Simulation of facial growth based on longitudinal data: Age progression and age regression between 7 and 17 years of age using 3D surface data

Three-Dimensional Geometric Morphometric Characterization of Facial Sexual Dimorphism in Juveniles

Background: The characterization of facial sexual dimorphic patterns in healthy populations serves as valuable normative data to tailor functionally effective surgical treatments and predict their aesthetic outcomes and to identify dysmorphic facial traits related to hormonal disorders and genetic syndromes. Although the analysis of facial sexual differences in juveniles of different ages has already been investigated, few studies have approached this topic with three-dimensional (3D) geometric morphometric (GMM) analysis, whose interpretation may add important clinical insight to the current understanding. This study aims to investigate the location and extent of facial sexual variations in juveniles through a spatially dense GMM analysis. Methods: We investigated 3D stereophotogrammetric facial scans of 304 healthy Italians aged 3 to 18 years old (149 males, 155 females) and categorized into four different age groups: early childhood (3-6 years), late childhood (7-12 years), puberty (13-15 years), and adolescence (16-18 years). Geometric morphometric analyses of facial shape (allometry, general Procrustes analysis, Principal Component Analysis, Procrustes distance, and Partial Least Square Regression) were conducted to detail sexually dimorphic traits in each age group. Results: The findings confirmed that males have larger faces than females of the same age, and significant differences in facial shape between the two sexes exist in all age groups. Juveniles start to express sexual dimorphism from 3 years, even though biological sex becomes a predictor of facial soft tissue morphology from the 7th year of life, with males displaying more protrusive medial facial features and females showing more outwardly placed cheeks and eyes. Conclusions: We provided a detailed characterization of facial change trajectories in the two sexes along four age classes, and the provided data can be valuable for several clinical disciplines dealing with the craniofacial region. Our results may serve as comparative data in the early diagnosis of craniofacial abnormalities and alterations, as a reference in the planning of personalized surgical and orthodontic treatments and their outcomes evaluation, as well as in several forensic applications such as the prediction of the face of missing juveniles.

The True Appearance Behind Satisfaction in Young Women: A Study Using Stereophotogrammetry and FACE-Q

This cross-sectional observational study aimed to investigate the relationship between satisfaction with facial appearance among young women, as measured by the FACE-Q tool, and facial asymmetry quantified through stereophotogrammetry. A total of 50 women aged 18 to 30 years with a normal body mass index were recruited for the study. Participants were categorized as either symmetrical or asymmetrical based on facial asymmetry assessments obtained through clinical examination and stereophotogrammetry using the Vectra M3 system. Facial asymmetry was quantified using root mean square (RMS) distances, with participants classified into symmetrical (RMS ≤0.68) and asymmetrical (RMS >0.68) groups. The statistical analysis included the intraclass correlation coefficient (ICC) to assess the repeatability of RMS measurements (ICC=0.945), Receiver operating characteristic (ROC) curve analysis (area under the curve=0.900), and independent t tests to compare FACE-Q scores between groups. Results showed no significant differences in FACE-Q satisfaction scores between the symmetrical and asymmetrical groups. In addition, simple linear regression analysis indicated that RMS values were not predictive of FACE-Q scores, suggesting that facial asymmetry, as measured in this study, did not have a direct effect on self-reported satisfaction with appearance. These findings highlight the nuanced nature of individual satisfaction with facial appearance, suggesting that health care providers should combine clinical evaluation with empathetic communication to address both the aesthetic and functional concerns of patients more effectively.

Photoanthropometric study: are non-professional photographs suitable for objective and reliable analysis of facial features?

BACKGROUND

The face has been widely investigated using professionally taken frontal and lateral photographs, however, there is a lack of studies of non-professional facial photographs. It is not known if they could be suitable for facial analysis. The analysis of non-professional photographs could allow the performance of cost- effective longitudinal studies.

AIM

To determine if non-professional photographs could be used for a reliable analysis of facial features.

SUBJECTS AND METHODS

The frontal profiles of 18-21-year-olds (35 males, 39 females) were measured by direct anthropometry, in addition, professional photographs were taken and non-professional photographs were obtained. Anthropometric landmarks were superimposed on those photographs. The indices calculated on the basis of the measurements of direct anthropometry and both types of photographs were compared.

RESULTS

The comparison of the measurements of direct anthropometry and professional photographs showed no difference between 14 out of 25 male and 10 out of 25 female facial indices (p > 0.05) after comparing the results of direct anthropometry with those of non-professional photographs, no difference was found in 8 out of 25 male and 7 out of 25 female indices. These indices were mostly composed of vertical parameters and eye measurements.

CONCLUSION

Vertical facial dimensions and eye measurements may not only be used interchangeably for both facial photographs and direct anthropometry, but may also be suitable for objective and reliable facial analyses.

Three-dimensional analysis of modeled facial aging and sexual dimorphism from juvenile to elderly age

A detailed understanding of craniofacial ontogenetic development is important in a variety of scientific disciplines dealing with facial reconstruction, forensic identification, ageing prediction, and monitoring of pathological growth, including the effect of therapy. The main goals of this study were (1) the construction of the facial aging model using local polynomial regression fitting separately for both sexes, (2) evaluation of the aging effect not only on facial form as a whole but also on dimensions important for clinical practice, and (3) monitoring of the development of shape facial sexual dimorphism. Our study was based on the form and shape analysis of three-dimensional facial surface models of 456 individuals aged 14-83 years. The facial models were obtained using a structured light-based optical scanner and divided (for some analyses) into four age categories (juveniles, young adults, middle adults, and elderly adults). The methodology was based on geometric and classic morphometrics including multivariate statistics. Aging in both sexes shared common traits such as more pronounced facial roundness reducing facial convexity, sagging soft tissue, smaller visible areas of the eyes, greater nose, and thinner lips. In contrast to female faces, male faces increase in size until almost 30 years of age. After the age of 70, male facial size not only stagnates, like in females, but actually decreases slightly. Sexual dimorphic traits tended to diminish in the frontal and orbitonasal areas and increase in the gonial area.

Estimation in regret-regression using quadratic inference functions with ridge estimator

In this paper, we propose a new estimation method in estimating optimal dynamic treatment regimes. The quadratic inference functions in myopic regret-regression (QIF-MRr) can be used to estimate the parameters of the mean response at each visit, conditional on previous states and actions. Singularity issues may arise during computation when estimating the parameters in ODTR using QIF-MRr due to multicollinearity. Hence, the ridge penalty was introduced in rQIF-MRr to tackle the issues. A simulation study and an application to anticoagulation dataset were conducted to investigate the model’s performance in parameter estimation. The results show that estimations using rQIF-MRr are more efficient than the QIF-MRr.

A semi-automatic three-dimensional technique using a regionalized facial template enables facial growth assessment in healthy children from 1.5 to 5.0 years of age

Objectives

To develop a semi-automatic technique to evaluate normative facial growth in healthy children between the age of 1.5 and 5.0 years using three-dimensional stereophotogrammetric images.

Materials and Methods

Three-dimensional facial images of healthy children at 1.5, 2.0, 2.5, 3.0, 4.0 and 5.0 years of age were collected and positioned based on a reference frame. A general face template was used to extract the face and its separate regions from the full stereophotogrammetric image. Furthermore, this template was used to create a uniform distributed mesh, which could be directly compared to other meshes. Average faces were created for each age group and mean growth was determined between consecutive groups for the full face and its separate regions. Finally, the results were tested for intra- and inter-operator performance.

Results

The highest growth velocity was present in the first period between 1.5 and 2.0 years of age with an average of 1.50 mm (±0.54 mm) per six months. After 2.0 years, facial growth velocity declined to only a third at the age of 5.0 years. Intra- and inter-operator variability was small and not significant.

Conclusions

The results show that this technique can be used for objective clinical evaluation of facial growth. Example normative facial averages and the corresponding facial growth between the age 1.5 and 5.0 years are shown.

Clinical Relevance

This technique can be used to collect and process facial data for objective clinical evaluation of facial growth in the individual patient. Furthermore, these data can be used as normative data in future comparative studies.

Longitudinal composite 3D faces and facial growth trends in children 6-11 years of age using 3D cephalometric surface imaging

BACKGROUND

Normative craniofacial anthropometry provides clinically important reference values used in the treatment of craniofacial conditions. Few objective datasets of normative data exist for children.

AIM

To establish normative data regarding craniofacial morphology changes with growth in children.

SUBJECTS AND METHODS

3D surface images of the same group of healthy children aged 6 - 11 years old recruited from a Dallas school were taken annually between the years 2015 - 2020. Composite 3D cephalometric faces were created for boys and girls of each age. General and craniofacial anthropometric measurements were compared.

RESULTS

Seven hundred ninety one individual stereophotogrammetric acquisitions were used (400 boys, 391 girls) taken from 180 children. Linear facial, orbital, nasal, and oral anthropometric measurements revealed a consistent increase in magnitude with age. Composite 3D face comparisons revealed prominent vertical and anteroposterior growth trends in the lower and upper facial regions.

CONCLUSION

This study presents a longitudinal 3D control dataset of the same group of children over a 6-year period that can serve as reference norms for facial growth values and trends in children aged 6-11 years. The composite 3D normative faces are available for clinical and research purposes upon request, which may be interrogated and measured according to user need and preference.

Can a spontaneous smile invalidate facial identification by photo-anthropometry?

Purpose

Using images in the facial image comparison process poses a challenge for forensic experts due to limitations such as the presence of facial expressions. The aims of this study were to analyze how morphometric changes in the face during a spontaneous smile influence the facial image comparison process and to evaluate the reproducibility of measurements obtained by digital stereophotogrammetry in these situations.

Materials and Methods

Three examiners used digital stereophotogrammetry to obtain 3-dimensional images of the faces of 10 female participants (aged between 23 and 45 years). Photographs of the participants' faces were captured with their faces at rest (group 1) and with a spontaneous smile (group 2), resulting in a total of 60 3-dimensional images. The digital stereophotogrammetry device obtained the images with a 3.5-ms capture time, which prevented undesirable movements of the participants. Linear measurements between facial landmarks were made, in units of millimeters, and the data were subjected to multivariate and univariate statistical analyses using Pirouette® version 4.5 (InfoMetrix Inc., Woodinville, WA, USA) and Microsoft Excel® (Microsoft Corp., Redmond, WA, USA), respectively.

Results

The measurements that most strongly influenced the separation of the groups were related to the labial/buccal region. In general, the data showed low standard deviations, which differed by less than 10% from the measured mean values, demonstrating that the digital stereophotogrammetry technique was reproducible.

Conclusion

The impact of spontaneous smiles on the facial image comparison process should be considered, and digital stereophotogrammetry provided good reproducibility.

Prediction of face age progression with generative adversarial networks

Face age progression, goals to alter the individual's face from a given face image to predict the future appearance of that image. In today's world that demands more security and a touchless unique identification system, face aging attains tremendous attention. The existing face age progression approaches have the key problem of unnatural modifications of facial attributes due to insufficient prior knowledge of input images and nearly visual artifacts in the generated output. Research has been continuing in face aging to handle the challenge to generate aged faces accurately. So, to solve the issue, the proposed work focuses on the realistic face aging method using AttentionGAN and SRGAN. AttentionGAN uses two separate subnets in a generator. One subnet for generating multiple attention masks and the other for generating multiple content masks. Then attention mask is multiplied with the corresponding content mask along with an input image to finally achieve the desired results. Further, the regex filtering process is performed to separates the synthesized face images from the output of AttentionGAN. Then image sharpening with edge enhancement is done to give high-quality input to SRGAN, which further generates the super-resolution face aged images. Thus, presents more detailed information in an image because of its high quality. Moreover, the experimental results are obtained from five publicly available datasets: UTKFace, CACD, FGNET, IMDB-WIKI, and CelebA. The proposed work is evaluated with quantitative and qualitative methods, produces synthesized face aged images with a 0.001% error rate, and is also evaluated with the comparison to prior methods. The paper focuses on the various practical applications of super-resolution face aging using Generative Adversarial Networks (GANs).

Was facial width-to-height ratio subject to sexual selection pressures? A life course approach

Sexual selection researchers have traditionally focused on adult sex differences; however, the schedule and pattern of sex-specific ontogeny can provide insights unobtainable from an exclusive focus on adults. Recently, it has been debated whether facial width-to-height ratio (fWHR; bi-zygomatic breadth divided by midface height) is a human secondary sexual characteristic (SSC). Here, we review current evidence, then address this debate using ontogenetic evidence, which has been under-explored in fWHR research. Facial measurements were collected from 3D surface images of males and females aged 3 to 40 (Study 1; US European-descent, n = 2449), and from 2D photographs of males and females aged 7 to 21 (Study 2; Bolivian Tsimane, n = 179), which were used to calculate three fWHR variants (which we call fWHRnasion, fWHRstomion, and fWHRbrow) and two other common facial masculinity ratios (facial width-to-lower-face-height ratio, fWHRlower, and cheekbone prominence). We test whether the observed pattern of facial development exhibits patterns indicative of SSCs, i.e., differential adolescent growth in either male or female facial morphology leading to an adult sex difference. Results showed that only fWHRlower exhibited both adult sex differences as well as the classic pattern of ontogeny for SSCs-greater lower-face growth in male adolescents relative to females. fWHRbrow was significantly wider among both pre- and post-pubertal males in the Bolivian Tsimane sample; post-hoc analyses revealed that the effect was driven by large sex differences in brow height, with females having higher placed brows than males across ages. In both samples, all fWHR measures were inversely associated with age; that is, human facial growth is characterized by greater relative elongation in the mid-face and lower face relative to facial width. This trend continues even into middle adulthood. BMI was also a positive predictor of most of the ratios across ages, with greater BMI associated with wider faces. Researchers collecting data on fWHR should target fWHRlower and fWHRbrow and should control for both age and BMI. Researchers should also compare ratio approaches with multivariate techniques, such as geometric morphometrics, to examine whether the latter have greater utility for understanding the evolution of facial sexual dimorphism.

Exploring the midline soft tissue surface changes from 12 to 15 years of age in three distinct country population cohorts

INTRODUCTION

Several studies have highlighted differences in the facial features in a White European population. Genetics appear to have a major influence on normal facial variation, and environmental factors are likely to have minor influences on face shape directly or through epigenetic mechanisms.

AIM

The aim of this longitudinal cohort study is to determine the rate of change in midline facial landmarks in three distinct homogenous population groups (Finnish, Latvian, and Welsh) from 12.8 to 15.3 years of age. This age range covers the pubertal growth period for the majority of boys and girls.

METHODS

A cohort of children aged 12 were monitored for facial growth in three countries [Finland (n = 60), Latvia (n = 107), and Wales (n = 96)]. Three-dimensional facial surface images were acquired (using either laser or photogrammetric methods) at regular intervals (6-12 months) for 4 years. Ethical approval was granted in each country. Nine midline landmarks were identified and the relative spatial positions of these surface landmarks were measured relative to the mid-endocanthion (men) over a 4-year period.

RESULTS

This study reports the children who attended 95 per cent of all scanning sessions (Finland 48 out of 60; Latvia 104 out of 107; Wales 50 out of 96). Considerable facial variation is seen for all countries and sexes. There are clear patterns of growth that show different magnitudes at different age groups for the different country groups, sexes, and facial parameters. The greatest single yearly growth rate (5.4 mm) was seen for Welsh males for men-pogonion distance at 13.6 years of age. Males exhibit greater rates of growth compared to females. These variations in magnitude and timings are likely to be influenced by genetic ancestry as a result of population migration.

CONCLUSION

The midline points are a simple and valid method to assess the relative spatial positions of facial surface landmarks. This study confirms previous reports on the subtle differences in facial shapes and sizes of male and female children in different populations and also highlights the magnitudes and timings of growth for various midline landmark distances to the men point.

Three-dimensional mixed longitudinal study of facial growth changes and variability of facial form in preschool children using stereophotogrammetry

OBJECTIVES

Since the normal, non-pathological facial growth in preschool children is not sufficiently reported, the aim was to follow growth changes of facial surface, sex differences and facial variability in preschool children using 3D stereophotogrammetry.

SETTINGS AND SAMPLE POPULATION

Mixed longitudinal sample of healthy Caucasian preschool children without head and facial trauma or craniofacial anomalies from 3.4 to 6.7 years of age consisted of 25 girls and 17 boys.

MATERIALS AND METHODS

136 3D facial models from optical scanner Vectra 3D were evaluated by geometric morphometrics (CPC-DCA, PCA, per-vertex t test).

RESULTS

In both sexes, the lower face was widened and elongated, and the prominences of the superciliary arches, lower orbital region, nose, lips and chin increased. Facial surface increments were more even in girls with a maximum between the fourth and fifth year of age, while in boys, there was the most intensive growth between fifth and sixth year of age. Sexual dimorphism was very stable during investigated period, only less statistically significant at the age of 3 years. Boys had more prominent lateral lower part of forehead, nose and lips than girls in every age category.

CONCLUSIONS

The longitudinal growth of the face between third and sixth year of age was similar in both sexes, facial sex differences were found in terms of intensity, size and timing. Variability of facial form showed that boys' faces were larger on average and facial shape did not differ. The knowledge of facial growth is essential for diagnostics and clinical practice.

Parental reference photos do not always improve the accuracy of forensic age progressions

During long-term missing children cases, forensic artists construct age-progressions to estimate the child's current appearance. It is commonly believed that incorporating information about the child's biological relatives is critical in accurately estimating the child's current appearance. However, some evidence suggests that predicting appearance based on inheritance of features may be error prone. The present studies examine whether age-progressions constructed with the aid of a biological reference photos led to better recognition than those constructed without a biological reference. We also investigated whether there would be any variation depending on the age-range of the age-progressions. Eight professional forensic artists created age-progressions based upon photographs provided by each of our eight targets. Half of their age progressions with the aid of parental reference photos and half without parental reference photos. Furthermore, half were age-progressed across a longer age-range (5-20 years) and half covered a shorter age-range (12-20 years). In Experiment 1 similarity scores were higher over shorter age-ranges. Further, across longer age-ranges age-progressions created with the aid of a parental reference were lower than those without a reference. In Experiment 2 recognition performance was higher across shorter age-ranges. Additionally, across longer age-ranges age-progressions created with the aid of a parental reference were recognized worse than those without a reference. These results suggest that in long-term missing person cases, forensic artists may benefit from not relying on biological references. Finally, consistent with previous research (e.g. Lampinen et al., 2012) age-progressions provided no benefit over using outdated photographs.