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Biomedical Engineering, IEEE Transactions on

Issue 6 • Date June 1984

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Displaying Results 1 - 16 of 16
  • IEEE Transactions on Biomedical Engineering - Table of contents

    Publication Year: 1984 , Page(s): c1
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  • IEEE Engineering in Medicine and Biology Society

    Publication Year: 1984 , Page(s): c2
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  • An Effective Algorithm for Extracting Serial Endocardial Borders from 2-Dimensional Echocardiograms

    Publication Year: 1984 , Page(s): 441 - 447
    Cited by:  Papers (45)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4655 KB)  

    An effective image processing algorithm for extracting the endocardial border from a series of 2-dimensional echocardiograms (2D echo) is proposed. The main steps involved in this algorithm are coordinate transformation, regional co-occurrence matrix thresholding, search region limiting, border detecting, and spatial and temporal smoothing. Using these steps, some major difficulties related to 2D echo image processing including low signal-to-noise ratio, echo drop out, and gray level intensity variability have been dramatically reduced. All endocardial borders in an entire cardiac cycle are computed. This is done automatically on the basis of observer-drawn outlines at end systole and end diastole. These outlines facilitate the quantitative analysis by defining a range in which both boundary dimension and shape changes should occur. Image processing is restricted to this range. The validation studies have been perfonned on test balloons where both image quality has been changed and complex motion abnormalities have been experimentally produced. Good results have also been obtained in patient studies. View full abstract»

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  • Computation of the Input Impedances of a Catheter for Cardiac Volumetry

    Publication Year: 1984 , Page(s): 448 - 453
    Cited by:  Papers (14)
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    Electrical impedances between the electrodes of a catheter in a spheroidal model of the left ventricle are calculated analytically. The fields in the configuration are computed using eigen function expansions of the Laplace equation. For certain realistic combinations of specific conductances of the blood and the myocardium, numerical results are given. These results show the dependence of the impedances on the volume of the ventricle while keeping the length of the major axis of the ventricle constant. Also, the accuracy of the model and the dependence of the total conductance of the ventricle on its shape, and on the conductivity of the tissues surrounding it, are discussed. The theoretical results are compared against the experimental values of conductances, measured post mortem in a canine heart, for different volumes. View full abstract»

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  • Artifacts in Wiener Kernels Estimated Using Gaussian White Noise

    Publication Year: 1984 , Page(s): 454 - 461
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3126 KB)  

    Wiener's nonlinear system identification theory characterizes a system function with a set of kernels of integrals. One method of determining these Wiener kernels is the cross-correlation technique proposed by Lee and Schetzen, which uses Gaussian white noise as the input to the unknown system. Because a test stimulus is only an approximation of infinitely long Gaussian white noise, it is possible that artifacts are generated during the estimation of the kernels. To help identify and characterize these artifacts, Wiener kernel estimates for two simple nonlinear model systems were made using a pseudorandom Gaussian white noise sequence. The results showed that because of the approximation of a Gaussian distribution, artifacts appear in the estimated kernels due to a form of aliasing. These artifacts can be reduced by increasing the sequence length of the input noise. View full abstract»

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  • High-Resolution Alignment of Sampled Waveforms

    Publication Year: 1984 , Page(s): 462 - 468
    Cited by:  Papers (70)
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    Waveforms are often sampled faster than the Nyquist rate to obtain desired temporal resolution, even though, theoretically, oversampling adds no information and should not be necessary. This paper shows how high resolution can be achieved efficiently from data sampled at the Nyquist rate by working with coefficients of the Fourier-series expansion of the continuous interpolating waveform. Practical algorithms are presented for aligning and comparing waveforms, locating peaks, resolving superimpositions, and averaging overlapping waveforms. The algorithms prove to be more accurate, and to require fewer computations and less storage than techniques which employ continuous oversampling in many signal-processing applications, particularly template matching. View full abstract»

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  • Time-Delay for Two-Compartment Models Used for Study of Enterohepatic Circulation of Drugs

    Publication Year: 1984 , Page(s): 469 - 472
    Cited by:  Papers (3)
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    A two-component model with time lag was proposed to describe pharmacokinetics of drugs subject to enterohepatic circulation. An analytic expansion of the amount of drug, at any time, in the central compartment after an intravenous bolus, or an oral intake, or a constant infusion, from a zero or nonzero equilibrium is given. By computer simulations, plasma level profiles are obtained and lead to rebounds and secondary peaks, according to experimental evidences. View full abstract»

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  • Comments on "Pole-Zero Modeling and Classification of Phonocardiograms"

    Publication Year: 1984 , Page(s): 473 - 474
    Cited by:  Papers (1)
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    Recently,1 the Steiglitz-McBride method was used to identify the two most dominant frequencies in aortic heart sounds from porcine prosthetic heart valves. A quadratic classifier was developed to evaluate valve sounds in a test set. We have corrected computational errors, recomputed their results, and interchanged the training and test sets to yield new results. View full abstract»

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  • Corneal Markers and Reflections Yield Translation Invariance - A Theoretical Analysis

    Publication Year: 1984 , Page(s): 474 - 477
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (924 KB)  

    The theoretical significance of the simultaneous measurement of corneal markers and reflections in animals is evaluated. This measure yields a translation invariant estimate of eye rotation, but is complicated by several factors discussed in this communication. Computed range and accuracy estimates for an apparently feasible example of this approach provide modest performance when subjects (typical cats) are allowed ±2 mm of head translation movement. View full abstract»

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  • Impedance of Skeletal Muscle from 1 Hz to 1 MHz

    Publication Year: 1984 , Page(s): 477 - 481
    Cited by:  Papers (40)
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    We have measured the transverse and longitudinal impedance of skeletal muscle from 1 Hz to 1 MHz. An Ag-AgCl four-electrode test cell minimizes polarization error. We measured more than 100 samples from five mammals and chickens. Our tests showed that the transverse impedance changes with time at rates dependent on temperature due to muscle degradation. Thus, we performed tests within 20-30 min after sacrifice. The highest ratio of transverse to longitudinal impedance was 23. We fit our data to the usual three-element RC model. View full abstract»

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  • The Time-Dependent Equivalent Dipole Source for the Response to Median Nerve Stimulation

    Publication Year: 1984 , Page(s): 481 - 483
    Cited by:  Papers (7)
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    A single current dipole source, varying in time, is used to characterize the neural generators of a component of the response evoked by median nerve stimulation. By allowing the equivalent source to move in time, it may be possible to model the movement of currents along sensory pathways. View full abstract»

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  • Comments on "Multichannel Signal Processing Based on Logic Averaging"

    Publication Year: 1984 , Page(s): 483 - 484
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    In this comment, the method proposed in the above paper1 to detect surface activity of the His-Purkinje system (HPS), and to increase the signal-to-noise ratio (SNR) of the measured signal, is criticized; the computation of the SNR figure is proved to be based on an erroneous notion of the signal-to-noise concept. View full abstract»

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  • Author's Reply2

    Publication Year: 1984 , Page(s): 484 - 486
    Cited by:  Papers (1)
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    A summary statement of our elaborated response is as follows. There are a number of legitimate concepts of signal-to-noise ratio. Likewise, there are a number of legitimate operational methods to make this estimate. That ours was legitimate is expanded upon in the following response. View full abstract»

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  • Construction and Position Verification of a Thermocouple Esophageal Temperature Probe

    Publication Year: 1984 , Page(s): 486 - 488
    Cited by:  Papers (1)
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    The construction and evaluation of a thermocouple probe for measuring esophageal temperature is described. The position of the probe within the esophagus is determined electrocardiographically, by observing the changes in ECG traces obtained from a surface electrode and an esophageal lead. The electrocardiographic method of determining probe position is demonstrated and verified by radiography. View full abstract»

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  • IEEE Transactions on Biomedical Engineering Statement of Editorial Policy

    Publication Year: 1984 , Page(s): 488-a
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    Freely Available from IEEE
  • Institutional listings

    Publication Year: 1984 , Page(s): 488b
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Aims & Scope

IEEE Transactions on Biomedical Engineering contains basic and applied papers dealing with biomedical engineering. Papers range from engineering development in methods and techniques with biomedical applications to experimental and clinical investigations with engineering contributions.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Bin He
Department of Biomedical Engineering