rendering method of 2-dimensional vibration presentation
TRANSCRIPT
Rendering Method of 2-Dimensional Vibration Presentation for Improving
Fidelity of Haptic TextureJunya Kurogi1, Satoshi Saga1
1Kumamoto University, JAPAN
Contact email: {kurogi,saga}@saga-lab.org
Junya Kurogi
β’ Junya Kurogi received the BS and MS degrees in engineering
from Kumamoto University in 2017 and 2019, respectively. He
had been engaged in research on a tactile display employing
virtual reality. Since 2020, he has been an engineer at Nishi-
Nippon Railroad Co., Ltd.
Our goal
β’ Developing a rendering method for texture displayβ’ Based on two dimensional vibration hardware
β’ From the recorded vibration, we reproduce the fidelity of the texture
Displaying method of recorded accelerationThe recorded acceleration πππ
π is described by the movement length of the finger β« π₯πππ₯, β« π¦πππ¦
πππ = πππ₯
π + πππ¦π
= πππ β« |π₯π|ππ₯ , β« |π¦π|ππ¦
π β π₯, π¦ ππππππ‘πππ ππ π£πππππ‘πππ ,π β π₯, π¦ (ππππππ‘πππ ππ πππ£πππππ‘)
Thus , the replaying acceleration ππ is described as
ππ β« π₯πππ₯, β« π¦πππ¦ = πΌ β πππ₯π β« π₯πππ₯ + π½ β πππ¦
π β« π¦πππ¦
Where, π₯ππ = (πΌ, π½), Ξππ = 1
Problem of the displaying method
β’ Many random textures can be reproduced by the method
β’ In some textures, the method cannot reproduce the fidelityβ’ Certain spatial frequency textures, such as
tiled-floor
β’ We employ image features
Use of image features
1. Acquire features using AKAZE
2. Extract the size information
3. Obtain averaged one-dimensionalinformation
4. Augment the size information
Average to Y
Ave
rage t
o X
Further processing
β’ The vibration of no feature area is diminished by the augmentation
β’ To avoid this diminishing, we apply the logs
π0: before applying logs π1: after applying logs
Augmented vibration applying image features
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Acceleration of tile
π π‘ =
πππ π‘ (one dimension)
ππ π‘ (two dimension)
πππ π‘ β ππ₯0 π₯, π¦ + ππ
π π‘ β ππ¦0 π₯, π¦ (image feature)
πππ π‘ β ππ₯1 π₯, π¦ + ππ
π π‘ β ππ¦1 π₯, π¦ (log scaled image feature)
Image feature(π0)
Log scaled image feature (π1)
Γ
Γ
Textures for experiment
β’ We prepared 10 types of textures and collect the acceleration information
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β ArtificialGrass1
β ArtificialGrass2
β Carpet1 β Carpet2 β Tile
β SandPaper
β PlaceMat1
β PlaceMat2
β PunchedPlastic Sheet
β PlaceMat3
Experiment procedureβ’ Rendering method for comparison
1. One dimensional vibration
2. Two dimensional vibration
3. Feature augmentation π0(without log)
4. Feature augmentation π1(with log)
β»For the textures other than Tile, Place Mat1 and Punched Plastic Sheet, we applied the method of 1, 2 only
β’ Evaluation method
β 5 stages Likert scale
β’ Participants
β7 healthy men aged 22 to 24.
βThey wore headphones and eye mask to remove the visual/auditory effect
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0
0.5
1
1.5
2
2.5
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3.5
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4.5
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Artificial
Grass1
Artificial
Grass2
Carpet1 Carpet2 Tile Sand
Paper
Place
Mat1
Place
Mat2
Place
Mat3
Punched
Plastic
Sheet
One-dimensionas Two-dimensions
Image feature (eβ) Image feature (eβ)
* **
Result
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Error bar = S.E.
* shows π < 0.05 under t-test orπΌ < 0.05 under Tukeyβs test
Discussion
β’ The proposed method is suitable for presenting textures with random spatial frequencies and a relatively hard tactile sensation
βArtificial Grass2, Sand Paper, Place Mat2
β’ The method is suitable for some texture with a constant spatial frequency
βTile, Place Mat1
βEspecially, the image feature π0shows significant difference
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0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
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One-dimensionas Two-dimensions
Image feature (eβ) Image feature (eβ)
* **
Comparison betweenimage feature augmentation methods
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0
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80
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Tile Place Mat1 Punched Plastic Sheet
Se
lecti
on
pro
ba
bil
ity(%
)
Image feature (eβ)
Image feature (eβ)
Discussionβ’ π0 has high fidelity on Place Mat1
π0οΌ Enhancement of feature pointsπ1οΌReducing the diminishing of vibration
β’Longest spatial period induces the enhancement of feature point than vibration intensity
β’ For short spatial period, the augmentation is not effective in Punched Plastic Sheet
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0
20
40
60
80
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Tile Place Mat1 Punched Plastic
Sheet
Se
lecti
on
pro
ba
bil
ity(%
)
Image feature (eβ)
Image feature (eβ)
0
0.2
0.4
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0.8
1
1.2
0 200 400 600 800
Pixel
0
0.2
0.4
0.6
0.8
1
1.2
0 200 400 600 800
Pixle
π 0(π₯)
π 1(π₯)
π0: without log π1: with log
Discussion
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0
20
40
60
80
100
Tile Place Mat1 Punched Plastic
Sheet
Se
lecti
on
pro
ba
bil
ity(%
)
Image feature (eβ)
Image feature (eβ)
π 1(π₯)
2γ1.3γ 0.9γ
β’ π0 has high fidelity on Place Mat1
π0οΌ Enhancement of feature pointsπ1οΌReducing the diminishing of vibration
β’Longest spatial period induces the enhancement of feature point than vibration intensity
β’ For short spatial period, the augmentation is not effective in Punched Plastic Sheet
Conclusions
β’ Purpose
β’ Proposal of a presentation method that accurately presents vibration information in the two-dimensional direction
β’ Proposal of vibration presentation method using superimposition of image features
β’ Verify the tactile reproducibility of each method
β’ Result
β’ Two-dimensional vibration presentation is suitable for hard, random textures with spatial frequencies
β’ An image feature augmentation method is useful for textures with a constant spatial frequency
β’ Future work
β’ Presentation of softness by dynamic vibration control
β’ Establishment of a texture selection method suitable for using the image feature superimposition method
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