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ABSTRACT: Objective : To evaluate three-dimensional nasal morphology following primary reconstruction in children with unilateral cleft lip and palate relative to contemporaneous noncleft data. Design : Prospective, cross-sectional, controlled study. Setting : Glasgow Dental Hospital and School, Faculty of Medicine, Glasgow University. Patients and Participants : Two groups of 3-year-old children (21 with unilateral cleft lip and palate and 96 controls) with facial images taken using a three-dimensional, vision-based capture technique. Methods : Three-dimensional images of the face were reflected so the cleft was on the left side to create a homogeneous group for statistical analysis. Three-dimensional coordinates of anthropometric landmarks were extracted from facial images by a single operator. A set of linear measurements was used to compare cleft and control subjects on right and left sides, adjusting for sex differences. Results : The mean nasal base width and the width of the nostril floor on right and left sides differed significantly between control and unilateral cleft lip and palate groups. The measurements were greater in children with unilateral cleft lip and palate. The differences in the mean nasal height and mean nasal projection between the groups were not statistically significant. Mean columellar lengths were different between the left and right sides in children with unilateral cleft lip and palate. Conclusions : There were significant nasal deformities following the surgical repair of unilateral cleft lip and palate.
The Cleft Palate-Craniofacial Journal 09/2011; 48(5):571-7. · 0.82 Impact Factor
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ABSTRACT: Objective : To evaluate three-dimensional lip morphology, following primary reconstruction in children with unilateral cleft lip and palate relative to contemporaneous noncleft data. Design : Prospective, cross-sectional, controlled study. Setting : Glasgow Dental Hospital and School, University of Glasgow, U.K. Patients and Participants : Two groups of 3-year-old children (21 with unilateral cleft lip and palate and 96 controls) with facial images taken using a three-dimensional vision-based capture technique. Methods : Three-dimensional images of the face were reflected so the cleft was on the left side to create a homogeneous group for statistical analysis. Three-dimensional coordinates of anthropometric landmarks were extracted from facial images. Three-dimensional, generalized Procrustes superimposition was implemented and a set of linear measurements were used to compare cleft and control subjects for right and left sides, adjusting for sex differences. Results : Crista philtri on both the cleft and noncleft sides were displaced laterally and posteriorly; there was also a statistically significant increase in philtrum width. No significant differences between cleft and control regarding the cutaneous height of the upper lip. The lip in the cleft patients was flatter than in the noncleft individuals, with less prominence of labialis superioris. Conclusions : Stereophotogrammetry allows detection of residual dysmorphology following cleft repair. There was significant increase of the philtrum width. The lip appeared flatter and more posterior displaced in unilateral cleft lip and palate patients compared with controls.
The Cleft Palate-Craniofacial Journal 09/2011; 48(5):578-83. · 0.82 Impact Factor
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ABSTRACT: We present a self-correction approach to improving the 3D reconstruction of a multi-view 3D photogrammetry system. The self-correction approach has been able to repair the reconstructed 3D surface damaged by depth discontinuities. Due to self-occlusion, multi-view range images have to be acquired and integrated into a watertight non-redundant mesh model in order to cover the extended surface of an imaged object. The integrated surface often suffers from ¿dent¿ artifacts produced by depth discontinuities in the multi-view range images. In this paper we propose a novel approach to correcting the 3D integrated surface such that the dent artifacts can be repaired automatically. We show examples of 3D reconstruction to demonstrate the improvement that can be achieved by the self-correction approach. This self-correction approach can be extended to integrate range images obtained from alternative range capture devices.
Computer Vision Workshops (ICCV Workshops), 2009 IEEE 12th International Conference on; 11/2009
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ABSTRACT: The aim of this investigation was to assess the feasibility of building a virtual human face digitally by superimposing a photo-realistic three-dimensional (3D) soft-tissue surface on bone in the correct relationship and evaluating the registration errors associated with this method. The 3D soft-tissue surface of the face was captured using a fast stereophotogrammetry method and the underlying bone was recorded using a 3D computed tomography (CT) scanner. Using the Procrustes registration method, the outer surface of the 3D CT scan and the photo-realistic soft-tissue surfaces were merged into a single Virtual Reality Modelling Language (VRML) file and displayed using a standard VRML viewer. Quantitative measurements of registration errors were calculated in the reconstructed human head models using the signed closest point distance from the photo-realistic skin surface to the transformed CT skin surface. The registration errors between most parts of the aligned surfaces were within +/-1.5mm. The errors were relatively large around the eyebrows, eyelids and cheeks. Simultaneous recording of the face and skull may reduce this error.
International Journal of Oral and Maxillofacial Surgery 06/2007; 36(5):423-8. · 1.51 Impact Factor
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ABSTRACT: A mesh conformation approach that makes use of deformable generic meshes has been applied to establishing correspondences between 3D shapes with missing data. Given a group of shapes with correspondences, we can build up a statistical shape model by applying principal component analysis (PCA). The conformation at first globally maps the generic mesh to the 3D shape based on manually located corresponding landmarks, and then locally deforms the generic mesh to clone the 3D shape. The local deformation is constrained by minimizing the energy of an elastic model. An algorithm was also embedded in the conformation process to fill missing surface data of the shapes. Using synthetic data, we demonstrate that the conformation preserves the configuration of the generic mesh and hence it helps to establish good correspondences for shape analysis. Case studies of the principal component analysis of shapes were presented to illustrate the successes and advantages of our approach.
3D Data Processing, Visualization and Transmission, 2004. 3DPVT 2004. Proceedings. 2nd International Symposium on; 10/2004
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ABSTRACT: This paper presents an improved method to construct dense correspondences for 3D facial analysis, which are capable of providing a full 3D description of a surface and extending the conventional landmark-based approaches. Based on the technique of elastic deformation, the dense correspondences are established by mapping a generic model onto the 3D surface of an individual. The method used here is accurate in driving the conformation of the generic model and efficient in dealing with outliers, which can appear during local deformation. The experiments indicate for open surfaces as face with this method, more than 95 percent of triangles on the deformed generic mesh are within the range of 1 mm to the original model and the average landmark errors are only 2 mm.
Pattern Recognition, 2004. ICPR 2004. Proceedings of the 17th International Conference on; 09/2004
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ABSTRACT: A novel method for integrating multiple range images in a multi-view stereo imaging system is presented here. Due to self-occlusion an individual range image provides only a partial model of an object surface. Therefore multiple range images from differing viewpoints must be captured and merged to extend the surface area that can be captured. In our approach range images are decomposed into subset patches and then evaluated in a "confidence competition". Redundant patches are removed whilst winning patches are merged to complete a single plausible mesh that represents the acquired object surface.
Pattern Recognition, 2004. ICPR 2004. Proceedings of the 17th International Conference on; 09/2004
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Journal of orthodontics 07/2004; 31(2):154-62.
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ABSTRACT: Part I of this paper describes the background, general concepts, available techniques and the clinical applications of recording external craniofacial morphology in three dimensions. Part II explores the different 3D techniques of imaging the dental arches, and their possible uses in orthodontic diagnosis and treatment.
Journal of orthodontics 04/2004; 31(1):62-70.
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ABSTRACT: The aim of this study was to assess the accuracy of a newly developed three-dimensional (3D) imaging system in recording facial morphology.
Twenty-one infants with cleft lip each had a full-face alginate impression taken at the time of primary lip repair, and a stone cast was constructed from each impression. Five anthropometric points were marked on each cast. Each cast was digitized, and the 3D co-ordinates of the five points were obtained using a co-ordinate measuring machine (CMM, Ferranti) of documented accuracy (9.53 microm). Each cast was scanned in four positions using a computerized stereophotogrammetry (C3D) system. The five points were located on the 3D images, and their 3D co-ordinates were extracted by three operators. The co-ordinate systems produced by C3D were aligned, via translation and rotation, to match the CMM co-ordinate system using partial ordinary procrustes analysis. The displacements of the adjusted C3D co-ordinates from the reference co-ordinates were then measured. Three different types of errors were identified: operator, system, and registration errors.
Operator error was within 0.2 mm of the true co-ordinates of the landmarks. C3D was accurate within 0.4 mm. The average displacement of points over the 21 casts at four positions for the three operators was 0.79 mm (median 0.68).
The presented 3D imaging system is reliable in recording facial deformity and could be utilized in recording cleft deformities and measuring the changes following surgery
The Cleft Palate-Craniofacial Journal 10/2003; 40(5):523-9. · 0.82 Impact Factor
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Computer Vision for Virtual Human Modelling (Ref. No. 1998/433), IEE Colloquium on; 08/1998
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ABSTRACT: The authors detail the procedures used in the development of an
active stereo probe (ASP) precision stereo vision system that combines
animate oculomotor reflexes with a novel active illumination source.
They describe how a mathematical model of the ASP imaging geometry and
kinematics was utilized at all stages of the development process to
ensure that the final system complied with the required performance
criteria. The results of a series of simulation analysis experiments are
presented together with their implications for the design and
fabrication of the final system. Some initial results on surface
reconstruction from stereograms captured by the completed head are
presented
Intelligent Control, 1992., Proceedings of the 1992 IEEE International Symposium on; 09/1992
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ABSTRACT: An experiment is presented that combines active and passive vision techniques. The authors have demonstrated that it is possible to recover dense range map information from stereograms of scenes bathed in random noise 'textured light' by employing scale-space signal matching techniques.
Electronics Letters 04/1990; · 0.96 Impact Factor
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ABSTRACT: This paper considers the construction of a biologically inspired front-end for computer vision based on an artificial retina pyramid with a self-organised pseudo-randomly tessellated receptive field tessellation. The organisation of photoreceptors and receptive fields in biological retinae locally resembles a hexagonal mosaic, whereas globally these are organised with a very densely tessellated central foveal region which seamlessly merges into an increasingly sparsely tessellated periphery. In contrast, conventional computer vision approaches use a rectilinear sampling tessellation which samples the whole field of view with uniform density. Scale-space interest points which are suitable for higher level attention and reasoning tasks are efficiently extracted by our vision front-end by performing hierarchical feature extraction on the pseudo-randomly spaced visual information. All operations were conducted on a geometrically irregular foveated representation (data structure for visual information) which is radically different to the uniform rectilinear arrays used in conventional computer vision.
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ABSTRACT: OBJECTIVE: To validate a new method of facial volumetric assessment that is dependent on the use of stereophotogrammetric models and a software-based Facial Analysis Tool. DESIGN: The method was validated in vitro with three-dimensional (3D) models of a lifelike plastic female dummy head and in vivo with a male-subject head. METHODS: Thirty facial silicone explants were added in the nasal and perioral regions of each head, and their volumes were obtained by three different algorithms. These were compared with the actual values obtained by a "water displacement" method. RESULTS: The least mean error was found with the "tetrahedron formation" method followed by the "projection" method and the "back-plane construction" method. The error with the tetrahedron formation method was 0.071 cm(3) (95% confidence interval [CI]: -0.074 to 0.2161 cm3) with the in vitro models and 0.314 cm3 (95% CI: -0.080 to 0.708 cm3) with the in vivo models. The increased volumetric assessment error observed in vivo was attributed to the registration procedure and possible changes in facial expression. CONCLUSIONS: These results encourage the use of this method in the 3D assessment of orthognathic surgical outcome, provided a standardized facial expression is used for image acquisition.
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ABSTRACT: Many 3-dimensional (3D) techniques have been utilized to register and analyze the face in 3 dimensions, but each system has its own merits and disadvantages. C3D is a relatively new 3D imaging system that was developed to capture the 3D geometry of the face. Landmark identification on 3D facial models is facilitated by a software-based facial analysis tool developed by the authors. The reproducibility of landmark identification was high for 20 of the chosen points (standard deviations of repeated placements of landmarks around their centroids were 0.5 mm or less). The method is useful in studying facial soft tissue changes following orthognathic surgery and other types of facial surgery, as well as assessing facial soft tissue growth and development of the craniofacial complex
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ABSTRACT: Objective: Although one goal in cleft lip surgery is to avoid serious scarring, residual scars are often observed after primary surgery. The goal of this preliminary report was to present the standardized application of laser technology to reduce the appearance of residual scars. Design: Ten patients with scarring after unilateral and bilateral cleft lip surgery were treated with a Dual Mode erbium yttrium-aluminum-garnet laser. This laser was recently introduced and had been used only for cosmetic applications, skin resurfacing, and correction of acne scars. Results: An improvement in the clinical appearance of the laser-treated scars was observed after the first treatment, with continued improvement after the second laser session. The clinically observed improvements were corroborated by the patients' reports concerning satisfaction with the result. Conclusions: The combined mechanisms of ablation/coagulation and shrinking of the skin caused by the laser, in addition to observed patient satisfaction and low risk associated with the procedure, suggest that this treatment approach can be effective in the correction of residual scarring in patients with cleft lip.
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ABSTRACT: OBJECTIVE: The aim of this study was to characterize the soft tissue facial features of infants without cleft and to report on the correlation between these with weight, length, and head circumference. DESIGN: This was a prospective study using a noninvasive three-dimensional (3D) stereophotogrammetry (C3D) system to capture the images of the participants. Landmarks were identified on the 3D facial images. Means and SDs were derived for facial distances and angles. A facial asymmetry score was calculated for each image. Two sample Student's t tests, Pearson's correlation coefficients and analysis of covariance were used to ascertain any gender differences and determine whether these could be explained by weight differences. PARTICIPANTS: Eighty-three infants, 41 boys and 42 girls, were captured at rest with their lips apart, at approximately 3 months of age. RESULTS: Significant sex differences, of 1 to 2 mm, were found in several facial dimensions, such as face height and nose width. The larger facial measurements correlated significantly with body measurements. Analysis of variance confirmed these differences could be explained by differences in weight. There were no sex differences in the nose/mouth width ratios or in any of the angles measured, suggesting that there may be little sex difference in shape. A slight degree of asymmetry in the faces of infants without cleft was detected. CONCLUSIONS: Comparisons between noncleft controls and infants with cleft should take cognizance of normal age and sex variations in height and weight that occur among infants.
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ABSTRACT: We present a novel method of image expansion using vector quantisation. The algorithm is inspired by fractal coding and uses a statistical model of the relationship between details at different scales of the image to interpolate detail at one octave above the highest spatial frequency in the original image. Our method aims at overcoming the drawbacks associated with traditional approaches such as pixel interpolation, which smoothes the scaled-up images, or fractal coding, which bears high computational cost and has limited use due to patent restrictions. The proposed method is able to regenerate plausible image detail that was irretrievable when traditional approaches are used. The vector quantisation-based method outperforms conventional approaches in terms of both objective and subjective evaluations. 1 Introduction Digital cinema sequences can be captured at a number of different resolutions, for example 2K pixels across or 4K pixels across. The cameras used for high resolutions are expensive and the data files they produce are large. Because of this, studios may chose to capture some sequences at lower resolution and others at high resolution. The different resolution sequences are later merged during post production. The merger requires that some form of image expansion be performed on the lower resolution sequences. In this paper we present a new method of doing the image expansion that has some advantages over the orthodox interpolation methods. The paper is organised as follows. Section 2 will review some of the existing techniques of image expansion and highlight their shortcomings. In Section 3, we will describe the proposed algorithm in details including the process of training the algorithm, constructing the library used in it, and producing as well as enhancing the expanded image using the algorithm. Section 4 contains our experimental results in which our proposed method is evaluated. The paper concludes in Section 5.
