MScMS-II: an innovative IR-based indoor coordinate measuring system for large-scale metrology applications

According to the current great interest concerning large-scale metrology applications in many different fields of manufacturing industry, technologies and techniques for dimensional measurement have recently shown a substantial improvement. Ease-of-use, logistic and economic issues, as well as metrological performance are assuming a more and more important role among system requirements. This paper describes the architecture and the working principles of a novel infrared (IR) optical-based system, designed to perform low-cost and easy indoor coordinate measurements of large-size objects. The system consists of a distributed network-based layout, whose modularity allows fitting differently sized and shaped working volumes by adequately increasing the number of sensing units. Differently from existing spatially distributed metrological instruments, the remote sensor devices are intended to provide embedded data elaboration capabilities, in order to share the overall computational load. The overall system functionalities, including distributed layout configuration, network self-calibration, 3D point localization, and measurement data elaboration, are discussed. A preliminary metrological characterization of system performance, based on experimental testing, is also presente

Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery

One of the main challenges for computer-assisted surgery (CAS) is to determine the intra-opera- tive morphology and motion of soft-tissues. This information is prerequisite to the registration of multi-modal patient-specific data for enhancing the surgeon’s navigation capabilites by observ- ing beyond exposed tissue surfaces and for providing intelligent control of robotic-assisted in- struments. In minimally invasive surgery (MIS), optical techniques are an increasingly attractive approach for in vivo 3D reconstruction of the soft-tissue surface geometry. This paper reviews the state-of-the-art methods for optical intra-operative 3D reconstruction in laparoscopic surgery and discusses the technical challenges and future perspectives towards clinical translation. With the recent paradigm shift of surgical practice towards MIS and new developments in 3D opti- cal imaging, this is a timely discussion about technologies that could facilitate complex CAS procedures in dynamic and deformable anatomical regions

Rubberized cord thickness measurement based on laser triangulation, Part I: Technology

U radu je prezentiran konceptualni okvir tehnologije merenja ekvivalnentne debljine gumiranog korda primenom optičke triangulacije. Detaljno je izložen analitički model laserskog proksimetra i razmatrani su osnovni problemi vezani za funkcionisanje i primenu laserske triangulacije u merenju distance objekata sa izrazito tekstuiranom površinom koja poseduje neuniformna optička svojstva. Predložena je nova metoda koja omogućava robusnu i visokopreciznu estimaciju efektivne debljine gumiranog korda. Ova metoda je bazirana na struktuiranju površi na tri sloja i statističkoj karaketerizaciji ovih slojeva. Pokazano je da tekstura gumiranog korda odgovara klasi Gausovih površi, na osnovu čega je moguće precizno i vrlo robusno izračunavanje ekvivalnetne debljine samo na osnovu estimiranih parametara normalne raspodele skeniranog uzorka površi. Laboratorijski eksperimenti su potvrdili praktičnu upotrebljivost ove metode i stvorile realne osnove za razvoj nove tehnologije mernih sistema koji će moći da zamene konvencionalna rešenja bazirna na senzorima sa prirodnim ili veštačkim švorima radioaktivnog zračenja.Steel and textile cord coating is one of the key rubber processing technologies in tire making industry. Specifications are very demanding. In particular, thickness variation across the sheet profile and downstream is very difficult to fulfill. For in-process thickness measurement the most common are systems based on non-contact beta or gamma radiation sensors. Regardless of their wide use, non-contact radiation sensors possess serious drawbacks: they are measuring thickness in indirect way only, they are highly sensitive to variations of material properties, and probably the most critical one, they are potentially dangerous for both personnel and environment. Recent advances in optoelectronics have founded new alternative method for non-contact thickness measurement based on laser triangulation. Extremely delicate optical properties of fresh calendered rubber and severe environmental conditions create serious problems in implementation of this technology. This two-part paper presents a general conceptual framework for in-process laser-based thickness measurement, and proposes a new method for processing acquired sensory data based on statistical surface characterization. Proposed method is experimentally verified, and based on these results the new measuring systems are developed and implemented in industry

Rubberized cord thickness measurement based on laser triangulation, Part I: Technology

U radu je prezentiran konceptualni okvir tehnologije merenja ekvivalnentne debljine gumiranog korda primenom optičke triangulacije. Detaljno je izložen analitički model laserskog proksimetra i razmatrani su osnovni problemi vezani za funkcionisanje i primenu laserske triangulacije u merenju distance objekata sa izrazito tekstuiranom površinom koja poseduje neuniformna optička svojstva. Predložena je nova metoda koja omogućava robusnu i visokopreciznu estimaciju efektivne debljine gumiranog korda. Ova metoda je bazirana na struktuiranju površi na tri sloja i statističkoj karaketerizaciji ovih slojeva. Pokazano je da tekstura gumiranog korda odgovara klasi Gausovih površi, na osnovu čega je moguće precizno i vrlo robusno izračunavanje ekvivalnetne debljine samo na osnovu estimiranih parametara normalne raspodele skeniranog uzorka površi. Laboratorijski eksperimenti su potvrdili praktičnu upotrebljivost ove metode i stvorile realne osnove za razvoj nove tehnologije mernih sistema koji će moći da zamene konvencionalna rešenja bazirna na senzorima sa prirodnim ili veštačkim švorima radioaktivnog zračenja.Steel and textile cord coating is one of the key rubber processing technologies in tire making industry. Specifications are very demanding. In particular, thickness variation across the sheet profile and downstream is very difficult to fulfill. For in-process thickness measurement the most common are systems based on non-contact beta or gamma radiation sensors. Regardless of their wide use, non-contact radiation sensors possess serious drawbacks: they are measuring thickness in indirect way only, they are highly sensitive to variations of material properties, and probably the most critical one, they are potentially dangerous for both personnel and environment. Recent advances in optoelectronics have founded new alternative method for non-contact thickness measurement based on laser triangulation. Extremely delicate optical properties of fresh calendered rubber and severe environmental conditions create serious problems in implementation of this technology. This two-part paper presents a general conceptual framework for in-process laser-based thickness measurement, and proposes a new method for processing acquired sensory data based on statistical surface characterization. Proposed method is experimentally verified, and based on these results the new measuring systems are developed and implemented in industry

Tele-Autonomous control involving contact

Object localization and its application in tele-autonomous systems are studied. Two object localization algorithms are presented together with the methods of extracting several important types of object features. The first algorithm is based on line-segment to line-segment matching. Line range sensors are used to extract line-segment features from an object. The extracted features are matched to corresponding model features to compute the location of the object. The inputs of the second algorithm are not limited only to the line features. Featured points (point to point matching) and featured unit direction vectors (vector to vector matching) can also be used as the inputs of the algorithm, and there is no upper limit on the number of the features inputed. The algorithm will allow the use of redundant features to find a better solution. The algorithm uses dual number quaternions to represent the position and orientation of an object and uses the least squares optimization method to find an optimal solution for the object's location. The advantage of using this representation is that the method solves for the location estimation by minimizing a single cost function associated with the sum of the orientation and position errors and thus has a better performance on the estimation, both in accuracy and speed, than that of other similar algorithms. The difficulties when the operator is controlling a remote robot to perform manipulation tasks are also discussed. The main problems facing the operator are time delays on the signal transmission and the uncertainties of the remote environment. How object localization techniques can be used together with other techniques such as predictor display and time desynchronization to help to overcome these difficulties are then discussed

A novel haptic model and environment for maxillofacial surgical operation planning and manipulation

This paper presents a practical method and a new haptic model to support manipulations of bones and their segments during the planning of a surgical operation in a virtual environment using a haptic interface. To perform an effective dental surgery it is important to have all the operation related information of the patient available beforehand in order to plan the operation and avoid any complications. A haptic interface with a virtual and accurate patient model to support the planning of bone cuts is therefore critical, useful and necessary for the surgeons. The system proposed uses DICOM images taken from a digital tomography scanner and creates a mesh model of the filtered skull, from which the jaw bone can be isolated for further use. A novel solution for cutting the bones has been developed and it uses the haptic tool to determine and define the bone-cutting plane in the bone, and this new approach creates three new meshes of the original model. Using this approach the computational power is optimized and a real time feedback can be achieved during all bone manipulations. During the movement of the mesh cutting, a novel friction profile is predefined in the haptical system to simulate the force feedback feel of different densities in the bone