The problem of unsupervised segmentation of coronary angiograms is investigated. An algorithm which uses an iterative line search procedure to adapt the segmentation thresholds is proposed. This algorithm is parallel in nature, and could be implemented on a disturbed computer architecture. Based on the angiogram's histogram, two thresholds are obtained which classify the pixels into three types: artery, background, and unclassified, The threshold adaptation is an iterative process. A heuristic line search is conducted throughout the neighborhoods of the unclassified pixels. The results of the search are used to adapt the thresholds. The process is continued until all pixels are classified as either artery or background. The algorithm was implemented on an IBM PC/AT-based imaging system and tested with coronary arteriogram images. Preliminary results demonstrated the algorithm's usefulness in enhancing the arterial structure, even under low signal-to-noise ratios. Furthermore, the segmentation was achieved within a few iterations.<>
{"title":"Adaptive segmentation of coronary angiograms","authors":"D. Kottke, Ying Sun","doi":"10.1109/NEBC.1988.19408","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19408","url":null,"abstract":"The problem of unsupervised segmentation of coronary angiograms is investigated. An algorithm which uses an iterative line search procedure to adapt the segmentation thresholds is proposed. This algorithm is parallel in nature, and could be implemented on a disturbed computer architecture. Based on the angiogram's histogram, two thresholds are obtained which classify the pixels into three types: artery, background, and unclassified, The threshold adaptation is an iterative process. A heuristic line search is conducted throughout the neighborhoods of the unclassified pixels. The results of the search are used to adapt the thresholds. The process is continued until all pixels are classified as either artery or background. The algorithm was implemented on an IBM PC/AT-based imaging system and tested with coronary arteriogram images. Preliminary results demonstrated the algorithm's usefulness in enhancing the arterial structure, even under low signal-to-noise ratios. Furthermore, the segmentation was achieved within a few iterations.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131607869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The major practical problem in applying Fourier domain techniques to medical imagery has been the large number of calculations required for substantial image sizes with resultant non-real-time operation. The recent development of an imaging supercomputer with associated two-dimensional fast Fourier transform software has now made possible the calculation of (120*128)-pixel two-dimensional Fourier transforms, multiplication by an arbitrary filter function, and inverse two-dimensional Fourier transformation possible in real time. Here, plain-film projection radiographs are digitized and a variety of high-pass, low-pass and bandpass filters are applied in the transform domain. The preliminary results suggest that such real-time spatial filtering may be particularly attractive to radiologists because of the ability to see simultaneously both the unprocessed and processed radiograph and to utilize rapidly and assess a variety of available filters.<>
{"title":"Real time frequency domain processing of medical images","authors":"M. Fox","doi":"10.1109/NEBC.1988.19407","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19407","url":null,"abstract":"The major practical problem in applying Fourier domain techniques to medical imagery has been the large number of calculations required for substantial image sizes with resultant non-real-time operation. The recent development of an imaging supercomputer with associated two-dimensional fast Fourier transform software has now made possible the calculation of (120*128)-pixel two-dimensional Fourier transforms, multiplication by an arbitrary filter function, and inverse two-dimensional Fourier transformation possible in real time. Here, plain-film projection radiographs are digitized and a variety of high-pass, low-pass and bandpass filters are applied in the transform domain. The preliminary results suggest that such real-time spatial filtering may be particularly attractive to radiologists because of the ability to see simultaneously both the unprocessed and processed radiograph and to utilize rapidly and assess a variety of available filters.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115728026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is shown that velocity storage can be generalized to three dimensions to explain the cross-coupling from horizontal slow phase velocity to vertical and roll eye velocity. The key conclusion is that the eigenvalues and the orientation of the eigenvectors of the system matrix associated with the velocity storage integrator are closely linked to the gravitational field. Gravity appears to maintain the eigenvectors with the smallest eigenvalues, i.e. the principal axes of storage, close to the spatial vertical regardless of head orientation.<>
{"title":"Modelling the three dimensional structure of velocity storage in the vestibulo-ocular reflex (VOR)","authors":"D. Sturm, T. Rapham","doi":"10.1109/NEBC.1988.19379","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19379","url":null,"abstract":"It is shown that velocity storage can be generalized to three dimensions to explain the cross-coupling from horizontal slow phase velocity to vertical and roll eye velocity. The key conclusion is that the eigenvalues and the orientation of the eigenvectors of the system matrix associated with the velocity storage integrator are closely linked to the gravitational field. Gravity appears to maintain the eigenvectors with the smallest eigenvalues, i.e. the principal axes of storage, close to the spatial vertical regardless of head orientation.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121573751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The encoder characteristics of cat, hairy skin, slowly adapting Type I (T1) receptors were studied by activating them with swept period grating stimuli drawn over the skin's surface. It was hypothesized that the puncate organization of these receptors and the possibility of action potentials from one dome blocking the responses from other domes would result in a receptor behaving as a matched filter to specific periods of a grating stimulus. Laboratory experiment and preliminary numerical modeling results of receptor responses that support the matched-filter hypothesis are presented.<>
{"title":"Spatial frequency tuning in cutaneous type I receptors","authors":"F. Looft","doi":"10.1109/NEBC.1988.19399","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19399","url":null,"abstract":"The encoder characteristics of cat, hairy skin, slowly adapting Type I (T1) receptors were studied by activating them with swept period grating stimuli drawn over the skin's surface. It was hypothesized that the puncate organization of these receptors and the possibility of action potentials from one dome blocking the responses from other domes would result in a receptor behaving as a matched filter to specific periods of a grating stimulus. Laboratory experiment and preliminary numerical modeling results of receptor responses that support the matched-filter hypothesis are presented.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121900358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Jarmul, E. Nunziata, C. Perez, L. E. Lipetz, H. Weed
The overall transfer function for a tactile vision information system (TVIS) used as an aid to the visually impaired is described. Included in this transfer function are the electromechanical vibrators, the skin interface, and the tactile skin sensors. In previous work, individual components have been analyzed, but no attempt has been made to evaluate the process in its entirety. Each transfer function is also analyzed in detail to describe the input-output relationships important in the effective transfer of optical information in a TVIS. The overall transfer function is developed and its equation is given. Here, a theoretically derived stimulation waveform was used for the vibrator driving current. Under computer simulation, this waveform reduces the vibrator noise levels to less than 70 dB(C) while requiring only 3 mW of power for each vibrator to elicit tactile sensation.<>
{"title":"Transfer function of electromechanical-tactile stimulation","authors":"E. Jarmul, E. Nunziata, C. Perez, L. E. Lipetz, H. Weed","doi":"10.1109/NEBC.1988.19368","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19368","url":null,"abstract":"The overall transfer function for a tactile vision information system (TVIS) used as an aid to the visually impaired is described. Included in this transfer function are the electromechanical vibrators, the skin interface, and the tactile skin sensors. In previous work, individual components have been analyzed, but no attempt has been made to evaluate the process in its entirety. Each transfer function is also analyzed in detail to describe the input-output relationships important in the effective transfer of optical information in a TVIS. The overall transfer function is developed and its equation is given. Here, a theoretically derived stimulation waveform was used for the vibrator driving current. Under computer simulation, this waveform reduces the vibrator noise levels to less than 70 dB(C) while requiring only 3 mW of power for each vibrator to elicit tactile sensation.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115357704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An interferometer in which a single-mode, polarization-preserving fiber serves as the conduit of light for both the object arm and the reference arm is described. By a noise-cancelling optical configuration, the system is able to measure displacements on the order of tens of nanometers. It was applied to measuring the ocular pulse of a model eye. The optics are described with reference to the interface between the optical fringe signal and the electronic processing circuitry. There appear to be several attractive qualities about this instrument with regard to potential clinical applications, so that further development is warranted.<>
{"title":"Measuring the ocular pulse with an optical fiber interferometer","authors":"A. Drake, D. Campagna","doi":"10.1109/NEBC.1988.19343","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19343","url":null,"abstract":"An interferometer in which a single-mode, polarization-preserving fiber serves as the conduit of light for both the object arm and the reference arm is described. By a noise-cancelling optical configuration, the system is able to measure displacements on the order of tens of nanometers. It was applied to measuring the ocular pulse of a model eye. The optics are described with reference to the interface between the optical fringe signal and the electronic processing circuitry. There appear to be several attractive qualities about this instrument with regard to potential clinical applications, so that further development is warranted.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129090518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A simple noninvasive technique to obtain the ejection pressure from the flow measurement is presented. A simple electronic-analog model is designed and implemented to obtain the ejection pressure using a Doppler velocity probe. This technique can be extended to measure the arterial pressure pulses for the diagnosis of, for instance, occlusive vascular diseases.<>
{"title":"Noninvasive analog measurements of ventricular ejection pressure","authors":"M. Tangella, C. Bowman, J.K. Li","doi":"10.1109/NEBC.1988.19374","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19374","url":null,"abstract":"A simple noninvasive technique to obtain the ejection pressure from the flow measurement is presented. A simple electronic-analog model is designed and implemented to obtain the ejection pressure using a Doppler velocity probe. This technique can be extended to measure the arterial pressure pulses for the diagnosis of, for instance, occlusive vascular diseases.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"201 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130336348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The authors discuss the present status of the rehabilitation engineer and provide suggestions on how to increase interest in the field. The suggestions include: (1) introduction of formal undergraduate and graduate training programs; (2) establishment of professional qualification and certification criteria; (3) offering malpractice insurance to individual rehabilitation engineers; (4) more employment opportunity in hospitals for rehabilitation engineers; and (5) extension of malpractice insurance and modification of malpractice and product liability laws to cover the modification of available equipment by rehabilitation engineers.<>
{"title":"Understanding rehabilitation engineering","authors":"M. Youdin, R. Sturm, A. Youdin","doi":"10.1109/NEBC.1988.19372","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19372","url":null,"abstract":"The authors discuss the present status of the rehabilitation engineer and provide suggestions on how to increase interest in the field. The suggestions include: (1) introduction of formal undergraduate and graduate training programs; (2) establishment of professional qualification and certification criteria; (3) offering malpractice insurance to individual rehabilitation engineers; (4) more employment opportunity in hospitals for rehabilitation engineers; and (5) extension of malpractice insurance and modification of malpractice and product liability laws to cover the modification of available equipment by rehabilitation engineers.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"226 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130798713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recordings of gastric electrical activity from the abdominal surface are generally contaminated by interferences from other biological sources and by additive noise, which makes a routing interpretation difficult. The technique of linear prediction has been used to enhance the quality of the embedded gastric signal component. The results indicate that linear prediction is capable of separating the gastric electrical signal component from uncorrelated interferences. Moreover, this approach has the intrinsic ability to track irregularities of the gastric activity, such as tachygastria, which is demonstrated by examples.<>
{"title":"Linear prediction of canine gastric signals","authors":"M. Tanyel, C. Rao, W. Chey, K.Y. Lee","doi":"10.1109/NEBC.1988.19391","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19391","url":null,"abstract":"Recordings of gastric electrical activity from the abdominal surface are generally contaminated by interferences from other biological sources and by additive noise, which makes a routing interpretation difficult. The technique of linear prediction has been used to enhance the quality of the embedded gastric signal component. The results indicate that linear prediction is capable of separating the gastric electrical signal component from uncorrelated interferences. Moreover, this approach has the intrinsic ability to track irregularities of the gastric activity, such as tachygastria, which is demonstrated by examples.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"2012 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133352511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A neural-network approach to the learning of invariant spectral features in cerebral-palsied speech is introduced. The technique is a hybrid conventional digital signal processing/neural network strategy. The objective at this stage is to learn features of nonverbal speech, and to do so in a manner which is robust to the abnormalities of such speech and which is minimally dependent on a priori modeling or parameterization. Thus, it is hoped that these features will be useful as input to a higher-level word recognizer.<>
{"title":"Neural network learning of spectral features of nonverbal speech","authors":"S. Lerner, J. Deller","doi":"10.1109/NEBC.1988.19339","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19339","url":null,"abstract":"A neural-network approach to the learning of invariant spectral features in cerebral-palsied speech is introduced. The technique is a hybrid conventional digital signal processing/neural network strategy. The objective at this stage is to learn features of nonverbal speech, and to do so in a manner which is robust to the abnormalities of such speech and which is minimally dependent on a priori modeling or parameterization. Thus, it is hoped that these features will be useful as input to a higher-level word recognizer.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132094353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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