Angelos Skembris, Elias Koukoutsis, Constantin Papaodysseus, Eleftherios Kayafas
Geometric Feature Extraction for Precise Measurements in Intramedullary Nail images

Closed Intramedullary Nailing (CIN) is a surgical procedure which requires that the surgeon accurately locates the optimal drilling position for inserting locking screws to stabilize and lock into position a nail inserted into the patient's bone. This procedure is difficult and is usually accomplished via X-ray fluoroscopic imaging, which results in large radiation exposure for both the patient and the surgical team. In this paper we present a method for making precise measurements of the nail geometric characteristics depicted in Xray images in order to assist the surgeon during the determination of the nail body's position, assessment of any possible deformation during the insertion process, and the position and orientation of the nail holes' axes. This is achieved by firstly segmenting nail image to extract the area of the nail. Then, the nail body's shape is measured with the use of a deformable polygon that approximates the shape of the nail. The projections of the nail holes are then approximated with piecewise ellipses with the use of the Nelder-Mead minimization algorithm. Preliminary results show that using this method, we can achieve precise measurements of the nail body and hole projections in the X-ray image. These measurements can be used to construct a 3D model of the nail relative to the bone, which can in turn be used for the determination of the optimal drilling angle.

Jerzy Hoja, Michal Kowalewski, Grzegorz Lentka
Universal Laboratory Measurement System for Evaluation of the Impedance Spectroscopy Method Based on Multi-harmonic Excitation Signal

The paper presents universal laboratory measurement system for evaluation of the impedance spectroscopy method based on multi-harmonic excitation signal. The system is mainly designed to optimise the method for impedance spectrum digital measurement dedicated to implement in low-cost portable instrument oriented for diagnostics of technical objects located in the field. Due to time constraints during field measurements, it is important to shorten acquisition time of impedance spectrum by using multi-harmonic excitation. Implementation of the method in the field-worthy instrument requires optimisation procedures in terms of hardware complexity and power consumption requirements minimisation. The results of simulation tests as well as experimental verification were presented.

Marek Zielinski, Maciej Gurski, Dariusz Chaberski
Architecture of the Multi-Tap-Delay-Line Time-Interval Measurement Module Implemented in FPGA Device

This paper describes architecture of the Multi-Tap-Delay-Line (MTDL) time-interval measurement module of high resolution implemented in single FPGA device. A new architecture of the measurement module enables to collect of sixteen time-stamps during single measuring cycle. It means that measured time-interval can be precisely interpolated from collection of the sixteen time-stamps after each measuring cycle. Such architecture of the measurement module leads straight to increase of resolution, to limit total duration time of the measurements and to decrease of duty cycle of the measurement instrument.

Pedro Ramos, Fernando Janeiro
Improving the convergence of gene expression programming in impedance spectroscopy

This paper describes the latest major improvement made to gene expression programming (GEP) for use in impedance spectroscopy. This change consists on systematically analysing the fittest element of each population of the GEP to identify circuit components that are useless in the sense that they do not significantly contribute to the impedance response at the analysed frequency range. These components are then removed from the circuit making it less complex. The performance of the proposed improvements is analyzed on both simulated and measured impedance frequency responses.

Jose Maria Sierra-Fernandez, Juan José González de la Rosa, Agustín Agüera-Pérez, José Carlos Palomares-Salas
Detection and characterization of amplitude defects using Spectral Kurtosis

This paper describes a new procedure for analyze amplitude defects, based on Spectral Kurtosis (SK). It extracts the kurtosis of each frequency component, which is related to the amplitude evolution. The proposed procedure allows the identification and characterization of frequencies with constant or very variable amplitude. An amplitude defect involves a step in the amplitude level, and that affect to frequencies around 50 Hz, which originally are not present, and could be detected by the SK. Some theoretical situations and a real one will be analyzed in order to proof the great capacities of the SK in the analysis of this kind of defect.