erwan/phd-thesis
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Remove "see" before section or figure reference

Browse Source
This commit is contained in:
Erwan Normand
2024-09-16 12:57:05 +02:00
parent 8705affcc4
commit 3b66b69fa1
21 changed files with 145 additions and 133 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
3-manipulation/visual-hand/2-method.tex
View File

@@ -25,7 +25,7 @@ As a reference, we considered no visual hand rendering, as is common in AR~\cite
%
Users have no information about hand tracking and no feedback about contact with the virtual objects, other than their movement when touched.
%
As virtual content is rendered on top of the real environment, the hand of the user can be hidden by the virtual objects when manipulating them (see \secref{hands}).
As virtual content is rendered on top of the real environment, the hand of the user can be hidden by the virtual objects when manipulating them (\secref{hands}).
\subsubsection{Occlusion (Occl,~\figref{method/hands-occlusion})}
@@ -94,13 +94,13 @@ Following the guidelines of \textcite{bergstrom2021how} for designing object man
\subsubsection{Push Task}
\label{push-task}
The first manipulation task consists in pushing a virtual object along a real flat surface towards a target placed on the same plane (see \figref{method/task-push}).
The first manipulation task consists in pushing a virtual object along a real flat surface towards a target placed on the same plane (\figref{method/task-push}).
%
The virtual object to manipulate is a small \qty{50}{\mm} blue and opaque cube, while the target is a (slightly) bigger \qty{70}{\mm} blue and semi-transparent volume.
%
At every repetition of the task, the cube to manipulate always spawns at the same place, on top of a real table in front of the user.
%
On the other hand, the target volume can spawn in eight different locations on the same table, located on a \qty{20}{\cm} radius circle centered on the cube, at \qty{45}{\degree} from each other (see again \figref{method/task-push}).
On the other hand, the target volume can spawn in eight different locations on the same table, located on a \qty{20}{\cm} radius circle centered on the cube, at \qty{45}{\degree} from each other (again \figref{method/task-push}).
%
Users are asked to push the cube towards the target volume using their fingertips in any way they prefer.
%
@@ -112,7 +112,7 @@ The task is considered completed when the cube is \emph{fully} inside the target
\subsubsection{Grasp Task}
\label{grasp-task}
The second manipulation task consists in grasping, lifting, and placing a virtual object in a target placed on a different (higher) plane (see \figref{method/task-grasp}).
The second manipulation task consists in grasping, lifting, and placing a virtual object in a target placed on a different (higher) plane (\figref{method/task-grasp}).
%
The cube to manipulate and target volume are the same as in the previous task. However, this time, the target volume can spawn in eight different locations on a plane \qty{10}{\cm} \emph{above} the table, still located on a \qty{20}{\cm} radius circle at \qty{45}{\degree} from each other.
%

2
3-manipulation/visual-hand/3-3-ranks.tex
View File

@@ -16,7 +16,7 @@
%
Friedman tests indicated that both ranking had statistically significant differences (\pinf{0.001}).
%
Pairwise Wilcoxon signed-rank tests with Holm-Bonferroni adjustment were then used on both ranking results (see \secref{metrics}):
Pairwise Wilcoxon signed-rank tests with Holm-Bonferroni adjustment were then used on both ranking results (\secref{metrics}):
\begin{itemize}
\item \textit{Push Ranking}: Occlusion was ranked lower than Contour (\p{0.005}), Skeleton (\p{0.02}), and Mesh (\p{0.03});

2
3-manipulation/visual-hand/3-4-questions.tex
View File

@@ -19,7 +19,7 @@
%
Friedman tests indicated that all questions had statistically significant differences (\pinf{0.001}).
%
Pairwise Wilcoxon signed-rank tests with Holm-Bonferroni adjustment were then used each question results (see \secref{metrics}):
Pairwise Wilcoxon signed-rank tests with Holm-Bonferroni adjustment were then used each question results (\secref{metrics}):
\begin{itemize}
\item \textit{Difficulty}: Occlusion was considered more difficult than Contour (\p{0.02}), Skeleton (\p{0.01}), and Mesh (\p{0.03}).

12
3-manipulation/visual-hand/4-discussion.tex
View File

@@ -3,19 +3,19 @@
We evaluated six visual hand renderings, as described in \secref{hands}, displayed on top of the real hand, in two virtual object manipulation tasks in AR.
During the Push task, the Skeleton hand rendering was the fastest (see \figref{results/Push-CompletionTime-Hand-Overall-Means}), as participants employed fewer and longer contacts to adjust the cube inside the target volume (see \figref{results/Push-ContactsCount-Hand-Overall-Means} and \figref{results/Push-MeanContactTime-Hand-Overall-Means}).
During the Push task, the Skeleton hand rendering was the fastest (\figref{results/Push-CompletionTime-Hand-Overall-Means}), as participants employed fewer and longer contacts to adjust the cube inside the target volume (\figref{results/Push-ContactsCount-Hand-Overall-Means} and \figref{results/Push-MeanContactTime-Hand-Overall-Means}).
%
Participants consistently used few and continuous contacts for all visual hand renderings (see Fig. 3b), with only less than ten trials, carried out by two participants, quickly completed with multiple discrete touches.
Participants consistently used few and continuous contacts for all visual hand renderings (Fig. 3b), with only less than ten trials, carried out by two participants, quickly completed with multiple discrete touches.
%
However, during the Grasp task, despite no difference in completion time, providing no visible hand rendering (None and Occlusion renderings) led to more failed grasps or cube drops (see \figref{results/Grasp-CompletionTime-Hand-Overall-Means} and \figref{results/Grasp-MeanContactTime-Hand-Overall-Means}).
However, during the Grasp task, despite no difference in completion time, providing no visible hand rendering (None and Occlusion renderings) led to more failed grasps or cube drops (\figref{results/Grasp-CompletionTime-Hand-Overall-Means} and \figref{results/Grasp-MeanContactTime-Hand-Overall-Means}).
%
Indeed, participants found the None and Occlusion renderings less effective (see \figref{results/Ranks-Grasp}) and less precise (see \figref{questions}).
Indeed, participants found the None and Occlusion renderings less effective (\figref{results/Ranks-Grasp}) and less precise (\figref{questions}).
%
To understand whether the participants' previous experience might have played a role, we also carried out an additional statistical analysis considering VR experience as an additional between-subjects factor, \ie VR novices vs. VR experts (\enquote{I use it every week}, see \secref{participants}).
%
We found no statistically significant differences when comparing the considered metrics between VR novices and experts.
Interestingly, all visual hand renderings showed grip apertures very close to the size of the virtual cube, except for the None rendering (see \figref{results/Grasp-GripAperture-Hand-Overall-Means}), with which participants applied stronger grasps, \ie less distance between the fingertips.
Interestingly, all visual hand renderings showed grip apertures very close to the size of the virtual cube, except for the None rendering (\figref{results/Grasp-GripAperture-Hand-Overall-Means}), with which participants applied stronger grasps, \ie less distance between the fingertips.
%
Having no visual hand rendering, but only the reaction of the cube to the interaction as feedback, made participants less confident in their grip.
%
@@ -23,7 +23,7 @@ This result contrasts with the wrongly estimated grip apertures observed by \tex
%
Also, while some participants found the absence of visual hand rendering more natural, many of them commented on the importance of having feedback on the tracking of their hands, as observed by \textcite{xiao2018mrtouch} in a similar immersive OST-AR setup.
Yet, participants' opinions of the visual hand renderings were mixed on many questions, except for the Occlusion one, which was perceived less effective than more \enquote{complete} visual hands such as Contour, Skeleton, and Mesh hands (see \figref{questions}).
Yet, participants' opinions of the visual hand renderings were mixed on many questions, except for the Occlusion one, which was perceived less effective than more \enquote{complete} visual hands such as Contour, Skeleton, and Mesh hands (\figref{questions}).
%
However, due to the latency of the hand tracking and the visual hand reacting to the cube, almost all participants thought that the Occlusion rendering to be a \enquote{shadow} of the real hand on the cube.

4
3-manipulation/visuo-haptic-hand/2-method.tex
View File

@@ -5,7 +5,7 @@ Providing haptic feedback during free-hand manipulation in AR is not trivial, as
%
Moreover, it is important to leave the user capable of interacting with both virtual and real objects, avoiding the use of haptic interfaces that cover the fingertips or palm.
%
For this reason, it is often considered beneficial to move the point of application of the haptic rendering elsewhere on the hand.% (see \secref{haptics}).
For this reason, it is often considered beneficial to move the point of application of the haptic rendering elsewhere on the hand.% (\secref{haptics}).
This second experiment aims to evaluate whether a visuo-haptic hand rendering affects the performance and user experience of manipulation of virtual objects with bare hands in AR.
%
@@ -102,7 +102,7 @@ We considered the same two tasks as in Experiment \#1, described in \secref[visu
\item \emph{{Vibrotactile Positioning}:} the five positionings for providing vibrotactile hand rendering of the virtual contacts, as described in \secref{positioning}.
\item \emph{Contact Vibration Technique}: the two contact vibration techniques, as described in \secref{technique}.
\item \emph{visual Hand rendering}: two visual hand renderings from the first experiment, Skeleton (Skel) and None, as described in \secref[visual_hand]{hands}; we considered Skeleton as it performed the best in terms of performance and perceived effectiveness and None as reference.
\item \emph{Target}: we considered target volumes located at NW and SW during the Push task, and at NE, NW, SW, and SE during the Grasp task (see \figref{tasks}); we considered these targets because they presented different difficulties.
\item \emph{Target}: we considered target volumes located at NW and SW during the Push task, and at NE, NW, SW, and SE during the Grasp task (\figref{tasks}); we considered these targets because they presented different difficulties.
\end{itemize}
To account for learning and fatigue effects, the positioning of the vibrotactile hand rendering (positioning) was counter-balanced using a balanced \numproduct{10 x 10} Latin square.

2
3-manipulation/visuo-haptic-hand/3-3-questions.tex
View File

@@ -32,7 +32,7 @@ Although the Distance technique provided additional feedback on the interpenetra
\figref{questions} shows the questionnaire results for each vibrotactile positioning.
%
Questionnaire results were analyzed using Aligned Rank Transform (ART) non-parametric analysis of variance (see \secref{metrics}).
Questionnaire results were analyzed using Aligned Rank Transform (ART) non-parametric analysis of variance (\secref{metrics}).
%
Statistically significant effects were further analyzed with post-hoc pairwise comparisons with Holm-Bonferroni adjustment.
%

2
3-manipulation/visuo-haptic-hand/3-results.tex
View File

@@ -14,7 +14,7 @@
\subfig[0.24]{results/Grasp-GripAperture-Location-Overall-Means}%[\centering Distance between thumb and the other fingertips when grasping.]
\end{subfigswide}
Results were analyzed similarly as for the first experiment (see \secref{results}).
Results were analyzed similarly as for the first experiment (\secref{results}).
%
The LMM were fitted with the order of the five vibrotactile positionings (Order), the vibrotactile positionings (Positioning), the visual hand rendering (Hand), the {contact vibration techniques} (Technique), and the target volume position (Target), and their interactions as fixed effects and Participant as random intercept.

16
3-manipulation/visuo-haptic-hand/4-discussion.tex
View File

@@ -3,7 +3,7 @@
We evaluated sixteen visuo-haptic renderings of the hand, in the same two virtual object manipulation tasks in AR as in the first experiment, as the combination of two vibrotactile contact techniques provided at four delocalized positions on the hand with the two most representative visual hand renderings established in the first experiment.
In the Push task, vibrotactile haptic hand rendering has been proven beneficial with the Proximal positioning, which registered a low completion time, but detrimental with the Fingertips positioning, which performed worse (see \figref{results/Push-CompletionTime-Location-Overall-Means}) than the Proximal and Opposite (on the contralateral hand) positionings.
In the Push task, vibrotactile haptic hand rendering has been proven beneficial with the Proximal positioning, which registered a low completion time, but detrimental with the Fingertips positioning, which performed worse (\figref{results/Push-CompletionTime-Location-Overall-Means}) than the Proximal and Opposite (on the contralateral hand) positionings.
%
The cause might be the intensity of vibrations, which many participants found rather strong and possibly distracting when provided at the fingertips.
%
@@ -13,9 +13,9 @@ Another reason could be the visual impairment caused by the vibrotactile motors
We observed different strategies than in the first experiment for the two tasks.
%
During the Push task, participants made more and shorter contacts to adjust the cube inside the target volume (see \figref{results/Push-Contacts-Location-Overall-Means} and \figref{results/Push-TimePerContact-Location-Overall-Means}).
During the Push task, participants made more and shorter contacts to adjust the cube inside the target volume (\figref{results/Push-Contacts-Location-Overall-Means} and \figref{results/Push-TimePerContact-Location-Overall-Means}).
%
During the Grasp task, participants pressed the cube 25~\% harder on average (see \figref{results/Grasp-GripAperture-Location-Overall-Means}).
During the Grasp task, participants pressed the cube 25~\% harder on average (\figref{results/Grasp-GripAperture-Location-Overall-Means}).
%
The Fingertips and Proximal positionings led to a slightly larger grip aperture than the others.
%
@@ -23,23 +23,23 @@ We think that the proximity of the vibrotactile rendering to the point of contac
%
This could also be the cause of the higher number of failed grasps or cube drops: indeed, we observed that the larger the grip aperture, the higher the number of contacts.
%
Consequently, the Fingertips positioning was slower (see \figref{results/Grasp-CompletionTime-Location-Overall-Means}) and more prone to error (see \figref{results/Grasp-Contacts-Location-Overall-Means}) than the Opposite and Nowhere positionings.
Consequently, the Fingertips positioning was slower (\figref{results/Grasp-CompletionTime-Location-Overall-Means}) and more prone to error (\figref{results/Grasp-Contacts-Location-Overall-Means}) than the Opposite and Nowhere positionings.
In both tasks, the Opposite positioning also seemed to be faster (see \figref{results/Push-CompletionTime-Location-Overall-Means}) than having no vibrotactile hand rendering (Nowhere positioning).
In both tasks, the Opposite positioning also seemed to be faster (\figref{results/Push-CompletionTime-Location-Overall-Means}) than having no vibrotactile hand rendering (Nowhere positioning).
%
However, participants also felt more workload (see \figref{questions}) with this positioning opposite to the site of the interaction.
However, participants also felt more workload (\figref{questions}) with this positioning opposite to the site of the interaction.
%
This result might mean that participants focused more on learning to interpret these sensations, which led to better performance in the long run.
Overall, many participants appreciated the vibrotactile hand renderings, commenting that they made the tasks more realistic and easier.
%
However, the closer to the contact point, the better the vibrotactile rendering was perceived (see \figref{questions}).
However, the closer to the contact point, the better the vibrotactile rendering was perceived (\figref{questions}).
%
This seemed inversely correlated with the performance, except for the Nowhere positioning, \eg both the Fingertips and Proximal positionings were perceived as more effective, useful, and realistic than the other positionings despite lower performance.
Considering the two tasks, no clear difference in performance or appreciation was found between the two contact vibration techniques.
%
While the majority of participants discriminated the two different techniques, only a minority identified them correctly (see \secref{technique_results}).
While the majority of participants discriminated the two different techniques, only a minority identified them correctly (\secref{technique_results}).
%
It seemed that the Impact technique was sufficient to provide contact information compared to the Distance technique, which provided additional feedback on interpenetration, as reported by participants.