Mid Sweden University

Since 2008, a variety of systems have been designed to detect events in security cameras. There are also more than a hundred journal articles and conference papers published in this field. However, no survey has focused on recognizing events in the surveillance system. Thus, motivated us to provide a comprehensive review of the different developed event detection systems. We start our discussion with the pioneering methods that used the TRECVid-SED dataset and then developed methods using VIRAT dataset in TRECVid evaluation. To better understand the designed systems, we describe the components of each method and the modifications of the existing method separately. We have outlined the significant challenges related to untrimmed security video action detection. Suitable metrics are also presented for assessing the performance of the proposed models. Our study indicated that the majority of researchers classified events into two groups on the basis of the number of participants and the duration of the event for the TRECVid-SED Dataset. Depending on the group of events, one or more models to identify all the events were used. For the VIRAT dataset, object detection models to localize the first stage activities were used throughout the work. Except one study, a 3D convolutional neural network (3D-CNN) to extract Spatio-temporal features or classifying different activities were used. From the review that has been carried, it is possible to conclude that developing an automatic surveillance event detection system requires three factors: accurate and fast object detection in the first stage to localize the activities, and classification model to draw some conclusion from the input values.

Objectives

The aim of this study was to determine capillaroscopic changes in patients with systemic lupus erythematosus (SLE) and their predictors.

Methods

Fifty-nine SLE patients and 31 controls were enrolled in a cross-sectional study. Nailfold capillaroscopy examinations were performed, and qualitative semi-quantitative and quantitative parameters were evaluated in all fingers. Demographic features and lupus characteristics, such as renal involvement, medications, laboratory data, disease activity (SLEDAI) and damage, were recorded. The predictors of capillaroscopic abnormalities were obtained by backward stepwise regression analysis.

Results

Capillary numbers of right hands were significantly lower in patients than in controls [8.74 (1.66) vs. 9.63 (1.80), P = 0.0001]. Capillaries were wider in patients than in controls in right [56.32 μm (16.76) vs. 50.43 μm (10.16), P = 0.002] and left hands [54.40 (15.02) vs. 49.71 (9.77), P = 0.005]. Capillaries were shorter in SLE patients than in controls. Multivariate analysis revealed that the main associative factors of microvascular abnormalities were gender, drinking tea and hydroxychloroquine use for giant capillaries, SLEDAI and low C3 for avascularity and age, lupus nephritis and corticosteroid use for ramification.

Conclusion

Most nailfold capillaroscopic abnormalities were more common in SLE patients than in controls. Hydroxychloroquine, corticosteroids, SLEDAI, low complement and lupus nephritis may be the major prognostic factors for microvascular changes in SLE patients.

Nailfold capillaroscopy (NC) is a highly sensitive, safe, and non-invasive technique to assess involvement rate of microvascularity in dermatomyositis and systemic sclerosis. A large number of studies have focused on NC pattern description, classification, and scoring system validation, but minimal information has been published on the accuracy and precision of the measurement. The objective of this review article is to identify different factors affecting the reliability and validity of the assessment in NC. Several factors can affect the reliability of the examination, e.g., physiological artifacts, the nailfold imaging instrument, human factors, and the assessment rules and standards. It is impossible to avoid all artifacts, e.g., skin transparency, physically injured fingers, and skin pigmentation. However, minimization of the impact of some of these artifacts by considering some protocols before the examination and by using specialized tools, training, guidelines, and software can help to reduce errors in the measurement and assessment of NC images. Establishing guidelines and instructions for automatic characterization and measurement based on machine learning techniques also may reduce ambiguities and the assessment time.

Background: Nailfold capillaroscopy (NC) is a diagnostic imaging technique that is used to assess the blood capillary network in the nailfold area. NC is routinely used for patients with microcirculation problems, such as systemic sclerosis and other connective tissue diseases.  Experts commonly use subjective evaluation as a reference point in images of nailfold video capillaroscopy, so it is important to reduce the inherent ambiguities in human judgment and diagnosis. Image quality is an important factor that affects measurement error and assessment time of NC images.

Objective: In this study, a new image enhancement technique was introduced and evaluated subjectively.

Methods: In total, 475 nailfold video capillaroscopy images from 18 healthy subjects and 41 systemic lupus erythematosus patients were used. The images were randomly divided into two sets, one each with 275 and 200. Eight independent observers who were familiar with the capillaroscopy technique participated in this study. The set of 275 images was evaluated by three observers with the forced–choice pairwise comparison method. Elliptic broken line (EBL) was used to count the number of capillaries. The intra- and inter-observer reliability of the original and enhanced images was evaluated on 200 images by five observers.

Result: Except for eight images, all observers preferred the enhanced images in the visual quality comparison method. The intra-class correlation coefficient (ICC) of intra- and inter-observer reliability increased from 0.76-0.84 to 0.82-0.89, respectively, when using the enhancement method.

Conclusion: By improving the image quality, more capillary details will be visible, and an observer can document more details that may not be visible in the original image and can do so more efficiently.

Nailfold capillaroscopy is a practical method for identifying and obtaining morphological changes in capillaries which might reveal relevant information about diseases and health. Capillaroscopy is harmless, and seems simple and repeatable. However, there is lack of established guidelines and instructions for acquisition as well as the interpretation of the obtained images; which might lead to various ambiguities. In addition, assessment and interpretation of the acquired images are very subjective. In an attempt to overcome some of these problems, in this study a new modified technique for assessment of nailfold capillary density is introduced. The new method is named elliptic broken line (EBL) which is an extension of the two previously known methods by defining clear criteria for finding the apex of capillaries in different scenarios by using a fitted elliptic. A graphical user interface (GUI) is developed for pre-processing, manual assessment of capillary apexes and automatic correction of selected apexes based on 90° rule. Intra- and inter-observer reliability of EBL and corrected EBL is evaluated in this study. Four independent observers familiar with capillaroscopy performed the assessment for 200 nailfold videocapillaroscopy images, form healthy subject and systemic lupus erythematosus patients, in two different sessions. The results show elevation from moderate (ICC = 0.691) and good (ICC = 0.753) agreements to good (ICC = 0.750) and good (ICC = 0.801) for intra- and inter-observer reliability after automatic correction of EBL. This clearly shows the potential of this method to improve the reliability and repeatability of assessment which motivates us for further development of automatic tool for EBL method.

Capillaries play a crucial role in the microcirculatory system by exchanging metabolic substrates and waste products between blood and various tissues. The behavior of capillaries is affiliated with the number of capillaries per unit volume of tissue. Among the various noninvasive techniques available for analyzing skin microcirculation, nailfold capillaroscopyis considered to be a simple and easy-to-perform technique that allows a direct in-vivo visualization of the capillary network.Capillary density is one of the most important parameters in the studies involving capillaroscopy images. Capillary density in most of studies is defined as the number of capillaries in a one-millimeter span of the distal row in each finger or toe. This definition is silent about counting or excluding the number of the capillary with different shapes. However, there is no single standard for counting the number of capillaries in a span of one millimeter. In this paper, a novel method is proposed for determining the nailfold capillary density. This method is a modified combination of two existing techniques: the direct observation and the 90◦ method.Compared to the two existing approaches, the proposed method is more straightforward and easy to use for cases in which the capillaries have different shapes and sizes. Through different examples, we have shown how this method can be used to select the apex point of the capillary and subsequently count the number of capillaries with several papillae.

Video nailfold capillaroscopy (NFC), considered as an extension of the widefield technique, allows a more accurate measuring andstoring of capillary data and a better defining, analyzing, and quantifying of capillary abnormalities. Capillaroscopic study is oftenperformed on the patients suspected of having microcirculation problems such as Raynaud’s phenomenon as the main indicationfor nailfold capillaroscopy. Capillaroscopic findings based on microcirculation studies can provide useful information in the fieldsof pathophysiology, differential diagnosis, and monitoring therapy. Nailfold capillaroscopy provides a vital assessment in clinicalpractices and research; for example, its reputation in the early diagnosis of systemic sclerosis is well established and it is also usedas a classification criterion in this regard. This review focuses on the manner of performing video nailfold capillaroscopy and on acommon approach for measuring capillary dimensions in fingers and toes.

In this study, the Homo-Separation of Variables method is introduced to find the exact solution of somecoupled nonlinear partial differential equations. This analytical method is a new combination of two powerfuland popular methods; namely the homotopy perturbation method (HPM) and the separation of variables method.The exact solution is constructed by choosing an appropriate initial approximation in addition to retaining onlythe first term of the series obtained by HPM. The proposed method is capable of reducing the computational loadconsiderably when compared to other classical method.

In this study, we find the exact solution of certain partial differential equations (PDE) by proposing and using the Homo-Separation of Variables method. This novel analytical method is a combination of the homotopy perturbation method (HPM) with the separation of variables method. The exact solutions are con-structed by choosing an appropriate initial approximation in addition to only one term of the series obtained by HPM. The proposed method is introduced an efficient tool for solving a wide class of partial differential equations. It is straight-forward, easy to understand and fast requiring low computational load.

Abstract: In this study, we propose a new algorithm to find exact solution of nonlinear time- fractional partialdifferential equations. The new algorithm basically illustrates how two powerful algorithms, the homotopy pertur-bation method and the Sumudu transform method can be combined and used to get exact solutions of fractionalpartial differential equations. We also present four different examples to illustrate the preciseness and effectivenessof this algorithm.