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Book ; Online: LEAP-VO

Chen, Weirong / Chen, Le / Wang, Rui / Pollefeys, Marc

Long-term Effective Any Point Tracking for Visual Odometry

2024

Abstract: Visual odometry estimates the motion of a moving camera based on visual input. Existing methods, mostly focusing on two-view point tracking, often ignore the rich temporal context in the image sequence, thereby overlooking the global motion patterns and ... ...

Abstract	Visual odometry estimates the motion of a moving camera based on visual input. Existing methods, mostly focusing on two-view point tracking, often ignore the rich temporal context in the image sequence, thereby overlooking the global motion patterns and providing no assessment of the full trajectory reliability. These shortcomings hinder performance in scenarios with occlusion, dynamic objects, and low-texture areas. To address these challenges, we present the Long-term Effective Any Point Tracking (LEAP) module. LEAP innovatively combines visual, inter-track, and temporal cues with mindfully selected anchors for dynamic track estimation. Moreover, LEAP's temporal probabilistic formulation integrates distribution updates into a learnable iterative refinement module to reason about point-wise uncertainty. Based on these traits, we develop LEAP-VO, a robust visual odometry system adept at handling occlusions and dynamic scenes. Our mindful integration showcases a novel practice by employing long-term point tracking as the front-end. Extensive experiments demonstrate that the proposed pipeline significantly outperforms existing baselines across various visual odometry benchmarks. Comment: 15 pages, 11 figures
Keywords	Computer Science - Computer Vision and Pattern Recognition
Publishing date	2024-01-03
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Expression of visfatin in gingival crevicular fluid and gingival tissues in different periodontal conditions: a cross-sectional study.

Xiao, Kang / Chen, Ling / Mao, Yudian / Bao, Han / Chen, Weirong / Li, Xiang / Wu, Yun

BMC oral health

2024 Volume 24, Issue 1, Page(s) 514

Abstract: Background: Studies have shown that visfatin is an inflammatory factor closely related to periodontitis. We examined the levels of visfatin in gingival crevicular fluid (GCF) and gingival tissues under different periodontal conditions, in order to ... ...

Abstract	Background: Studies have shown that visfatin is an inflammatory factor closely related to periodontitis. We examined the levels of visfatin in gingival crevicular fluid (GCF) and gingival tissues under different periodontal conditions, in order to provide more theoretical basis for exploring the role of visfatin in the pathogenesis of periodontitis. Methods: We enrolled 87 subjects, with 43 in the chronic periodontitis (CP) group, 21 in the chronic gingivitis (CG) group, and 23 in the periodontal health (PH) group. Periodontal indexes (PD, AL, PLI, and BI) were recorded. GCF samples were collected for visfatin quantification, and gingival tissues were assessed via immunohistochemical staining. Results: Visfatin levels in GCF decreased sequentially from CP to CG and PH groups, with statistically significant differences (P < 0.05). The CP group exhibited the highest visfatin levels, while the PH group had the lowest. Gingival tissues showed a similar trend, with significant differences between groups (P < 0.001). Periodontal indexes were positively correlated with visfatin levels in both GCF and gingival tissues (P < 0.001). A strong positive correlation was observed between visfatin levels in GCF and gingival tissues (rs = 0.772, P < 0.001). Conclusion: Greater periodontal destruction corresponded to higher visfatin levels in GCF and gingival tissues, indicating their potential collaboration in damaging periodontal tissues. Visfatin emerges as a promising biomarker for periodontitis and may play a role in its pathogenesis.
MeSH term(s)	Humans ; Gingival Crevicular Fluid/chemistry ; Nicotinamide Phosphoribosyltransferase/metabolism ; Nicotinamide Phosphoribosyltransferase/analysis ; Male ; Female ; Cross-Sectional Studies ; Gingiva/metabolism ; Adult ; Chronic Periodontitis/metabolism ; Gingivitis/metabolism ; Periodontal Index ; Middle Aged ; Cytokines/metabolism ; Cytokines/analysis
Chemical Substances	Nicotinamide Phosphoribosyltransferase (EC 2.4.2.12) ; nicotinamide phosphoribosyltransferase, human (EC 2.4.2.12) ; Cytokines
Language	English
Publishing date	2024-05-02
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2091511-1
ISSN	1472-6831 ; 1472-6831
ISSN (online)	1472-6831
ISSN	1472-6831
DOI	10.1186/s12903-024-04299-2
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: "Capsule drape wrap"-a new technology for iridoschisis management during phacoemulsification.

Chen, Hui / Chen, Wan / Lin, Yong-Bin / Chen, Wei-Rong

International journal of ophthalmology

2023 Volume 16, Issue 6, Page(s) 984–987

Abstract: Aim: To introduce a new technique for iridoschisis management during phacoemulsification: "capsule drape wrap".: Methods: "Capsule drape wrap" technique was used for an 80-year-old man with idiopathic iridoschisis in the right eye during ... ...

Abstract	Aim: To introduce a new technique for iridoschisis management during phacoemulsification: "capsule drape wrap". Methods: "Capsule drape wrap" technique was used for an 80-year-old man with idiopathic iridoschisis in the right eye during phacoemulsification. The inserted flexible nylon iris hooks to hold anterior capsule in place, the margin of the anterior capsule could act as drape wrap, tracking the fibrillary iris strands firmly from free floating and stabilizing the capsular bags simultaneously. Results: The eye with iridoschisis was successfully treated. Iris fibrils remained immobile during the procedure, and despite the severity of iridoschisis, there were no intraoperative complications such as tear of the iris, hyphema, iris prolapse, loss of mydriasis, or rupture of the posterior lens capsule during phacoemulsification. The best-corrected visual acuity was increased by 0.1 (logMAR) 6mo after the surgery. Conclusion: "Capsule drape wrap" for iridoschisis is easily manageable, prevents further disruption to the loose iris fibers and ensures the stability of capsule-iris complex simultaneously, consequently minimizing the risk of surgical complications in phacoemulsification.
Language	English
Publishing date	2023-06-18
Publishing country	China
Document type	Journal Article
ZDB-ID	2663246-9
ISSN	2227-4898 ; 2222-3959
ISSN (online)	2227-4898
ISSN	2222-3959
DOI	10.18240/ijo.2023.06.23
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Article ; Online: Refining and extending measures for fricative spectra, with special attention to the high-frequency rangea).

Shadle, Christine H / Chen, Wei-Rong / Koenig, Laura L / Preston, Jonathan L

The Journal of the Acoustical Society of America

2023 Volume 154, Issue 3, Page(s) 1932–1944

Abstract: Fricatives have noise sources that are filtered by the vocal tract and that typically possess energy over a much broader range of frequencies than observed for vowels and sonorant consonants. This paper introduces and refines fricative measurements that ... ...

Abstract	Fricatives have noise sources that are filtered by the vocal tract and that typically possess energy over a much broader range of frequencies than observed for vowels and sonorant consonants. This paper introduces and refines fricative measurements that were designed to reflect underlying articulatory and aerodynamic conditions These show differences in the pattern of high-frequency energy for sibilants vs non-sibilants, voiced vs voiceless fricatives, and non-sibilants differing in place of articulation. The results confirm the utility of a spectral peak measure (FM) and low-mid frequency amplitude difference (AmpD) for sibilants. Using a higher-frequency range for defining FM for female voices for alveolars is justified; a still higher range was considered and rejected. High-frequency maximum amplitude (Fh) and amplitude difference between low- and higher-frequency regions (AmpRange) capture /f-θ/ differences in English and the dynamic amplitude range over the entire spectrum. For this dataset, with spectral information up to 15 kHz, a new measure, HighLevelD, was more effective than previously used LevelD and Slope in showing changes over time within the frication. Finally, isolated words and connected speech differ. This work contributes improved measures of fricative spectra and demonstrates the necessity of including high-frequency energy in those measures.
MeSH term(s)	Female ; Humans ; Language ; Speech
Language	English
Publishing date	2023-09-28
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
ZDB-ID	219231-7
ISSN	1520-8524 ; 0001-4966
ISSN (online)	1520-8524
ISSN	0001-4966
DOI	10.1121/10.0021075
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Article ; Online: An acoustic study of Cantonese alaryngeal speech in different speaking conditions.

Cox, Steven R / Huang, Ting / Chen, Wei-Rong / Ng, Manwa L

The Journal of the Acoustical Society of America

2023 Volume 153, Issue 5, Page(s) 2973

Abstract: Esophageal (ES) speech, tracheoesophageal (TE) speech, and the electrolarynx (EL) are common methods of communication following the removal of the larynx. Our recent study demonstrated that intelligibility may increase for Cantonese alaryngeal speakers ... ...

Abstract	Esophageal (ES) speech, tracheoesophageal (TE) speech, and the electrolarynx (EL) are common methods of communication following the removal of the larynx. Our recent study demonstrated that intelligibility may increase for Cantonese alaryngeal speakers using clear speech (CS) compared to their everyday "habitual speech" (HS), but the reasoning is still unclear [Hui, Cox, Huang, Chen, and Ng (2022). Folia Phoniatr. Logop. 74, 103-111]. The purpose of this study was to assess the acoustic characteristics of vowels and tones produced by Cantonese alaryngeal speakers using HS and CS. Thirty-one alaryngeal speakers (9 EL, 10 ES, and 12 TE speakers) read The North Wind and the Sun passage in HS and CS. Vowel formants, vowel space area (VSA), speaking rate, pitch, and intensity were examined, and their relationship to intelligibility were evaluated. Statistical models suggest that larger VSAs significantly improved intelligibility, but slower speaking rate did not. Vowel and tonal contrasts did not differ between HS and CS for all three groups, but the amount of information encoded in fundamental frequency and intensity differences between high and low tones positively correlated with intelligibility for TE and ES groups, respectively. Continued research is needed to understand the effects of different speaking conditions toward improving acoustic and perceptual characteristics of Cantonese alaryngeal speech.
MeSH term(s)	Humans ; Speech, Alaryngeal/methods ; Speech, Esophageal ; Speech ; Larynx, Artificial ; Acoustics ; Speech Intelligibility ; Speech Acoustics
Language	English
Publishing date	2023-05-20
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural
ZDB-ID	219231-7
ISSN	1520-8524 ; 0001-4966
ISSN (online)	1520-8524
ISSN	0001-4966
DOI	10.1121/10.0019471
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Article ; Online: Assessing accuracy of resonances obtained with reassigned spectrograms from the "ground truth" of physical vocal tract models.

Shadle, Christine H / Fulop, Sean A / Chen, Wei-Rong / Whalen, D H

The Journal of the Acoustical Society of America

2023 Volume 155, Issue 2, Page(s) 1253–1263

Abstract: The reassigned spectrogram (RS) has emerged as the most accurate way to infer vocal tract resonances from the acoustic signal [Shadle, Nam, and Whalen (2016). "Comparing measurement errors for formants in synthetic and natural vowels," J. Acoust. Soc. Am. ...

Abstract	The reassigned spectrogram (RS) has emerged as the most accurate way to infer vocal tract resonances from the acoustic signal [Shadle, Nam, and Whalen (2016). "Comparing measurement errors for formants in synthetic and natural vowels," J. Acoust. Soc. Am. 139(2), 713-727]. To date, validating its accuracy has depended on formant synthesis for ground truth values of these resonances. Synthesis is easily controlled, but it has many intrinsic assumptions that do not necessarily accurately realize the acoustics in the way that physical resonances would. Here, we show that physical models of the vocal tract with derivable resonance values allow a separate approach to the ground truth, with a different range of limitations. Our three-dimensional printed vocal tract models were excited by white noise, allowing an accurate determination of the resonance frequencies. Then, sources with a range of fundamental frequencies were implemented, allowing a direct assessment of whether RS avoided the systematic bias towards the nearest strong harmonic to which other analysis techniques are prone. RS was indeed accurate at fundamental frequencies up to 300 Hz; above that, accuracy was somewhat reduced. Future directions include testing mechanical models with the dimensions of children's vocal tracts and making RS more broadly useful by automating the detection of resonances.
MeSH term(s)	Child ; Humans ; Voice ; Acoustics ; Speech Acoustics ; Vibration ; Sound Spectrography
Language	English
Publishing date	2023-12-11
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural
ZDB-ID	219231-7
ISSN	1520-8524 ; 0001-4966
ISSN (online)	1520-8524
ISSN	0001-4966
DOI	10.1121/10.0024548
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Book ; Online: Uncertainty-Driven Dense Two-View Structure from Motion

Chen, Weirong / Kumar, Suryansh / Yu, Fisher

2023

Abstract: This work introduces an effective and practical solution to the dense two-view structure from motion (SfM) problem. One vital question addressed is how to mindfully use per-pixel optical flow correspondence between two frames for accurate pose estimation ...

Abstract	This work introduces an effective and practical solution to the dense two-view structure from motion (SfM) problem. One vital question addressed is how to mindfully use per-pixel optical flow correspondence between two frames for accurate pose estimation -- as perfect per-pixel correspondence between two images is difficult, if not impossible, to establish. With the carefully estimated camera pose and predicted per-pixel optical flow correspondences, a dense depth of the scene is computed. Later, an iterative refinement procedure is introduced to further improve optical flow matching confidence, camera pose, and depth, exploiting their inherent dependency in rigid SfM. The fundamental idea presented is to benefit from per-pixel uncertainty in the optical flow estimation and provide robustness to the dense SfM system via an online refinement. Concretely, we introduce our uncertainty-driven Dense Two-View SfM pipeline (DTV-SfM), consisting of an uncertainty-aware dense optical flow estimation approach that provides per-pixel correspondence with their confidence score of matching; a weighted dense bundle adjustment formulation that depends on optical flow uncertainty and bidirectional optical flow consistency to refine both pose and depth; a depth estimation network that considers its consistency with the estimated poses and optical flow respecting epipolar constraint. Extensive experiments show that the proposed approach achieves remarkable depth accuracy and state-of-the-art camera pose results superseding SuperPoint and SuperGlue accuracy when tested on benchmark datasets such as DeMoN, YFCC100M, and ScanNet. Code and more materials are available at http://vis.xyz/pub/dtv-sfm. Comment: Accepted for publication at IEEE Robotics and Automation Letters (RA-L) 2023
Keywords	Computer Science - Computer Vision and Pattern Recognition ; Computer Science - Robotics
Subject code	004
Publishing date	2023-02-01
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Leveraging Neural Radiance Fields for Uncertainty-Aware Visual Localization

Chen, Le / Chen, Weirong / Wang, Rui / Pollefeys, Marc

2023

Abstract: As a promising fashion for visual localization, scene coordinate regression (SCR) has seen tremendous progress in the past decade. Most recent methods usually adopt neural networks to learn the mapping from image pixels to 3D scene coordinates, which ... ...

Abstract	As a promising fashion for visual localization, scene coordinate regression (SCR) has seen tremendous progress in the past decade. Most recent methods usually adopt neural networks to learn the mapping from image pixels to 3D scene coordinates, which requires a vast amount of annotated training data. We propose to leverage Neural Radiance Fields (NeRF) to generate training samples for SCR. Despite NeRF's efficiency in rendering, many of the rendered data are polluted by artifacts or only contain minimal information gain, which can hinder the regression accuracy or bring unnecessary computational costs with redundant data. These challenges are addressed in three folds in this paper: (1) A NeRF is designed to separately predict uncertainties for the rendered color and depth images, which reveal data reliability at the pixel level. (2) SCR is formulated as deep evidential learning with epistemic uncertainty, which is used to evaluate information gain and scene coordinate quality. (3) Based on the three arts of uncertainties, a novel view selection policy is formed that significantly improves data efficiency. Experiments on public datasets demonstrate that our method could select the samples that bring the most information gain and promote the performance with the highest efficiency. Comment: 8 pages, 5 figures
Keywords	Computer Science - Computer Vision and Pattern Recognition ; Computer Science - Robotics
Subject code	006
Publishing date	2023-10-10
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Spatially Conditioned Speech Timing: Evidence and Implications.

Shaw, Jason A / Chen, Wei-Rong

Frontiers in psychology

2019 Volume 10, Page(s) 2726

Abstract: Patterns of relative timing between consonants and vowels appear to be conditioned in part by phonological structure, such as syllables, a finding captured naturally by the two-level feedforward model of Articulatory Phonology (AP). In AP, phonological ... ...

Abstract	Patterns of relative timing between consonants and vowels appear to be conditioned in part by phonological structure, such as syllables, a finding captured naturally by the two-level feedforward model of Articulatory Phonology (AP). In AP, phonological form - gestures and the coordination relations between them - receive an invariant description at the inter-gestural level. The inter-articulator level actuates gestures, receiving activation from the inter-gestural level and resolving competing demands on articulators. Within this architecture, the inter-gestural level is blind to the location of articulators in space. A key prediction is that intergestural timing is stable across variation in the spatial position of articulators. We tested this prediction by conducting an Electromagnetic Articulography (EMA) study of Mandarin speakers producing CV monosyllables, consisting of labial consonants and back vowels in isolation. Across observed variation in the spatial position of the tongue body before each syllable, we investigated whether inter-gestural timing between the lips, for the consonant, and the tongue body, for the vowel, remained stable, as is predicted by feedforward control, or whether timing varied with the spatial position of the tongue at the onset of movement. Results indicated a correlation between the initial position of the tongue gesture for the vowel and C-V timing, indicating that inter-gestural timing is sensitive to the position of the articulators, possibly relying on somatosensory feedback. Implications of these results and possible accounts within the Articulatory Phonology framework are discussed.
Language	English
Publishing date	2019-12-05
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2563826-9
ISSN	1664-1078
ISSN	1664-1078
DOI	10.3389/fpsyg.2019.02726
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Article ; Online: Formants are easy to measure; resonances, not so much: Lessons from Klatt (1986).

Whalen, D H / Chen, Wei-Rong / Shadle, Christine H / Fulop, Sean A

The Journal of the Acoustical Society of America

2022 Volume 152, Issue 2, Page(s) 933

Abstract: Formants in speech signals are easily identified, largely because formants are defined to be local maxima in the wideband sound spectrum. Sadly, this is not what is of most interest in analyzing speech; instead, resonances of the vocal tract are of ... ...

Abstract	Formants in speech signals are easily identified, largely because formants are defined to be local maxima in the wideband sound spectrum. Sadly, this is not what is of most interest in analyzing speech; instead, resonances of the vocal tract are of interest, and they are much harder to measure. Klatt [(1986). in Proceedings of the Montreal Satellite Symposium on Speech Recognition, 12th International Congress on Acoustics, edited by P. Mermelstein (Canadian Acoustical Society, Montreal), pp. 5-7] showed that estimates of resonances are biased by harmonics while the human ear is not. Several analysis techniques placed the formant closer to a strong harmonic than to the center of the resonance. This "harmonic attraction" can persist with newer algorithms and in hand measurements, and systematic errors can persist even in large corpora. Research has shown that the reassigned spectrogram is less subject to these errors than linear predictive coding and similar measures, but it has not been satisfactorily automated, making its wider use unrealistic. Pending better techniques, the recommendations are (1) acknowledge limitations of current analyses regarding influence of F0 and limits on granularity, (2) report settings more fully, (3) justify settings chosen, and (4) examine the pattern of F0 vs F1 for possible harmonic bias.
MeSH term(s)	Acoustics ; Algorithms ; Canada ; Humans ; Language ; Speech Acoustics
Language	English
Publishing date	2022-08-17
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural
ZDB-ID	219231-7
ISSN	1520-8524 ; 0001-4966
ISSN (online)	1520-8524
ISSN	0001-4966
DOI	10.1121/10.0013410
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