It is generally accepted that augmented feedback, provided by a human expert or a technical display, effectively enhances motor learning. However, discussion of the way to most effectively provide augmented feedback has been controversial. Related studies have focused primarily on simple or artificial tasks enhanced by visual feedback. Recently, technical advances have made it possible also to investigate more complex, realistic motor tasks and to implement not only visual, but also auditory, haptic, or multimodal augmented feedback. The aim of this review is to address the potential of augmented unimodal and multimodal feedback in the framework of motor learning theories. The review addresses the reasons for the different impacts of feedback strategies within or between the visual, auditory, and haptic modalities and the challenges that need to be overcome to provide appropriate feedback in these modalities, either in isolation or in combination. Accordingly, the design criteria for successful visual, auditory, haptic, and multimodal feedback are elaborated.

/pdf/augmented-visual-auditory-haptic-and-multimodal-feedback-in-2jc0b0ky7k.pdf

Augmented visual, auditory, haptic, and multimodal feedback in motor learning: A review

This paper presents a system for performance-based character animation that enables any user to control the facial expressions of a digital avatar in realtime. The user is recorded in a natural environment using a non-intrusive, commercially available 3D sensor. The simplicity of this acquisition device comes at the cost of high noise levels in the acquired data. To effectively map low-quality 2D images and 3D depth maps to realistic facial expressions, we introduce a novel face tracking algorithm that combines geometry and texture registration with pre-recorded animation priors in a single optimization. Formulated as a maximum a posteriori estimation in a reduced parameter space, our method implicitly exploits temporal coherence to stabilize the tracking. We demonstrate that compelling 3D facial dynamics can be reconstructed in realtime without the use of face markers, intrusive lighting, or complex scanning hardware. This makes our system easy to deploy and facilitates a range of new applications, e.g. in digital gameplay or social interactions.

http://sofienbouaziz.com/pdf/RPBFA_SIGG11.pdf

Realtime performance-based facial animation

This survey summarizes almost 50 years of research and development in the field of Augmented Reality AR. From early research in the1960's until widespread availability by the 2010's there has been steady progress towards the goal of being able to seamlessly combine real and virtual worlds. We provide an overview of the common definitions of AR, and show how AR fits into taxonomies of other related technologies. A history of important milestones in Augmented Reality is followed by sections on the key enabling technologies of tracking, display and input devices. We also review design guidelines and provide some examples of successful AR applications. Finally, we conclude with a summary of directions for future work and a review of some of the areas that are currently being researched.

/pdf/a-survey-of-augmented-reality-2ce6xet7y5.pdf

A Survey of Augmented Reality

Past research on shape displays has primarily focused on rendering content and user interface elements through shape output, with less emphasis on dynamically changing UIs. We propose utilizing shape displays in three different ways to mediate interaction: to facilitate by providing dynamic physical affordances through shape change, to restrict by guiding users with dynamic physical constraints, and to manipulate by actuating physical objects. We outline potential interaction techniques and introduce Dynamic Physical Affordances and Constraints with our inFORM system, built on top of a state-of-the-art shape display, which provides for variable stiffness rendering and real-time user input through direct touch and tangible interaction. A set of motivating examples demonstrates how dynamic affordances, constraints and object actuation can create novel interaction possibilities.

https://static.ideaconnection.com/docs/12432/uist335-follmer.pdf

inFORM: dynamic physical affordances and constraints through shape and object actuation

The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) information. This fundamental restriction greatly limits our ability to perceive and to understand the complexity of real-world objects. Nearly 50% of the capability of the human brain is devoted to processing visual information [Human Anatomy & Physiology (Pearson, 2012)]. Flat images and 2D displays do not harness the brain's power effectively. With rapid advances in the electronics, optics, laser, and photonics fields, true 3D display technologies are making their way into the marketplace. 3D movies, 3D TV, 3D mobile devices, and 3D games have increasingly demanded true 3D display with no eyeglasses (autostereoscopic). Therefore, it would be very beneficial to readers of this journal to have a systematic review of state-of-the-art 3D display technologies.

/pdf/three-dimensional-display-technologies-3ed8rfdvht.pdf

Three-dimensional display technologies

We estimate surface normal maps of an object from either its diffuse or specular reflectance using four spherical gradient illumination patterns. In contrast to traditional photometric stereo, the spherical patterns allow normals to be estimated simultaneously from any number of viewpoints. We present two polarized lighting techniques that allow the diffuse and specular normal maps of an object to be measured independently. For scattering materials, we show that the specular normal maps yield the best record of detailed surface shape while the diffuse normals deviate from the true surface normal due to subsurface scattering, and that this effect is dependent on wavelength. We show several applications of this acquisition technique. First, we capture normal maps of a facial performance simultaneously from several viewing positions using time-multiplexed illumination. Second, we show that highresolution normal maps based on the specular component can be used with structured light 3D scanning to quickly acquire high-resolution facial surface geometry using off-the-shelf digital still cameras. Finally, we present a realtime shading model that uses independently estimated normal maps for the specular and diffuse color channels to reproduce some of the perceptually important effects of subsurface scattering.

/pdf/rapid-acquisition-of-specular-and-diffuse-normal-maps-from-1mualgsxzt.pdf

Rapid acquisition of specular and diffuse normal maps from polarized spherical gradient illumination

HoloDesk is an interactive system combining an optical see through display and Kinect camera to create the illusion that users are directly interacting with 3D graphics. A virtual image of a 3D scene is rendered through a half silvered mirror and spatially aligned with the real-world for the viewer. Users easily reach into an interaction volume displaying the virtual image. This allows the user to literally get their hands into the virtual display and to directly interact with an spatially aligned 3D virtual world, without the need for any specialized head-worn hardware or input device. We introduce a new technique for interpreting raw Kinect data to approximate and track rigid (e.g., books, cups) and non-rigid (e.g., hands, paper) physical objects and support a variety of physics-inspired interactions between virtual and real. In particular the algorithm models natural human grasping of virtual objects with more fidelity than previously demonstrated. A qualitative study highlights rich emergent 3D interactions, using hands and real-world objects. The implementation of HoloDesk is described in full, and example application scenarios explored. Finally, HoloDesk is quantitatively evaluated in a 3D target acquisition task, comparing the system with indirect and glasses-based variants.

/pdf/holodesk-direct-3d-interactions-with-a-situated-see-through-5664f776dq.pdf

HoloDesk: direct 3d interactions with a situated see-through display

We present Silicone iLluminated Active Peripherals (SLAP), a system of tangible, translucent widgets for use on multitouch tabletops. SLAP Widgets are cast from silicone or made of acrylic, and include sliders, knobs, keyboards, and buttons. They add tactile feedback to multi-touch tables, improving input accuracy. Using rear projection, SLAP Widgets can be relabeled dynamically, providing inexpensive, battery-free, and untethered augmentations. Furthermore, SLAP combines the flexibility of virtual objects with physical affordances. We evaluate how SLAP Widgets influence the user experience on tabletops compared to virtual controls. Empirical studies show that SLAPWidgets are easy to use and outperform virtual controls significantly in terms of accuracy and overall interaction time.

/pdf/slap-widgets-bridging-the-gap-between-virtual-and-physical-4jfxqo37wn.pdf

SLAP widgets: bridging the gap between virtual and physical controls on tabletops

We introduce FingerFlux, an output technique to generate near-surface haptic feedback on interactive tabletops. Our system combines electromagnetic actuation with permanent magnets attached to the user's hand. FingerFlux lets users feel the interface before touching, and can create both attracting and repelling forces. This enables applications such as reducing drifting, adding physical constraints to virtual controls, and guiding the user without visual output. We show that users can feel vibration patterns up to 35 mm above our table, and that FingerFlux can significantly reduce drifting when operating on-screen buttons without looking.

FingerFlux: near-surface haptic feedback on tabletops

We present a system for the actuation of tangible magnetic widgets (Madgets) on interactive tabletops. Our system combines electromagnetic actuation with fiber optic tracking to move and operate physical controls. The presented mechanism supports actuating complex tangibles that consist of multiple parts. A grid of optical fibers transmits marker positions past our actuation hardware to cameras below the table. We introduce a visual tracking algorithm that is able to detect objects and touches from the strongly sub-sampled video input of that grid. Six sample Madgets illustrate the capabilities of our approach, ranging from tangential movement and height actuation to inductive power transfer. Madgets combine the benefits of passive, untethered, and translucent tangibles with the ability to actuate them with multiple degrees of freedom.

Malte Weiss

Papers

Rapid acquisition of specular and diffuse normal maps from polarized spherical gradient illumination

HoloDesk: direct 3d interactions with a situated see-through display

SLAP widgets: bridging the gap between virtual and physical controls on tabletops

FingerFlux: near-surface haptic feedback on tabletops

Madgets: actuating widgets on interactive tabletops