scholarly journals Integration and Application of Multimodal Measurement Techniques: Relevance of Photogrammetry to Orthodontics

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8026
Author(s):  
Dariusz Pojda ◽  
Agnieszka Anna Tomaka ◽  
Leszek Luchowski ◽  
Michał Tarnawski
Keyword(s):  
Imaging Modality ◽  
Measurement Techniques ◽  
Laser Scanner ◽  
3D Scanner ◽  
Video Footage ◽  
Video Recordings ◽  
Lighting Conditions ◽  
Laser Scanners ◽  
2D Imaging ◽  
The Impact

Multimodal imaging, including 3D modalities, is increasingly being applied in orthodontics, both as a diagnostic tool and especially for the design of intraoral appliances, where geometric accuracy is very important. Laser scanners and other precision 3D-imaging devices are expensive and cumbersome, which limits their use in medical practice. Photogrammetry, using ordinary 2D photographs or video recordings to create 3D imagery, offers a cheaper and more convenient alternative, replacing the specialised equipment with handy consumer cameras. The present study addresses the question of to what extent, and under what conditions, this technique can be an adequate replacement for the 3D scanner. The accuracy of simple surface reconstruction and of model embedding achieved with photogrammetry was verified against that obtained with a triangulating laser scanner. To roughly evaluate the impact of image imperfections on photogrammetric reconstruction, the photographs for photogrammetry were taken under various lighting conditions and were used either raw or with a blur-simulating defocus. Video footage was also tested as another 2D-imaging modality feeding data into photogrammetry. The results show the significant potential of photogrammetric techniques.

scholarly journals UNCERTAINTY PROPAGATION FOR TERRESTRIAL MOBILE LASER SCANNER

2016 ◽  
Vol XLI-B3 ◽  
pp. 331-335 ◽  
Author(s):  
c Mezian ◽  
Bruno Vallet ◽  
Bahman Soheilian ◽  
Nicolas Paparoditis
Keyword(s):  
Uncertainty Analysis ◽  
Covariance Matrix ◽  
Uncertainty Propagation ◽  
Laser Scanner ◽  
Point Clouds ◽  
3D Point Clouds ◽  
Laser Scanners ◽  
Propagation Technique ◽  
The Impact

Laser scanners are used more and more in mobile mapping systems. They provide 3D point clouds that are used for object reconstruction and registration of the system. For both of those applications, uncertainty analysis of 3D points is of great interest but rarely investigated in the literature. In this paper we present a complete pipeline that takes into account all the sources of uncertainties and allows to compute a covariance matrix per 3D point. The sources of uncertainties are laser scanner, calibration of the scanner in relation to the vehicle and direct georeferencing system. We suppose that all the uncertainties follow the Gaussian law. The variances of the laser scanner measurements (two angles and one distance) are usually evaluated by the constructors. This is also the case for integrated direct georeferencing devices. Residuals of the calibration process were used to estimate the covariance matrix of the 6D transformation between scanner laser and the vehicle system. Knowing the variances of all sources of uncertainties, we applied uncertainty propagation technique to compute the variance-covariance matrix of every obtained 3D point. Such an uncertainty analysis enables to estimate the impact of different laser scanners and georeferencing devices on the quality of obtained 3D points. The obtained uncertainty values were illustrated using error ellipsoids on different datasets.

scholarly journals APPROACHES FOR MAPPING NIGHT-TIME ROAD ENVIRONMENT LIGHTING CONDITIONS

2020 ◽  
Vol V-1-2020 ◽  
pp. 199-205
Author(s):  
M.T. Vaaja ◽  
M. Maksimainen ◽  
M. Kurkela ◽  
J.-P. Virtanen ◽  
T. Rantanen ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Measurement Techniques ◽  
Point Clouds ◽  
Future Research ◽  
3D Measurement ◽  
Night Time ◽  
Road Lighting ◽  
Lighting Conditions ◽  
Potential Applications ◽  
2D Imaging

Abstract. The integration of the 3D measurement techniques with luminance imaging has increased the potential for mapping night-time road lighting conditions. In this study, we present selected static and mobile approaches for the purpose. The measurement methods include conventional 2D imaging luminance photometry and the integration of the luminance imaging with terrestrial and mobile laser scanning. In addition, we present our initial experiences with performing integrated luminance mapping and photogrammetric reconstruction from drone imagery. All of the presented methods require that the camera is calibrated with a reference luminance source. Our results show the results of luminance calibration and feasibility of 3D luminance point clouds for evaluating road surface luminances. In addition, we discuss the other potential applications, limitations and future research.

scholarly journals UNCERTAINTY PROPAGATION FOR TERRESTRIAL MOBILE LASER SCANNER

2016 ◽  
Vol XLI-B3 ◽  
pp. 331-335 ◽  
Author(s):  
c Mezian ◽  
Bruno Vallet ◽  
Bahman Soheilian ◽  
Nicolas Paparoditis
Keyword(s):  
Uncertainty Analysis ◽  
Covariance Matrix ◽  
Uncertainty Propagation ◽  
Laser Scanner ◽  
Point Clouds ◽  
3D Point Clouds ◽  
Laser Scanners ◽  
Propagation Technique ◽  
The Impact

Laser scanners are used more and more in mobile mapping systems. They provide 3D point clouds that are used for object reconstruction and registration of the system. For both of those applications, uncertainty analysis of 3D points is of great interest but rarely investigated in the literature. In this paper we present a complete pipeline that takes into account all the sources of uncertainties and allows to compute a covariance matrix per 3D point. The sources of uncertainties are laser scanner, calibration of the scanner in relation to the vehicle and direct georeferencing system. We suppose that all the uncertainties follow the Gaussian law. The variances of the laser scanner measurements (two angles and one distance) are usually evaluated by the constructors. This is also the case for integrated direct georeferencing devices. Residuals of the calibration process were used to estimate the covariance matrix of the 6D transformation between scanner laser and the vehicle system. Knowing the variances of all sources of uncertainties, we applied uncertainty propagation technique to compute the variance-covariance matrix of every obtained 3D point. Such an uncertainty analysis enables to estimate the impact of different laser scanners and georeferencing devices on the quality of obtained 3D points. The obtained uncertainty values were illustrated using error ellipsoids on different datasets.

Handheld Laser Scanner Research

2019 ◽  
Vol 952 (10) ◽  
pp. 47-54
Author(s):  
A.V. Komissarov ◽  
A.V. Remizov ◽  
M.M. Shlyakhova ◽  
K.K. Yambaev
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Test Site ◽  
Optical Systems ◽  
Advantages And Disadvantages ◽  
Site Survey ◽  
Laser Scanners ◽  
Three Dimensional Models ◽  
The Stability

The authors consider hand-held laser scanners, as a new photogrammetric tool for obtaining three-dimensional models of objects. The principle of their work and the newest optical systems based on various sensors measuring the depth of space are described in detail. The method of simultaneous navigation and mapping (SLAM) used for combining single scans into point cloud is outlined. The formulated tasks and methods for performing studies of the DotProduct (USA) hand-held laser scanner DPI?8X based on a test site survey are presented. The accuracy requirements for determining the coordinates of polygon points are given. The essence of the performed experimental research of the DPI?8X scanner is described, including scanning of a test object at various scanner distances, shooting a test polygon from various scanner positions and building point cloud, repeatedly shooting the same area of the polygon to check the stability of the scanner. The data on the assessment of accuracy and analysis of research results are given. Fields of applying hand-held laser scanners, their advantages and disadvantages are identified.

scholarly journals Effect of temperature, CO2 and O2 on motility and mobility of Anisakidae larvae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël
Keyword(s):  
Enzymatic Digestion ◽  
Infected Fish ◽  
Effect Of Temperature ◽  
Video Recordings ◽  
Different Temperatures ◽  
Semi Solid ◽  
Zoonotic Parasites ◽  
The Impact ◽  
Phosphate Buffered Saline

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.

scholarly journals Ovarian Dysgerminoma in Pregnant Women with Viable Fetus: A Rare Case Report

2021 ◽  
pp. 141-146
Author(s):  
Reda Youssef ◽  
Gamal Sayed Ahmed ◽  
Samir Alhyassat ◽  
Sanaa Badr ◽  
Ahmed Sabry ◽  
...  
Keyword(s):  
Gestational Age ◽  
Ovarian Neoplasms ◽  
Imaging Modality ◽  
Reproductive Age ◽  
Diagnostic Challenge ◽  
Short Period ◽  
Ovarian Dysgerminoma ◽  
The Impact ◽  
In Pregnancy

Dysgerminoma is an uncommon malignant tumor arising from the germ cells of the ovary. Its association with pregnancy is extremely rare, with a reported incidence of about 0.2–1 per 100,000 pregnancies. Women in the reproductive age group are more commonly affected. It can be extremely rare to conceive naturally, without assisted reproductive interventions, in cases with ovarian dysgerminoma. If a pregnancy does occur with a concurrent dysgerminoma, it is even more unusual to carry the pregnancy to viability or childbirth without fetal or maternal compromise. We report a case of right ovarian dysgerminoma in a young female with a viable intrauterine pregnancy at 10 weeks, which is rarely diagnosed and managed at this gestational age. Numerous factors played a role in her favorable outcome, including early suspicion by ultrasound and presenting history, surgery, histopathological assessment, imaging, and involvement of the multidisciplinary oncology team. Ovarian neoplasms may rapidly increase in size within a short period with little or no symptoms. This poses a diagnostic challenge for obstetricians and oncologists. Hence, we aimed to evaluate the role of imaging in pregnancy using ultrasound as an imaging modality for both early detection of ovarian neoplasms and for follow-up. In conclusion, patients with ovarian dysgerminoma in pregnancy can have favorable outcomes. Treatment should be individualized on a case-to-case basis, depending on many factors; cancer stage, previous reproductive history, the impact of imaging in staging or follow-up of tumor on the fetus, fetal gestational age, and whether termination of the pregnancy can improve survival or morbidity for the mother.

scholarly journals LiDAR-Based Glass Detection for Improved Occupancy Grid Mapping

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2263
Author(s):  
Haileleol Tibebu ◽  
Jamie Roche ◽  
Varuna De Silva ◽  
Ahmet Kondoz
Keyword(s):  
Laser Scanner ◽  
Point Clouds ◽  
Light Detection And Ranging ◽  
Test Results ◽  
New Approach ◽  
Occupancy Grid ◽  
Laser Scanners ◽  
Novel Method ◽  
Occupancy Grid Mapping ◽  
Cartesian Coordinate

Creating an accurate awareness of the environment using laser scanners is a major challenge in robotics and auto industries. LiDAR (light detection and ranging) is a powerful laser scanner that provides a detailed map of the environment. However, efficient and accurate mapping of the environment is yet to be obtained, as most modern environments contain glass, which is invisible to LiDAR. In this paper, a method to effectively detect and localise glass using LiDAR sensors is proposed. This new approach is based on the variation of range measurements between neighbouring point clouds, using a two-step filter. The first filter examines the change in the standard deviation of neighbouring clouds. The second filter uses a change in distance and intensity between neighbouring pules to refine the results from the first filter and estimate the glass profile width before updating the cartesian coordinate and range measurement by the instrument. Test results demonstrate the detection and localisation of glass and the elimination of errors caused by glass in occupancy grid maps. This novel method detects frameless glass from a long range and does not depend on intensity peak with an accuracy of 96.2%.

Speech Methodologies in Cleft Palate Assessment: A Pilot Project to Compare Two Phonetically Different Sentence Sets

2013 ◽  
Vol 20 (1) ◽  
pp. 49-72
Author(s):  
Jennie Smith ◽  
Tim Pring ◽  
Debbie Sell
Keyword(s):  
Cleft Palate ◽  
Pilot Project ◽  
Wilcoxon Test ◽  
Consecutive Series ◽  
Video Recordings ◽  
Significant Difference ◽  
The Difference ◽  
Audio Video ◽  
Age Range ◽  
The Impact

Objective: To investigate the impact of the phonetic content of two sentence sets on speech outcomes, specifically the effects of nasal phonemes. Method: Audio-video recordings of a consecutive series of 15 participants (age range 4–22 years), with cleft palate (syndromic or non-syndromic), with and without velopharyngeal dysfunction were taken. Participants repeated Sentence Set 1 (with nasals across sentences) and Sentence Set 2 (without nasals except the three nasal target sentences) during a routine speech recording. Two experienced Specialist Speech and Language Therapists, blinded to the study’s purpose, analyzed participants’ speech using the Cleft Audit Protocol for Speech-Augmented (CAPS-A). On day 1, recordings included Sentence Set 1. On day 2, 23 days later, recordings included Sentence Set 2. Main results: The difference between Sentence Set 1 and Sentence Set 2 ‘total scores’ (sum of scores on all CAPS-A parameters) was significant. The Pearson Product Moment showed high correlation. A Wilcoxon test revealed a significant difference between Sets 1 and 2 on the hypernasality parameter, and this alone accounted for the significant difference in total scores. Conclusion: The inclusion or exclusion of nasal consonants in the sentence set significantly affected perceptual ratings of hypernasality but none of the other CAPS-A parameters, highlighting the need for further investigation into perceptual nasality ratings.

scholarly journals Pallidal stimulation as treatment for camptocormia in Parkinson’s disease

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yijie Lai ◽  
Yunhai Song ◽  
Daoqing Su ◽  
Linbin Wang ◽  
Chencheng Zhang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Case Reports ◽  
Structural Connectivity ◽  
Video Recordings ◽  
Lead Placement ◽  
Pallidal Stimulation ◽  
The Impact ◽  
Deep Brain

AbstractCamptocormia is a common and often debilitating postural deformity in Parkinson’s disease (PD). Few treatments are currently effective. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) shows potential in treating camptocormia, but evidence remains limited to case reports. We herein investigate the effect of GPi-DBS for treating camptocormia in a retrospective PD cohort. Thirty-six consecutive PD patients who underwent GPi-DBS were reviewed. The total and upper camptocormia angles (TCC and UCC angles) derived from video recordings of patients who received GPi-DBS were used to compare camptocormia alterations. Correlation analysis was performed to identify factors associated with the postoperative improvements. DBS lead placement and the impact of stimulation were analyzed using Lead-DBS software. Eleven patients manifested pre-surgical camptocormia: seven had lower camptocormia (TCC angles ≥ 30°; TCC-camptocormia), three had upper camptocormia (UCC angles ≥ 45°; UCC-camptocormia), and one had both. Mean follow-up time was 7.3 ± 3.3 months. GPi-DBS improved TCC-camptocormia by 40.4% (angles from 39.1° ± 10.1° to 23.3° ± 8.1°, p = 0.017) and UCC-camptocormia by 22.8% (angles from 50.5° ± 2.6° to 39.0° ± 6.7°, p = 0.012). Improvement in TCC angle was positively associated with pre-surgical TCC angles, levodopa responsiveness of the TCC angle, and structural connectivity from volume of tissue activated to somatosensory cortex. Greater improvement in UCC angles was seen in patients with larger pre-surgical UCC angles. Our study demonstrates potential effectiveness of GPi-DBS for treating camptocormia in PD patients. Future controlled studies with larger numbers of patients with PD-related camptocormia should extend our findings.

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