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Remove "see" before section or figure reference

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Erwan Normand
2024-09-16 12:57:05 +02:00
parent 8705affcc4
commit 3b66b69fa1
21 changed files with 145 additions and 133 deletions
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18
2-perception/xr-perception/2-method.tex
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@@ -15,7 +15,7 @@
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If so, the velocity of the finger marker ${}^c\dot{\mathbf{X}}_f$ is estimated using discrete derivative of position and adaptive low-pass filtering, then transformed onto the texture frame $\mathcal{F}_t$.
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The vibrotactile signal $s_k$ is generated by modulating the finger velocity ${}^t\hat{\dot{X}}_f$ in the texture direction with the texture period $\lambda$ (see \eqref{signal}).
The vibrotactile signal $s_k$ is generated by modulating the finger velocity ${}^t\hat{\dot{X}}_f$ in the texture direction with the texture period $\lambda$ (\eqref{signal}).
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The signal is sampled at 48~kHz and sent to the voice-coil actuator via an audio amplifier.
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@@ -56,9 +56,9 @@ The system is composed of three main components: the pose estimation of the trac
\subfig[0.992]{method/apparatus}
\end{subfigs}
A fiducial marker (AprilTag) is glued to the top of the actuator (see \figref{method/device}) to track the finger pose with a camera (StreamCam, Logitech) which is placed above the experimental setup and capturing \qtyproduct{1280 x 720}{px} images at \qty{60}{\hertz} (see \figref{method/apparatus}).
A fiducial marker (AprilTag) is glued to the top of the actuator (\figref{method/device}) to track the finger pose with a camera (StreamCam, Logitech) which is placed above the experimental setup and capturing \qtyproduct{1280 x 720}{px} images at \qty{60}{\hertz} (\figref{method/apparatus}).
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Other markers are placed on the tangible surfaces to augment to estimate the relative position of the finger with respect to the surfaces (see \figref{setup}).
Other markers are placed on the tangible surfaces to augment to estimate the relative position of the finger with respect to the surfaces (\figref{setup}).
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Contrary to similar work 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}, using vision-based tracking allows both to free the hand movements and to augment any tangible surface.
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@@ -75,13 +75,13 @@ The velocity of the marker is estimated using the discrete derivative of the pos
To be able to compare virtual and augmented realities, we then create a virtual environment that closely replicate the real one.
%Before a user interacts with the system, it is necessary to design a virtual environment that will be registered with the real environment during the experiment.
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Each real element tracked by a marker is modelled virtually, \ie the hand and the augmented tangible surface (see \figref{renderings}).
Each real element tracked by a marker is modelled virtually, \ie the hand and the augmented tangible surface (\figref{renderings}).
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In addition, the pose and size of the virtual textures are defined on the virtual replicas.
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During the experiment, the system uses marker pose estimates to align the virtual models with their real-world counterparts. %, according to the condition being tested.
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This allows to detect if a finger touches a virtual texture using a collision detection algorithm (Nvidia PhysX), and to show the virtual elements and textures in real-time, aligned with the real environment (see \figref{renderings}), using the considered AR or VR headset.
This allows to detect if a finger touches a virtual texture using a collision detection algorithm (Nvidia PhysX), and to show the virtual elements and textures in real-time, aligned with the real environment (\figref{renderings}), using the considered AR or VR headset.
In our implementation, the virtual hand and environment are designed with Unity and the Mixed Reality Toolkit (MRTK).
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@@ -89,9 +89,9 @@ The visual rendering is achieved using the Microsoft HoloLens~2, an OST-AR heads
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It was chosen over VST-AR because OST-AR only adds virtual content to the real environment, while VST-AR streams a real-time video capture of the real environment~\cite{macedo2023occlusion}.
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Indeed, one of our objectives (see \secref{experiment}) is to directly compare a virtual environment that replicates a real one. %, rather than a video feed that introduces many supplementary visual limitations.
Indeed, one of our objectives (\secref{experiment}) is to directly compare a virtual environment that replicates a real one. %, rather than a video feed that introduces many supplementary visual limitations.
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To simulate a VR headset, a cardboard mask (with holes for sensors) is attached to the headset to block the view of the real environment (see \figref{method/headset}).
To simulate a VR headset, a cardboard mask (with holes for sensors) is attached to the headset to block the view of the real environment (\figref{method/headset}).
\subsection{Vibrotactile Signal Generation and Rendering}
@@ -99,7 +99,7 @@ To simulate a VR headset, a cardboard mask (with holes for sensors) is attached
A voice-coil actuator (HapCoil-One, Actronika) is used to display the vibrotactile signal, as it allows the frequency and amplitude of the signal to be controlled independently over time, covers a wide frequency range (\qtyrange{10}{1000}{\Hz}), and outputs the signal accurately with relatively low acceleration distortion\footnote{HapCoil-One specific characteristics are described in its data sheet: \url{https://web.archive.org/web/20240228161416/https://tactilelabs.com/wp-content/uploads/2023/11/HapCoil_One_datasheet.pdf}}.
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The voice-coil actuator is encased in a 3D printed plastic shell and firmly attached to the middle phalanx of the user's index finger with a Velcro strap, to enable the fingertip to directly touch the environment (see \figref{method/device}).
The voice-coil actuator is encased in a 3D printed plastic shell and firmly attached to the middle phalanx of the user's index finger with a Velcro strap, to enable the fingertip to directly touch the environment (\figref{method/device}).
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The actuator is driven by a Class D audio amplifier (XY-502 / TPA3116D2, Texas Instrument). %, which has proven to be an effective type of amplifier for driving moving-coil~\cite{mcmahan2014dynamic}.
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@@ -131,7 +131,7 @@ Note that the finger position and velocity are transformed from the camera frame
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However, when a new finger position is estimated at time $t_j$, the phase $\phi_j$ needs to be adjusted as well with the frequency to ensure a continuity in the signal as described in \eqref{signal}.
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This approach avoids sudden changes in the actuator movement thus affecting the texture perception in an uncontrolled way (see \figref{method/phase_adjustment}) and, contrary to previous work~\cite{asano2015vibrotactile,friesen2024perceived}, it enables no constraints a free exploration of the texture by the user with no constraints on the finger speed.
This approach avoids sudden changes in the actuator movement thus affecting the texture perception in an uncontrolled way (\figref{method/phase_adjustment}) and, contrary to previous work~\cite{asano2015vibrotactile,friesen2024perceived}, it enables no constraints a free exploration of the texture by the user with no constraints on the finger speed.
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Finally, as \textcite{ujitoko2019modulating}, a square wave is chosen over a sine wave to get a rendering closer to a real grating texture with the sensation of crossing edges, and because the roughness perception of sine wave textures has been shown not to reproduce the roughness perception of real grating textures~\cite{unger2011roughness}.
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