Non-rigid registration of sculptured surfaces in Internet environment

Abstract

Ovaj rad ima za cilj da prouči fenomen digitalne rekonstrukcije i prepoznavanja spoljašnjih anatomskih pokazatelja i uparivanja istih sa raznim vidovima deformiteta kičmenog stuba u cilju neinvazivne identifikacije deformiteta. Pristup je zasnovan na korišćenju digitalizovanih dorzalnih površi pacijenata, dobijenih različitim modalitetima i senzorima. Analizom 3D krivina i njenih projekcija u sagitalnoj i frontalnoj ravni detektuje se stepen deformiteta, kao i progresija, čime se stvaraju osnove za neinvazivnu dijagnostiku i praćenje, trenda stanja pacijenta tokom sprovođenja terapije. Istraživanje je usmereno ka sveobuhvatnoj proceni trenda i zastupljenosti idiopatskih skolioza i drugih deformiteta, kroz razvoj novih 3D sistema za vizuelizaciju i dijagnostiku deformiteta. Očekuje se da ovakav pristup značajno unapredi postojeće metode u radu sa pacijentima, kao i da stvori čvrstu osnovu za kreiranje Web-orijentisanih baza podataka, informacionih sistema i relevantnih aplikacija za praćenje deformiteta kičmenog stuba. Tradicionalna dijagnostika deformiteta kičmenog stuba, koja podrazumeva izlaganje pacijenata štetnom jonizujućem zračenju, zamenjuje se novim neinvazivnim (bezopasnim) metodama. Kako bi se izbegle ili značajno redukovale metode koje su potencijalno opasne, primenjuju se i razvijaju nove na bazi optičkih i laserskih uređaja za snimanje topografije leđne površi. Rezultat takvog snimanja je oblak tačaka, odnosno diskretizovana reprezentacija složene, deformabilne dorzalne površi. 3D rekonstrukcija i semantička identifikacija/anotacija skulpturnih i „free form” površi predstavlja veliki izazov u nauci. To se posebno odnosi na pristupe njihovoj registraciji (prepoznavanju diskretizovanih zapisa dobijenih različitim multi-senzorskim mernim sistemima za različite konfiguracije), matematičkom opisu, prostornoj i ravanskoj analizi, parametarske opise deformabilnosti površi, identifikaciju i opis ostalih parametara kojima se bliže definiše deformitet i topologija (tip krivina, spoljašnji i unutrašnji pokazatelji, aksijalna rotacija, i sl.). Jedan od osnovnih ciljeva rada na doktorskoj disertaciji je razvoj novih algoritama za 3D registraciju, modeliranje i sveobuhvatnu analizu diskretizovanih deformabilnih skulpturnih dorzalnih površi pacijenata sa deformitetima kičmenog stuba. Primena tih algoritama putem Internet portala treba da doprinese bržem i preciznijem dijagnostikovanju deformiteta kičmenog stuba, pouzdanoj klasifikaciji, permanentnom monitoringu, kao i kreiranju Web-orijentisanih baza podataka za regionalno praćenje rasprostranjenosti, opštih i specifičnih karakteristika oboljenja. U tom smislu, planirana je verifikacija rezultata kroz kliničku implementaciju i testiranje Web-orijentisanog sistema za praćenje deformiteta kičmenog stuba (skolioza, kifoza, lordoza) pozantijeg pod nazivom ScolioMedIS u Centru za fizikalnu medicinu i rehabilitaciju i Klinici za ortopediju i traumatologiju Kliničkog centara Kragujevac, ali i u drugim zainteresovanim zdravstvenim ustanovama u regionu.This dissertation aims in studying the phenomenon of digital (virtual) recognition of external anatomical parameters (indices) and matching them with various modalities of spinal deformities in order to provide noninvasive identification and classification of the deformities. The approach is based on the usage of digitized patients’ back surface obtained by various modalities and sensors. Analysis of 3D curves and their projections in the sagittal and frontal planes the degree of deformity can be detected, as well as the deformity progression, thus creating the basis for noninvasive diagnosis and monitoring of the disease, its trend and dynamics during the therapy. This research is directed towards a comprehensive assessment of the trend and the presence of idiopathic scoliosis and other deformities, through the development of new 3D classification scheme for the deformity ranking. It is expected that this approach will significantly improve the existing methods of patient’s treatment, and to create a sound basis for creation of Web-oriented databases, information systems and relevant applications for spinal deformity monitoring. Traditional diagnosis methods of spinal deformities, which involve exposing the patients to harmful ionizing radiation, are replacing by a new non-invasive (harmless) methods. In order to avoid or significantly reduce the methods that are potentially dangerous and harmful, new ones are developing based on optical and laser devices for imaging of the surface topography of the back. The result of such scanning is a cloud of points, i.e. discretized representation of the complex, deformable (non-rigid, elastic) surfaces of the human back. 3D reconstruction and semantic identification/annotation of sculptured and “free form” surfaces emerge as a big scientific challenge. This especially holds for the approaches to their registration (recognition of discretized records obtained by various multi-sensor measurement systems at different configurations), spatial and planar analysis, parametric descriptions of the elastic deformation of the surfaces, and identification and description of other parameters that more closely define the deformity and its topology (type of curvature, translation, rotation, etc.). One of the main goals of the Ph.D. thesis is the development of new algorithms for the registration and comprehensive analysis of the discretized deformable sculptured surface of a back and a chest of patients with spinal deformities. The application of these algorithms through the Internet portal should contribute to faster and more accurate diagnosis of spinal deformities, reliable classification, permanency of monitoring, as well as creating Web-oriented databases for regional monitoring of presence, general and specific disease characteristics. In that course, it is planned to verify the research results through the clinical implementation and validation of Web-oriented system for spinal deformities (scoliosis, kyphosis, lordosis) monitoring at the Center for Physical Medicine and Rehabilitation and the Clinic of Orthopedics and Traumatology, both units of Clinical Center Kragujevac (Serbia), as well as in other interested health care institutions in the region