J. Siira

Bio: J. Siira is an academic researcher from University of British Columbia. The author has contributed to research in topics: Haptic technology. The author has an hindex of 1, co-authored 1 publications receiving 116 citations.

Haptic texturing-a stochastic approach

Abstract: All objects have a surface roughness which manifests itself as small forces when objects slide under load against each other. Simulating this roughness haptically enriches the interaction between a user and a virtual world, just as creating graphical textures enhances the depiction of a scene. As with graphical textures, a major design constraint for haptic textures is the generation of a sufficiently "realistic" texture given hard constraints on computational costs. The authors present a simple, fast algorithm to synthesize haptic textures from statistical properties of surfaces. The synthesized texture can be overlaid on other contact models, such as hard contact with Coulomb friction. The algorithm requires minimal hardware support, and can be implemented on a variety of force-feedback mechanisms. It has been successfully implemented on a two-degree-of-freedom haptic interface (the Pantograph).

Haptic rendering: introductory concepts

Abstract: Haptic rendering allows users to "feel" virtual objects in a simulated environment. We survey current haptic systems and discuss some basic haptic-rendering algorithms. In the past decade we've seen an enormous increase in interest in the science of haptics. Haptics broadly refers to touch interactions (physical contact) that occur for the purpose of perception or manipulation of objects. These interactions can be between a human hand and a real object; a robot end-effector and a real object; a human hand and a simulated object (via haptic interface devices); or a variety of combinations of human and machine interactions with real, remote, or virtual objects. Rendering refers to the process by which desired sensory stimuli are imposed on the user to convey information about a virtual haptic object.

Efficient Point-Based Rendering Techniques for Haptic Display of Virtual Objects

Abstract: Computer haptics, an emerging field of research that is analogous to computer graphics, is concerned with the generation and rendering of haptic virtual objects. In this paper, we propose an efficient haptic rendering method for displaying the feel of 3-D polyhedral objects in virtual environments (VEs). Using this method and a haptic interface device, the users can manually explore and feel the shape and surface details of virtual objects. The main component of our rendering method is the “neighborhood watch” algorithm that takes advantage of precomputed connectivity information for detecting collisions between the end effector of a force-reflecting robot and polyhedral objects in VEs. We use a hierarchical database, multithreading techniques, and efficient search procedures to reduce the computational time such that the haptic servo rate after the first contact is essentially independent of the number of polygons that represent the object. We also propose efficient methods for displaying surface properties of objects such as haptic texture and friction. Our haptic-texturing techniques and friction model can add surface details onto convex or concave 3-D polygonal surfaces. These haptic-rendering techniques can be extended to display dynamics of rigid and deformable objects.

Creating Realistic Virtual Textures from Contact Acceleration Data

Abstract: Modern haptic interfaces are adept at conveying the large-scale shape of virtual objects, but they often provide unrealistic or no feedback when it comes to the microscopic details of surface texture. Direct texture-rendering challenges the state of the art in haptics because it requires a finely detailed model of the surface's properties, real-time dynamic simulation of complex interactions, and high-bandwidth haptic output to enable the user to feel the resulting contacts. This paper presents a new, fully realized solution for creating realistic virtual textures. Our system employs a sensorized handheld tool to capture the feel of a given texture, recording three-dimensional tool acceleration, tool position, and contact force over time. We reduce the three-dimensional acceleration signals to a perceptually equivalent one-dimensional signal, and then we use linear predictive coding to distill this raw haptic information into a database of frequency-domain texture models. Finally, we render these texture models in real time on a Wacom tablet using a stylus augmented with small voice coil actuators. The resulting virtual textures provide a compelling simulation of contact with the real surfaces, which we verify through a human subject study.

Haptic Rendering : Foundations, Algorithms, and Applications

Abstract: For a long time, human beings have dreamed of a virtual world where it is possible to interact with synthetic entities as if they were real. It has been shown that the ability to touch virtual objects increases the sense of presence in virtual environments. This book provides an authoritative overview of state-of-theart haptic rendering algorithms and their applications. The authors examine various approaches and techniques for designing touch-enabled interfaces for a number of applications, including medical training, model design, and maintainability analysis for virtual prototyping, scientific visualization, and creative processes.