Marcin Witkowski

Method of pectus excavatum measurement based on structured light technique

We present an automatic method for assessment of pectus excavatum severity based on an optical 3-D markerless shape measurement. A four-directional measurement system based on a structured light projection method is built to capture the shape of the body surface of the patients. The system setup is described and typical measurement parameters are given. The automated data analysis path is explained. Their main steps are: normalization of trunk model orientation, cutting the model into slices, analysis of each slice shape, selecting the proper slice for the assessment of pectus excavatum of the patient, and calculating its shape parameter. We develop a new shape parameter (I(3ds)) that shows high correlation with the computed tomography (CT) Haller index widely used for assessment of pectus excavatum. Clinical results and the evaluation of developed indexes are presented.

Automatic recognition of surface landmarks of anatomical structures of back and posture

Faulty postures, scoliosis and sagittal plane deformities should be detected as early as possible to apply preventive and treatment measures against major clinical consequences. To support documentation of the severity of deformity and diminish x-ray exposures, several solutions utilizing analysis of back surface topography data were introduced. A novel approach to automatic recognition and localization of anatomical landmarks of the human back is presented that may provide more repeatable results and speed up the whole procedure. The algorithm was designed as a two-step process involving a statistical model built upon expert knowledge and analysis of three-dimensional back surface shape data. Voronoi diagram is used to connect mean geometric relations, which provide a first approximation of the positions, with surface curvature distribution, which further guides the recognition process and gives final locations of landmarks. Positions obtained using the developed algorithms are validated with respect to accuracy of manual landmark indication by experts. Preliminary validation proved that the landmarks were localized correctly, with accuracy depending mostly on the characteristics of a given structure. It was concluded that recognition should mainly take into account the shape of the back surface, putting as little emphasis on the statistical approximation as possible.

Locating and tracing of anatomical landmarks based on full-field four-dimensional measurement of human body surface

Four-dimensional (4D) (3D+time) measurement systems make it possible today to measure objects while moving and deforming. One of the fields where 4D systems prove themselves useful is medicine--particularly orthopedics and neural sciences--where measurement results may be used to estimate dynamic parameters of a patients movement. Relatively new in 4D, optical full-field shape measurement systems capture more data than standard marker-based systems and open new ways for clinical diagnosis. However, before this is possible, the appropriate 4D data processing and analysis methods need to be developed. We present a new data analysis path for 4D data input as well as new shape parameters describing local features of a surface. The developed shape parameters are easier and quicker to calculate than standard surface parameters, such as curvatures, but they give results that are very similar to the latter. The presented 4D data analysis path allows characteristic areas on the body, so-called anatomical landmarks, to be located and traces them in time along the measurement sequence. We also present the general concepts and describe selected steps of the developed 4D data analysis path. The algorithms were implemented and tested on real and computer-generated data representing the surface of lower limbs. Finally, we give sample processing and analysis results.

3D Diagnostic System for Anatomical Structures Detection Based on a Parameterized Method of Body Surface Analysis

Features of trunk and postural deformations are clinically observed to detect related musculoskeletal disorders, namely scoliosis, kyphosis or other thoracic deformities. High variability and controversial reliability of results of postural screening require new solutions to be employed. Standardized criteria for correct body posture are needed for further studies. The aim of this work was to present the current status of development of the 3D diagnostic system for anatomical structures detection. The designed system is based on a parameterized method of body surface analysis for automated measurement of the three-dimensional shape of patient’s trunk. This system uses structured light to measure patient’s body in 3D space by projection of a set of raster images on its surface. A unique feature of the presented system is the ability to operate on remote sites and carry out measurement interpretation by telemedicine utilizing a data warehouse. The system comprises of three independent modules which deal with measurement, data archiving and its analysis. Communication between modules is performed over the TCP/IP protocol, incorporating two different channels for each client, dedicated to two kinds of data - text channel, for transmission of XML documents used for delivering commands and information and binary channel for the transfer of large binary data, such as clouds of points or photographs. Presented modules altogether allow to measure the full shape of subject’s 3D surface along with measurement data storage and analysis for support of screening and diagnosis.

3D anthropometric algorithms for the estimation of measurements required for specialized garment design

A complete guide for anthropometric data acquisition from a 3D scan is introduced.A comparison with manual measurements and a state-of-the-art system is presented.Common 3D anthropometry problems and origins are discussed. 3D anthropometry is key to the automation and facilitation of tedious, costly, and time-consuming traditional anthropometric tasks such as the size designation of a specialized garment.This article provides a short survey of 3D anthropometry in garment design. The results show that due to a lack of detailed, complex analyses of the entire anthropometric procedure from a raw body scan to a set of anthropometric measurements, there was a need to prepare and describe a comprehensive system from scratch. The aim of this article is, therefore, to present the developed 3D anthropometric solution, along with fully documented algorithms for automatic measurement extraction from a 3D body scan, results of tests, and its validation.Based on a list of desired measurements, a general processing path was prepared. Its methods are described in detail, including algorithms for body segmentation, characteristic points localization (body landmarking), and final specific measurements of girth, arc, and linear lengths (widths and heights). Furthermore, pseudo-code for the algorithms and 3D description of the characteristic points is included in Appendices A and B. The scanning procedure and posture recommendations are explained. Finally, test results and analyses are presented.The validation dataset consisted of 40 subjects (21 male and 19 female volunteers) aged between 25 and 55 years, weighing from 55 to 105kg and 150 to 205cm tall. Each of the subjects was measured once manually and three times automatically by both our system and the Human Solutions system to check the repeatability of the consecutive measurements. The performance of the 3D anthropometric system was evaluated by comparing its output with the manual measurements treated as the best possible ground truth. The output was also compared with the results from a leading commercial 3D anthropometric scanning solution provided by Human Solutions GmbH. The accuracy of both systems was measured using both the relative percent and millimeter difference error. Consistency and absolute agreement between systems and manual measurements were evaluated using the Intraclass Correlation Coefficient (ICC) method. Finally, comparability between the manual and automated measurements was assessed according to ISO 20685. It appeared that for our system, only 5 out of 26 measurement types passed the highly demanding test from ISO 20685 and for the Human Solutions system, 3 out of 26 types passed the test. However, most of the accuracy, consistency, and absolute agreement results appeared to be on a satisfactory level according to garment design experts taking part in the project. Girth measurements were characterized by the highest degree of consistency and absolute agreement, while arc length measurements were still acceptable, but least satisfactory. The degrees of general consistency and absolute agreement between our system and manual measurements fell into the excellent interval of the ICC practical significance measure. These tests also showed high inter-rater agreement between the proposed system and the commercial one (the Human Solutions product). It appeared that the current version of the system can provide results relatively close to those of the state-of-the-art solution. However the system still needs further development and tests on a larger population, as it is not completely free of errors, particularly those resulting from improper body landmarking and inconsistent posture.

Structured-Light-Based System for Shape Measurement of the Human Body in Motion

The existing methods for measuring the shape of the human body in motion are limited in their practical application owing to immaturity, complexity, and/or high price. Therefore, we propose a method based on structured light supported by multispectral separation to achieve multidirectional and parallel acquisition. Single-frame fringe projection is employed in this method for detailed geometry reconstruction. An extended phase unwrapping method adapted for measurement of the human body is also proposed. This method utilizes local fringe parameter information to identify the optimal unwrapping path for reconstruction. Subsequently, we present a prototype 4DBODY system with a working volume of 2.0 × 1.5 × 1.5 m3, a measurement uncertainty less than 0.5 mm and an average spatial resolution of 1.0 mm for three-dimensional (3D) points. The system consists of eight directional 3D scanners functioning synchronously with an acquisition frequency of 120 Hz. The efficacy of the proposed system is demonstrated by presenting the measurement results obtained for known geometrical objects moving at various speeds as well actual human movements.

A Potential Use of 3-D Scanning to Evaluate the Chemical Composition of Pork Meat.

UNLABELLED The aim of this study was to determine the possibility of 3-D scanning method in chemical composition evaluation of pork meat. The sampling material comprised neck muscles (1000 g each) obtained from 20 pork carcasses. The volumetric estimation process of the elements was conducted on the basis of point cloud collected using 3-D scanner. Knowing the weight of neck muscles, their density was calculated which was subsequently correlated with the content of basic chemical components of the pork meat (water, protein and fat content, determined by standard methods). The significant correlations (P ≤ 0.05) between meat density and water (r = 0.5213), protein (r = 0.5887), and fat (r = -0.6601) content were obtained. Based on the obtained results it seems likely to employ the 3-D scanning method to compute the meat chemical composition. PRACTICAL APPLICATION The use of the 3-D scanning method in industrial practice will allow to evaluate the chemical composition of meat in online mode on a dressing and fabrication line and in a rapid, noninvasive manner. The control of the raw material using the 3-D scanning will allow to make visual assessment more objective and will enable optimal standardization of meat batches prior to processing stage. It will ensure not only the repeatability of product quality characteristics, but also optimal use of raw material-lean and fat meat. The knowledge of chemical composition of meat is essential due to legal requirements associated with mandatory nutrition facts labels on food products.

Multidirectional four-dimensional shape measurement system

Currently, a lot of different scanning techniques are used for 3D imaging of human body. Most of existing systems are based on static registration of internal structures using MRI or CT techniques as well as 3D scanning of outer surface of human body by laser triangulation or structured light methods. On the other hand there is an existing mature 4D method based on tracking in time the position of retro-reflective markers attached to human body. There are two main drawbacks of this solution: markers are attached to skin (no real skeleton movement is registered) and it gives (x, y, z, t) coordinates only in those points (not for the whole surface). In this paper we present a novel multidirectional structured light measurement system that is capable of measuring 3D shape of human body surface with frequency reaching 60Hz. The developed system consists of two spectrally separated and hardware-synchronized 4D measurement heads. The principle of the measurement is based on single frame analysis. Projected frame is composed from sine-modulated intensity pattern and a special stripe allowing absolute phase measurement. Several different geometrical set-ups will be proposed depending on type of movements that are to be registered.

Internet virtual studio: low-cost augmented reality system for WebTV

In this paper a concept of a Internet Virtual Studio as a modern system for production of news, entertainment, educational and training material is proposed. This system is based on virtual studio technology and integrated with multimedia data base. Its was developed for web television content production. In successive subentries the general system architecture, as well as the architecture of modules one by one is discussed. The authors describe each module by presentation of a brief information about work principles and technical limitations. The presentation of modules is strictly connected with a presentation of their capabilities. Results produced by each of them are shown in the form of exemplary images. Finally, exemplary short production is presented and discussed.

Surface shape parameters and analysis of data captured with use of 4D surface scanners

The recent development of electro-optical instrumentation allowed constructing 4D (3D + time) structure-light scanners which may be used to measure the surface of human body in motion. The main advantage of structure-light scanners is the possibility of capturing data from the whole measured body surface, while traditional marker-based systems acquire data only form markers attached to skin of the examined patient. The paper describes new parameters describing the local shape of measured surface. The distribution maps of these parameters allow discrimination of various surface types and in effect localization and tracing of under-skin anatomical structures in time. The presented parameters give similar results to well-known curvatures but are easier and quicker to calculate. Moreover the calculation process of the new parameters is more numerically stable itself. The developed path of processing and analysis of 4D measurement data has been presented. It contains the following stages: data acquisition, volumetric model creation, calculations of shape parameters, selecting areas of interest, locating and tracing of anatomical landmarks. Exemplary results of application of developed parameters and methods to real measurement and computer generated data are also presented.