Evaluation of Facial Anthropometry Using Three-Dimensional Photogrammetry and Direct Measuring Techniques

Objective In this investigation, the precision of a commercial three-dimensional digitizer in the detection of facial landmarks in human adults was assessed. Methods Fifty landmarks were identified and marked on the faces of five men, on five women, and on a stone cast of the face of one man. For each subject, the three-dimensional coordinates of the landmarks were obtained twice using an electromagnetic three-dimensional digitizer, and the duplicate digitizations were superimposed using common orientations and centers of gravity. Metric differences between homologous landmarks were assessed, and Dahlberg's error was computed. Results For both men and women, the error was 1.05% of the nasion-mid-tragion distance, while for the cast, it was 0.9%. When the duplicate digitizations were used to mathematically reconstruct the faces, and several distances, angles, volumes, and surfaces were computed, more than 80% of the measurements had coefficients of variation lower than 1%. Conclusions The digitizer can assess the coordinates of facial landmarks with sufficient precision, and reliable measurements can be obtained.

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Adaptation des procédés stéréologiques à la mesure des bulles d'air et des fissures dans le béton

Canadian Journal of Civil Engineering ◽

10.1139/l83-069 ◽

1983 ◽

Vol 10 (3) ◽

pp. 415-428 ◽

Cited By ~ 2

Author(s):

Jules Houde ◽

Serge Meilleur

Keyword(s):

Crack Density ◽

Three Dimensional ◽

Total Porosity ◽

Air Bubble ◽

Air Content ◽

Projected Length ◽

Measuring Techniques ◽

Plastic Concrete ◽

Image Analyser ◽

Bubble Sizes

Mathematical morphometry is the science of classifying forms through parameters such as length, area, perimeter, and projected length. Image analysers have been built to measure these parameters rapidly. Stereological equations are used to define three-dimensional characteristics from elementary count operations made in a plane.These techniques were used to characterize the air bubble system of six different concretes. All measurements were made on polished sections with a linear traverse apparatus as well as with an image analyser. The precision of the data obtained is about equal with both measuring techniques. The image analyser was able to measure the air content and the spacing factor in one-eighth of the time necessary for a linear traverse; moreover, histograms of the bubble sizes were readily available.Measurements of cracks caused by early freezing of plastic concrete made on the linear traverse apparatus, coupled with total porosity measurements by the image analyser, were used to relate the decrease of compressive strength to the increased crack density.

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The role of the golden proportion in the evaluation of facial esthetics

The Angle Orthodontist ◽

10.2319/111812-883.1 ◽

2013 ◽

Vol 83 (5) ◽

pp. 801-808 ◽

Cited By ~ 22

Author(s):

Alberto Rossetti ◽

Marcio De Menezes ◽

Riccardo Rosati ◽

Virgilio F. Ferrario ◽

Chiarella Sforza

Keyword(s):

Golden Ratio ◽

Three Dimensional ◽

Human Face ◽

Healthy Young Adult ◽

Golden Proportion ◽

Facial Esthetics ◽

3D Stereophotogrammetry ◽

Student’S T ◽

Facial Anthropometry

ABSTRACT Objective: To demonstrate if one or more golden relationships between different measurements of the human face exist. Materials and Methods: To make our measurements, we used three-dimensional (3D) stereophotogrammetry, which has proved to be the “gold standard” in the field of facial anthropometry. We obtained 3D stereophotogrammetric facial acquisitions of 400 healthy young adult subjects, then had them scored by an Evaluation Jury. Each subject received an esthetic evaluation ranging from 0 to 40. Individuals with a score larger than 28 were considered very attractive (VA), and individuals with a score lower than 12 were considered not attractive (NA). Fifteen subjects per group were chosen by chance, with a final total group of 60 subjects: 15 VA males, 15 NA males, 15 VA females, and 15 NA females. For each subject, a set of facial distances was obtained from the stereophotogrammetric facial reconstruction, and 10 ratios were computed. The effects of sex and attractiveness were tested by analysis of variance. Additionally, Student's t-tests verified if the ratios were statistically different from the golden ratio. Results: For nine ratios, no significant effects of sex or attractiveness were found. Only the eye-mouth distance/height of the mandible ratio was significantly influenced by sex (P = .035) and attractiveness (P = .032). Seven out of 10 ratios were statistically different from the hypothetical value of 1.618, and only three of them were similar to the golden ratio. Conclusions: Ratios between 3D facial distances were not related to attractiveness. Most of the facial ratios were different from the golden ratio.

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Velocity Measurements in Metallic Melts

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2005-77089 ◽

2005 ◽

Cited By ~ 1

Author(s):

S. Eckert ◽

G. Gerbeth ◽

T. Gundrum ◽

F. Stefani

Keyword(s):

Velocity Structure ◽

Liquid Metals ◽

Three Dimensional ◽

Optical Probe ◽

Mean Velocity ◽

Application Range ◽

Inverse Reconstruction ◽

Measuring Techniques ◽

Local Measurements ◽

Velocity Measuring

Various developments of velocity measuring techniques, their tests in different liquid metals, and applications in hot melts are reported. A Mechano-Optical Probe (MOP) performing local measurements up to temperatures of about 700°C has been developed and successfully tested. The Ultrasound Doppler Velocimetry (UDV) can be considered as another attractive technique to get velocity data from opaque flows. To extend the application range to higher temperatures and to abrasive liquids a new integrated ultrasonic sensor with an acoustic wave guide has been designed. First successful measurements in a CuSn melt of about 620°C and in liquid Al of about 750°C were carried out. A fully contactless investigation of the mean velocity field is possible by magnetic tomography. Local measurements of the induced magnetic field and the application of inverse reconstruction techniques allow an analysis of the flow structure. A first demonstration experiment showing the feasibility of this approach for the reconstruction of the three-dimensional mean velocity structure is presented.

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X-Ray Microtomography of Microcellular Polymers

10.1115/imece2000-1950 ◽

2000 ◽

Author(s):

Ryszard Pyrz

Keyword(s):

Three Dimensional ◽

Stress And Strain ◽

Geometrical Parameters ◽

Non Destructive Testing ◽

Destructive Testing ◽

X Ray ◽

Testing Method ◽

Measuring Techniques ◽

Measured Stress ◽

Non Destructive

Abstract Among modern measuring techniques, which are designed to reconstruct and to measure three-dimensional aspects of microstructure on mesoscopic scale lengths, the X-ray microtomography seems to be very well suited to yield this information. Generally, X-ray microtomography is the X-ray based non-destructive testing method that was first developed for medical purposes and only recently applied to materials characterization. Monitoring materials’ microstructure using X-ray microtomography allows reconstructing a three-dimensional image of the specimen from non-destructive, serial sections and processing it in order to visualize and measure three-dimensional features. Thus valuable information can be deduced from the correlation of measured stress and strain values with a number of internal geometrical parameters which cannot be measured at the specimen surface.

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