diff --git a/2-perception/vhar-textures/1-introduction.tex b/2-perception/vhar-textures/1-introduction.tex index a8affaa..4ffec67 100644 --- a/2-perception/vhar-textures/1-introduction.tex +++ b/2-perception/vhar-textures/1-introduction.tex @@ -3,7 +3,7 @@ Among the various haptic texture augmentations, data-driven methods allow to cap Databases of visuo-haptic textures have been developed in this way \cite{culbertson2014one,balasubramanian2024sens3}, but they have not yet been explored in an immersive and direct touch context with \AR and wearable haptics. In this chapter, we investigate whether simultaneous and \textbf{co-localized visual and wearable haptic texture augmentation of tangible surfaces} in \AR can be perceived in a coherent and realistic manner, and to what extent each sensory modality would contribute to the overall perception of the augmented texture. -We used nine pairs of \textbf{data-driven visuo-haptic textures} from the \HaTT database \cite{culbertson2014one}, which we rendered using the wearable visuo-haptic augmentatio nsystem presented in \chapref{vhar_system}.%, an \OST-\AR headset, and a wearable voice-coil device worn on the finger. +We used nine pairs of \textbf{data-driven visuo-haptic textures} from the \HaTT database \cite{culbertson2014one}, which we rendered using the wearable visuo-haptic augmentatio nsystem presented in \chapref{vhar_system}. %, an \OST-\AR headset, and a wearable voice-coil device worn on the finger. In a \textbf{user study}, 20 participants freely explored in direct touch the combination of the visuo-haptic texture pairs to rate their coherence, realism and perceived roughness. We aimed to assess \textbf{which haptic textures were matched with which visual textures}, how the roughness of the visual and haptic textures was perceived, and whether \textbf{the perceived roughness} could explain the matches made between them. diff --git a/2-perception/vhar-textures/3-results.tex b/2-perception/vhar-textures/3-results.tex index a2553b0..6fe4b02 100644 --- a/2-perception/vhar-textures/3-results.tex +++ b/2-perception/vhar-textures/3-results.tex @@ -145,7 +145,7 @@ The coherence of the texture pairs was considered moderate (\mean{4.6}, \sd{1.2} \begin{subfigs}{results_questions}{Boxplots of the questionnaire results for each visual hand rendering.}[ Pairwise Wilcoxon signed-rank tests with Holm-Bonferroni adjustment: * is \pinf{0.05}, ** is \pinf{0.01} and *** is \pinf{0.001}. - Lower is better for Difficulty and Uncomfortable; higher is better for Realism and Textures Match.% + Lower is better for Difficulty and Uncomfortable; higher is better for Realism and Textures Match. ][ \item By modality. \item By task. diff --git a/2-perception/xr-perception/1-introduction.tex b/2-perception/xr-perception/1-introduction.tex index 8ccbed8..a10f4cc 100644 --- a/2-perception/xr-perception/1-introduction.tex +++ b/2-perception/xr-perception/1-introduction.tex @@ -2,8 +2,8 @@ Still, it is known that the visual rendering of a tangible can influence the perception of its haptic properties (\secref[related_work]{visual_haptic_influence}), and that the perception of same haptic force-feedback or vibrotactile rendering can differ between \AR and \VR, probably due to difference in perceived simultaneity between visual and haptic stimuli (\secref[related_work]{ar_vr_haptic}). Indeed, in \AR, the user can see their own hand touching, the haptic device worn and the \RE, while in \VR they are hidden by the \VE. -In this chapter, we investigate the \textbf{role of the visual virtuality} of the hand (real or virtual) and its environment (\AR or \VR) on the perception of a \textbf{tangible surface whose haptic roughness is augmented} with a wearable haptics.%voice-coil device worn on the finger. -To do so, we used the visuo-haptic system presented in \chapref{vhar_system} to render virtual vibrotactile patterned textures (\secref[related_work]{texture_rendering}) to augment the tangible surface being touched.% touched by the finger.% that can be directly touched with the bare finger. +In this chapter, we investigate the \textbf{role of the visual virtuality} of the hand (real or virtual) and its environment (\AR or \VR) on the perception of a \textbf{tangible surface whose haptic roughness is augmented} with a wearable haptics. %voice-coil device worn on the finger. +To do so, we used the visuo-haptic system presented in \chapref{vhar_system} to render virtual vibrotactile patterned textures (\secref[related_work]{texture_rendering}) to augment the tangible surface being touched. % touched by the finger.% that can be directly touched with the bare finger. We evaluated, in \textbf{user study with psychophysical methods and extensive questionnaire}, the perceived roughness augmentation in three visual rendering conditions: \textbf{(1) without visual augmentation}, in \textbf{(2) \OST-\AR with a realistic virtual hand} rendering, and in \textbf{(3) \VR with the same virtual hand}. To control for the influence of the visual rendering, the tangible surface was not visually augmented and stayed the same in all conditions. diff --git a/2-perception/xr-perception/4-results.tex b/2-perception/xr-perception/4-results.tex index 0e46a24..959460e 100644 --- a/2-perception/xr-perception/4-results.tex +++ b/2-perception/xr-perception/4-results.tex @@ -27,9 +27,8 @@ All pairwise differences were statistically significant. ] \begin{subfigs}{discrimination_accuracy}{Results of the vibrotactile texture roughness discrimination task. }[][ - \item Estimated \PSE of each visual rendering, defined as the amplitude difference at which both reference and comparison textures are perceived to be equivalent.%, \ie the accuracy in discriminating vibrotactile roughness. - \item Estimated \JND of each visual rendering. - %, defined as the minimum perceptual amplitude difference, \ie the sensitivity to vibrotactile roughness differences. + \item Estimated \PSE of each visual rendering, defined as the amplitude difference at which both reference and comparison textures are perceived to be equivalent. %, \ie the accuracy in discriminating vibrotactile roughness. + \item Estimated \JND of each visual rendering. %, defined as the minimum perceptual amplitude difference, \ie the sensitivity to vibrotactile roughness differences. ] \subfig[0.35]{results/trial_pses} \subfig[0.35]{results/trial_jnds} diff --git a/2-perception/xr-perception/5-discussion.tex b/2-perception/xr-perception/5-discussion.tex index 39e85e2..d2de1cd 100644 --- a/2-perception/xr-perception/5-discussion.tex +++ b/2-perception/xr-perception/5-discussion.tex @@ -8,7 +8,7 @@ A \PSE difference in the same range was found for perceived stiffness, with the %However, the difference between the \level{Virtual} and \level{Mixed} conditions was not significant. % Surprisingly, the \PSE of the \level{Real} rendering was shifted to the right (to be "rougher", \percent{7.9}) compared to the reference texture, whereas the \PSEs of the \level{Virtual} (\percent{5.1}) and \level{Mixed} (\percent{1.9}) renderings were perceived as \enquote{smoother} and closer to the reference texture (\figref{results/trial_predictions}). -The sensitivity of participants to roughness differences also varied, with the \level{Real} rendering having the best \JND (\percent{26}), followed by the \level{Virtual} (\percent{30}) and \level{Virtual} (\percent{33}) renderings (\figref{results/trial_jnds}). +The sensitivity of participants to roughness differences also varied, with the \level{Real} rendering having the best \JND (\percent{26}), followed by the \level{Virtual} (\percent{30}) and \level{Mixed} (\percent{33}) renderings (\figref{results/trial_jnds}). These \JND values are in line with and at the upper end of the range of previous studies \cite{choi2013vibrotactile}, which may be due to the location of the actuator on the top of the finger middle phalanx, being less sensitive to vibration than the fingertip. Thus, compared to no visual rendering (\level{Real}), the addition of a visual rendering of the hand or environment reduced the roughness sensitivity (\JND) and the roughness perception (\PSE), as if the virtual vibrotactile textures felt \enquote{smoother}. diff --git a/4-conclusion/conclusion.tex b/4-conclusion/conclusion.tex index abf2d50..18dbd07 100644 --- a/4-conclusion/conclusion.tex +++ b/4-conclusion/conclusion.tex @@ -71,7 +71,7 @@ This would allow a complete portable and wearable visuo-haptic system to be used The main limitation of this user study was the absence of a visual representation of the virtual patterned texture. This is indeed a source of information as important as haptic sensations for the perception of both real textures \cite{baumgartner2013visual,bergmanntiest2007haptic,vardar2019fingertip} and virtual textures \cite{degraen2019enhancing,gunther2022smooth}, and their interaction in the overall perception is complex. -In particular, it remains to be investigated how the vibrotactile patterned textures can be represented visually in a convincing way, as the visuo-haptic coupling of such patterned textures is not trivial \cite{unger2011roughness}.% even with real textures \cite{klatzky2003feeling}. +In particular, it remains to be investigated how the vibrotactile patterned textures can be represented visually in a convincing way, as the visuo-haptic coupling of such patterned textures is not trivial \cite{unger2011roughness}. % even with real textures \cite{klatzky2003feeling}. \paragraph{Broader Visuo-Haptic Conditions}