WIP vhar_system

2-perception/vhar-system/1-introduction.tex

@@ -1,20 +1,23 @@
-%\noindent La principale augmentation haptique de texture consiste à simuler la rugosité d'une surface périodique de grille
+\noindent One approach to render virtual haptic textures consists in simulating the roughness of a periodic grating surface as a vibrotactile sinusoidal.
+The vibrations are rendered to a voice-coil actuator embedded in a hand-held tool or worn on the finger, but to create the illusion of touching a pattern with a fixed spatial period, the frequency of signal must be modulated according to the finger movement (\secref[related_work]{texture_rendering}).
+Previous work either used mechanical system to track the movement at high frequency \cite{strohmeier2017generating,friesen2024perceived}, or required the user to move at a constant speed  to keep the signal frequency constant \cite{asano2015vibrotactile,ujitoko2019modulating}.
+However, this method has not yet been integrated in an \AR context, where the user should be able to freely touch and explore the visuo-haptic texture augmentations.
 
-%By providing timely vibrations synchronized with the movement of the tool or the finger moving on a real object, the perceived roughness of the surface can be augmented \cite{culbertson2015should,asano2015vibrotactile}.
-%While these virtual haptic textures are perceived as similar to real textures \cite{culbertson2015should}, they have been evaluated using hand-held tools and not yet in a direct finger contact with the surface context, in particular combined with visual textures in an immersive \VE.
-%Second, many works have investigated the haptic augmentation of textures, but few have integrated them with immersive \VEs or have considered the influence of the visual rendering on their perception.
-%Such techniques place the actuator \emph{close} to the point of contact with the \RE, leaving the user free to directly touch the tangible.
+%which either constrained hand to a constant speed to keep the signal frequency constant \cite{asano2015vibrotactile,friesen2024perceived}, or used mechanical sensors attached to the hand \cite{friesen2024perceived,strohmeier2017generating}
 
-In this chapter, we propose a system for rendering coherent visual and haptic virtual textures that augment tangible surfaces.
+In this chapter, we propose a \textbf{system for rendering visual and haptic virtual textures that augment tangible surfaces}.
 It is implemented with an immersive \OST-\AR headset Microsoft HoloLens~2 and a wearable vibrotactile (voice-coil) device worn on the outside of finger (not covering the fingertip, \secref[related_work]{vhar_haptics}).
-The visuo-haptic augmentations can be viewed freely from any angle and touched directly with the bare finger, as if they were real textures.
-To ensure real-time and realible renderings, the hand and the tangibles are tracked using a webcam and marker-based tracking.
+The visuo-haptic augmentations can be \textbf{viewed from any angle} and \textbf{explored freely with the bare finger}, as if they were real textures.
+To ensure both real-time and reliable renderings, the hand and the tangibles are tracked using a webcam and marker-based tracking.
 The haptic textures are rendered as a real-time vibrotactile signal representing a patterned grating texture that is synchronized with the finger movement on the augmented tangible surface.
 
 \noindentskip The contributions of this chapter are:
 \begin{itemize}
-  \item The rendering of virtual vibrotactile roughness textures representing a patterned grating texture in real time from free finger movements.
+  \item The rendering of virtual vibrotactile roughness textures representing a patterned grating texture in real time from free finger movements and using vision-based tracking.
   \item A system to provide a coherent visuo-haptic texture augmentations of the \RE in a direct touch context using an immersive \AR headset and wearable haptics.
 \end{itemize}
 
 \noindentskip In the remainder of this chapter, we describe the principles of the system, how the real and virtual environments are registered, the generation of the vibrotactile textures, and measures of visual and haptic rendering latencies.
+
+% We describe a system for rendering vibrotactile roughness textures in real time, on any tangible surface, touched directly with the index fingertip, with no constraints on hand movement and using a simple camera to track the finger pose.
+% We also describe how to pair this tactile rendering with an immersive \AR or \VR headset visual display to provide a coherent, multimodal visuo-haptic augmentation of the \RE.