This workshop introduces the concepts and workings of the ECG, and signal processing techniques used to glean information from raw recordings. In the hands-on coding exercises, you will be asked to apply the signal processing methods on a clinical prediction problem.
Traditional signal processing techniques have proven very effective in extracting information from signal morphology. This chapter will describe the principles of the ECG, and explore interpretable techniques applied on a relevant clinical problem: the classification of heart beats.
Biomedical Signal Processing Pdf Free 15
This section provides a simple overview of the ECG to support the signal processing in the rest of the chapter. For an in-depth description of action potentials and the ECG, see (Venegas and Mark 2004).
Although feature engineering and parameter tuning is required, these fundamental signal processing techniques offer full transparency and interpretability, which is important in the medical setting. In addition, the algorithms are relatively inexpensive to compute, and simple to implement, making them highly applicable to remote monitoring applications.
Once the features have been extracted from the CWT matrices for each labeled beat, the task is reduced to a straightforward supervised classification problem. Most of the algorithmic novelty is already applied in the signal processing section before actually reaching this point, which is the starting point for many machine-learning problems.
The perpetual physiologic monitoring of people from richer countries via their mobile devices, along with the increasing accessibility of these technologies for people from low resourced countries, presents the unprecedented opportunity to learn from vast amounts of physiologic data. As the volume of physiologic signals collected across the globe continues to explode, so too will the utility of signal processing techniques applied to them.
But despite the popularity of this field, most clinical problems are not perfectly solved. The single aspect that makes signal processing both effective and challenging is the unstructured time-series data. Clearly the large number of samples contain actionable information, but the building of structured features from this data can seem almost unbound. Unlike a structured table of patient demographics and disease statuses for example, the raw samples of an arbitrary length signal are not immediately actionable. One would have to choose window lengths, the algorithm(s) to apply, the number of desired feature desired, and so forth, before having any actionable information.
Magnetic resonance imaging (MRI) is an inherently slow imaging modality, since it acquires multi-dimensional k-space data through 1-D free induction decay or echo signals. This often limits the use of MRI, especially for high resolution or dynamic imaging. Accordingly, many investigators has developed various acceleration techniques to allow fast MR imaging. For the last two decades, one of the most important breakthroughs in this direction is the introduction of compressed sensing (CS) that allows accurate reconstruction from sparsely sampled k-space data. The recent FDA approval of compressed sensing products for clinical scans clearly reflect the maturity of this technology. Therefore, this paper reviews the basic idea of CS and how this technology have been evolved for various MR imaging problems.
Despite this close link to signal sampling theory, until the first demonstration of the sensitivity encoding (SENSE) technique by Prussemann [1], MR imaging was not considered as an important research topic for signal processing. Specifically, Prussemann et al. [1] showed that spatial diversity information from coil sensitivity maps have additional information that can be exploited for fast signal acquisition. Furthermore, Sodickson et al. [2] proposed the simultaneous acquisition of spatial harmonics (SMASH). These works gave a birth of parallel imaging and iterative reconstruction methods, and has resulted in a flurry of novel ideas and algorithms, including Generalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) by Griswold [3] and k-t space method for cardiac imaging such as [4,5,6,7,8,9].
Compressed sensing (CS) theory [12, 16, 17] addresses the accurate recovery of unknown sparse signals from underdetermined linear measurements and has become one of the main research topics in the signal processing area for the last two decades [18,19,20,21,22,23]. Most of the compressed sensing theories have been developed to address the so-called single measurement vector (SMV) problems [12, 16, 17]. More specifically, let m and n be positive integers such that m
Wearable non-invasive biosensors for the continuous monitoring of metabolites in sweat can detect a few analytes at sufficiently high concentrations, typically during vigorous exercise so as to generate sufficient quantity of the biofluid. Here we report the design and performance of a wearable electrochemical biosensor for the continuous analysis, in sweat during physical exercise and at rest, of trace levels of multiple metabolites and nutrients, including all essential amino acids and vitamins. The biosensor consists of graphene electrodes that can be repeatedly regenerated in situ, functionalized with metabolite-specific antibody-like molecularly imprinted polymers and redox-active reporter nanoparticles, and integrated with modules for iontophoresis-based sweat induction, microfluidic sweat sampling, signal processing and calibration, and wireless communication. In volunteers, the biosensor enabled the real-time monitoring of the intake of amino acids and their levels during physical exercise, as well as the assessment of the risk of metabolic syndrome (by correlating amino acid levels in serum and sweat). The monitoring of metabolites for the early identification of abnormal health conditions could facilitate applications in precision nutrition.
W.G., M.W., Y.Y. and J.M. initiated the concept and designed the studies; W.G. supervised the work; M.W., Y.Y. and J.M. led the experiments and collected the overall data; Y.S., J.T., D.M., C.Y. and C.X. contributed to sensor characterization, validation and sample analysis; N.H. contributed to the signal processing and app development. J.S.M., T.K.H. and Z.L. contributed to the design of the human studies. W.G., M.W., Y.Y. and J.M. co-wrote the paper. All authors contributed to the data analysis and provided feedback on the manuscript.
There are many subdisciplines within biomedical engineering, including the design and development of active and passive medical devices, orthopedic implants, medical imaging, biomedical signal processing, tissue and stem cell engineering, and clinical engineering, just to name a few. Request information to become a biomedical engineer today.
Perform preprocessing, feature engineering, signal labeling, and dataset generation for machine learning and deep learning workflows. Use the Signal Labeler app to create ground truth datasets and extract features to train AI models.
Accelerate the execution of your signal processing algorithms using a Graphics Processing Unit (GPU). Generate portable C/C++ source code, standalone executables, or standalone applications from your MATLAB code.
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