Adaptive Data Transmission Algorithm for the System of Inertial Sensors for Hand Movement Acquisition.

Modern systems of intelligent sensors commonly use radio data transmission. Hand movement acquisition with the use of inertial sensors requires the processing and transmission of a relatively large amount of data, which may be associated with a significant load on the network structure. Network traffic limitation, without losing the quality of monitoring parameters from the sensor system, is therefore important for the functioning of the radio network which integrates both the teletransmission sensor system and the data acquisition server. The paper presents a wearable solution for hand movement acquisition, which uses data transmission in the Wi-Fi standard and contains 16 MEMS (Micro Electro Mechanical System) sensors. An adaptive algorithm to control radio data transmission for the sensor system has been proposed. The algorithm implemented in the embedded system controls the change of the frame length, the length of the transmission frame and the frequency of its sending, which reduces the load on the network router. The use of the algorithm makes it possible to reduce the power consumption by the sensor system by up to 19.9% and to limit the number of data transferred by up to about 91.6%, without losing the quality of the monitored signal. The data analysis showed no statistically significant differences (p > 0.05) between the signal reconstructed from the complete data and processed by the algorithm.

Surgery Training System Supported by Organic Materials.

The aim of the study was the qualitative assessment of new materials based on a polycarbonate matrix in terms of its use in 3D printing and its processing and geometric modification (cutting). Filaments made of the new material doped with talc in five different proportions were visually inspected with a microscope. The calibration and test models were made using the FFF (fused filament fabrication) technique. In addition, its susceptibility to the drill and the behavior of the shavings were assessed and the temperature changing during drilling was measured. The implant was inserted to measure its resonance stability in each of the holes made and translated into the value of the implant stability quotient (ISQ) ranging from 1 to 100. The results were compared to those obtained for the training model of the skull bone. The amount of filler has been shown to affect the composite. Moreover, due to the properties of talc, a compatibilizer (polyol) was used. Differences were observed between the model made of the commercial material, the model made of the dried, tested material, and the model made of the undried material. It was confirmed that the presence of water in the material during its processing is important.

The Object Segmentation from the Microstructure of a FSW Dissimilar Weld.

Friction stir welding (FSW) is an environmentally friendly, solid-state welding technique. In this research work, we analyze the microstructure of a new type of FSW weld applying a two- stage framework based on image processing algorithms containing a segmentation step and microstructure analysis of objects occurring in different layers. A dual-speed tool as used to prepare the tested weld. In this paper, we present the segmentation method for recognizing areas containing particles forming bands in the microstructure of a dissimilar weld of aluminum alloys made by FSW technology. A digital analysis was performed on the images obtained using an Olympus GX51 light microscope. The image analysis process consisted of basic segmentation methods in conjunction with domain knowledge and object detection located in different layers of a weld using morphological operations and point transformations. These methods proved to be effective in the analysis of the microstructure images corrupted by noise. The segmentation parts as well as single objects were separated enough to analyze the distribution on different layers of the specimen and the variability of shape and size of the underlying microstructures, which was not possible without computer vision support.

The bone microstructure from anterior cruciate ligament footprints is similar after ligament reconstruction and does not affect long-term outcomes.

PURPOSE: The purpose of this study was to assess the quality of the bone tissue microstructure from the footprints of the anterior cruciate ligament (ACL) and its impact on late follow-up outcomes in patients who undergo anterior cruciate ligament reconstruction (ACLR). METHODS: The records of 26 patients diagnosed with a completely torn ACL who underwent ACLR were collected. During the surgery performed using the Felmet method, bone blocks from the native ACL footprints were collected. The primary measurements of the bone microstructure were made using a microtomographic scanner. In late follow-up examinations, a GNRB arthrometer was used. RESULTS: There was no significant difference in the bone microstructure assessed using micro-CT histomorphometric data according to the blood test results, plain radiographs, age or anthropometric data. There was no difference in the bone volume/total volume ratio or trabecular thickness in the area of the native ACL footprints. Routine preoperative examinations were not relevant to the quality of the bone microstructure. The elapsed time from an ACL injury to surgery had no relevance to the results of arthrometry. CONCLUSION: The similarities in the microstructure of bone blocks from ACL footprints from the femur and tibia allow the variable use of these blocks to stabilize grafts in the Felmet method. The bone microstructure is not dependent on the time from injury to surgery. Histomorphometric values of the structure of the femoral and tibial ACL footprints have no impact on the long-term stability of the operated knee joint. TRIAL REGISTRATION: The approval of the Bioethics Committee of the Silesian Medical Chamber in Katowice, Poland (resolution 16/2014) was given for this research. LEVEL OF EVIDENCE: II.

Bioresorbable Stent in Anterior Cruciate Ligament Reconstruction.

The exact causes of failure of anterior cruciate ligament (ACL) reconstruction are still unknown. A key to successful ACL reconstruction is the prevention of bone tunnel enlargement (BTE). In this study, a new strategy to improve the outcome of ACL reconstruction was analyzed using a bioresorbable polylactide (PLA) stent as a catalyst for the healing process. The study included 24 sheep with 12 months of age. The animals were randomized to the PLA group (n = 16) and control group (n = 8), subjected to the ACL reconstruction with and without the implantation of the PLA tube, respectively. The sheep were sacrificed 6 or 12 weeks post-procedure, and their knee joints were evaluated by X-ray microcomputed tomography with a 50 µm resolution. While the analysis of tibial and femoral tunnel diameters and volumes demonstrated the presence of BTE in both groups, the enlargement was less evident in the PLA group. Also, the microstructural parameters of the bone adjacent to the tunnels tended to be better in the PLA group. This suggested that the implantation of a bioresorbable PLA tube might facilitate osteointegration of the tendon graft after the ACL reconstruction. The beneficial effects of the stent were likely associated with osteogenic and osteoconductive properties of polylactide.

Modelling the degree of porosity of the ceramic surface intended for implants.

The main goal of the study was to develop a model of the degree of surface porosity of a biomaterial intended for implants. The model was implemented using MATLAB. A computer simulation was carried out based on the developed model, which resulted in a two-dimensional image of the modelled surface. Then, an algorithm for computerised image analysis of the surface of the actual oxide bioceramic layer was developed, which enabled determining its degree of porosity. In order to obtain the confocal micrographs of a few areas of the biomaterial, measurements were performed using the LEXT OLS4000 confocal laser microscope. The image analysis was carried out using MountainsMap Premium and SPIP. The obtained results allowed determining the input parameters of the program, on the basis of which porous biomaterial surface images were generated. The last part of the study involved verification of the developed model. The modelling method was tested by comparing the obtained results with the experimental data obtained from the analysis of surface images of the test material.

Differences between sexes in the standard and advanced dimensioning of lateral meniscal allografts.

BACKGROUND: There are many different methods of meniscal allograft measurements, which depend on individual tissue bank procedures. Due to the lack of a standardised method of dimensioning, measurement results may vary between individual cases. Consequently, allograft may be mismatched to the patient's knee anatomy. The purpose of this study was to measure four meniscal dimensions - two standard and two specific - and then compare them between sexes. METHODS: Fourteen cadaveric lateral menisci (seven male and seven female) were scanned using a microtomography scanner. The obtained three-dimensional (3-D) models of each meniscus were analysed, taking into account four dimensions: circumference, width, central meniscal concavity, and total meniscal volume. The computer researcher was not informed of the original data of the meniscal samples until the calculations were completed. RESULTS: No statistical between-sex differences were found in the standard dimensions. The specific dimensions, in turn, presented statistically significant between-sex differences (P>0.05). The mean difference between male and female total volume of the meniscus was equal to 36.59%, and the mean difference between male and female central meniscal concavity surface was equal to 31.22%. CONCLUSION: This study found that sex should be taken into account as an important factor during a matching procedure performed by tissue bank staff.

The matching method for veins images.

BACKGROUND: A common problem in medical practice is the localization of subcutaneous veins and arteries. Automatization of this procedure may help to develop bloodbot rigs and improve use of image guided surgery. METHOD: It is not necessary to have a full 3D model in order to determine their location by calculating the spatial coordinates of veins axes in the adopted coordinate system. A much better solution is pre-segmentation, which provides veins axes, and further search for stereo correspondence in the segmented images. The computational complexity of this approach is much smaller, which ensures its quick operation. A disparity map necessary for the calculation of spatial coordinates is created according to the principle that the most likely correct distance between homologous elements is the minimum distance value. To increase the effectiveness of the method, the difference in the distance between the homologous points and their neighbours is further analysed. RESULTS: The method is illustrated with examples of the authors' own images of subcutaneous veins as well as standard images used for the evaluation of new methods for seeking stereo correspondence. In addition, the method has been compared with three recognized and widely used algorithms for matching images. The effectiveness of the new method reaches 100% of properly matched pixels. The largest percentage of mismatches is 27%. The lowest value of standard deviation is 0.1 and the highest 10 pixels. The proposed method is at least two times faster than other presented methods.

Microscale's relationship between Young's modulus and tissue density. Prediction of displacements.

The study presents an experimental verification of Wagner et al.'s relationship in microscale and proposes a modification of this relationship. For this purpose, 11 cubic specimens were microcomputed tomography scanned and mechanically tested with the displacement full-field measurements using a digital image correlation system. Then, numerical simulations of the compression tests were performed using a finite elements method. The Young's modulus distributions assigned to the finite elements models were calculated using both of Wagner et al.'s relationships: original and modified. Comparison of the experimental and numerical results indicated the accuracy of numerical solutions for both relationships.

Bone tunnel enlargement following hamstring anterior cruciate ligament reconstruction: a comprehensive review.

Nowadays, bone tunnel enlargement (BTE) after anterior cruciate ligament reconstruction is a well-known phenomenon. It has been identified, investigated and described by many authors during the last thirty years. Nevertheless, the etiology of bone tunnel enlargement still remains unclear. It is known that the causes are multifactorial and may include the surgical technique, the method of fixation, materials used, type of graft as well as biological factors. Due to the recent popularization of the use of hamstring grafts in anterior cruciate ligament reconstruction, the bone tunnel enlargement phenomenon is becoming increasingly common. In this review article, the authors focus on compiling current knowledge about the etiology, diagnosis, and the possibility of reducing the occurrence of this phenomenon by using the latest methods of supporting reconstruction surgery.

Rapid dynamic changes of the geometry of the anterior segment of the eye: A method of automatic spatial correction of a temporal sequence of OCT images.

INTRODUCTION: Ocular dynamics is a very complex phenomenon which has not been well studied and understood yet. The way in which the eye responds to pulsatile changes of the blood pressure or even the electric activity of the heart depends not only on the mechanical properties of each individual structure of the eye globe, but also on its internal conditions, such as the degree of accommodation or intraocular pressure (IOP). METHOD: This paper presents a method for correcting these undesired movements that could increase the sensitivity of the technique and its reliability in the estimation of pulsatile dynamics. The presented algorithm uses fully automatic detection of the structures that form an angle and fully automatic stabilisation of each individual image being a part of a captured sequence. RESULTS AND CONCLUSIONS: The procedures described above were applied to the data of nine subjects taking part in the study. For all of them it turned out that the most representative area for fitting the images is the area of the irido-corneal angle apex. The presented algorithm significantly improved the spatial stability of the images in the temporal sequences of the tomographic images. The use of such correction makes it possible to distinguish the subtle pulsatile fluctuations of the ocular structures in the anterior segment, that can be associated with the activity of the retinal blood vessels and/or electric activity of the heart, from the undesired involuntary movements of the eye or the whole head.

Assessment of possibilities of ceramic biomaterial fracture surface reconstruction using laser confocal microscopy and long working distance objective lenses.

A numerical description of fracture is an important step in the search of the correlation between specific micromechanisms of decohesion and material characteristics designated with the use of fracture mechanics methods. This issue is essential for the proper orientation of the search for basic relationships between chemical composition, technology, structure, and properties of materials. It often happens that fracture surfaces are well developed, which can significantly hinder or even prevent the measurement and reconstruction of the tested material surface geometry. In this article, comparative measurements of a biomaterial surface were performed using laser confocal microscopy. To this end, short working distance lenses dedicated to a focused UV laser beam and long working distance objective lenses were used. The article includes a quantitative comparative analysis and interpretation of the obtained results.

Quantitative assessment of the impact of blood pulsation on images of the pupil in infrared light.

Pulsation in the blood vessels of the eye has a big impact on the dynamics of the entire eyeball and its individual elements. Blood pulsation in the retina can be recorded by the pupil, whose size is also subject to dynamic changes. The study involved synchronous measurements of pupil size using a high-speed camera, and blood pulsation using a pulse oximeter placed on the ear lobe. In addition, there were no metrologically significant differences in the phase shift between the average brightness of the individual pupil quadrants. Blood pulsation in other ocular tissues can affect the dynamics of the optical properties of the eye. As demonstrated in this paper, it affects the pupil behavior and its parameters to a considerable extent.

Maximum sphere method for shell patency measurements in viviparous land snails based on X-ray microcomputed tomography imaging.

This article presents the working principle of an algorithm designed for the purpose of examining a section of the snail shell canal. The procedure of scanning the specimens is described as well as the tests performed using the proposed algorithm. Also, the digital models used for testing the algorithm are described. The article contains a description of the initial processing of the data, including segmentation and detection of the edges of the image. A flowchart of the algorithm is presented together with its implementation. The data obtained in the course of the microtomographic scanning of one of the snails and a digital model of a canal created for this purpose were subjected to the application of the measurement algorithm. This algorithm was aimed at conducting a spatial analysis of the varying dimensions in the canal section. The process of applying the algorithm and the measurement errors are presented and discussed on the basis of the results.

Quantitative assessment of responses of the eyeball based on data from the Corvis tonometer.

BACKGROUND: The "air-puff" tonometers, include the Corvis, are a type of device for measuring intraocular pressure and biomechanics parameters. The paper attempts to analyse this response and its relationship with other parameters measured in the Corvis tonometer. METHODS: A number of 13,400 2D images were acquired from the Corvis device and analysed (32 healthy and 16 ill people). A new method has been proposed for the analysis of responses of the eyeball based on morphological transformations and contextual operations. RESULTS: The proposed algorithm enables to determine responses of the eyeball to an air puff coming from the Corvis tonometer. Additionally, responses of the eyeball have been linked to some selected features of corneal deformation. The results include, among others: (1) distinguishability between the left and right eye with an error of 7%; (2) the correlation between the area under the curve in corneal deformation and the response of the eyeball -0.26; (3) the correlation between the highest concavity time and the maximum deformation amplitude of 0.4. All these features are obtained fully automatically and repetitively at a time of 3.8s per patient (Core i7 10GB RAM). DISCUSSION: It is possible to measure additional parameters of the eye deformation which are not available in the original software of the Corvis tonometer. The use of the proposed methods of image analysis and processing provides results directly from the eye response measurement when measuring intraocular pressure.

Dynamic thermal imaging analysis in the effectiveness evaluation of warming and cooling formulations.

Warming cosmetics and medicines are used to accelerate recovery from injuries whereas cooling preparations are used in the pains of muscles, joints, spine, bruises or edema. The paper verifies subjective heating or warming sensations with respect to the measured temperature changes. The influence of three formulations, labelled C1, C2, W1, on skin reaction was tested. The first two formulations (C1, C2) had a cooling effect while the formulation W1 had warming properties. Two hundred thermal images with a resolution of N×M=120×120 pixel were acquired with the Flir i7 infrared camera. The paper also shows how to analyse low resolution thermal images and their practical usefulness. For this purpose, a dedicated algorithm for image analysis and processing, which uses morphological operations, segmentation and area analysis, was applied. Application of both C1 and C2 resulted in subjective perception of feeling cold. Approximately 7min following application of the formulation C1, the skin temperature returned to baseline levels. The minimum skin temperature after using the formulation C1 was 27.5 °C and it was registered at the time of application. Application of W1, which by definition is a warming formulation, caused a sensation of coolness in the first minutes following the application. The perception of cool and warm sensations after the application of topical formulations is in no way correlated with the skin temperature assessed using a thermal imaging method.

Calibration and segmentation of skin areas in hyperspectral imaging for the needs of dermatology.

INTRODUCTION: Among the currently known imaging methods, there exists hyperspectral imaging. This imaging fills the gap in visible light imaging with conventional, known devices that use classical CCDs. A major problem in the study of the skin is its segmentation and proper calibration of the results obtained. For this purpose, a dedicated automatic image analysis algorithm is proposed by the paper's authors. MATERIAL AND METHOD: The developed algorithm was tested on data acquired with the Specim camera. Images were related to different body areas of healthy patients. The resulting data were anonymized and stored in the output format, source dat (ENVI File) and raw. The frequency λ of the data obtained ranged from 397 to 1030 nm. Each image was recorded every 0.79 nm, which in total gave 800 2D images for each subject. A total of 36'000 2D images in dat format and the same number of images in the raw format were obtained for 45 full hyperspectral measurement sessions. As part of the paper, an image analysis algorithm using known analysis methods as well as new ones developed by the authors was proposed. Among others, filtration with a median filter, the Canny filter, conditional opening and closing operations and spectral analysis were used. The algorithm was implemented in Matlab and C and is used in practice. RESULTS: The proposed method enables accurate segmentation for 36'000 measured 2D images at the level of 7.8%. Segmentation is carried out fully automatically based on the reference ray spectrum. In addition, brightness calibration of individual 2D images is performed for the subsequent wavelengths. For a few segmented areas, the analysis time using Intel Core i5 CPU RAM M460@2.5GHz 4GB does not exceed 10 s. CONCLUSIONS: The obtained results confirm the usefulness of the applied method for image analysis and processing in dermatological practice. In particular, it is useful in the quantitative evaluation of skin lesions. Such analysis can be performed fully automatically without operator's intervention.

A new algorithm and problems in automatic anterior eye chamber volume determining.

This study investigates the problem of automatic determination of the anterior eye chamber volume using previously published as well as new algorithms of image analysis and processing proposed by the authors. A new method for determining the anterior eye chamber volume that provides more accurate results has been proposed. The entire algorithm was implemented in Matlab and C language. 60,000 images were obtained using OCT SS-1000 CASIA and Zeiss Visante OCT. The acquired images of the anterior segment of the eye had a resolution of 256×1024 pixels with a measuring range of 8×16mm(2). The images were acquired during routine medical examination at the Clinical Department of Ophthalmology, District Railway Hospital in Katowice, Poland, and were analysed in accordance with the Declaration of Helsinki. The new algorithm uses edge detection, morphological operations, binarization and filtration. The proposed algorithm gave the anterior chamber surface measurement error at the level of 4.3% and the anterior chamber volume measurement error of 12%. For comparison, the surface measurement error of the tomograph software was at 6.7%. Thus the obtained results were better by 2.4%. The proposed algorithm provides reproducible results automatically at a runtime of 3s per patient using a Core i7 PC computer with 8GB of RAM.

Selected parameters of the corneal deformation in the Corvis tonometer.

INTRODUCTION: Contemporary ophthalmology knows many methods of measuring intraocular pressure, namely the methods of non-contact and impression applanation tonometry. In non-contact applanation tonometers, e.g. the Corvis, the corneal flattening is caused by an air puff. Image registration of the corneal deflection performed by a tonometer enables to determine other interesting biomechanical parameters of the eye, which are not available in the tonometer. The measurement of new selected parameters is presented in this paper. MATERIAL AND METHOD: Images with an M × N × I resolution of 200 × 576 × 140 pixels were acquired from the Corvis device in the source recording format *.cst. A total of 13'400 2D images of patients examined routinely in the Clinical Department of Ophthalmology, in District Railway Hospital in Katowice, Poland, were analysed in accordance with the Declaration of Helsinki. A new method has been proposed for the analysis of corneal deflection images in the Corvis tonometer with the use of the Canny edge detection method, mathematical morphology methods and context-free operations. RESULTS: The resulting image analysis tool allows determination of the response of the cornea and the entire eyeball to an air puff. The paper presents the method that enables the measurement of the amplitude of curvature changes in the frequency range from 150 to 500 Hz and automatic designation of the eyeball movement direction. The analysis of these data resulted in 3 new features of dynamics of the eye reaction to an air puff. Classification of these features enabled to propose 4 classes of deformation. The proposed algorithm allows to obtain reproducible results fully automatically at a time of 5 s per patient using the Core i5 CPU M460 @ 2.5GHz 4GB of RAM. CONCLUSIONS: The paper presents the possibility of using a profiled algorithm of image analysis, proposed by the authors, to measure additional cornea deformation parameters. The new tool enables automatic measurement of the additional new parameters when using the Corvis tonometer. A detailed clinical examination based on this method will be presented in subsequent papers.

Prediction of Young׳s modulus of trabeculae in microscale using macro-scale׳s relationships between bone density and mechanical properties.

According to the literature, there are many mathematical relationships between density of the trabecular bone and mechanical properties obtained in macro-scale testing. In micro-scale, the measurements provide only the ranges of Young׳s modulus of trabeculae, but there are no experimentally tested relationships allowing the calculation of the distribution of Young׳s modulus of trabeculae within these experimental ranges. This study examined the applicability of relationships between bone density and mechanical properties obtained in macro-scale testing for the calculation of Young׳s modulus distribution in micro-scale. Twelve cubic specimens from eleven femoral heads were cut out and micro-computed tomography (micro-CT) scanned. A mechanical compression test and Digital Image Correlation (DIC) measurements were performed to obtain the experimental displacement and strain full-field evaluation for each specimen. Five relationships between bone density and Young׳s modulus were selected for the test; those were given by Carter and Hayes (1977), Ciarelli et al. (2000), Kaneko et al. (2004), Keller (1994) for the human femur, and Li and Aspden, 1997. Using these relationships, five separate finite element (FE) models were prepared, with different distribution of Young׳s modulus of trabeculae for each specimen. In total, 60 FE analyses were carried out. The obtained displacement and strain full-field measurements from numerical calculations and experiment were compared. The results indicate that the highest accuracy of the numerical calculation was obtained for the Ciarelli et al. (2000) relationship, where the relative error was 17.87% for displacements and 50.94 % for strains. Therefore, the application of the Ciarelli et al. (2000) relationship in the microscale linear FE analysis is possible, but mainly to determine bone displacement.