Hiromi T. Tanaka

Online re-mesh and multi-rate deformation simulation by GPU for haptic interaction with large scale elastic objects

In this paper, we propose an approach to generate high quality force and deformation using a novel automatic space and time adaptive level of detail technique in combination with a parallel computation using a graphics processing unit (GPU). The elastic object is represented by a multi-resolution hierarchy of tetrahedral adaptive volume mesh. The tetrahedral adaptive volume mesh and the time step of the deformation simulation are locally refined by online re-mesh and multi-rate simulation to concentrate the computational load into the regions that deform the most. In order to compute the online re-mesh and multi-rate deformation simulation on a GPU efficiently, we propose a novel data structure which consists of an extended and transposed connection table, a node list and a separated mass list. This effective computation is achieved by the relocatability of the connection table and optimized memory access at the computation of both deformation and re-meshing. Through evaluation experiments, we confirm the feasibility and the effectiveness of the proposed approach.

A texture-based direct-touch interaction system for 3D woven cultural property exhibition

We propose a texture-based direct-touch interaction system for 3D woven cultural property exhibition of the Tenmizuhiki tapestries Hirashaji Houou Monyou Shishu of Fune-hoko of Gion Festival in Kyoto. In the field of digital archive, it is important to archive and represent the cultural property at the high-definition. To archive the shape, color and texture of the cultural property, it is important to archive and represent not only visual effect but haptic impression. Recently, in the field of haptics, various haptic rendering devices have been developed, and various haptic rendering techniques to touch the virtual object have been proposed. In haptic rendering for the high-definition virtual object, it is difficult to render the haptic impression smoothly and calculate the reaction force at realtime. Therefore, it is require the realtime and high-definition haptic rendering techniques. In our previous work, we proposed a texture-based haptic modeling and rendering techniques at realtime and with high-definition. However, our techniques are not based on the measurement. Moreover, in the field of digital archive, it is necessary to represent the digital archived cultural property intuitively and interactively. Therefore, we applied our texture-based haptic modeling and rendering techniques for the digital archive, and we developed a realtime and direct-touch interaction system for 3D cultural property exhibition.

Development of a High-Definition and Multispectral Image Capturing System for Digital Archiving of Early Modern Tapestries of Kyoto Gion Festival

We developed a two-shot 6-band image capturing system consisting of a large-format camera, a customized interference filter, and a scanning digital back to capture a 185-M-pixel images. The interference filter is set in front of the camera lens to obtain a 6-band image, that is, two 3-band images, one taken with the filter and the other without it. After correction of optical aberrations caused by the interference filter as well as system arrangement errors, the two images are combined into a 6-band image. The 6-band image was converted into a color-managed RGB image embedded ICC profile. In experiments, object images were captured as several divided parts and synthesized as almost 500-M-pixel image by using an image stitching technique. Resolution of the captured images is 0.02 mm/pixel. This paper discusses the camera system with its focus on some early modern tapestries used in the Kyoto Gion Festival. After the experiments, we interviewed a craftsman to assess the image’s importance in archiving and analyzing fabric structures.

Multimodal digital archiving and reproduction of the world cultural heritage "Gion Festival in Kyoto"

We propose a multimodal digital archiving and reproduction of the world cultural heritage Gion Festival in Kyoto. In this digital museum project, we make Virtual Kyoto more highly-developed and detailed, and develop the system where users can experience the things and events related to Gion Festival with several virtual reality technologies. Specifically, we develop the interactive system based on human five senses such as the contents where users can experience high-defined decorations of Yamahoko with visual and haptic senses, the high-quality sounds of the Festival music and the virtual Yamahoko float ceremony in the 3D vision environment combined these contents. Virtual Kyoto is 4 dimensionality city model with GIS and VR technologies, and the platform where the aspect of historical city, Kyoto can be rendered from past to present. Therefore, users can select any period and location and experience the contents of histories, cultures, arts and entertainments in Virtual Kyoto. Moreover, we can not only handle high order contents but also describe many kinds of contents synthesizing them. This paper describes a multimodal digital archiving and reproduction of Gion Festival and virtual experience of parading of floats in detail.

Development of a portable anisotropic reflectance measurement system for modeling and rendering of bidirectional texture functions

Recently, Computer Graphics (CG) productions need the novel method to represent realistic CG objects. It is very difficult for their creators to set parameters of the reflection models that express correctly surface reflection of real objects.

Extracting Tactile Sensation Information from Multi-illuminated Images of Tangible Cultural Property

In recent years, haptic devices have been developed to give users the sensation of physically touching virtual objects. However, these studies have focused mainly on developing haptic hardware, and algorithms for synthesizing the tactile sensation signals have not been well studied. In this paper, a technique is proposed for synthesizing tactile vibrational signals based on the ability to measure surface structure by the use of multiple photographic images taken at different illumination angles. The vibrational signal of the tactile device is synthesized using natural noise. The virtual reality system consists of a 3D visual display, a force feedback device and a vibration tactile sensation device.

Adaptive and embedded deformation model: An approach to haptic interaction with complex inhomogeneous elastic objects

We propose a novel approach to haptic interact with complex inhomogeneous elastic objects like organs. In surgery simulations, representation of complex inhomogeneous elastic objects which have various physical properties and geometries is required. Also, consideration of geometric nonlinearity is required. At present, in order to simulate such objects correctly, we have to use the nonlinear FEM model with high resolution meshes. Furthermore, higher update rate (about from several hundred [Hz]) is required for stable force feedback. Therefore, computational cost becomes problem. In this paper, to solve this problem, we propose an adaptive and embedded deformation model. This approach uses both an online re-mesh deformation model and a corotational FEM model together. Our approach can update an inverse of a global stiffness matrix of a corotational FEM model quickly during the online remeshing (tetrahedron subdivision/simplification). In addition, an efficient computation algorithm by GPU is also proposed. We implemented this approach into our prototype surgery simulation system, and then we performed evaluation experiments to verify the feasibility and effectiveness of our approach.

High-Resolution and multi-spectral capturing for digital archiving of large 3d woven cultural artifacts

We propose a high-resolution and multi-spectral capturing for digital archiving of large 3D woven cultural artifacts. In the field of digital archive, it is important to measure, model, and represent the shape, color, and texture of the cultural artifact at high-definition, not only physical appearance but haptic impression. The many of the decorative hangings on the Fune-hoko in the Gion Festival in Kyoto, are very large and stuffed with cotton, so that they have a very noticeable 3D shape. Therefore, a high-resolution and multi-spectral capturing and a large-scale 3D measuring are necessary for the digital archiving of large 3D woven cultural artifact. Then we captured high-resolution images with a two-shot type 6-band image capturing system at low-cost, and modeled woven cultural artifacts in 3D. This paper describes a 3D measurement system with wheel-rail, a capturing system with multi-band camera, and a 3D modeling of large woven cultural artifacts, and show a high-resolution 3D model with multi-band image.

Collision detection and modeling of rigid and deformable objects in laparoscopic simulator

Laparoscopic simulators are viable alternatives for surgical training and rehearsal. Haptic devices can also be incorporated with virtual reality simulators to provide additional cues to the users. However, to provide realistic feedback, the haptic device must be updated by 1kHz. On the other hand, realistic visual cues, that is, the collision detection and deformation between interacting objects must be rendered at least 30 fps. Our current laparoscopic simulator detects the collision between a point on the tool tip, and on the organ surfaces, in which haptic devices are attached on actual tool tips for realistic tool manipulation. The triangular-mesh organ model is rendered using a mass spring deformation model, or finite element method-based models. In this paper, we investigated multi-point-based collision detection on the rigid tool rods. Based on the preliminary results, we propose a method to improve the collision detection scheme, and speed up the organ deformation reaction. We discuss our proposal for an efficient method to compute simultaneous multiple collision between rigid (laparoscopic tools) and deformable (organs) objects, and perform the subsequent collision response, with haptic feedback, in real-time.

A real-time sensing and rendering of haptic perception based on bilateral control

In recent years, various haptic devices and sensors have been developed. However, development of the haptic sensor is expensive, and there is a difference in performance between these sensors and haptic rendering devices (For example, measuring method, resolution, maximum measuring force of haptic sensor and maximum rendering force of haptic rendering device, and minimum moving distance, etc.). Therefore, it is difficult to render the difference of haptic impression by the obtained data with haptic sensor. Moreover, traditional researches on the haptic sensing can not measure the various haptic informations such as the shape, hardness, and friction at same time[Okamoto et al. 2012]. Therefore, we develop a real-time sensing method of haptic perception parameter such as the shape, hardness, and friction force, based on bilateral control while feeling the haptic impression.