Katarzyna Karpienko

Determination of refractive index dispersion using fiber-optic low-coherence Fabry–Perot interferometer: implementation and validation

Abstract. We present the implementation and validation of low-coherence Fabry–Perot interferometer for refractive index dispersion measurements of liquids. A measurement system has been created with the use of four superluminescent diodes with different optical parameters, a fiber-optic coupler and an optical spectrum analyzer. The Fabry–Perot interferometer cavity has been formed by the fiber-optic end and mirror surfaces mounted on a micromechanical stage. The positive result of the validation procedure has been determined through statistical analysis. All obtained results were 99.999% statistically significant and were characterized by a strong positive correlation (r>0.98). The accuracy of the measured result of implemented low-coherence Fabry–Perot interferometer sensor is from 83% to 94%, which proves that the sensor can be used in the measurement of refractive index dispersion of liquids.

Blood equivalent phantom vs whole human blood, a comparative study

Preclinical research of biomedical optoelectronic devices is often performed with the use of blood phantoms — a simplified physical model of blood. The aim of this study is the comparison and distinction between blood phantoms as well as whole human blood measurements. We show how the use of such phantoms may influence the incorrect interpretation of measured signal. On the other hand, we highlight how the use of blood phantoms enables to investigate the phenomena that otherwise are almost impossible to be noticed.

System supporting behavioral therapy for children with autism

In this paper, a system supporting behavioral therapy for autistic children is presented. The system consists of sensors network, base station and a brooch indicating persons emotional states. The system can be used to measure values of physiological parameters that are associated with changes in the emotional state. In the future, it can be useful to inform the autistic child and the therapist about the emotional state of the interlocutor objectively, on the basis of performed measurements. The selected physiological parameters were chosen during the experiment which was designed and conducted by authors. In this experiment, a group of volunteers under controlled conditions was exposed to a stressful situation caused by the picture or sound. For each of the volunteers, a set of physiological parameters, was recorded, including: skin conductance, heart rate, peripheral temperature, respiration rate and electromyography. The bio-statistical analysis allowed us to discern the proper physiological parameters that are most associated to changes due to emotional state of a patient, such as: skin conductance, temperatures and respiration rate. This allowed us to design electronic sensors network for supporting behavioral therapy for children with autism.

Reliability and validity of optoelectronic method for biophotonical measurements

Reliability and validity of measurements is of utmost importance when assessing measuring capability of instruments developed for research. In order to perform an experiment which is legitimate, used instruments must be both reliable and valid. Reliability estimates the degree of precision of measurement, the extent to which a measurement is internally consistent. Validity is the usefulness of an instrument to perform accurate measurements of quantities it was designed to measure. Statistical analysis for reliability and validity control of low-coherence interferometry method for refractive index measurements of biological fluids is presented. The low-coherence interferometer is sensitive to optical path difference between interfering beams. This difference depends on the refractive index of measured material. To assess the validity and reliability of proposed method for blood measurements, the statistical analysis of the method was performed on several substances with known refractive indices. Analysis of low-coherence interferograms considered the mean distances between fringes. Performed statistical analysis for validity and reliability consisted of Grubb’s test for outliers, Shapiro-Wilk test for normal distribution, T-Student test, standard deviation, coefficient of determination and r-Pearson correlation. Overall the tests proved high statistical significance of measurement method with confidence level < 0.0001 of measurement method.

Application of the laser diode with central wavelength 975 nm for the therapy of neurofibroma and hemangiomas

This paper presents a newly developed dermatological laser (with a central wavelength 975 nm) for application in therapies requiring deep penetration of tissue, e.g., cutaneous (dermal) neurofibroma (von Recklinghausen disease) and hemangiomas. This laser can work either in pulses or continues wave mode. Laser radiation is transmitted toward the application region by optical fiber with a diameter of 0.6 mm. The compact design of the laser facilitates its transport and increases the comfort of use.

Selection of physiological parameters for optoelectronic system supporting behavioral therapy of autistic children

In this article the procedure of selection of physiological parameters for optoelectronic system supporting behavioral therapy of autistic children is proposed. Authors designed and conducted an experiment in which a group of 30 health volunteers (16 females and 14 males) were examined. Under controlled conditions people were exposed to a stressful situation caused by the picture or sound (1kHz constant sound, which was gradually silenced and finished with a shot sound). For each of volunteers, a set of physiological parameters were recorded, including: skin conductance, heart rate, peripheral temperature, respiration rate and electromyography. The selected characteristics were measured in different locations in order to choose the most suitable one for the designed therapy supporting system. The bio-statistical analysis allowed us to discern the proper physiological parameters that are most associated to changes due to emotional state of a patient, such as: skin conductance, temperatures and respiration rate. This allowed us to design optoelectronic sensors network for supporting behavioral therapy of children with autism.

Gyroscope-Based Game Revealing Progress of Children with Autism

The paper concerns the automation of measuring progress of children with autism spectrum disorder. The proposed approach combines diverse approaches: e-technologies and mobile applications for autism, behavioral metrics derived from gyroscope and game state with machine learning methods to find interconnections between the metrics and the progress of a child. The paper presents a gyroscope-based game, specifically designed as an investigation tool for therapy progress monitoring. The game enables registration of behavioral patterns of use of the applications and tablet. The paper presents how the game was used in a study of behavioral metrics. 31 children with autism took part in the study. Each of them played the game several times during a 6-months period. The data gathered during the gameplay are used to calculate a set of metrics, that might be used in evaluation of a childs progress. Results in terms of classification accuracy reach 80%, however they depend on the particular skill category. The best accuracies are obtained for evaluation of stereotypic behaviors and gross motor skills of a child. The approach presented in the study is novel and was not applied before, therefore it might be interesting for other researchers working on supporting technologies for autism. The results might be also interesting for practitioners applying e-technologies in autistics therapy.

Computed aided system for separation and classification of the abnormal erythrocytes in human blood

The human peripheral blood consists of cells (red cells, white cells, and platelets) suspended in plasma. In the following research the team assessed an influence of nanodiamond particles on blood elements over various periods of time. The material used in the study consisted of samples taken from ten healthy humans of various age, different blood types and both sexes. The markings were leaded by adding to the blood unmodified diamonds and oxidation modified. The blood was put under an impact of two diamond concentrations: 20μl and 100μl. The amount of abnormal cells increased with time. The percentage of echinocytes as a result of interaction with nanodiamonds in various time intervals for individual specimens was scarce. The impact of the two diamond types had no clinical importance on red blood cells. It is supposed that as a result of longlasting exposure a dehydratation of red cells takes place, because of the function of the cells. The analysis of an influence of nanodiamond particles on blood elements was supported by computer system designed for automatic counting and classification of the Red Blood Cells (RBC). The system utilizes advanced image processing methods for RBCs separation and counting and Eigenfaces method coupled with the neural networks for RBCs classification into normal and abnormal cells purposes.

Fiber optic Fabry-Pérot sensors: modeling versus measurements results

This paper describes how parameters of investigated substances and the fiber-optic Fabry-Pérot sensing interferometer affect the spectrum of the optical radiation at the output of the sensor. First, the modeling of the operation of the sensing interferometer was conducted. Most important parameters and effects that were taken into account are: dependences of the refractive indices of the core and the cladding, as well the mode field diameter of a single mode fiber on the wavelength, changes in the parameters of an optical beam inside the interferometer caused by refractive index and the absorption of the medium inside the cavity, including the intensity of the beam, the beam diameter, the beam divergence, the curvature of the wavefront, and the phase shift caused by the Gouy effect. Impact of these parameters and effects on the spectrum of the optical radiation at the output of the sensor was subsequently investigated. Following, spectra from selected Fabry-Pérot optical sensors, applied to measurement of refractive index, were presented. Measurement results were compared with the spectra obtained by modeling.

Combined analysis of whole human blood parameters by Raman spectroscopy and spectral-domain low-coherence interferometry

In this article the simultaneous investigation of blood parameters by complementary optical methods, Raman spectroscopy and spectral-domain low-coherence interferometry, is presented. Thus, the mutual relationship between chemical and physical properties may be investigated, because low-coherence interferometry measures optical properties of the investigated object, while Raman spectroscopy gives information about its molecular composition. A series of in-vitro measurements were carried out to assess sufficient accuracy for monitoring of blood parameters. A vast number of blood samples with various hematological parameters, collected from different donors, were measured in order to achieve a statistical significance of results and validation of the methods. Preliminary results indicate the benefits in combination of presented complementary methods and form the basis for development of a multimodal system for rapid and accurate optical determination of selected parameters in whole human blood. Future development of optical systems and multivariate calibration models are planned to extend the number of detected blood parameters and provide a robust quantitative multi-component analysis.