Jakub Michoński

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.

Art documentation quality in function of 3D scanning resolution and precision

Currently, a lot of different 3D scanning devices are used for 3D acquisition of art artifact surface shape and color. Each of them has different technical parameters starting from measurement principle (structured light, laser triangulation, interferometry, holography) and ending on parameters like measurement volume size, spatial resolution and precision of output data and color information. Some of the 3D scanners can grab additional information like surface normal vectors, BRDF distribution, multispectral color. In this paper, the problem of establishing of threshold for technical parameters of 3D scanning process as a function of required information about the object is discussed. Only two main technical parameters are under consideration, in order to cover as many different 3D scanning devices as possible - measurement sampling density (MSD - represented by number of points per square millimeter) and measurement uncertainty (MU - directly influencing final data accuracy). Also different materials and finishing techniques require different thresholds of MSD and MU parameters to collect similar documentation (for example documentation of object state for art conservation department) of different objects. In this paper we consider exemplary painting on canvas, wallpainting, graphics prints and stone samples to visualize what object features can be observed within different values of MSD and MU parameters.

Application of multi-resolution 3D techniques in crime scene documentation with bloodstain pattern analysis

In forensic documentation with bloodstain pattern analysis (BPA) it is highly desirable to obtain non-invasively overall documentation of a crime scene, but also register in high resolution single evidence objects, like bloodstains. In this study, we propose a hierarchical 3D scanning platform designed according to the top-down approach known from the traditional forensic photography. The overall 3D model of a scene is obtained via integration of laser scans registered from different positions. Some parts of a scene being particularly interesting are documented using midrange scanner, and the smallest details are added in the highest resolution as close-up scans. The scanning devices are controlled using developed software equipped with advanced algorithms for point cloud processing. To verify the feasibility and effectiveness of multi-resolution 3D scanning in crime scene documentation, our platform was applied to document a murder scene simulated by the BPA experts from the Central Forensic Laboratory of the Police R&D, Warsaw, Poland. Applying the 3D scanning platform proved beneficial in the documentation of a crime scene combined with BPA. The multi-resolution 3D model enables virtual exploration of a scene in a three-dimensional environment, distance measurement, and gives a more realistic preservation of the evidences together with their surroundings. Moreover, high-resolution close-up scans aligned in a 3D model can be used to analyze bloodstains revealed at the crime scene. The result of BPA such as trajectories, and the area of origin are visualized and analyzed in an accurate model of a scene. At this stage, a simplified approach considering the trajectory of blood drop as a straight line is applied. Although the 3D scanning platform offers a new quality of crime scene documentation with BPA, some of the limitations of the technique are also mentioned.

Automated full-3D digitization system for documentation of paintings

In this paper, a fully automated 3D digitization system for documentation of paintings is presented. It consists of a specially designed frame system for secure fixing of painting, a custom designed, structured light-based, high-resolution measurement head with no IR and UV emission. This device is automatically positioned in two axes (parallel to the surface of digitized painting) with additional manual positioning in third, perpendicular axis. Manual change of observation angle is also possible around two axes to re-measure even partially shadowed areas. The whole system is built in a way which provides full protection of digitized object (moving elements cannot reach its vicinity) and is driven by computer-controlled, highly precise servomechanisms. It can be used for automatic (without any user attention) and fast measurement of the paintings with some limitation to their properties: maximum size of the picture is 2000mm x 2000mm (with deviation of flatness smaller than 20mm) Measurement head is automatically calibrated by the system and its possible working volume starts from 50mm x 50mm x 20mm (10000 points per square mm) and ends at 120mm x 80mm x 60mm (2500 points per square mm). The directional measurements obtained with this system are automatically initially aligned due to the measurement head’s position coordinates known from servomechanisms. After the whole painting is digitized, the measurements are fine-aligned with color-based ICP algorithm to remove any influence of possible inaccuracy of positioning devices. We present exemplary digitization results along with the discussion about the opportunities of analysis which appear for such high-resolution, 3D computer models of paintings.

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.

Tracking of aging process by multiple 3D scans analysis

Currently, a lot of different 3D scanning devices are used for 3D acquisition of art artifact surface shape and color. Each of them has different technical parameters starting from measurement principle (structured light, laser triangulation, interferometry, holography) and ending on parameters like measurement volume size, spatial resolution and precision of output data and color information. Some of the 3D scanners can grab additional information like surface normal vectors, BRDF distribution, multispectral color. In this paper, we plan to present results of the measurements with selected sampling densities together with discussion of the problem of recognition and assessment of the aging process. We focus our interest on features that are important for the art conservators to define state of preservation of the object as well as to assess changes on the surface from last and previous measurement. Also different materials and finishing techniques requires different algorithms for detection and localization of aging changes. In this paper we consider exemplary stone samples to visualize what object features can be detected and tracked during aging process. The changes in sandstone surface shape, affected by salt weathering, will be presented as well as possibilities of identification of surface degradation on real object (garden relief made in sandstone).

Supporting of Postural Deformities Diagnosis Using 3D Scanning

Traditionally posture deformity assessment for screening purposes is performed by visual examination of patient’s body by an expert. During further follow-up of the diagnosed deformity full spine, X-Ray 2D images are acquired. 3D medical imaging (Computer Tomography and MRI) is used when the spinal surgery is considered. Visual examination is subjective and is strongly dependent on expert knowledge. X-Ray and tomographic imaging exposure can be contraindicated in some cases (i.e. pregnancy). During last two decades, the dynamic development of methods and systems for 3D scanning and algorithms for measurement data analysis is observed. 3D scanning is successfully applied in modern industrial production lines, documentation of cultural heritage and human body analysis. Recently, algorithms for data analysis allow for 100% inspection of complex geometry and have increasing support for control of the technological process parameters on the base of calculated deviation between measurement and assumed 3D model. In this paper, we present an alternative approach for back posture analysis based on structured light 3D scanning. We present three different systems: mobile solution for prescreening of back shape, full body 3D scanner for monitoring of posture deformities and 4D scanner for dynamic analysis. Such a three-stage system fit into the idea of evidence-based medicine. Each of presented devices produces 3D geometry data representing the surface of patient’s body. Each of them has also accompanying software that has been developed for processing of geometry data into a final form that is easily interpreted by medical experts (angles, asymmetries, 3D models, changes in time of analyzed measures, etc.).

Posture and low back pain during pregnancy — 3D study

OBJECTIVES Back pain is a common complaint of pregnant women. The posture, curvatures of the spine and the center of gravity changes are considered as the mechanisms leading to pain. The study aimed to assess spinal curvatures and static postural characteristics with three-dimensional surface topography and search for relationships with the occurrence of back pain complaints among pregnant women. MATERIAL AND METHODS The study was conducted from December 2012 to February 2014. Patients referred from University Clinic of Gynecology and Obstetrics were examined outpatient at the Posture Study Unit of Department of Orthopaedics and Traumatology. Sixty-five women at 4-39 weeks of pregnancy were assessed and surveyed with Oswestry Disability Index; posture was evaluated using surface topography. RESULTS The study confirmed that difficulties in sitting and standing are significant in the third trimester of the pregnancy. The overall tendency for significant lumbar curvature changes in pregnant women was not confirmed. Major changes in sagittal trunk inclination in relation to the plumb line were not observed in the study group. CONCLUSIONS The issue regarding how the pregnancy causes changes in spinal curvature and posture remains open for further studies. Presented method of 3D surface topography can reveal postural changes, but that requires several exams of each subject and strict follow-up of the series of cases.

Manual versus automatic indices assessment based on a marker-less, three dimensional, structural light surface topography postural evaluation. Preliminary study

Methods A 3D Orthoscreen system, designed for postural deformity telediagnostics, using the structural light method, was used for school screening [2,3]. Clouds of dots were acquired for every subject. POTSI, DAPI, kyphosis and lordosis were measured, after marker-less landmarking of anatomical back structures, manually and automatically, for the same subjects. 50 subjects were assessed, 22 male adolescent subjects (average age 15.18 years from 14 to 17) and 28 females (average age 14.55 from 14 to 16) were examined. Their clouds of dots were acquired and saved. Clouds were retrieved and analyzed utilizing 3D Orthoscreen system. An operator (trained professional) retrieved 3D data and analyzed by pointing landmarks manually or automatically. After landmarking, procedure Indices and angular measurements were calculated by the system. MedCalc statistical software (Version 12.1.4.0) was used to calculate Inter-rater correlation for measurements.

Novel active-SfM solution for three-dimensional crime scene documentation

As forensic science technologies progress, digital photography in the crime scene documentation is being replaced in favor of high-precision 3D measurements. Three-dimensional documentation presents every object in the context of the entire crime scene and allows accurate measurements between potentially important traces, like bloodstains or weapons. These and other advanced 3D documentation and analysis tools have improved the possibilities of investigation to a previously unattainable level. We present a novel solution for detailed 3D documentation, which overcomes the limitations of commonly used 3D measurement techniques, e.g. highly accurate Structured Light Scanning or convenient to use Structure from Motion. Our solution, called active-SfM, involves the use of special projection devices to project a random pattern on the part of the scene under measurement. This modification makes the measurement process robust and reliable, even when measuring featureless surfaces. The reconstructed 3D model has better quality and surface uniformity than the result of standard Structure from Motion measurements. Moreover, the acquisition process remains as quick and easy to use as before the modifications. We present newly developed equipment: wireless projection devices and controllers, that were designed especially to be used by forensic technicians on crime scenes and that are compatible with stock cameras used by them in everyday practice. We also present a full set of developed algorithms that transform input images into the final 3D model. The proposed solution complements the hierarchical, three-dimensional measurement system developed in recent years by Polish Central Forensic Laboratory of the Police, CYBID Ltd., and Warsaw University of Technology, designed especially for crime scene documentation. The whole documentation process is supervised by a specialized CrimeView3D application, a software platform for measurement management and data visualization. We also present the outcome of measurement sessions that were conducted on both simulated and real crime scenes with the cooperation of Technicians from Central Forensic Laboratory of Police.