methods for antropometric analysis of 3d body scanner data
TRANSCRIPT
Methods for antropometric analysis of 3D Body Scanner dataChristian Lovato
Discussion
References
Introduction Method
Graduate School of Sciences Engineering MedicinePh.D. Program in Multimodal Imaging in Biomedicine
Results
Take-home message
Faculty of Medicine and SurgeryDepartment of Neurological, Neuropsychological, Morphological and Movement Sciences
Recent advances on scanning techniques make possible to acquire high resolution models of the human body that can be extremely useful in order to assist people involved in anthropometric studies, but also for other appli-cations like medical diagnosis, clothing design, computer animation and entertainment.
Traditional anthropometry largely rely on expert use of tapes and calipers, that are generally limited to 1D information. Body scanning technology provides 3D data of body surface, so the measurement capabilities can be directly extended to body volumes and surface areas. Moreover, measure-ment practices result more reliable and less expensive [1].
Whereas there are commercial application are avaiable for anthropometry, active research is focused on protocols and computer algorithms that can improve 3D analysis applied to clinical practice and diagnosis.
Most of data we process come from Breuckmann Bodyscan® owned by Faculty of Exercise and Sport Science. We also perform experiments on body acquisi-tions coming from other scanning devices, in order to obtain device indepen-dent procedures.To validate the anthropometric measurements performed by body scanner ac-quisitions, has been developed a software application[2] that allow to repro-duce in-silico traditional anthropometric procedures.In order to compute biological parameters on large number of subjects, it's useful to have an automated processing pipeline. This pipeline should perform mesh pre-processing and, as desired, more sophisticated high level measure-ments over speci�c subject ranges.For high level analysis on human shapes, we make experiments with state of art mesh analysis algorithms, like skeleton analysis[3] and HKS[4] based feature analysis.
The research is done in collaboration with the VIPS Lab., of the Dept. of Com-puter Science
The validation step was performed developing a tool that allow to mimic the traditional tape and calipers measurements. The application, developed in MS Visual Studio and VTK libraries, allow a skilled anthropometris to indentify anthorpometric points on a body mesh and perform measurements.Manual and computer based measurement was performed on 12 subjects and com-pared. Preliminary results has been presented.
Some snapshot of the application, representing a di�erent kind of measure: height,lenght, planar girths and 4-point geodesic girth
The whole body scanner processing pipeline[5]. After the "raw" geometrical processing methods already developed we plan to add a �ner processing able to detect automati-cally anthropometric features and improving measurements precision. Pipeline is imple-mented using C++, Matlab and Meshlab.
The high resolution interactive hole-�lling procedure, able to close reasonably large holes like the hair region, not reliably acquired by most scanners. A: original data acquired with a structured light scanner, without using cap. B: segmentation of the reliable regions, presenting large holes. C: The generic model of the part of interest (in this case the head: the region corresponding to the segmented part in B is extracted and used as input for a nonlinear registration procedure. D: After the registration, patches are extracted and zip-pering is performed
HKS based feature points detection and classi�cation applied to body shape.
In �gure are shown feature points detected at di�erent scales. Point colors indicate the lablel associated with the speci�c point
Surface data -some zones not covered (holes)Mesh defects -some mesh points lack of geometrical congruenceArtifacts -movement: a living subject moves physiologically -Black/re�ective surfacesGood precision and density
1. M Mortara, G Patane, and M. Spagnuolo. From geometric to semantic humanbody models. Computers & Graphics, page 185196, 20062. C. Lovato, U. Castellani, S. Fantoni, C. Milanese, C. Zancanaro, A. Giachetti. Computer assisted estimation of anthropometric parameters from whole body scanner data in N. Magnenat-Thalmann (Ed.): 3DPH 2009 pp.71-83 3. C. Lovato, U. Castellani and A.Giachetti Automatic segmentation of scanned human body using curve skeleton analysis proc. Mirage 2009, Springer, LNCS, 20094. Sun J., Ovsjanikov M., Guibas L.: A concise and provably informative multi-scale signature based on heat di�usion. In Euro-graphics Symposium on Geometry Processing (SGP) (2009)5. Lovato C., Castellani U., Zancanaro C., Giachetti A., Geometrical processing of 3D body scanner data for anthropometric appli-cations , Proceedings of "3D Body Scanning Technologies" , Lugano , 19-20 Ottobre , 2010 ,eds. N.D'Apuzzo, pp. 341-348
Digital antropometry can relevantly improve the the analysis of human body shape and its evolution. It allow to exend antropometric analysis in new �elds, like the possibility of correlate shape indicators with biological variables (i.e. methabolic indicators).
Our work is focused on:- the selection, customization and implementation of geometry processing tool useful to process human body models created by whole body scanners, in order to obtain speci�c anthropometric measurements-the implementation of a pipe (that the use of open source programs and custom applications) not depending on a particular scanner or acquisition protocol able to extract a lot of useful information from heterogeneous models, allowing the use of advanced algorithms for body parts recognition and landmarks location.
We obtained encouraging results, but there seems to be already a lot of work to do, in order to achieve our goals.
Body scanner technology provide a new way to examine human body. Body scanners are chep and are broadly di�using because of their wide range of applications.When enough research will be carried out, this technology will pre-sumably o�er some real opportunities for improvement of public health.