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 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.

scholarly journals Accuracy of joint line restoration based on three-dimensional registration of the contralateral tibial tuberosity and the fibular tip

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sandro Hodel ◽  
Anna-Katharina Calek ◽  
Philipp Fürnstahl ◽  
Sandro F. Fucentese ◽  
Lazaros Vlachopoulos
Keyword(s):  
Three Dimensional ◽  
Joint Line ◽  
Surface Registration ◽  
Tibial Tuberosity ◽  
Anatomical Landmarks ◽  
3D Registration ◽  
Level Of Evidence ◽  
Computed Tomographic ◽  
Contralateral Tibia ◽  
Novel Method

Abstract Purpose To assess a novel method of three-dimensional (3D) joint line (JL) restoration based on the contralateral tibia and fibula. Methods 3D triangular surface models were generated from computed tomographic data of 96 paired lower legs (48 cadavers) without signs of pathology. Three segments of the tibia and fibula, excluding the tibia plateau, were defined (tibia, fibula, tibial tuberosity (TT) and fibular tip). A surface registration algorithm was used to superimpose the mirrored contralateral model onto the original model. JL approximation and absolute mean errors for each segment registration were measured and its relationship to gender, height, weight and tibia and fibula length side-to-side differences analyzed. Fibular tip to JL distance was measured and analyzed. Results Mean JL approximation did not yield significant differences among the three segments. Mean absolute JL error was highest for the tibia 1.4 ± 1.4 mm (range: 0 to 6.0 mm) and decreased for the fibula 0.8 ± 1.0 mm (range: 0 to 3.7 mm) and for TT and fibular tip segment 0.7 ± 0.6 (range: 0 to 2.4 mm) (p = 0.03). Mean absolute JL error of the TT and fibular tip segment was independent of gender, height, weight and tibia and fibula length side-to-side differences. Mean fibular tip to JL distance was 11.9 ± 3.4 mm (range: 3.4 to 22.1 mm) with a mean absolute side-to-side difference of 1.6 ± 1.1 mm (range: 0 to 5.3 mm). Conclusion 3D registration of the contralateral tibia and fibula reliably approximated the original JL. The registration of, TT and fibular tip, as robust anatomical landmarks, improved the accuracy of JL restoration independent of tibia and fibula length side-to-side differences. Level of evidence IV

Preliminary Study to Determine the Reference Plane of Patients with a Unilateral Cleft Lip and Palate

2017 ◽  
Vol 54 (6) ◽  
pp. 707-714
Author(s):  
Na-Ri Kim ◽  
Soo-Byung Park ◽  
Sang Min Shin ◽  
Yong-Seok Choi ◽  
Seong-Sik Kim ◽  
...  
Keyword(s):  
Euclidean Distance ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Three Dimensional ◽  
Procrustes Analysis ◽  
Cone Beam ◽  
Reference Plane ◽  
Preliminary Study ◽  
Procrustes Superimposition ◽  
Squared Euclidean Distance

Objective The objective of this study was to determine the three-dimensional midsagittal reference planes for unilateral cleft lip and palate (UCLP) patients that can be easily applied in a clinical setting. Design This was a retrospective analysis. Patients There were 35 UCLP patients (25 men, 10 women; 28.1 ± 6.9 years old) in this study. Methods With landmark's three-dimensional coordinates obtained from cone-beam computed tomography, the symmetric midsagittal reference planes were calculated by applying the ordinary Procrustes superimposition method using the original and mirror images. Procrustes analysis was also used to find the closest landmarks to the calculated symmetric midsagittal reference plane and test its compatibility with the symmetrical midsagittal reference plane. Main Outcome Measure The three nearest landmarks to the symmetric midsagittal reference plane were Opisthion, Basion, and Nasion. Results The averages of the sums of the squared Euclidean distance and squared Procrustes distance differences between the two configurations and shapes fabricated by the symmetrical and landmark-based midsagittal reference planes, respectively, were calculated as 1.836 ± 3.295 and 1.519 × 10–5 ± 2.351 × 10–5. Conclusion It was confirmed that the midsagittal reference planes from these selected landmarks for UCLP patients were compatible with symmetric midsagittal reference planes from the Procrustes analysis and the asymmetric measurements.

Measuring facial symmetry: a perception-based approach using 3D shape and color

2015 ◽  
Vol 60 (1) ◽  
Author(s):  
Philipp Berssenbrügge ◽  
Maren Lingemann-Koch ◽  
Amalia Abeler ◽  
Christoph Runte ◽  
Susanne Jung ◽  
...  
Keyword(s):  
Maxillofacial Surgery ◽  
Three Dimensional ◽  
Objective Measure ◽  
Facial Asymmetry ◽  
Asymmetry Index ◽  
Subjective Perception ◽  
Facial Symmetry ◽  
Facial Esthetics ◽  
Novel Approach ◽  
Surgical Methods

AbstractFacial symmetry is an important factor affecting esthetics. Thus, its restoration is an essential task in maxillofacial surgery. The aim of this study is to develop an objective measure of facial asymmetry by a novel approach where both the shape and the color are taken into account and to validate its correlation with perception.Optical three-dimensional (3D) face scans of 30 healthy adults are performed. Face-specific asymmetry indices are calculated by quantifying color differences as well as spatial distances between 3D data of a face and its mirrored copy. Subjective ratings of symmetry and attractiveness of the faces by 100 subjects are used to validate these indices.The symmetry ratings show significant correlations with color and geometric asymmetry indices. The attractiveness ratings correlate only weakly with both indices. However, the product of the indices exhibits significant correlations with both attractiveness and symmetry ratings.The presented combined asymmetry index comprising shape and coloring turned out to reflect subjective perception of both facial symmetry and attractiveness. It thus promises to be a valid objective measure for facial esthetics, which could contribute, e.g., to the evaluation of surgical methods as well as to the design of craniofacial prostheses.

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 Spinal Palpation Error and Its Impact on Skin Marker-Based Spinal Alignment Measurement in Adult Spinal Deformity

2021 ◽  
Vol 9 ◽  
Author(s):  
Pieter Severijns ◽  
Thomas Overbergh ◽  
Stefan Schmid ◽  
Lieven Moke ◽  
Lennart Scheys
Keyword(s):  
Spinal Deformity ◽  
Adult Spinal Deformity ◽  
Three Dimensional ◽  
Ground Truth ◽  
Anatomical Landmarks ◽  
Spinal Alignment ◽  
Body Morphology ◽  
Skin Marker ◽  
The Impact ◽  
Mean Square Errors

Spinal alignment measurement in spinal deformity research has recently shifted from using mainly two-dimensional static radiography toward skin marker-based motion capture approaches, allowing three-dimensional (3D) assessments during dynamic conditions. The validity and accuracy of such skin marker-based methods is highly depending on correct marker placement. In this study we quantified, for the first time, the 3D spinal palpation error in adult spinal deformity (ASD) and compared it to the error in healthy spines. Secondly, the impact of incorrect marker placement on the accuracy of marker-based spinal alignment measurement was investigated. 3D, mediolateral and inferosuperior palpation errors for thoracolumbar and lumbar vertebral levels were measured on biplanar images by extracting 3D positions of skin-mounted markers and their corresponding anatomical landmarks in 20 ASD and 10 healthy control subjects. Relationships were investigated between palpation error and radiographic spinal alignment (lordosis and scoliosis), as well as body morphology [BMI and soft tissue (ST) thickness]. Marker-based spinal alignment was measured using a previously validated method, in which a polynomial is fit through the marker positions of a motion trial and which allows for radiograph-based marker position correction. To assess the impact of palpation error on spinal alignment measurement, the agreement was investigated between lordosis and scoliosis measured by a polynomial fit through, respectively, (1) the uncorrected marker positions, (2) the palpation error-corrected (optimal) marker positions, and (3) the anatomically corrected marker positions (toward the vertebral body), and their radiographic equivalents expressed as Cobb angles (ground truth), using Spearman correlations and root mean square errors (RMSE). The results of this study showed that, although overall accuracy of spinal level identification was similar across groups, mediolateral palpation was less accurate in the ASD group (ASDmean: 6.8 mm; Controlmean: 2.5 mm; p = 0.002). Significant correlations with palpation error indicated that determining factors for marker misplacement were spinal malalignment, in particular scoliotic deformity (r = 0.77; p < 0.001), in the ASD group and body morphology [i.e., increased BMI (rs = 0.78; p = 0.008) and ST thickness (rs = 0.66; p = 0.038)] in healthy spines. Improved spinal alignment measurements after palpation error correction, shows the need for radiograph-based marker correction methods, and therefore, should be considered when interpreting spinal kinematics.

Sign in / Sign up

Export Citation Format

Share Document