Remove comments

2-related-work/2-wearable-haptics.tex

@@ -52,8 +52,6 @@ Moreover, as detailed in \secref{object_properties}, cutaneous sensations are ne
   \subfig{leonardis20173rsr}
 \end{subfigs}
 
-% Tradeoff realistic and cost + analogy with sound, Hi-Fi costs a lot and is realistic, but 40$ BT headphone is more practical and enough, as cutaneous feedback without kinesthesic could be enough for wearable haptics and far more affordable and comfortable than world- or body-grounded haptics + cutaneous even better than kine for rendering surface curvature and fine manipulation
-
 \subsection{Wearable Haptic Devices for the Hand}
 \label{wearable_haptic_devices}
 
@@ -114,7 +112,6 @@ The simplicity of this approach allows the belt to be placed anywhere on the han
 \begin{subfigs}{tangential_belts}{Tangential motion actuators and compression belts. }[][
   \item A skin strech actuator for the fingertip \cite{leonardis2015wearable}.
   \item A 3 \DoF actuator capable of normal and tangential motion on the fingertip \cite{schorr2017fingertip}.
-    %\item A shearing belt actuator for the fingertip \cite{minamizawa2007gravity}.
   \item The hRing, a shearing belt actuator for the proximal phalanx of the finger \cite{pacchierotti2016hring}.
   \item Tasbi, a wristband capable of pressure and vibrotactile feedback \cite{pezent2022design}.
   ]
@@ -185,27 +182,19 @@ In particular, the visual rendering of a touched object can also influence the p
 \textcite{bhatia2024augmenting} categorize the haptic augmentations into three types: direct touch, touch-through, and tool-mediated.
 In \emph{direct touch}, the haptic device does not cover the inside of the hand so as not to impair the interaction of the user with the \RE, and is typically achieved with wearable haptics.
 In touch-through and tool-mediated, or \emph{indirect feel-through} \cite{jeon2015haptic}, the haptic device is placed between the hand and the \RE.
-%We are interested in direct touch augmentations with wearable haptics (\secref{wearable_haptic_devices}), as their integration with \AR is particularly promising for free hand interaction with visuo-haptic augmentations.
 Many haptic augmentations were first developed with touch-through devices, and some (but not all) were later transposed to direct touch augmentation with wearable haptic devices.
-%We also focus on tactile augmentations stimulating the mechanoreceptors of the skin (\secref{haptic_sense}), thus excluding temperature perception, as they are the most common existing haptic interfaces.
 
 Since we have chosen to focus in \secref{object_properties} on the haptic perception of roughness and hardness of objects, we review below the methods to modify the perception of these properties.
 Of course, wearable haptics can also be used in a direct touch context to modify the perceived friction \cite{konyo2008alternative,salazar2020altering}, weight \cite{minamizawa2007gravity}, or local deformation \cite{salazar2020altering} of real objects, but they are rare \cite{bhatia2024augmenting} and will not be detailed here.
 
-% \cite{klatzky2003feeling} : rendering roughness, friction, deformation, temperatures
-% \cite{girard2016haptip} : renderings with a tangential motion actuator
-
 \subsubsection{Roughness Augmentation}
 \label{texture_rendering}
 
 To modify the perception of the haptic roughness (or texture, see \secref{roughness}) of a real object, vibrations are typically applied to the skin by the haptic device as the user moves over the surface.
-%This is because running the finger or a tool on a textured surface generates pressures and vibrations (\secref{roughness}) at frequencies that are too high for rendering capabilities of most haptic devices \cite{campion2005fundamental,culbertson2018haptics}.
 There are two main approaches to modify virtual textures perception: \emph{simulation models} and \emph{data-driven models} \cite{klatzky2013haptic,culbertson2018haptics}.
 
 \paragraph{Simulation Models}
 
-%Simulations of virtual textures are based on the physics of the interaction between the finger and the surface, and are used to generate the vibrations that the user feels when running the finger over the surface.
-
 The simplest texture simulation model is a 1D sinusoidal grating $v(t)$ with spatial period $\lambda$ and amplitude $A$ that is scanned by the user at velocity $\dot{x}(t)$:
 \begin{equation}{grating_rendering}
   v(t) = A \sin(\frac{2 \pi \dot{x}(t)}{\lambda})
@@ -220,8 +209,6 @@ The perceived roughness increased proportionally to the virtual texture amplitud
 \textcite{ujitoko2019modulating} instead used a square wave signal and a hand-held stylus with an embedded voice-coil.
 \textcite{friesen2024perceived} compared the frequency modulation of \eqref{grating_rendering} with amplitude modulation (\figref{friesen2024perceived}), and found that the frequency modulation was perceived as more similar to real sinusoidal gratings for lower spatial periods (\qty{0.5}{\mm}) but both modulations were effective for higher spatial periods (\qty{1.5}{\mm}).
 
-%\textcite{friesen2024perceived} proposed
-
 The model in \eqref{grating_rendering} can be extended to 2D textures by adding a second sinusoidal grating with an orthogonal orientation as \textcite{girard2016haptip}.
 More complex models have also been developed to be physically accurate and reproduce with high fidelity the roughness perception of real patterned surfaces \cite{unger2011roughness}, but they require high-fidelity force feedback devices that are expensive and have a limited workspace.
 
@@ -241,9 +228,6 @@ A similar database, but captured from a direct touch context with the fingertip,
 A common limitation of these data-driven models is that they can only render \emph{isotropic} textures: their record does not depend on the position of the measure, and the rendering is the same regardless of the direction of the movement.
 This was eventually addressed to include the user's velocity direction into the capture, modelling and rendering of the textures \cite{abdulali2016datadriven,abdulali2016datadrivena}.
 
-%A third approach is to model
-%Alternative models have been proposed to both render both isotropic and patterned textures \cite{chan2021hasti}., or to simulate the vibrations from the (visual) texture maps used to visually render a \ThreeD object \cite{chan2021hasti}.
-
 Using the user's velocity magnitude and normal force as input, these data-driven models are able to interpolate from the scan measures to generate a virtual texture in real time as vibrations with a high realism.
 When comparing real textures felt through a stylus with their virtual models rendered with a voice-coil actuator attached to the stylus (\figref{culbertson2012refined}), the virtual textures were found to accurately reproduce the perception of roughness, but hardness and friction were not rendered properly \cite{culbertson2014modeling}.
 \textcite{culbertson2015should} further showed that the perceived realism of the virtual textures, and similarity to the real textures, depended mostly on the user's velocity magnitude but not on the user's force as inputs to the model, \ie responding to velocity magnitude is sufficient to render isotropic virtual textures.
@@ -331,38 +315,6 @@ A challenge with this technique is to provide the vibration feedback at the righ
 Vibrations on contact have been employed with wearable haptics, but to the best of our knowledge only to render virtual objects \cite{pezent2019tasbi,teng2021touch,sabnis2023haptic}.
 We describe them in the \secref{vhar_haptics}.
 
-%A promising alternative approach
-%\cite{kildal20103dpress}
-
-%\begin{subfigs}{vibtration_grains}{Augmenting perceived stiffness of a real surface with vibrations. }
-%    \subfigsheight{35mm}
-%    \subfig{sabnis2023haptic_device}
-%    \subfig{sabnis2023haptic_control}
-%\end{subfigs}
-
-%\textcite{choi2021perceived} combined and compared these two rendering approaches (spring-damper and exponential decaying sinusoids) but to render purely virtual surfaces.
-%They found that the perceived intensity of the virtual hardness $\tilde{h}$ followed a power law, similarly to \eqref{hardness_intensity}, with the amplitude $a$, the %frequency $f$ and the damping $b$ of the vibration, but not the decay time $\tau$.
-%\cite{park2023perceptual}
-
-%\subsubsection{Friction}
-%\label{friction_rendering}
-
-%\cite{konyo2008alternative}
-%\cite{provancher2009fingerpad}
-%\cite{smith2010roughness}
-%\cite{jeon2011extensions}
-%\cite{salazar2020altering}
-%\cite{yim2021multicontact}
-
-%\subsubsection{Weight}
-%\label{weight_rendering}
-
-%\cite{minamizawa2007gravity}
-%\cite{minamizawa2008interactive}
-%\cite{jeon2011extensions}
-%\cite{choi2017grabity}
-%\cite{culbertson2017waves}
-
 \subsection{Conclusion}
 \label{wearable_haptics_conclusion}
 
@@ -372,6 +324,3 @@ While many haptic devices can be worn on the hand, only a few can be considered
 If the haptic rendering of the device is timely associated with the user's touch actions on a real object, the perceived haptic properties of the object can be modified.
 Several haptic augmentation methods have been developed to modify the perceived roughness and hardness, mostly using vibrotactile feedback and, to a lesser extent, pressure feedback.
 However, not all of these haptic augmentations have yet been already transposed to wearable haptics, and the use of wearable haptic augmentations has not yet been investigated in the context of \AR.
-
-%, unlike most previous actuators that are designed specifically for fingertips and would require mechanical adaptation to be placed on other parts of the hand.
-% thanks to the vibration propagation and the sensory capabilities distributed throughout the skin, they can be placed without adaption and on any part of the hand