We have proposed the visual and haptic interface for the tele-echo system where ultrasound (US) probing can be instructed from a diagnostic to measurement site via network. In the measurement site, the surface of a patient body was captured with a CCD camera and the shape of patient was measured using the triangulation. In the diagnostic site, three dimensional image of a patient was reconstructed and a medical doctor could touch the virtual patient body with a haptic device. The position, orientation and tilt of a US probe was transmitted from the diagnostic to the measurement site with our previous proposed mark, called 'Web-Mark' and the mark was projected on the patient directly. The experimental results demonstrated that the proposed system enables to obtain US images, long axis and apex image in the shorter time as compared with the system using two dimensional information of the patient only.

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In the medical education, a surgery simulator which is effective to train the necessary skills is greatly expected in the current social context (e.g. kindness to animals). To realize the advanced surgery simulator, various technological issues should be overcome. One is modeling of geometrical and physical characteristics of soft deformable objects. Another is modeling of topological transformations such as cutting and needle insertion. Furthermore, the real-time and interactive operation with haptic sense is required. In this paper, the above various modeling technics which make the core technologies for the surgery simulator are discussed in consideration of both reality and real-time calculation. The validity of proposed method is demonstrated by interactive simulation.

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While common approaches to haptic description in virtual reality system were to present simplified physical models like stiffness and viscosity of the virtual objects, reconstruction of the sense of touch based on the actual haptic measurements were not fully investigated. To realize such a presentation of touch, it is necessary to compare the three-dimensional force from a virtual object with that from a real object in a standardized experimental condition. In this paper, we propose a system consisting of a haptic device and a 3D force sensor. This system can acquire 3D force information from a real object as well as a virtual object. Using the system, we compared the force from a real object with that from a virtual object, in a physical and psychological manner.

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This paper gives a method to represent interaction between elastic objects for medical VR simulation. To simulate collisions of multiple organs is indispensable for realistic deformation and haptic display. The interaction model defines displacements of colliding elements based on normal stress. The proposed model not only prevents unrealistic overlap of the objects, but also produces accurate deformation and force feedback considering stiffness of the objects. A prototype simulator of rectal palpation is constructed for evaluation of the proposed model. The results of experiments confirmed the method expresses organ-organ interaction in real time, and provides realistic and perceivable force feedback.

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Although careful planning is a key for successful surgery, conventional computer assisted application cannot support detailed planning because it cannot simulate complex physical behavior of soft tissues provided by a series of surgical procedures. This paper proposes an adaptive physics-based framework that simulates both interactive cutting and accurate deformation on reconstructed virtual bodies. The framework modifies tetrahedral mesh via cutting manipulation and dynamically constructs stiffness matrix required for finite element based simulation. Using the proposed methods, the authors developed a strategic planning system that supports decision of surgical approach and applied measured clinical dataset of an aortic aneurysm case. Some experiments and usability tests confirmed the developed system enables preoperative rehearsal of constructing surgical fields and efficiently supports strategic planning.

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In the field of mixed reality which merges real and virtual spaces, computer vision technology plays an important role in measuring and recognizing the real world. Especially, in geometrical registration of the two spaces, vision-based or vision-assisted methods tend to augment or replace conventional physical 6DOF sensors. In this paper, the existing methods so far proposed are reviewed and categorized, and then we proceed to discuss on their usefulness, problems, and future prospects.

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Recently digital cameras have become very popular. Many people have taken large quantities of digital photographs and published them onto WWW. Therefore, we discuss methods for creating Image-Based VR by reusing photographs on WWW. In the former paper, we proposed 'Spatial-Hyperlink' as basic element for linking photographs taken at the same place. In this paper, we discuss pseudo-3D spatial animations for traversing from one photo to spatial-linked photo. We also show our prototype system named "STAMP" and our experimental uses.

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Large-field visual motions induce postural sway. This postural sway contributes to stabilizing the posture in our everyday life. The purpose of this study was to investigate the spatio-temporal sensitivity of visually-induced postural sway. We presented a radial motion that was a simulation of observer's linear motion going through a cloud of dots. Heading direction was varied, and subject's postural sway was measured. In results, the direction of postural sway was qualitatively in the opposite direction to heading direction. This suggests that postural sway is basically consistent with heading direction. However, quantitatively the postural sway had an anisotropy between forward-backward axis and rightward-leftward axis: the sway in the latter axis was larger than in the former axis. Postural sway rapidly developed to 10% of maximum sway within 1-2[s], and gradually increased for 8-9[s]. This gradual development was characteristic of postural control in comparison with heading perception, which was very accurate with 500[ms] duration.

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This virtual reality system is very useful to represent and analyze complex physical simulation result. But it is very difficult to control virtual objects (represented numerical simulation data) with a general input device in Immersive Projection Technology like CAVE system, since such an input device has less function than a keyboard and we cannot remember the every procedure to control many virtual objects. A voice control is very suitable to control in a virtual reality space. So we appended a speech recognition system to virtual reality system: CompleXcope. In this paper, we explain about our virtual reality system, the method to link the virtual reality system and the speech recognition system, which can recognize unspecified person's voice, and practicability of this system.

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This paper deals with a virtual maze which displays invisible passages and walls for our palms in real space. Our virtual maze consists of a robotic positioner and a force-reflecting gripper, and we can move the gripper smoothly with small force along the virtual passage. First, we describe the hardware system and the software system of the virtual maze. Next, we show the experimental performance of our virtual maze. Finally, we report haptic exploration results of the invisible maze by using the virtual maze, and discuss the relation between the arrival time at the goal and the difficulty of the maze, and the haptic memory of invisible passages.

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We evaluated the effects of the intensity of inaudible high frequency components (HFC) of sounds on human by employing a multiparametric approach, consisting of a behavioral experiment using comfortable listening level (CLL), psychological experiment using Scheffe's paired comparison method and physiological experiment using electroencephalogram. The enhancement of HFC significantly increased the CLL and made the sounds more natural and richer in reality and information, which suggests that the sounds with enhanced HFC increase positive impression and comfort of the sound. The sounds with enhanced HFC also showed a trend to increase the power of the alpha frequency range of electroencephalogram.

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We examined effects of bedside wellness system (BSW; Mitsubishi Electric Corporation) on exercise capacity, neurohormonal factors, and autonomic nervous system in healthy subjects. Mean heart rate, blood pressure, and heart rate viability did not change between exercises with and without virtual reality (VR). VR did not influence catecholamine levels, cortisol level, and heart rate decay for the first 30 seconds immediately after exercise. The latency to reach target heart rate tended to prolong in with VR condition, which suggests the possibility of VR to reduce initial exercise load in patients with heart failure.

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