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1.
Comput Math Methods Med ; 2022: 1905151, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35069776

RESUMO

The goal of this project is to write a program in the C++ language that can recognize motions made by a subject in front of a camera. To do this, in the first place, a sequence of distance images has been obtained using a depth camera. Later, these images are processed through a series of blocks into which the program has been divided; each of them will yield a numerical or logical result, which will be used later by the following blocks. The blocks into which the program has been divided are three; the first detects the subject's hands, the second detects if there has been movement (and therefore a gesture has been made), and the last detects the type of gesture that has been made accomplished. On the other hand, it intends to present to the reader three unique techniques for acquiring 3D images: stereovision, structured light, and flight time, in addition to exposing some of the most used techniques in image processing, such as morphology and segmentation.


Assuntos
Gestos , Processamento de Imagem Assistida por Computador/métodos , Reconhecimento Automatizado de Padrão/métodos , Interface Usuário-Computador , Biologia Computacional , Mãos/fisiologia , Humanos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Imageamento Tridimensional/métodos , Imageamento Tridimensional/estatística & dados numéricos , Movimento/fisiologia , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Gravação em Vídeo/métodos , Gravação em Vídeo/estatística & dados numéricos
2.
Sci Rep ; 11(1): 21893, 2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34751189

RESUMO

Age-related macular degeneration (AMD) is a progressive retinal disease, causing vision loss. A more detailed characterization of its atrophic form became possible thanks to the introduction of Optical Coherence Tomography (OCT). However, manual atrophy quantification in 3D retinal scans is a tedious task and prevents taking full advantage of the accurate retina depiction. In this study we developed a fully automated algorithm segmenting Retinal Pigment Epithelial and Outer Retinal Atrophy (RORA) in dry AMD on macular OCT. 62 SD-OCT scans from eyes with atrophic AMD (57 patients) were collected and split into train and test sets. The training set was used to develop a Convolutional Neural Network (CNN). The performance of the algorithm was established by cross validation and comparison to the test set with ground-truth annotated by two graders. Additionally, the effect of using retinal layer segmentation during training was investigated. The algorithm achieved mean Dice scores of 0.881 and 0.844, sensitivity of 0.850 and 0.915 and precision of 0.928 and 0.799 in comparison with Expert 1 and Expert 2, respectively. Using retinal layer segmentation improved the model performance. The proposed model identified RORA with performance matching human experts. It has a potential to rapidly identify atrophy with high consistency.


Assuntos
Algoritmos , Atrofia Geográfica/diagnóstico por imagem , Degeneração Macular/diagnóstico por imagem , Tomografia de Coerência Óptica/métodos , Idoso , Idoso de 80 Anos ou mais , Aprendizado Profundo , Feminino , Humanos , Masculino , Redes Neurais de Computação , Variações Dependentes do Observador , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Epitélio Pigmentado da Retina/diagnóstico por imagem , Tomografia de Coerência Óptica/estatística & dados numéricos
3.
Comput Math Methods Med ; 2021: 1053242, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34659445

RESUMO

Most traditional superpixel segmentation methods used binary logic to generate superpixels for natural images. When these methods are used for images with significantly fuzzy characteristics, the boundary pixels sometimes cannot be correctly classified. In order to solve this problem, this paper proposes a Superpixel Method Based on Fuzzy Theory (SMBFT), which uses fuzzy theory as a guide and traditional fuzzy c-means clustering algorithm as a baseline. This method can make full use of the advantage of the fuzzy clustering algorithm in dealing with the images with the fuzzy characteristics. Boundary pixels which have higher uncertainties can be correctly classified with maximum probability. The superpixel has homogeneous pixels. Meanwhile, the paper also uses the surrounding neighborhood pixels to constrain the spatial information, which effectively alleviates the negative effects of noise. The paper tests on the images from Berkeley database and brain MR images from the Brain web. In addition, this paper proposes a comprehensive criterion to measure the weights of two kinds of criterions in choosing superpixel methods for color images. An evaluation criterion for medical image data sets employs the internal entropy of superpixels which is inspired by the concept of entropy in the information theory. The experimental results show that this method has superiorities than traditional methods both on natural images and medical images.


Assuntos
Algoritmos , Lógica Fuzzy , Interpretação de Imagem Assistida por Computador/métodos , Encéfalo/diagnóstico por imagem , Biologia Computacional , Humanos , Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Processamento de Imagem Assistida por Computador/métodos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Imageamento por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos
4.
Comput Math Methods Med ; 2021: 5527698, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34239598

RESUMO

Skin cancer is the most common cancer of the body. It is estimated that more than one million people worldwide develop skin cancer each year. Early detection of this cancer has a high effect on the disease treatment. In this paper, a new optimal and automatic pipeline approach has been proposed for the diagnosis of this disease from dermoscopy images. The proposed method includes a noise reduction process before processing for eliminating the noises. Then, the Otsu method as one of the widely used thresholding method is used to characterize the region of interest. Afterward, 20 different features are extracted from the image. To reduce the method complexity, a new modified version of the Thermal Exchange Optimization Algorithm is performed to the features. This improves the method precision and consistency. To validate the proposed method's efficiency, it is implemented to the American Cancer Society database, its results are compared with some state-of-the-art methods, and the final results showed the superiority of the proposed method against the others.


Assuntos
Algoritmos , Dermoscopia/métodos , Melanoma/diagnóstico por imagem , Neoplasias Cutâneas/diagnóstico por imagem , Biologia Computacional , Heurística Computacional , Simulação por Computador , Bases de Dados Factuais , Aprendizado Profundo , Dermoscopia/estatística & dados numéricos , Detecção Precoce de Câncer/métodos , Detecção Precoce de Câncer/estatística & dados numéricos , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Melanoma/classificação , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Razão Sinal-Ruído , Neoplasias Cutâneas/classificação , Máquina de Vetores de Suporte , Termografia/métodos , Termografia/estatística & dados numéricos
5.
Comput Math Methods Med ; 2021: 6321860, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34306177

RESUMO

In the past few decades, the field of image processing has seen a rapid advancement in the correlation filters, which serves as a very promising tool for object detection and recognition. Mostly, complex filter equations are used for deriving the correlation filters, leading to a filter solution in a closed loop. Selection of optimal tradeoff (OT) parameters is crucial for the effectiveness of correlation filters. This paper proposes extended particle swarm optimization (EPSO) technique for the optimal selection of OT parameters. The optimal solution is proposed based on two cost functions. The best result for each target is obtained by applying the optimization technique separately. The obtained results are compared with the conventional particle swarm optimization method for various test images belonging from different state-of-the-art datasets. The obtained results depict the performance of filters improved significantly using the proposed optimization method.


Assuntos
Algoritmos , Processamento de Imagem Assistida por Computador/métodos , Reconhecimento Automatizado de Padrão/métodos , Biologia Computacional , Simulação por Computador , Humanos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Software
6.
Comput Math Methods Med ; 2021: 6656942, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34188691

RESUMO

In the process of prenatal ultrasound diagnosis, accurate identification of fetal facial ultrasound standard plane (FFUSP) is essential for accurate facial deformity detection and disease screening, such as cleft lip and palate detection and Down syndrome screening check. However, the traditional method of obtaining standard planes is manual screening by doctors. Due to different levels of doctors, this method often leads to large errors in the results. Therefore, in this study, we propose a texture feature fusion method (LH-SVM) for automatic recognition and classification of FFUSP. First, extract image's texture features, including Local Binary Pattern (LBP) and Histogram of Oriented Gradient (HOG), then perform feature fusion, and finally adopt Support Vector Machine (SVM) for predictive classification. In our study, we used fetal facial ultrasound images from 20 to 24 weeks of gestation as experimental data for a total of 943 standard plane images (221 ocular axial planes, 298 median sagittal planes, 424 nasolabial coronal planes, and 350 nonstandard planes, OAP, MSP, NCP, N-SP). Based on this data set, we performed five-fold cross-validation. The final test results show that the accuracy rate of the proposed method for FFUSP classification is 94.67%, the average precision rate is 94.27%, the average recall rate is 93.88%, and the average F1 score is 94.08%. The experimental results indicate that the texture feature fusion method can effectively predict and classify FFUSP, which provides an essential basis for clinical research on the automatic detection method of FFUSP.


Assuntos
Face/diagnóstico por imagem , Ultrassonografia Pré-Natal/métodos , Fenda Labial/diagnóstico por imagem , Fissura Palatina/diagnóstico por imagem , Biologia Computacional , Feminino , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Gravidez , Máquina de Vetores de Suporte , Ultrassonografia Pré-Natal/estatística & dados numéricos
7.
Comput Math Methods Med ; 2021: 5588385, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34055039

RESUMO

For the low optimization accuracy of the cuckoo search algorithm, a new search algorithm, the Elite Hybrid Binary Cuckoo Search (EHBCS) algorithm, is improved by feature weighting and elite strategy. The EHBCS algorithm has been designed for feature selection on a series of binary classification datasets, including low-dimensional and high-dimensional samples by SVM classifier. The experimental results show that the EHBCS algorithm achieves better classification performances compared with binary genetic algorithm and binary particle swarm optimization algorithm. Besides, we explain its superiority in terms of standard deviation, sensitivity, specificity, precision, and F-measure.


Assuntos
Algoritmos , Biologia Computacional/métodos , Máquina de Vetores de Suporte , Animais , Aves , Classificação , Biologia Computacional/estatística & dados numéricos , Bases de Dados Factuais/estatística & dados numéricos , Feminino , Humanos , Masculino , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Fatores de Risco
8.
Comput Math Methods Med ; 2021: 5868949, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34055040

RESUMO

With the rapid development of science and technology, ultrasound has been paid more and more attention by people, and it is widely used in engineering, diagnosis, and detection. In this paper, an ultrasonic image recognition method based on immune algorithm is proposed for ultrasonic images, and its method is applied to medical ultrasound liver image recognition. Firstly, this paper grays out the ultrasound liver image and selects the region of interest of the image. Secondly, it extracts the feature based on spatial gray matrix independent matrix, spatial frequency decomposition, and fractal features. Then, the immune algorithm is used to classify and identify the normal liver, liver cirrhosis, and liver cancer ultrasound images. Finally, based on the deficiency of the immune algorithm, it is combined with the support vector machine to form an optimized immune algorithm, which improves the performance of ultrasonic liver image classification and recognition. The simulation shows that this paper can effectively classify the normal liver, liver cirrhosis, and liver cancer ultrasound images. Compared with the traditional immune algorithm, this paper combines the immune algorithm with the support vector machine, and the optimized immune algorithm can effectively improve the performance of ultrasonic liver image classification and recognition.


Assuntos
Algoritmos , Interpretação de Imagem Assistida por Computador/métodos , Fígado/diagnóstico por imagem , Ultrassonografia/métodos , Biologia Computacional , Simulação por Computador , Humanos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Cirrose Hepática/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Modelos Imunológicos , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Máquina de Vetores de Suporte , Ultrassonografia/estatística & dados numéricos
9.
Comput Math Methods Med ; 2020: 6317415, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33204300

RESUMO

Segmentation accuracy is an important criterion for evaluating the performance of segmentation techniques used to extract objects of interest from images, such as the active contour model. However, segmentation accuracy can be affected by image artifacts such as intensity inhomogeneity, which makes it difficult to extract objects with inhomogeneous intensities. To address this issue, this paper proposes a hybrid region-based active contour model for the segmentation of inhomogeneous images. The proposed hybrid energy functional combines local and global intensity functions; an incorporated weight function is parameterized based on local image contrast. The inclusion of this weight function smoothens the contours at different intensity level boundaries, thereby yielding improved segmentation. The weight function suppresses false contour evolution and also regularizes object boundaries. Compared with other state-of-the-art methods, the proposed approach achieves superior results over synthetic and real images. Based on a quantitative analysis over the mini-MIAS and PH2 databases, the superiority of the proposed model in terms of segmentation accuracy, as compared with the ground truths, was confirmed. Furthermore, when using the proposed model, the processing time for image segmentation is lower than those when using other methods.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Biologia Computacional , Simulação por Computador , Bases de Dados Factuais/estatística & dados numéricos , Aprendizado Profundo , Dermoscopia/estatística & dados numéricos , Feminino , Humanos , Mamografia/estatística & dados numéricos , Modelos Estatísticos , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos
10.
Comput Math Methods Med ; 2020: 7359375, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33082840

RESUMO

Prostate cancer is one of the most common cancers in men. Early detection of prostate cancer is the key to successful treatment. Ultrasound imaging is one of the most suitable methods for the early detection of prostate cancer. Although ultrasound images can show cancer lesions, subjective interpretation is not accurate. Therefore, this paper proposes a transrectal ultrasound image analysis method, aiming at characterizing prostate tissue through image processing to evaluate the possibility of malignant tumours. Firstly, the input image is preprocessed by optical density conversion. Then, local binarization and Gaussian Markov random fields are used to extract texture features, and the linear combination is performed. Finally, the fused texture features are provided to SVM classifier for classification. The method has been applied to data set of 342 transrectal ultrasound images obtained from hospitals with an accuracy of 70.93%, sensitivity of 70.00%, and specificity of 71.74%. The experimental results show that it is possible to distinguish cancerous tissues from noncancerous tissues to some extent.


Assuntos
Neoplasias da Próstata/classificação , Neoplasias da Próstata/diagnóstico por imagem , Biologia Computacional , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Masculino , Cadeias de Markov , Conceitos Matemáticos , Distribuição Normal , Fenômenos Ópticos , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Máquina de Vetores de Suporte , Ultrassonografia/métodos , Ultrassonografia/estatística & dados numéricos
11.
PLoS One ; 15(10): e0237570, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33044975

RESUMO

Photo-identification (photo-id) is a method used in field studies by biologists to monitor animals according to their density, movement patterns and behavior, with the aim of predicting and preventing ecological risks. However, these methods can introduce subjectivity when manually classifying an individual animal, creating uncertainty or inaccuracy in the data as a result of the human criteria involved. One of the main objectives in photo-id is to implement an automated mechanism that is free of biases, portable, and easy to use. The main aim of this work is to develop an autonomous and portable photo-id system through the optimization of image classification algorithms that have high statistical dependence, with the goal of classifying dorsal fin images of the blue whale through offline information processing on a mobile platform. The new proposed methodology is based on the Scale Invariant Feature Transform (SIFT) that, in conjunction with statistical discriminators such as the variance and the standard deviation, fits the extracted data and selects the closest pixels that comprise the edges of the dorsal fin of the blue whale. In this way, we ensure the elimination of the most common external factors that could affect the quality of the image, thus avoiding the elimination of relevant sections of the dorsal fin. The photo-id method presented in this work has been developed using blue whale images collected off the coast of Baja California Sur. The results shown have qualitatively and quantitatively validated the method in terms of its sensitivity, specificity and accuracy on the Jetson Tegra TK1 mobile platform. The solution optimizes classic SIFT, balancing the results obtained with the computational cost, provides a more economical form of processing and obtains a portable system that could be beneficial for field studies through mobile platforms, making it available to scientists, government and the general public.


Assuntos
Nadadeiras de Animais/anatomia & histologia , Balaenoptera/anatomia & histologia , Aplicativos Móveis , Fotografação/métodos , Algoritmos , Animais , Bases de Dados Factuais , Processamento de Imagem Assistida por Computador/métodos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Fotografação/estatística & dados numéricos
12.
Comput Math Methods Med ; 2020: 1981728, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32765639

RESUMO

EEG pattern recognition is an important part of motor imagery- (MI-) based brain computer interface (BCI) system. Traditional EEG pattern recognition algorithm usually includes two steps, namely, feature extraction and feature classification. In feature extraction, common spatial pattern (CSP) is one of the most frequently used algorithms. However, in order to extract the optimal CSP features, prior knowledge and complex parameter adjustment are often required. Convolutional neural network (CNN) is one of the most popular deep learning models at present. Within CNN, feature learning and pattern classification are carried out simultaneously during the procedure of iterative updating of network parameters; thus, it can remove the complicated manual feature engineering. In this paper, we propose a novel deep learning methodology which can be used for spatial-frequency feature learning and classification of motor imagery EEG. Specifically, a multilayer CNN model is designed according to the spatial-frequency characteristics of MI EEG signals. An experimental study is carried out on two MI EEG datasets (BCI competition III dataset IVa and a self-collected right index finger MI dataset) to validate the effectiveness of our algorithm in comparison with several closely related competing methods. Superior classification performance indicates that our proposed method is a promising pattern recognition algorithm for MI-based BCI system.


Assuntos
Interfaces Cérebro-Computador/estatística & dados numéricos , Eletroencefalografia/estatística & dados numéricos , Imaginação , Redes Neurais de Computação , Algoritmos , Bases de Dados Factuais , Aprendizado Profundo , Humanos , Imaginação/fisiologia , Conceitos Matemáticos , Modelos Neurológicos , Córtex Motor/fisiologia , Reconhecimento Automatizado de Padrão/estatística & dados numéricos
13.
Comput Math Methods Med ; 2020: 9812019, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32774445

RESUMO

In this paper, we present a parallel framework based on MPI for a large dataset to extract power spectrum features of EEG signals so as to improve the speed of brain signal processing. At present, the Welch method has been wildly used to estimate the power spectrum. However, the traditional Welch method takes a lot of time especially for the large dataset. In view of this, we added the MPI into the traditional Welch method and developed it into a reusable master-slave parallel framework. As long as the EEG data of any format are converted into the text file of a specified format, the power spectrum features can be extracted quickly by this parallel framework. In the proposed parallel framework, the EEG signals recorded by a channel are divided into N overlapping data segments. Then, the PSD of N segments are computed by some nodes in parallel. The results are collected and summarized by the master node. The final PSD results of each channel are saved in the text file, which can be read and analyzed by Microsoft Excel. This framework can be implemented not only on the clusters but also on the desktop computer. In the experiment, we deploy this framework on a desktop computer with a 4-core Intel CPU. It took only a few minutes to extract the power spectrum features from the 2.85 GB EEG dataset, seven times faster than using Python. This framework makes it easy for users, who do not have any parallel programming experience in constructing the parallel algorithms to extract the EEG power spectrum.


Assuntos
Algoritmos , Eletroencefalografia/estatística & dados numéricos , Big Data , Encéfalo/fisiologia , Interfaces Cérebro-Computador/estatística & dados numéricos , Bases de Dados Factuais/estatística & dados numéricos , Eletroencefalografia/instrumentação , Análise de Fourier , Humanos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Linguagens de Programação , Processamento de Sinais Assistido por Computador
14.
Comput Math Methods Med ; 2020: 7595174, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32565883

RESUMO

Image segmentation is still an open problem especially when intensities of the objects of interest are overlapped due to the presence of intensity inhomogeneities. A bias correction embedded level set model is proposed in this paper where inhomogeneities are estimated by orthogonal primary functions. First, an inhomogeneous intensity clustering energy is defined based on global distribution characteristics of the image intensities, and membership functions of the clusters described by the level set function are then introduced to define the data term energy of the proposed model. Second, a regularization term and an arc length term are also included to regularize the level set function and smooth its zero-level set contour, respectively. Third, the proposed model is extended to multichannel and multiphase patterns to segment colorful images and images with multiple objects, respectively. Experimental results and comparison with relevant models demonstrate the advantages of the proposed model in terms of bias correction and segmentation accuracy on widely used synthetic and real images and the BrainWeb and the IBSR image repositories.


Assuntos
Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Algoritmos , Inteligência Artificial/estatística & dados numéricos , Viés , Encéfalo/diagnóstico por imagem , Análise por Conglomerados , Biologia Computacional , Bases de Dados Factuais , Humanos , Imageamento Tridimensional/estatística & dados numéricos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Modelos Estatísticos , Neuroimagem/estatística & dados numéricos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos
15.
Comput Math Methods Med ; 2020: 5694265, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32351614

RESUMO

Towards providing efficient human-robot interaction, surface electromyogram (EMG) signals have been widely adopted for the identification of different limb movement intentions. Since the available EMG signal sensors are highly susceptible to external interferences such as electromagnetic artifacts and muscle fatigues, the quality of EMG recordings would be mostly corrupted, which may decay the performance of EMG-based control systems. Given the fact that the muscle shape changes (MSC) would be different when doing various limb movements, the MSC signal would be nonsensitive to electromagnetic artifacts and muscle fatigues and maybe promising for movement intention recognition. In this study, a novel nanogold flexible and stretchable sensor was developed for the acquisition of MSC signals utilized for decoding multiple classes of limb movement intents. More precisely, four sensors were used to measure the MSC signals from the right forearm of each subject when they performed seven classes of movements. Also, six different features were extracted from the measured MSC signals, and a linear discriminant analysis- (LDA-) based classifier was built for movement classification tasks. The experimental results showed that using MSC signals could achieve an average recognition rate of about 96.06 ± 1.84% by properly placing the four flexible and stretchable sensors on the forearm. Additionally, when the MSC sampling rate was greater than 100 Hz and the analysis window length was greater than 20 ms, the movement recognition accuracy would be only slightly increased. These pilot results suggest that the MSC-based method should be feasible in movement identifications for human-robot interaction, and at the same time, they provide a systematic reference for the use of the flexible and stretchable sensors in human-robot interaction systems.


Assuntos
Movimento/fisiologia , Robótica/instrumentação , Extremidade Superior/fisiologia , Interface Usuário-Computador , Dispositivos Eletrônicos Vestíveis/estatística & dados numéricos , Condutividade Elétrica , Eletromiografia/instrumentação , Eletromiografia/estatística & dados numéricos , Desenho de Equipamento , Ouro , Humanos , Músculo Esquelético/fisiologia , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Robótica/estatística & dados numéricos , Processamento de Sinais Assistido por Computador
16.
Comput Math Methods Med ; 2020: 8308173, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32328156

RESUMO

The basic experimental data of traditional Chinese medicine are generally obtained by high-performance liquid chromatography and mass spectrometry. The data often show the characteristics of high dimensionality and few samples, and there are many irrelevant features and redundant features in the data, which bring challenges to the in-depth exploration of Chinese medicine material information. A hybrid feature selection method based on iterative approximate Markov blanket (CI_AMB) is proposed in the paper. The method uses the maximum information coefficient to measure the correlation between features and target variables and achieves the purpose of filtering irrelevant features according to the evaluation criteria, firstly. The iterative approximation Markov blanket strategy analyzes the redundancy between features and implements the elimination of redundant features and then selects an effective feature subset finally. Comparative experiments using traditional Chinese medicine material basic experimental data and UCI's multiple public datasets show that the new method has a better advantage to select a small number of highly explanatory features, compared with Lasso, XGBoost, and the classic approximate Markov blanket method.


Assuntos
Bases de Dados de Produtos Farmacêuticos/estatística & dados numéricos , Medicamentos de Ervas Chinesas/química , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Algoritmos , Inteligência Artificial , Cromatografia Líquida de Alta Pressão , Biologia Computacional , Humanos , Cadeias de Markov , Espectrometria de Massas , Medicina Tradicional Chinesa/estatística & dados numéricos
17.
Comput Math Methods Med ; 2020: 8573754, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32273902

RESUMO

In recent years, asynchronous brain computer interface (BCI) systems have been utilized in many domains such as robot controlling, assistive technology, and rehabilitation. In such BCI systems, movement intention detection algorithms are used to detect movement desires. In recent years, movement-related cortical potential (MRCP), an electroencephalogram (EEG) pattern representing voluntary movement intention, attracts wide attention in movement intention detection. Unfortunately, low MRCP detection accuracy makes the asynchronous BCI system impractical for real usage. In order to develop an effective MRCP detection algorithm, EEG data have to be properly preprocessed. In this work, we investigate the relationship and effects of three factors including frequency bands, spatial filters, and classifiers on MRCP classification performance to determine best settings. In particular, we performed a systematic performance investigation on combinations of five frequency bands, five spatial filters, and six classifiers. The EEG data were acquired from subjects performing series of self-paced ankle dorsiflexions. Analysis of variance (ANOVA) statistical test was performed on F1 scores to investigate effects of these three factors. The results show that frequency bands and spatial filters depend on each other. The combinations directly affect the F1 scores, so they have to be chosen carefully. The results can be used as guidelines for BCI researchers to effectively design a preprocessing method for an advanced asynchronous BCI system, which can assist the stroke rehabilitation.


Assuntos
Interfaces Cérebro-Computador/estatística & dados numéricos , Intenção , Movimento , Adulto , Algoritmos , Biologia Computacional , Eletroencefalografia/estatística & dados numéricos , Potenciais Evocados , Feminino , Humanos , Modelos Lineares , Masculino , Movimento/fisiologia , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Análise de Componente Principal , Processamento de Sinais Assistido por Computador , Reabilitação do Acidente Vascular Cerebral/métodos , Reabilitação do Acidente Vascular Cerebral/estatística & dados numéricos , Máquina de Vetores de Suporte , Adulto Jovem
18.
IEEE Trans Neural Netw Learn Syst ; 31(8): 2832-2846, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-31199274

RESUMO

Class imbalance is a challenging problem in many classification tasks. It induces biased classification results for minority classes that contain less training samples than others. Most existing approaches aim to remedy the imbalanced number of instances among categories by resampling the majority and minority classes accordingly. However, the imbalanced level of difficulty of recognizing different categories is also crucial, especially for distinguishing samples with many classes. For example, in the task of clinical skin disease recognition, several rare diseases have a small number of training samples, but they are easy to diagnose because of their distinct visual properties. On the other hand, some common skin diseases, e.g., eczema, are hard to recognize due to the lack of special symptoms. To address this problem, we propose a self-paced balance learning (SPBL) algorithm in this paper. Specifically, we introduce a comprehensive metric termed the complexity of image category that is a combination of both sample number and recognition difficulty. First, the complexity is initialized using the model of the first pace, where the pace indicates one iteration in the self-paced learning paradigm. We then assign each class a penalty weight that is larger for more complex categories and smaller for easier ones, after which the curriculum is reconstructed by rearranging the training samples. Consequently, the model can iteratively learn discriminative representations via balancing the complexity in each pace. Experimental results on the SD-198 and SD-260 benchmark data sets demonstrate that the proposed SPBL algorithm performs favorably against the state-of-the-art methods. We also demonstrate the effectiveness of the SPBL algorithm's generalization capacity on various tasks, such as indoor scene image recognition and object classification.


Assuntos
Algoritmos , Aprendizado de Máquina , Reconhecimento Automatizado de Padrão/métodos , Dermatopatias/diagnóstico , Bases de Dados Factuais/estatística & dados numéricos , Humanos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos
19.
J Clin Monit Comput ; 34(2): 339-352, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30955160

RESUMO

Studies reveal that the false alarm rate (FAR) demonstrated by intensive care unit (ICU) vital signs monitors ranges from 0.72 to 0.99. We applied machine learning (ML) to ICU multi-sensor information to imitate a medical specialist in diagnosing patient condition. We hypothesized that applying this data-driven approach to medical monitors will help reduce the FAR even when data from sensors are missing. An expert-based rules algorithm identified and tagged in our dataset seven clinical alarm scenarios. We compared a random forest (RF) ML model trained using the tagged data, where parameters (e.g., heart rate or blood pressure) were (deliberately) removed, in detecting ICU signals with the full expert-based rules (FER), our ground truth, and partial expert-based rules (PER), missing these parameters. When all alarm scenarios were examined, RF and FER were almost identical. However, in the absence of one to three parameters, RF maintained its values of the Youden index (0.94-0.97) and positive predictive value (PPV) (0.98-0.99), whereas PER lost its value (0.54-0.8 and 0.76-0.88, respectively). While the FAR for PER with missing parameters was 0.17-0.39, it was only 0.01-0.02 for RF. When scenarios were examined separately, RF showed clear superiority in almost all combinations of scenarios and numbers of missing parameters. When sensor data are missing, specialist performance worsens with the number of missing parameters, whereas the RF model attains high accuracy and low FAR due to its ability to fuse information from available sensors, compensating for missing parameters.


Assuntos
Alarmes Clínicos/estatística & dados numéricos , Unidades de Terapia Intensiva , Aprendizado de Máquina , Cuidados Críticos/estatística & dados numéricos , Técnicas de Apoio para a Decisão , Sistemas Inteligentes , Reações Falso-Positivas , Humanos , Bases de Conhecimento , Monitorização Fisiológica/estatística & dados numéricos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Estudos Retrospectivos
20.
Comput Methods Programs Biomed ; 179: 104986, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31443868

RESUMO

BACKGROUND: Spike sorting is a basic step for implantable neural interfaces. With the growing number of channels, the process should be computationally efficient, automatic,robust and applicable on implantable circuits. NEW METHOD: The proposed method is a combination of fully-automatic offline and online processes. It introduces a novel method for automatically determining a data-aware spike detection threshold, computationally efficient spike feature extraction, automatic optimal cluster number evaluation and verification coupled with Self-Organizing Maps to accurately determine cluster centroids. The system has the ability of unsupervised online operation after initial fully-automatic offline training. The prime focus of this paper is to fully-automate the complete spike detection and sorting pipeline, while keeping the accuracy high. RESULTS: The proposed system is simulated on two well-known datasets. The automatic threshold improves detection accuracies significantly( > 15%) as compared to the most common detector. The system is able to effectively handle background multi-unit activity with improved performance. COMPARISON: Most of the existing methods are not fully-automatic; they require supervision and expert intervention at various stages of the pipeline. Secondly, existing works focus on foreground neural activity. Recent research has highlighted importance of background multi-unit activity, and this work is amongst the first efforts that proposes and verifies an automatic methodology to effectively handle them as well. CONCLUSION: This paper proposes a fully-automatic, computationally efficient system for spike sorting for both single-unit and multi-unit spikes. Although the scope of this work is design and verification through computer simulations, the system has been designed to be easily transferable into an integrated hardware form.


Assuntos
Potenciais de Ação , Neuroestimuladores Implantáveis/estatística & dados numéricos , Algoritmos , Interfaces Cérebro-Computador/estatística & dados numéricos , Simulação por Computador , Eletrodos Implantados/estatística & dados numéricos , Humanos , Modelos Neurológicos , Neurônios/fisiologia , Sistemas On-Line , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Processamento de Sinais Assistido por Computador , Aprendizado de Máquina não Supervisionado
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