The motion influence on respiration rate estimation from low-resolution thermal sequences during attention focusing tasks.

Global aging has led to a growing expectancy for creating home-based platforms for indoor monitoring of elderly people. A motivation is to provide a non-intrusive technique, which does not require special activities of a patient but allows for remote monitoring of elderly people while assisting them with their daily activities. The goal of our study was to evaluate motion performed by a person focused on a specific task and check if this motion disrupts estimation of respiration rate. The preliminary results show that it is possible to reliable estimate respiration rate by focusing attention of a patient on a certain activity. The respiratory rate analyzed for silent reading task was estimated with mean error 0.27 breaths per minute (bpm), while for reading aloud task with 1.18 bpm. The observed head motion during the reading aloud task was 1.5 higher that for silent reading and about two times smaller for a case in which subjects were not focused on any task.

Septic safe interactions with smart glasses in health care.

In this paper, septic safe methods of interaction with smart glasses, due to the health care environment applications consideration, are presented. The main focus is on capabilities of an optical, proximity-based gesture sensor and eye-tracker input systems. The design of both interfaces is being adapted to the open smart glasses platform that is being developed under the eGlasses project. Preliminary results obtained from the proximity sensor show that the recognition of different static and dynamic hand gestures is promising. The experiments performed for the eye-tracker module shown the possibility of interaction with simple Graphical User Interface provided by the near-to-eye display. Research leads to the conclusion of attractiveness of collaborative interfaces for interaction with smart glasses.

A probe for immittance spectroscopy based on the parallel electrode technique.

This paper presents the construction of a probe for immittance spectroscopy. The probe is based on the four-electrode technique. The current application electrodes are long parallel strips and have been partitioned into three segments to measure the immittance of relatively small volumes. The probe constant has been calculated assuming anisotropy of the materials examined. The experiments, based on the measurements of KCl solutions and numerical simulations (finite element method--FEM), have shown a high degree of consistency with the theoretical value. Experimental in vivo measurements on swine gluteal tissue were performed and the conductivity and permittivity reconstructed from these measurements are presented.

Relations between components of impedance cardiogram analyzed by means of finite element model and sensitivity theorem.

The main aim of the study is to establish a relation between different sources of Impedance cardiogram (ICG) as function of spatial distribution of conductivity. A three-dimensional model of a human thorax using the finite element method has been constructed. The model includes 35 horizontal layers consisting of up to 519 pentahedral elements that are automatically divided into tetrahedral ones before calculating the potential distribution. Electrode array configuration proposed by Kubicek et al. (Aerosp. Med. 37: 1208-1212, 1996) has been studied. A relationship proposed by Geselowitz (IEEE Trans. Biomed. Eng. 18: 38-41, 1971) has been used to calculate the sensitivity of the examined electrode array to conductivity changes inside the thorax. This relationship has allowed for the calculation of the contributions to ICG from spatially separated sources when modeling all changes in conductivity simultaneously. It has been confirmed that the main contributions to ICG signal come from ventricles, atria, aorta, and lungs. The relations between these components have been found to be dependent nonlinearly on spatial conductivity distribution. As a result, reliable and reproducible measurements of stroke volume (SV) using ICG are impossible. Nevertheless, ICG can be used to monitor relative changes of SV in all cases where the spatial distribution of conductivity and geometry of the subject, during the examination, is preserved. However, it does not mean that the accuracy of SV measurement will be the same in all these cases.

Stroke volume variability--cardiovascular response to orthostatic maneuver in patients with coronary artery diseases.

The dynamics of cardiovascular responses to postural stress have not been fully recognized. To determine whether coronary artery bypass grafting (CABG) has any effect on stroke volume variability (SVV), the power spectrum components of SVV were measured in 60 patients before and at 6 weeks after CABG. Stroke volume was assessed by means of the thoracic bioimpedance method. The thoracic impedance cardiogram and ECG were recorded in the supine and standing positions with controlled breathing rate (0.25 Hz) during 10-minute periods. The analysis of SVV was done by means of the autoregressive method. The total power, the power in the low-frequency band LFSV (0.05-0.15 Hz), the power in the high-frequency band HFSV (0.15-0.5 Hz), and the LFSV/HFSV ratio were analyzed. Before CABG, we did not notice any significant changes in the stroke volume spectral power indices. After CABG, all spectral indices were significantly decreased in the standing position.

Impedance mammograph 3D phantom studies.

The results obtained using the Technical University of Gdansk Electroimpedance Mammograph (TUGEM) of a 3D phantom study are presented. The TUGEM system is briefly described. The hardware contains the measurement head and DSP-based identification modules controlled by a PC computer. A specially developed reconstruction algorithm, Regulated Correction Frequency Algebraic Reconstruction Technique (RCFART), is used to obtain 3D images. To visualize results, the Advance Visualization System (AVS) is used. It allows a powerful image processing on a fast workstation or on a high-performance computer. Results of three types of 3D conductivity perturbations used in the study (aluminum, Plexiglas, and cucumber) are shown. The relative volumes of perturbations less than 2% of the measurement chamber are easily evidenced.

Cell for measurements of biological tissue complex conductivity.

The construction of the cell for measurement of complex electric conductivity is described. Two-chamber and four-electrode system with temperature stabilisation is developed. Guarding chamber and electrodes are used to minimise the leakage of current from the measurement chamber. The cell construction is examined by use of Finite Element Method. The model of the measurement cell is examined in order to improve the accuracy of measurements. The calibration procedure based on measurement of reference materials is presented. The frequency range of the cell is extended to 10 MHz with acceptable level of error. The examples of results from measurement breast normal and cancerous tissues are presented.

Examination of impedance cardiography properties--FEM model studies.

A FEM has been used to examine influence of tissues' conductivities and electrodes' array configurations on the results obtained by Impedance Cardiography. A Geselowitz's relationship has been applied to estimate partial contributions from each region of thorax. The obtained results have indicated the strong dependence of ICG signal on factors mentioned above. It seems that additional measurements and more advanced ICG waveform processing must be done to minimise errors in estimating parameters of mechanical work of heart by means of ICG.