Cutting tool tracking and recognition based on infrared and visual imaging systems using principal component analysis (PCA) and discrete wavelet transform (DWT) combined with neural networks

The implementation of computerised condition monitoring systems for the detection cutting tools’ correct installation and fault diagnosis is of a high importance in modern manufacturing industries. The primary function of a condition monitoring system is to check the existence of the tool before starting any machining process and ensure its health during operation. The aim of this study is to assess the detection of the existence of the tool in the spindle and its health (i.e. normal or broken) using infrared and vision systems as a non-contact methodology. The application of Principal Component Analysis (PCA) and Discrete Wavelet Transform (DWT) combined with neural networks are investigated using both types of data in order to establish an effective and reliable novel software program for tool tracking and health recognition. Infrared and visual cameras are used to locate and track the cutting tool during the machining process using a suitable analysis and image processing algorithms. The capabilities of PCA and Discrete Wavelet Transform (DWT) combined with neural networks are investigated in recognising the tool’s condition by comparing the characteristics of the tool to those of known conditions in the training set. The experimental results have shown high performance when using the infrared data in comparison to visual images for the selected image and signal processing algorithms

An interactive simulation tool for patient-specific clinical decision support in single-ventricle physiology

OBJECTIVE: Modeling of single-ventricle circulations has yielded important insights into their unique flow dynamics and physiology. Here we translated a state-of-the-art mathematical model into a patient-specific clinical decision support interactive Web-based simulation tool and show validation for all 3 stages of single-ventricular palliation. METHODS: Via the adoption a validated lumped parameter method, complete cardiovascular-pulmonary circulatory models of all 3 stages of single-ventricle physiology were created within a simulation tool. The closed-loop univentricular heart model includes scaling for growth and respiratory effects, and typical patient-specific parameters are entered through an intuitive user interface. The effects of medical or surgical interventions can be simulated and compared. To validate the simulator, patient parameters were collected from catheterization reports. Four simulator outputs were compared against catheterization findings: pulmonary to systemic flow ratio (Qp:Qs), systemic arterial saturation (SaO2), mean pulmonary arterial pressure (mPAp), and systemic–venous oxygen difference (SaO2–SvO2). RESULTS: Data from 60 reports were used. Compared with the clinical values, the simulator results were not significantly different in mean Qp:Qs, SaO2, or mPAp (P > .09). There was a statistical but clinically insignificant difference in average SaO–SvO2 (average difference 1%, P < .01). Linear regression analyses revealed a good prediction for each variable (Qp:Qs, R2 = 0.79; SaO2, R2 = 0.64; mPAp, R2 = 0.69; SaO2–SvO2, R2 = 0.93). CONCLUSIONS: This simulator responds quickly and predicts patient-specific hemodynamics with good clinical accuracy. By predicting postoperative and postintervention hemodynamics in all 3 stages of single-ventricle physiology, the simulator could assist in clinical decision-making, training, and consultation. Continuing model refinement and validation will further its application to the bedside

Instantaneous and time-averaged flow fields of multiple vortices in the tip region of a ducted propulsor

The instantaneous and time-averaged flow fields in the tip region of a ducted marine propulsor are examined. In this flow, a primary tip-leakage vortex interacts with a secondary, co-rotating trailing edge vortex and other co- and counter-rotating vorticity found in the blade wake. Planar particle imaging velocimetry (PIV) is used to examine the flow in a plane approximately perpendicular to the mean axis of the primary vortex. An identification procedure is used to characterize multiple regions of compact vorticity in the flow fields as series of Gaussian vortices. Significant differences are found between the vortex properties from the time-averaged flow fields and the average vortex properties identified in the instantaneous flow fields. Variability in the vortical flow field results from spatial wandering of the vortices, correlated fluctuations of the vortex strength and core size, and both correlated and uncorrelated fluctuations in the relative positions of the vortices. This variability leads to pseudo-turbulent velocity fluctuations. Corrections for some of this variability are performed on the instantaneous flow fields. The resulting processed flow fields reveal a significant increase in flow variability in a region relatively far downstream of the blade trailing edge, a phenomenon that is masked through the process of simple averaging. This increased flow variability is also accompanied by the inception of discrete vortex cavitation bubbles, which is an unexpected result, since the mean flow pressures in the region of inception are much higher than the vapor pressure of the liquid. This suggests that unresolved fine-scale vortex interactions and stretching may be occurring in the region of increased flow variability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47076/1/348_2005_Article_938.pd

Rapid prototyping compliant arterial phantoms for <it>in</it>-<it>vitro</it> studies and device testing

<p>Abstract</p> <p>Background</p> <p>Compliant vascular phantoms are desirable for <it>in</it>-<it>vitro</it> patient-specific experiments and device testing. TangoPlus FullCure 930® is a commercially available rubber-like material that can be used for PolyJet rapid prototyping. This work aims to gather preliminary data on the distensibility of this material, in order to assess the feasibility of its use in the context of experimental cardiovascular modelling.</p> <p>Methods</p> <p>The descending aorta anatomy of a volunteer was modelled in 3D from cardiovascular magnetic resonance (CMR) images and rapid prototyped using TangoPlus. The model was printed with a range of increasing wall thicknesses (0.6, 0.7, 0.8, 1.0 and 1.5 mm), keeping the lumen of the vessel constant. Models were also printed in both vertical and horizontal orientations, thus resulting in a total of ten specimens. Compliance tests were performed by monitoring pressure variations while gradually increasing and decreasing internal volume. Knowledge of distensibility was thus derived and then implemented with CMR data to test two applications. Firstly, a patient-specific compliant model of hypoplastic aorta suitable for connection in a mock circulatory loop for <it>in</it>-<it>vitro</it> tests was manufactured. Secondly, the right ventricular outflow tract (RVOT) of a patient necessitating pulmonary valve replacement was printed in order to physically test device insertion and assess patient’s suitability for percutaneous pulmonary valve intervention.</p> <p>Results</p> <p>The distensibility of the material was identified in a range from 6.5 × 10^-3 mmHg^-1 for the 0.6 mm case, to 3.0 × 10^-3 mmHg^-1 for the 1.5 mm case. The models printed in the vertical orientation were always more compliant than their horizontal counterpart. Rapid prototyping of a compliant hypoplastic aorta and of a RVOT anatomical model were both feasible. Device insertion in the RVOT model was successful.</p> <p>Conclusion</p> <p>Values of distensibility, compared with literature data, show that TangoPlus is suitable for manufacturing arterial phantoms, with the added benefit of being compatible with PolyJet printing, thus guaranteeing representative anatomical finishing, and quick and inexpensive fabrication. The appealing possibility of printing models of non-uniform wall thickness, resembling more closely certain physiological scenarios, can also be explored. However, this material appears to be too stiff for modelling the more compliant systemic venous system.</p