Accuracy of an automated method of 3D soft tissue landmark detection

2020 ◽  
Author(s):  
Sanjana Baksi ◽  
Simon Freezer ◽  
Takeshi Matsumoto ◽  
Craig Dreyer
Keyword(s):  
Soft Tissue ◽  
Three Dimensional ◽  
Reference Plane ◽  
Identification Algorithm ◽  
Anatomical Landmarks ◽  
Automated Identification ◽  
Automated Method ◽  
Landmark Identification ◽  
Technological Advances ◽  
Third Dimension

Summary Introduction Due to technological advances, the quantification of facial form can now be done via three-dimensional (3D) photographic systems such as stereophotogrammetry. To enable comparison with traditional cephalometry, soft-tissue anatomical landmark definitions have been modified to incorporate the third dimension. Annotating these landmarks manually, however, is still a time-consuming and arduous process. Objective To develop an automated algorithm to accurately identify anatomical landmarks on three-dimensional soft tissue images. Methods Thirty 3dMD images were selected from a private orthodontic practice consisting of 15 males and 15 females between 9 and 17 years of age. The soft-tissue 3D images were aligned along a reference plane to setup a Cartesian coordinate system. Screened by 2 observers, 21 landmarks were manually annotated and their coordinates defined. An automated landmark identification algorithm, based on their anatomical definitions, was developed to compare the landmark validity against the manually identified counterpart. Results Twenty-one landmarks were analysed in detail. Inter-observer and intra-observer reliability using ICC was >0.9. The average difference and standard deviation between manual and automated methods for all landmarks was 3.2 and 1.64 mm, respectively. Sixteen out of twenty-one landmarks had a mean difference less than 4 mm. The landmarks of greatest agreement (≤2 mm) were mainly in the midline: pronasale, subnasale, subspinale, labiale superius, stomion, with the exception of chelion right. Five linear facial measurements were found to have moderate to good agreement between the manual and automated identification methods. Conclusions The developed algorithm was determined to be clinically relevant in the detection of midsagittal landmarks and associated measurements within the studied sample of adolescent Caucasian subjects.

scholarly journals Reproducibility and reliability of three-dimensional soft tissue landmark identification using three-dimensional stereophotogrammetry

2016 ◽  
Vol 86 (6) ◽  
pp. 1004-1009 ◽  
Author(s):  
Asli Baysal ◽  
Ahmet Oguz Sahan ◽  
Mehmet Ali Ozturk ◽  
Tancan Uysal
Keyword(s):  
Soft Tissue ◽  
Statistical Significance ◽  
Intraclass Correlation ◽  
Three Dimensional ◽  
Correlation Coefficients ◽  
Intraclass Correlation Coefficients ◽  
Paired Samples ◽  
Landmark Identification ◽  
The Difference ◽  
Intraexaminer Reliability

ABSTRACT Objective: To evaluate the intraexaminer repeatability and interexaminer reproducibility of soft tissue landmarks on three-dimensional (3-D) stereophogrammetric images. Materials and Methods: Thirty-four stereophotogrammetric images were taken and 19 soft tissue points were identified. The images were obtained using the 3-DMD Face (3-DMD TM Ltd, Atlanta, Ga) system. Two examiners marked 34 images manually with a mouse-driven cursor 4 weeks apart. Intraexaminer marking differences were calculated and classified as <0.5 mm, 0.5–1 mm, and >1 mm. Intraclass correlation coefficients were calculated for intraexaminer reliability. A paired-samples t-test was used to evaluate the difference between the examiners. Interexaminer reproducibility was evaluated by kappa analysis. Statistical significance was set at P < .05. Results: Only one landmark (labiale superior) had an intraexaminer marking difference less than 0.5 mm. Existing landmarks had an intraexaminer difference less than 1 mm, but higher than 0.5 mm. The intraclass correlation coefficients (ICCs) indicated good intraexaminer repeatability for both observers. The ICC range for examiners 1 and 2 was 0.986–1.000 and 0.990–1.000, respectively. Kappa scores showed good interexaminer agreement, especially on the z-axis. Conclusions: Except labiale superior, the soft tissue landmarks used in this study were shown to have moderate reproducibility, but the difference between the landmarks was less than 1 mm, and they had clinically acceptable reproducibility.

scholarly journals Assessment of interobserver reliability in localization of hard and soft tissue landmarks and three-dimensional measurements of the upper airway based on these landmarks using CBCT images

2021 ◽  
Vol 7 (2) ◽  
pp. 54-60
Author(s):  
Jangam Daya K ◽  
Talreja Kajol M ◽  
Garcha Vikram ◽  
Patil Abhijeet V ◽  
Swatantramath Sunaina M ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Internal Consistency ◽  
Interobserver Reliability ◽  
Three Dimensional ◽  
Upper Airway ◽  
Anatomical Landmarks ◽  
Cross Sectional ◽  
Full Field ◽  
Excellent Internal Consistency ◽  
Dimensional Measurements

: To assess reliability in localization of hard and soft tissue landmarks of the upper airway and three-dimensional measurements of the upper airway based on these landmarks using CBCT images. : 22 full field of view (FOV) CBCT scan volumes were selected randomly and retrospectively made at the CBCT unit of Department of Oral Medicine and Radiology. Six anatomic landmarks that are relevant for upper airway analysiswere located and subsequently three-dimensional measurements (volume, minimum cross-sectional area (CSA), location of the CSA, anteroposterior and lateral dimensions of the CSA) in all planes (coronal, sagittal, axial) were performed based on these land marks by two observers, using Romexis software (4.2.0 R 10/13/15). : Correlation analysis by Cronbach’s Alpha.: Interobserver reliability of the landmark localization was excellent (Internal consistency 0.97-0.99) and for the three-dimensional upper airway measurements were good (Internal consistency 0.62-0.99).: The interobserver reliability of anatomical landmarks localization and three-dimensional measurements of the upper airway are good to excellent using Romexis software. Therefore, this methodology can be recommended for the upper airway analysis using CBCT images.

scholarly journals A novel method for 3D face symmetry reference plane based on weighted Procrustes analysis algorithm

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Yujia Zhu ◽  
Shengwen Zheng ◽  
Guosheng Yang ◽  
Xiangling Fu ◽  
Ning Xiao ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Facial Asymmetry ◽  
Ground Truth ◽  
Asymmetry Index ◽  
Position Error ◽  
Procrustes Analysis ◽  
Reference Plane ◽  
Anatomical Landmarks ◽  
Angle Error ◽  
Novel Method

Abstract Background We aimed to establish a novel method, using the weighted Procrustes analysis (WPA) algorithm, which assigns weight to facial anatomical landmarks, to construct a three-dimensional facial symmetry reference plane (SRP) for mandibular deviation patients. Methods Three-dimensional facial SRPs were independently extracted from 15 mandibular deviation patients using both our WPA algorithm and the standard PA algorithm. A reference plane was defined to serve as the ground truth. To determine whether the WPA SRP or the PA SRP was closer to the ground truth, we measured the position error of mirrored landmarks, the facial asymmetry index (FAI) error, and the angle error for the global face and each facial third partition. Results The average angle error between the WPA SRP and the ground truth was 1.66 ± 0.81°, which was smaller than that between the PA SRP and the ground truth. The position error of the mirrored landmarks constructed using the WPA algorithm in the global face (3.64 ± 1.53 mm) and each facial partition was lower than that constructed using the PA algorithm. The average FAI error of the WPA SRP was − 7.77 ± 17.02 mm, which was smaller than that of the PA SRP. Conclusions This novel automatic algorithm, based on weighted anatomic landmarks, can provide a more adaptable SRP than the standard PA algorithm when applied to severe mandibular deviation patients and can better simulate the diagnosis strategies of clinical experts.

scholarly journals A novel method for 3D face symmetry reference plane based on Weighted Procrustes Analysis algorithm

2020 ◽  
Author(s):  
Zhu Yujia ◽  
Shengwen Zheng ◽  
Guosheng Yang ◽  
Xiangling Fu ◽  
Yijiao Zhao ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Facial Asymmetry ◽  
Ground Truth ◽  
Asymmetry Index ◽  
Position Error ◽  
Procrustes Analysis ◽  
Reference Plane ◽  
Anatomical Landmarks ◽  
Angle Error ◽  
Novel Method

Abstract Background We aimed to establish a novel method based on Weighted Procrustes Analysis (WPA) algorithm that assigns weight to facial anatomical landmarks to automatically construct a three-dimensional facial Symmetry Reference Plane (SRP) for mandibular deviation patients. Methods Three-dimensional facial SRPs were extracted independently from 15 mandibular deviation patients, using both our WPA algorithm and the standard PA algorithm. A reference plane defined from professional experience served as the ground truth. To test whether the WPA SRP or the PA SRP was closer to the ground truth, we measured the position error of mirrored landmarks, the facial asymmetry index (FAI) error, and the angle error for the global face and for each facial third partitions. Results The average angle error between the WPA SRP and the ground truth was 1.66 ± 0.81°, which was smaller than that between the PA SRP and the ground truth. The position error of mirrored landmarks constructed using the WPA algorithm in the global face (3.64 ± 1.53 mm) and each facial partition was lower than the error of those constructed using the PA algorithm. The average FAI error of the WPA SRP was − 7.77 ± 17.02 mm, which was smaller than that of the PA SRP. Conclusions This novel automatic algorithm based on weighted anatomic landmarks provided a more adaptable SRP than the standard PA algorithm when applied to severe mandibular deviation patients and better simulated the diagnosis strategy of clinical experts.

scholarly journals A novel method for 3D face symmetry reference plane based on weighted Procrustes analysis algorithm

2020 ◽  
Author(s):  
Yujia Zhu ◽  
Shengwen Zheng ◽  
Guosheng Yang ◽  
Xiangling Fu ◽  
Ning Xiao ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Facial Asymmetry ◽  
Ground Truth ◽  
Asymmetry Index ◽  
Position Error ◽  
Procrustes Analysis ◽  
Reference Plane ◽  
Anatomical Landmarks ◽  
Angle Error ◽  
Novel Method

Abstract Background: We aimed to establish a novel method, using the weighted Procrustes analysis (WPA) algorithm, which assigns weight to facial anatomical landmarks, to construct a three-dimensional facial symmetry reference plane (SRP) for mandibular deviation patients.Methods: Three-dimensional facial SRPs were independently extracted from 15 mandibular deviation patients using both our WPA algorithm and the standard PA algorithm. A reference plane was defined to serve as the ground truth. To determine whether the WPA SRP or the PA SRP was closer to the ground truth, we measured the position error of mirrored landmarks, the facial asymmetry index (FAI) error, and the angle error for the global face and each facial third partition.Results: The average angle error between the WPA SRP and the ground truth was 1.66 ± 0.81°, which was smaller than that between the PA SRP and the ground truth. The position error of the mirrored landmarks constructed using the WPA algorithm in the global face (3.64 ± 1.53 mm) and each facial partition was lower than that constructed using the PA algorithm. The average FAI error of the WPA SRP was -7.77 ± 17.02 mm, which was smaller than that of the PA SRP.Conclusions: This novel automatic algorithm, based on weighted anatomic landmarks, can provide a more adaptable SRP than the standard PA algorithm when applied to severe mandibular deviation patients and can better simulate the diagnosis strategies of clinical experts.

scholarly journals Automated Motion Analysis of Bony Joint Structures from Dynamic Computer Tomography Images: A Multi-Atlas Approach

Diagnostics ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2062
Author(s):  
Benyameen Keelson ◽  
Luca Buzzatti ◽  
Jakub Ceranka ◽  
Adrián Gutiérrez ◽  
Simone Battista ◽  
...  
Keyword(s):  
Motion Estimation ◽  
Computer Tomography ◽  
Reference Frames ◽  
Intraclass Correlation ◽  
Ct Images ◽  
Joint Kinematics ◽  
Anatomical Landmarks ◽  
Automated Method ◽  
Landmark Identification

Dynamic computer tomography (CT) is an emerging modality to analyze in-vivo joint kinematics at the bone level, but it requires manual bone segmentation and, in some instances, landmark identification. The objective of this study is to present an automated workflow for the assessment of three-dimensional in vivo joint kinematics from dynamic musculoskeletal CT images. The proposed method relies on a multi-atlas, multi-label segmentation and landmark propagation framework to extract bony structures and detect anatomical landmarks on the CT dataset. The segmented structures serve as regions of interest for the subsequent motion estimation across the dynamic sequence. The landmarks are propagated across the dynamic sequence for the construction of bone embedded reference frames from which kinematic parameters are estimated. We applied our workflow on dynamic CT images obtained from 15 healthy subjects on two different joints: thumb base (n = 5) and knee (n = 10). The proposed method resulted in segmentation accuracies of 0.90 ± 0.01 for the thumb dataset and 0.94 ± 0.02 for the knee as measured by the Dice score coefficient. In terms of motion estimation, mean differences in cardan angles between the automated algorithm and manual segmentation, and landmark identification performed by an expert were below 1°. Intraclass correlation (ICC) between cardan angles from the algorithm and results from expert manual landmarks ranged from 0.72 to 0.99 for all joints across all axes. The proposed automated method resulted in reproducible and reliable measurements, enabling the assessment of joint kinematics using 4DCT in clinical routine.

scholarly journals A novel method for 3D face symmetry reference plane based on weighted Procrustes analysis algorithm

2020 ◽  
Author(s):  
Yujia Zhu ◽  
Shengwen Zheng ◽  
Guosheng Yang ◽  
Xiangling Fu ◽  
Yijiao Zhao ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Facial Asymmetry ◽  
Ground Truth ◽  
Asymmetry Index ◽  
Position Error ◽  
Procrustes Analysis ◽  
Reference Plane ◽  
Anatomical Landmarks ◽  
Angle Error ◽  
Novel Method

Abstract Background: We aimed to establish a novel method, using the weighted Procrustes analysis (WPA) algorithm, which assigns weight to facial anatomical landmarks, to construct a three-dimensional facial symmetry reference plane (SRP) for mandibular deviation patients.Methods: Three-dimensional facial SRPs were independently extracted from 15 mandibular deviation patients using both our WPA algorithm and the standard PA algorithm. A reference plane was defined to serve as the ground truth. To determine whether the WPA SRP or the PA SRP was closer to the ground truth, we measured the position error of mirrored landmarks, the facial asymmetry index (FAI) error, and the angle error for the global face and each facial third partition.Results: The average angle error between the WPA SRP and the ground truth was 1.66 ± 0.81°, which was smaller than that between the PA SRP and the ground truth. The position error of the mirrored landmarks constructed using the WPA algorithm in the global face (3.64 ± 1.53 mm) and each facial partition was lower than that constructed using the PA algorithm. The average FAI error of the WPA SRP was -7.77 ± 17.02 mm, which was smaller than that of the PA SRP.Conclusions: This novel automatic algorithm, based on weighted anatomic landmarks, can provide a more adaptable SRP than the standard PA algorithm when applied to severe mandibular deviation patients and can better simulate the diagnosis strategies of clinical experts.

Procedural Modeling in 3D GIS Environment

2014 ◽  
Vol 3 (3) ◽  
pp. 17-34 ◽  
Author(s):  
Eva Tsiliakou ◽  
Tassos Labropoulos ◽  
Efi Dimopoulou
Keyword(s):  
3D Modeling ◽  
3D Visualization ◽  
Good Practice ◽  
Three Dimensional ◽  
3D Models ◽  
Three Dimensional Model ◽  
Rapid Urbanization ◽  
Procedural Modeling ◽  
Technological Advances ◽  
Third Dimension

3D space registration and visualization has become an imperative need in order to optimally reflect all complex cases of rapid urbanization of property rights and restrictions. Besides, current technological advances as well as the availability of sophisticated software packages (proprietary or open source) call for 3D modeling especially in the GIS domain. Within this context, GIS community's present demands concerning the third dimension are discussed, while a variety of 3D modeling techniques is presented, with special emphasis on procedural modeling. Procedural modeling refers to a variety of techniques for the algorithmic generation of detailed 3D models and composite facade textures from sets of rules which are called grammars. In this paper procedural modeling is employed via CityEngine software focusing on the 3D visualization of the National Technical University of Athens (NTUA) campus' three-dimensional model, rendering a higher detail on the School of Rural and Surveying Engineering (SRSE). This algorithmic modeling concept is based on the principle that all real world buildings are defined by rules, since repetitive patterns and hierarchical components describe their geometry. The detailed geometries of the model derived from the application of CGA (Computer Generated Architecture) shape grammars on selected footprints, and the process resulted in a final 3D model, optimally describing the built environment and proved to be a good practice example of 3D visualization.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

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