance from the camera. If this method is formally extended for the perspective projection completely, the complicated calculations for differential are required. This gives rise to unstable recovery. In this study, we examine an extension of this method so as to treat the perspective projection approximately. In order to keep the simplicity of the original method, we propose the simple approximation of the derivative of the surface with respect to the image coordinate.

Related Ontology Subjects/Areas/Topics (4)